By Zinabu Hailu June, 2016 Addis Ababa, Ethiopia

ADDIS ABABA UNIVERSITY ADDIS ABABA INSTITUTE OF TECHNOLOGY SCHOOL OF CHEMICAL AND BIOENGINEERING

EFFECTS OF CONTROLLED ATMOSPHERE STORAGE AND TEMPERATURE ON QUALITY ATTRIBUTES OF MANGO

By Zinabu Hailu

June, 2016 Addis Ababa, Ethiopia

ADDISABABAUNIVERSITY ADDIS ABABA INSTITUTE OF TECHNOLOGY SCHOOL OF CHEMICAL AND BIO ENGINEERING

EFFECTS OF CONTROLLED ATMOSPHERE STORAGE AND TEMPERATURE ON QUALITY ATTRIBUTES OF MANGO

By: Zinabu Hailu

A Thesis Submitted to Addis Ababa Institute of Technology, School of Chemical and Bio Engineering in Partials Fulfillment of the Requirements for the Degree of Masters of Science in Food Engineering.

Advisor: Eng.Teshome Worku (Assistant Professor)

June, 2016 Addis Ababa, Ethiopia

ADDISABABAUNIVERSITY ADDISABABAINSTITUTEOFTECHNOLOGY SCHOOL OF CHEMICAL AND BIO ENGINEERING

EFFECTS OF CONTROLLED ATMOSPHERE STORAGE AND TEMPERATURES ON QUALITY ATTRIBUTES OF MANGO

By: Zinabu Hailu

Approved by the Examining Board:

Chairman, Department’s Signature Date

Graduate Committee:

Eng.Teshome Worku

Advisor Signature Date

Dr. Ashagrie Zewdu

External Examiner Signature Date

Dr. Ing.Zebene Kifile Dr. Shimelis Admassu Internal Examiner Signature Date

iii

ACKNOWLEDGEMENTS

Above of all, I thank the almighty God who gave me strength and encouragement and led me through all the rough and difficult times to complete this study

I wish to express my deepest appreciation to my advisors, Mr. Teshome Worku for his endless help in correcting, commenting, and encouraging to accomplish this work. I also like to appreciate their patience in following up this work from the very beginning to the end.

I am very grateful to Mr. Mekidim Asefa, for his assistance, invaluable comments and excellent supervision throughout my research work

I also extend my appreciation to Addis Ababa Institute of Technology, School of Chemical and Bio Engineering Laboratory staff members for their technical assistance during experimental work.

Finally, I would like to express my sincere gratitude to my families and friends who have been providing their support and encouragement. And also all others who directly and indirectly contributed to this manuscript are highly acknowledged for their voluntary participation.

TABLES OF CONTENT

ACKNOWLEDGEMENTS ...... i

TABLES OF CONTENT ...... ii

LIST OF TABLES ...... v

LIST OF FIGURES ...... vi

ACRONYMS ...... vii

ABSTRACT ...... viii

CHAPTER I ...... 1

1. INTRODUCTION ...... 1

1.1 Back ground ...... 1

1.2 Scope of the study ...... 3

1.3 Problem statement ...... 3

1.4 Objective ...... 4

1.4.1 General objective ...... 4

1.4.2 Specific objectives ...... 4

1.5 Significance of Study ...... 4

CHAPTER II ...... 5

2. LITERATURE REVIEW ...... 5

2.1 Origin and expansion of mango over the world ...... 5

2.2 Varieties of mango ...... 5

2.2.1 Keitt ...... 6

2.2.2 Kent ...... 6

2.2.3 Tommy Atkins ...... 7

2.3 Cultivation Practice ...... 8

2.3.1 Physicochemical characteristics ...... 8

2.3.2 Pests and diseases ...... 9

2.3.3 Maturity and harvesting indices ...... 11

2.3.4 Harvesting ...... 14

2.4 Post-Harvest Technology of Mango ...... 15

2.4.1 De-sapping ...... 15

2.4.2 Cleaning and washing of fruit ...... 16

2.4.3 Hot water-treatment (HWT) ...... 16

2.4.4 Sorting/grading ...... 16

2.4.5 Packaging and labeling ...... 17

2.4.6 Loading and Transportation ...... 17

2.5. Storage of Fruit...... 17

2.5.1 Storage at low temperature ...... 18

2.5.2 Storage at low pressure ...... 18

2.5.3 Storage by use of coating...... 19

2.5.4 Storage by using chemicals ...... 19

2.5.5 Modified Atmosphere Packaging (MAP) ...... 20

2.5.6 Controlled Atmosphere Storage Technology ...... 20

2.6 Application of CA storage...... 21

2.6.1 CA in Managing Chilling Injury (CI) ...... 22

2.6.2 CAS in Managing Postharvest Diseases ...... 23

CHAPTER III ...... 24

3. MATERIALS AND METHODS ...... 24

3.1 Materials ...... 24

3.1.1 Chemical and Reagents Used ...... 24

iii

3.1.2 Equipment Required ...... 24

3.2 Methods ...... 24

3.2.1 Raw Material Collection and Preparation ...... 24

3.3 Method of analysis for quality attributes of mango ...... 25

3.3.1 Color determination ...... 25

3.3.2 Titratable Acidity determination ...... 25

3.3.4 Weight loss ...... 26

3.3.5 Firmness measurement ...... 26

3.3.6 Sensory evaluation ...... 26

3.3.7 Experimental Design and Statistical analysis ...... 27

CHAPTER IV ...... 28

4. RESULTS AND DISCUSSION ...... 28

4.1 The Effect of CAS on Quality Attributes of cv. Keitt Mango ...... 28

4.2 Effect of Temperatures on Quality Attributes of Stored cv. Keitt Mango ...... 35

4.3 Effect of CAS and Temperatures on Sensory Quality Attributes (SQA) ...... 38

CHAPTER V ...... 40

5. CONCLUSION AND RECOMMENDATION ...... 40

5.1 Conclusions ...... 40

5.2 Recommendations ...... 41

REFERENCES ...... 42

APPENDIXES ...... 51

LIST OF TABLES Page

Table 2.1: Chemical compositions of fresh mango per 100 gram 8 Table: 2.2 Storage life and fruit quality in different varieties of mango influenced by CA 22 storage compositions temperature and period Table 2.3: CI influenced by compositions of CA, storage temperature and period in mango 23 Table 4.1: Mean results of mango quality attributes stored in CAS for 0-45 days 34 Table 4.2: Mean results of mango quality attributes stored in ambient atmosphere for 0-35 days 35 Table 4.3 Mean effect of Temperatures on mango quality attributes after 3 weeks storage. 36 Table 4.4: Effect of CAS on Sensory Quality Attributes of stored fruits 39 Table 4.5: Effect of Temperatures on Sensory Quality attributes (SQA 39 Table A1: Effect of CAS on Total soluble solid Keitt mangoes for 0-45 days storage 51 Table A2: Effect of CAS on Firmness of Keitt mangoes for 0-45 days storage 51 Table A3: Effect of CAS on Titrable Acidity of Keitt mangoes for 0-45 days storage 52 Table A4: Effect of CAS on Firmness of Keitt mangoes for 0-45 days storage 52 Table A5: Effect of CAS on Weight loss of Keitt mangoes for 0-45 days storage 53 Table A6: Effect of CAS on Firmness of Keitt mangoes for 0-45 days storage 53 Table B1: Effect of temperature(7oC) on Keitt mangoes for 0-21 days storage 54 Table B2: Effect of temperature(10oC) on Keitt mangoes for 0-21 days storage 54 Table B3: Effect of temperature(13oC) on Keitt mangoes for 0-21 days storage 54 Table B4: Effect of ambient temperature on Keitt mangoes for 0-21 days storage 55

Table C1: Effect of 10%CO2 + 6%O2 treatment on SQA of Keitt mango after 6 weeks storage 55

Table C2: Effect of CAS (8%CO2 + 6%O2) on SQA of Keitt mango after 6 weeks storage 56

Table C3: Effect of CAS (5%CO2 + 5%O2) on SQA of Keitt mango after 6 weeks storage 56 Table C4: Effect of ambient storage on SQA of Keitt mango after 6 weeks storage 57 Table D1: Effect of temperature (7oC) on SQA of Keitt mangoes after 3 weeks storage 57 Table D2: Effect of temperature (10oC) on SQA of Keitt mangoes after 3 weeks storage 58 Table D3: Effect of temperature (13oC) on SQA of Keitt mangoes after 3 weeks storage 58 Table D4: Effect of temperatures(Control)on SQA of Keitt mangoes after 3 weeks storage 59 Table D5: Sensory evaluation score card using nine point Hedonic scale 59

LIST OF FIGURES Page

Fig 2.1: Keitt type mango grow in Ethiopia 6 Fig 2.2: Kent type mango grow in Ethiopia 7 Fig 2.3: Tommy Atkins types of mango grow in Ethiopia 7 Fig 2.4: a , b, c, d, refers to tear shape pattern of anthracnose, stem end rot disease in mangoes 10 Fig 2.5: fruits picked with different stage of maturity 13 Fig: 3.1: Color indicator chart for Keitt mango during ripening 25 Fig 4.1: Skin color of mangoes at 7oC after storage under controlled atmosphere 29 Fig 4.2: Flesh firmness of mangoes at 7oC after storage under controlled atmosphere 30 Fig 4.3: Total soluble solid content of mangoes at 7oC after storage under controlled atmosphere. 31 Fig 4.4: Titrable acidity of mangoes at 7oC after storage under controlled atmosphere 32 Fig 4.5: pH of mangoes at 7oC after storage under controlled atmosphere 32 Fig 4.6: weight loss of mangoes at 7oC after storage under controlled atmosphere 33 Fig: 4.7 over all mean result of mango quality attributes stored at CAS 34 Fig 4.8: Photograph of Keitt variety mango fruit before storage 37 Fig 4.9: Photograph of Keitt type mango fruits stored at temperatures 7oC 38 Fig E1: Photograph of Keitt type mangoes to be analyzed 60 Fig E2: Keitt mangoes after 4 weeks storage on CAS (a) and ambient atmosphere (b) respectively 60 Fig E3: One-wire I button integrated with laptop to read temperature and humidity parameters. 60 Fig E4: Laboratory equipment used such as CAS and Modified storages 61 Fig E5: Analysis equipment such as portable refractometer and penetrometer 61 Fig E6: Photograph during measuring Firmness of the fruit within 5 and 7 days storage interval 62 Fig E7: Photograph during analysis of TSS and sensory evaluation of cv. Keitt mangoes after storage 62 Fig E8: Photograph analysis of TAA of cv. Keitt mangoes within 5 and 7 days storage interval 62

ACRONYMS

AAiT Addis Ababa Institute of Technology ANOVA Analysis of Variance AOAC Association of American Chemists CAS Controlled Atmosphere Storage CI Chilling Injury CSA Central Statistical Agency cv. Keitt Cultivar Keitt FAO Food and Agricultural Organization GAP Good Agricultural Practice GDP Good Distribution Practice GMP Good Manufacturing Practice HWT Hot water Treatment LSD List Significance Difference MAP Modified Atmospheric Packaging OVA Over all Acceptances SQA Sensory Quality Attributes SD Standard Deviation TAA Titrable Acidity TSS Total soluble Solid

vii

ABSTRACT This study was conducted to analyze the effects of Controlled Atmosphere Storage (CAS) and low temperatures on quality attributes of cv. Keitt mango. Mango is one of the choicest fruits in the world and popular due to its delicious taste, pleasant aroma and nutritional value. To date, only 3% of the total world production is being exported due to the perishable nature of the product, lack of proper storage and other postharvest related diseases. Post-harvest loss of mango in Ethiopia is estimated to be between 25-40% and would occurred during handling, transportation and storage. Storage loss could exist through main factors affecting the quality of mangoes which are atmospheric conditions and temperatures. CAS is an agricultural technology which monitor and adjust constantly the level of CO2 and O2 within storage to reduce the rate of physiological and biochemical changes, ethylene sensitivity and incidence of decay development of mangoes and also inhibit pathogen growth. Up to now only very few number of research was done on the effects of CAS on Ethiopian mango. Thus, this study hopes to shed some light on the determination of optimum storage condition of Ethiopian mango and in effect to reduce the large postharvest loss of mango. The experimental design was designed by randomized block design for both factors; CAS and temperatures. The Controlled Atmosphere Storage (CAS) had four experimental o treatments:-at constant storage temperature of 7 C and its atmospheric conditions A (10%CO2 +

6%O2), B (8%CO2+ 6%O2), C (5%CO2+5%O2) and Control (ambient condition). Storage temperature with 7, 10,13oC and control (ambient temperature) treatments also accomplished. The result showed the effect of CAS on weight loss and firmness of the cv. Keitt mango is significant between fruits stored in CAS and ambient atmosphere and LSD at 0.05=3.12 and 1.708 respectively. And the effect of temperature on TSS, TAA, pH, weight loss, firmness and skin color was significant effects between fruits stored within the designed treatments and their LSD values at 0.05 was( 0.317,6.58, 3.46, 4.148, 6.50 and 2.41).The effects of CAS and temperature on quality attributes of the stored fruits were confirmed by sensory analysis. Therefore, fruits stored at 7oC with 10%CO2 +6%O2 have best sensory preference to extend the storage life of cv. Keitt mangoes beyond 6weeks. In addition, fruits stored at 13oC without considering the effect of CA conditions also best and can store up to 21 days without Chilling Injuries (CI) effect. Finally, it can be conclude that CAS is important in extending storage life of cv. Keitt mango up to 6 weeks with the o optimum atmospheric conditions (at 7 C and 10%CO2 + 6%O2) and it can also store at temperature of 13oC for 3 weeks without significant quality loss and CI effect.

viii

CHAPTER I 1. INTRODUCTION

1.1 Back ground Mango (Mangifera indica) is a fleshy stone fruit belonging to the panes Mangifera, consisting of numerous tropical fruiting trees in the flowering plant family Anacardiaceae. Mango is native to the south Asia from where it was distributed worldwide to become one of the most cultivated fruit in the tropics. Mango is produced in most frost free tropical and sub-tropical climates, more than 85 countries in the world cultivate mango. World production of fresh cut mango is estimated to 28 million tons (FAO STAT, 2012).Moreover, it is also the most widely cultivated and globally traded tropical and subtropical fruit in the world(Kassahun and Dawuro 2014). But, to date only 3% of the total world production is being exported due to the perishable nature of the product, lack of proper storage and other postharvest related diseases (Leon et al, 1997). Mango serves as a fruit crop and as a subsistence crop for family farms. As it ripens at the end of the dry season and at the start of the rainy season, the mango is a fundamental source of nutrition for rural populations (Vayssières et al., 2012). Mango fruit is an excellent source of dietary antioxidants, such as ascorbic acid, carotenoids, and especially phenolic compounds (Ma et al, 2011). Mango fruits are very much relished for their, exotic flavor and delicious taste. They are also an excellent source of dietary fiber, provitamin A and vitamin C. A fruit with many versatile properties has naturally found application for processing into several products (Elias, 2007). Mango is a highly seasonal tropical fruit, very popular among millions of people in the tropics. It also occupies a prominent place among the best fruits of the world. However, it is in constant demand, there is a pre-harvest scarcity and at times a post-harvest glut for this fruit. The amount of mango production in Africa during 2009 is 13.6 million tones (FAO, 2009). In Sub-Saharan Africa (SSA), growing both domesticated and wild fruit species on farms diversifies the crop production options of small-scale farmers and can bring significant health, ecological and economic revenues. Ethiopia is agro-ecologically diverse and has a total area of 1.13 million km2. Many parts of the country are suitable for growing temperate, sub-tropical or tropical fruits. For example, substantial areas in the southern and south-western parts of the country receive sufficient rainfall to support fruits adapted to the respective climatic conditions. In addition, there are also many rivers and

streams which could be used to grow various fruits. Ethiopia has a potential irrigable area of 3.5 million ha with net irrigation area of about 1.61 million ha, of which currently only 4.6 % is utilized (Amer, 2002).Total fruit production in Ethiopia is about 500 thousand tones. Fruits have significant importance with a potential for domestic and export markets and industrial processing in Ethiopia. In Ethiopia mango is produced mainly in-west and east of Oromia, SNNPR, Benishangul and Amhara (Desta, 2005). Mango production in Ethiopia is in fluctuated conditions, because of occurrence of diseases, lack of proper management, lack of storage and also weather conditions (CSA, 2009). But, according to CSA (2013) cropping season mangoes contributed about 14.21% of the area of land allocated for fruit production and holds 14.55% of quintals of fruits produced in the country. But, the postharvest loss of perishable commodities is estimated to be as high as 50% in Ethiopia (FAO, 2011). Mango being a highly perishable fruit possesses a very short shelf life and reach to respiration peak of ripening process on 3rd or 4th day after harvesting at ambient temperature (Narayana et al., 1996). The shelf life of mango varies among its varieties depending on storage conditions. It ranges from 4 to 8 days at room temperature and 2-3 weeks in cold storage at 13ºC (Carrillo et al., 2000). This short period seriously limits the long distance commercial transport of this fruit (Gomer-Lim, 1997). Usually after harvesting, the ripening process in mature green mango takes 9-12 days (Herianus et al., 2003). The physiological changes may occur in harvested fruit due to unfavorable atmospheric conditions especially fluctuation in temperature and humidity. Fresh mango fruits have a short storage life of 10 to 12 days at room temperature and can also suffer low temperature injury (chilling injury) during refrigerated storage (Lakshminarayana, 1973).In addition; mango fruits have a short production season and storage life. Maintenance of fruit quality for a specific period of time before its consumption is important factor in the post-harvest life of the fruit. Controlling the storage life of mango can be achieved by adopting proper storing and select best methods which can reduce loss of mango fruit. Various methods to minimize/control loss and to enhance its shelf life without any detrimental effect on the quality are: storing with low temperature, storing with low pressure, storing by coating, storing by chemicals, modified atmosphere packaging and controlled atmosphere (Seyoum&Woldetsadik, 2000).The study focused on the effects of temperature and controlled atmosphere conditions to prevent storage loss and increasing storage life of Ethiopian mango by using controlled atmosphere technology

1.2 Scope of the study Mangoes are highly nutritious and best fruits of the world and there are over thousands varieties around the world, the most common are Keitt, Kent and Tommy Atkins. Mango is climacteric fruit it ripen rapidly after harvest and it is highly susceptible to pre-harvest and post-harvest handling. In Ethiopia, the post-harvest loss of mango is 26.3%. The post-harvest loss of mango would occurred through environmental factors (temperature, humidity and atmospheric conditions), lack of proper handling, and lack of proper storage and occurrence diseases. These factors results loss in its quality and production. Storage loss could exist through main factors which were atmospheric conditions and temperatures. Thus, the study focused on the effects of controlled atmosphere storage gas compositions and temperatures on quality attributes of cv. Keitt mango to reduce postharvest loss and maintain desired quality through Controlled Atmosphere Storage (CAS) technology. With this general objective the specific tasks were evaluating effects of CAS and temperatures, determine the quality attributes of mango, and determine sensory evaluation and optimum storage condition for mango.

1.3 Problem statement Mango is one of the perishable food product and is produced mainly in-west and east of Oromia, SNNPR, Benishangul and Amhara (Desta, 2005). More than 47 thousand hectares of land is under fruit crops in Ethiopia. Mangoes contributed about 12.61% of the area allocated for fruit production and took up 12.78% of fruit production in comparison to other fruits growing in the country and the annual consumption of mango by the processing plant at full production capacity is 8.6 tones which is only 1.8% of the current production of mango (Elias, 2007) and less than 2% of the produce is exported (Joosten, 2007), this is due to post harvest loss, about 26.3 % of mango product is lost (Tadesse, 1991). Moreover, the expansion of juice produced industry and juice houses has created a great demand for fresh mangoes fruit, but the supply of these fruits is less, that why it is important to extend storage life of fresh mango for better marketing opportunity and to reduce postharvest loss. Application of technologies which can reduce the post-harvest loss and extend the storage life of mangoes is very important. Controlled atmosphere is one of the technologies that control for the main factors that affect quality of mangoes such as: temperature, carbon dioxide and oxygen. Thus, study hopes that to shows some light on the determination of optimum storage condition of Ethiopian Mango to reduce post-harvest loss.

1.4 Objective

1.4.1 General objective The general objective of the project was effects of controlled atmosphere storage and temperatures on mango quality attributes to reduce post-harvest losses and maintain desired quality.

1.4.2 Specific objectives The specific objectives of the thesis are to:  Evaluate the effects of Controlled Atmosphere Storage (CAS) and temperatures on quality of mango fruit,  Investigate quality parameters of mango fruit such as Total Soluble Solid (TSS), Titreatable Acidity (TAA), firmness, weight loss, pH and skin color after storage,  Determine sensory evaluation of stored mango fruit,  Determine the optimum storage condition of mango fruit.

1.5 Significance of Study The study is believed to have the following significance:-  Reduce postharvest loss of mango fruits in Ethiopia  By determining the optimum storage condition would obtain mango with good quality and prolong shelf life mango without loss of quality attributes of mango.

CHAPTER II 2. LITERATURE REVIEW

2.1 Origin and expansion of mango over the world The mango, Magifera Indica L. is well known for its excellent exotic flavor and usually referred to as the king of fruit. It is a dicotyledonous plant belonging to the order spindles in the family Anacardiaceae. Mango was originated in the Indo-Burmese region (Subramanyam, Krishnamurthy, &Parpia, 1975). The fruit is eaten fresh and in several other by-products, including juices, nectars, purees (Rohrbach, &Ohr, 1994). Commercial mango production is reported in more than 85 countries. The prominent mango producing countries are India, China, Thailand, Indonesia, Philippines, Pakistan and Mexico (Yashoda, &Prabha, 2006). Mango production is increasing outside the traditional geographical regions of mango cultivations such as in Central and South America, Australia, South-east Asia, Hawaii, Egypt, Israel and South Africa, especially for export markets (Tharanathan et al., 2006). The most important exporting countries are Mexico (41% of the world market) followed by the Philippines (7.6%) and Pakistan (7.8%) (Sauco, 2004). Some mango fruit cultivars, such as from the Indian and the Sri Lankan regions, show strong aroma, intense peel coloration, delicious taste, and high nutritional value (Bessant, 2009). According to Baldwin (2008), there are 49 species and thousands of mango cultivars. The popularity of the fruit in the international market is due to its excellent flavor, attractive fragrance, beautiful color, taste and nutritional properties (Arauz, 2000). In addition, mangoes are good source of ascorbic acid, carotenoids and phenolic compounds, and other dietary antioxidants (Percival, 2005).

2.2 Varieties of mango There are over a thousand mango varieties around the world, with India having the greatest number (over 500 named). The commercial industries of the world rely on a handful of improved varieties supplemented with local varieties that are less suited to the export trade (Ian S. E. Bally, 2006). Common varieties worldwide are Tommy Atkins, Kent and Keitt and which are also grown in Ethiopia (Yeshitela et al.2005 and ILRI, 2011).

2.2.1 Keitt This open pollinated seedling of Mulgoba originated from Homestead (Florida) and was released in 1946. It is one of the latest maturing of all the recommended cultivars. It has an exceptional keeping quality and may be left on the trees long after the normal harvesting time (March-April). It has a greenish-yellow color with pink or red blush and lavender bloom. There are numerous white or yellow/red lenticels on the thick and fairly tough skin. The fruit shape is ovate and plump without a beak; it has a rounded base. The flesh is deep yellow, fairly firm but tender, melting, juicy and with only a little fiber near the seed. The flavor is rich and sweet with a pleasant aroma and excellent quality. The fairly small seed (7.5% of fruit weight) is monoembryonic. The tree is medium-sized, moderately vigorous, producing long arching branches and has a scraggy open appearance. The figures below shows that the Keitt type of mango fruit which is large with an average length of 11.7 cm and a width of 9.2 cm; it has an average weight of 456 g. (Young TW and Sauls JW. 1979).

Fig 2.1: Keitt type mango grow in Ethiopia (FAO, 2010)

2.2.2 Kent This open pollinated seedling of the cultivar Brooks originated in Miami, Florida, and was released in 1944. Kent is often mistaken for the quite similar looking cultivar Keitt but (just one difference) Kent matures earlier (March). The large fruit is greenish-yellow with a red or crimson blush on the shoulder. The fruit-shape is regular ovate with a rounded base and often with two slight beaks. The skin is thick and tough and small yellow lenticels are numerous; the flesh is juicy, melting, deep yellow, fibreless and of a rich flavor. The seed, embedded in a thick, woody stone (8.5% of fruit weight) is mono-embryonic. The tree is large and vigorous, with a dense upright canopy, and it produces good yields in the late mid-season.

The figure below shows that the Kent type of mango fruit, which is large greenish-yellow with a red or crimson blush on the shoulder and the average length, measures 12.4 cm with a width of 9.7 cm and an average weight of 545 g (Young TW and Sauls JW. 1979).

Fig 2.2: Kent type mango grow in Ethiopia (FAO, 2010)

2.2.3 Tommy Atkins This cultivar originated from a seed planted in the 1920s at Fort Lauderdale in Florida. Tommy Atkins has become an important commercial variety. The fruits are medium to large, oval to oblong, orange/yellow with a heavy red blush, numerous white lenticels and a broadly rounded base. The smooth skin is tough and thick. The flesh is firm and medium juicy with a moderate amount of fiber, yellow to deep yellow in color, mild and sweet with a strong pleasant aroma. The eating quality is fairly good; the seed is mono-embryonic and covered in a thick, woody stone (6.6% of total fruit weight). The tree is vigorous /large with a rounded canopy and it produces consistently heavy and good crops. It is an early to mid-season cultivar and is highly resistant to diseases. The Figure below shows that the tommy Atkins varieties of mango which have a medium to large sized and have an average weight of 384g (Young TW and Sauls JW. 1979).

Fig 2.3: Tommy Atkins types of mango grow in Ethiopia (FAO, 2010)

2.3 Cultivation Practice Mango will grow in a slightly acidic (5.5-7.5) and well-drained soil, whether it is sandy, loam or clay (Young et al., 1965). It is somewhat tolerant to alkalinity (Kadman et al., 1976). Mango is also drought-tolerant, and can withstand occasional flooding (Singh, 1960). For best flowering and fruit set, good timely rainfall is necessary rather than the total rain fall. Temperature plays an important role in mango flowering and its influence varies with cultivars (Schaffer et al., 1994). Temperatures in the range of 24-30°C are required for best flowering; however, during fruit development if sufficient water is provided the tree can withstand up to 48°C. Flower deformation and loss of pollen viability can occur at low temperatures (Popenoe, 1957; Issarakraisila et al., 1992). Cold temperatures can also limit the growth of the plant and can cause damage or even kill young trees; while it has been reported that older trees can endure up to –4°C for a few hours with limited damage (Crane and Campbell, 1991). 2.3.1 Physicochemical characteristics Mango is usually called the king of tropical fruits. It contains high levels of vitamins, proteins, lipids, amino acids and minerals as shown in Table 2.1. Chinese traditional medicine believes that mango can produce saliva and eliminate fever; it is good for the stomach disorders; and can break kidney and gall stones. Mango juice improves the nervous system and can be used to treat mental illness. Mango is named as divine food ( Ramanjaneya.et.al 1994). Table 2.1: Chemical compositions of fresh mango per 100 gram (Journal 2010) Constituents Quantity /100gm Water 87.5 g Energy 234 kJ Protein 0.6 g Fat 0.1 g Carbohydrate 15.0 g Fiber 0.5 g Ash 0.4 mg Vitamin C 3mg

2.3.2 Pests and diseases Mango is prone to a number of diseases at any stage of its development. Hence, plants in the nursery and the fruits in storage or transit are susceptible to disease. In many cases these diseases are due to mismanagement leading to infections at the harvesting time. In such cases, prevention can be done by using chemical spray. Bacteria, fungus, and flies are mainly responsible for the onset of diseases. Anthracnose disease caused by Colletotrichum gloeosporioides is one of the major common diseases for pre-and post-harvested fruits and is associated with high rain fall and humidity, (Fitzell and Peak, 1984).Moreover, it is of widespread occurrence in the field and in storage. The disease causes serious losses to young shoots, flowers and fruits under favorable climatic conditions (high humidity, frequent rains and the temperature range of 24- 32°C). The disease produces leaf spot; blossom blight, withered tip, twig blight and fruit rot symptoms (Aragaki, M., and M. Ishii. 1960). Powdery Mildew (Oidium mangiferae) also a serious diseases which can affects all varieties of mango and its symptom is the white superficial powdery fungal growth on leaves, stalk of panicles, flowers and young fruits. The affected flowers and fruits drop pre-maturely reducing the crop load considerably or might even prevent the fruit set. Rains or mists accompanied by cooler nights during flowering are congenial for the disease spread. Alternaria rot, or black spot is another postharvest fruit disease, which infects fruits during ripening. Anthracnosem (Figure 2.4 a) Stem end rot (Figure 2.4 b), black mould rot, bacterial black spot are common postharvest fruit diseases which can be prevented by using certain chemicals, or proper postharvest fruit treatment. There are a number of fungi which attack mango fruit at their mature stage during storage and transit: Pestalotiopsis Mangifera (Figure 2.4c), Colletotrichum gloeosporioides (Figure 2.4d), Ceratocystis fimbriata , Gloeosporium species, Dothiorella ribis, Penicillium, and Cladiosporium are some fungi which commonly infect mango fruits. Bactrocera dorsalis, Ceratitis capitata, Anastrepha suspense and Diaschamimorpha longicaudata are common flies which can damage fruit.

a) b)

c) d) Fig 2.4: a ,b, c, d, refers to tear shape pattern of anthracnose, stem end rot disease in mango, whitish gray lesion on mango leaf Pestalotiopsis.mangifera, typical anthracnose lesion on mango leaf caused by Colletotrichum gloeo-sporioides respectevily (from APS digital image collection, 2001 and Litz,1997).

The major pests attacking mangoes include: fruit fly and mango seed weevil. Minor ones are scales and mealy bugs. Fruit fly-This is one of the most serious pest of mango in the country affecting the marketing of fresh fruits. The female punctures the maturing fruits and lays eggs in small clusters inside the fruit. After hatching, the larvae feed on the fruit that appears normal from outside. The maggots later fall on the ground for further growth. When infested fruits are cut open, maggots of the fruit fly are seen in the damaged flesh. Mango seed weevil -This is a serious pest of mangoes in the tropics. The female lays eggs on partially developed fruits. The eggs hatch and the maggots bore through the flesh into the seed where they feed and develop damaging the seed. There is a discoloration at the point of entry.

Mango fruits are considered to be climacteric and they ripen rapidly after harvest. The storage, handling and transport potential of fruits is limited by susceptibility to diseases, sensitivity to storage temperatures below 12oC, and perishability due to ripening and softening (Acosta et al., 2000). The combination of storage temperature and duration of storage are considered to be the important factors that lead to chilling induced physiological and metabolic dysfunctions in plant cells. These dysfunctions lead to various visible disorders that are commonly used to assess the degree of chilling injury experienced by the fruits (Walker et al., 1990). In mangoes, the most common visual symptoms are dark, scald-like discolorations in the peel, beginning around lenticels and spreading outwards to produce a more or less circular lesion, pitting on the fruit peel, the development of off-flavors, discoloration of the pulp, and overall poor fruit quality (Nair et al.,2003). In general, for fresh mango fruit to be accepted by market, it has to be treated to ensure that it is free of fruit flies. Disinfestations can be done by chemical fumigation, or by nonchemical treatment, which consists of heating the fruits to specific temperature and maintaining this temperature for a defined period of time which could kill fly larvae and eggs. Vapor heat treatment (VHT), forced hot air treatment (FHAT), and hot water (HW) immersion are commonly used heat treatments for mango fruit (Esguerra and Lizada, 1990).

2.3.3 Maturity and harvesting indices Traditionally mango is harvested based on judgments through the growers by observing the appearance of the fruit. The selection of suitable maturity indices for harvest is very important. The quality and the postharvest life of mango fruit depend on the maturity stage at harvest. Therefore, the fruit has to be harvested at the suitable stage of maturity in order to develop the optimum sensory quality attributes and extended postharvest life (Yahia, 1998a). Immature fruit are more sensitive to chilling injury during cold storage and may fail to ripen adequately. Fruit harvested at over mature stage is highly susceptible to mechanical damage such as bruising, decay and water loss, resulting in quality deterioration (Yahia, 1998a). Over matured fruit show defects like jelly seeds or jelly pulp after harvest (Yahia, 1998a). Therefore, suitable maturity indices for harvesting are very important in order to minimize the quantitative and qualitative losses. Generally, physical, physiological and chemical parameters are used to define the maturity stage. Physical methods to determine maturity in mango include softness of the cheek, peel colour, development of shoulder, and specific gravity (Kosiyachinda, 1984). These factors are very useful,

but their application depends on the type of mango, region of cultivation, and type of market and consumers. Age of the fruit is also considered as a simple method to confirm maturity, calculated from induction, full bloom and fruit set. Generally, harvest maturity in mango is reached about 12 to 16 weeks after fruit set (Yahia, 1998a). However, days from full bloom is most recommended, because they can be implemented as a standardized factor (Yahia, 1998a). The age of fruit (days) at a certain harvest maturity based on full bloom or fruit set varies according to different geographical regions and cultivation conditions.

During fruit maturation, soluble solids content (SSC) tends to increase while titratable acidity (TA) decreases. According to Tharanathan et al. (2006) titratable acidity increased from the sixth to the tenth week after fruit set, and then with increase in fruit maturity a decline in titratable acidity was noted. Some mango cultivars are characterized by a strong taste and the SSC and TA or the SSC/TA can contribute to determining the suitable maturity stage for harvest. Sugars acids and phenolic compounds are the primary taste components in the fruit. SSC/TA ratio commonly indicates ripeness and taste for some markets; the higher the ratio the sweeter the fruit (Mizrach, Flitsanov, Schmilovitch, & Fuchs, 1999).

Flavor (taste and aroma) is an important quality trait that determines to a great extent, the consumer acceptance of the fruit. According to Baldwin (2010) flavor is taste plus odor and is mainly composed of sweetness, sourness, and aroma that correspond to sugars, acids and volatile compounds. Flavor is determined primarily by genetic factors and it can be affected due to pre- harvest conditions, postharvest handling, packing operations and storage. Changes in mango aroma can be attributed to transformational changes in fatty acid profile (from palmitic to palmitoleic acids) during ripening, and fruit can reach their best flavor if harvested after the start of ripening. Increase of glycosidically-bound aroma compounds (terpenes) was observed in the flesh of Kensington Pride mangoes as maturity progressed (Lalel, Singh, & Tan, 2003b).

Optimum skin color is an important fruit quality parameter that affects consumer acceptance and preference. The obvious noticeable change during ripening is skin color change from dark green to olive green or reddish or orangish yellow or yellow that forms a base color. Some cultivars show reddish bluish skin color mainly due to the presence of anthocyanins (Tharanathan et al., 2006).

These skin color changes are due to the disappearance of chlorophyll and the appearance of other pigments (carotenoids and/or anthocyanins) as mentioned before. Carotenoids are the predominant pigments in yellow cultivars. Presence of the anthocyanin phenondin-3-galacytosa has been reported in the skin of some types of cultivars (e.g. Tommy Atkins) (Proctor & Creasy, 1969). However, skin color is not considered as an adequate maturity index because it is commonly observed after the fruit has started to soften, in addition to that skin color is usually not very uniform in several mango cultivars. Uniform color development is observed in yellow cultivars, but some cultivars do not change the green skin color much. Skin color development is greatly influenced by the fruit position on the tree and fertilizer application practices, among other factors. Flesh color changes, however, are uniform when fruit advances in maturity stages, and therefore it can serve as adequate maturity index. Although it is a destructive index, it is used as a maturity index in several producing regions, because it is consistent (Kader, 2008a, 2008b). Carotenoids are responsible for the attractive flesh color, and at advanced maturity the flesh is usually yellow to orange (Medlicott, Bhogol, &Reynolds, 1986).The figure below shows that fruits picked at different stage of maturity.

Fig 2.5: Fruits picked with different stage of maturity (Medlicot et.al 1986)

2.3.4 Harvesting Harvesting is the most important factor, governing the post-harvest management. The harvesting of the fruit is done, either by hand picking, or plucking with a harvester at green mature stage. These and others methods of harvesting may cause mechanical damages such as bruising or cuts on the fruit surface will negatively affect fruit quality. The cut or bruised fruits are easily infected with decay causing fungi such as Aspergillus sp and Botryodiplodia, Diplodia natalensis (Yahia, 1998b). This is a large cost in mango production since all the fruit do not mature at the same time and therefore one tree requires to be harvested more than one time. Furthermore the large tree canopies and the inefficient supply of tree-size-controlling rootstocks also affect the harvest practices. The multiple picking requirements are one factor contributing to the difficulty to mechanize the harvesting practices. Other problems in mechanizing harvest of mango are the difficulty to determine the maturity of the fruit and that different cultivars have various colors, weight and size. In Ethiopia practices for harvesting mango differs but a common practice is hand picking from the ground, climbing the tree or using a ladder. Other ways to harvest mango in Ethiopia is using a long stick or scissors to cut the fruit from the tree (Hussen & Yimer, 2013). It is important to harvest mango fruits at a suitable stage of maturity since this determines the quality of the fruit and its durability (Yahia, 1998). If the fruits are harvested in an immature stage, the mangoes are more susceptible to chilling injuries when kept in a cold storage and the fruit may not ripen properly. Over mature fruit is sensitive to mechanical damages such as water loss, decay and bruising which deteriorate the quality. The final decision when to begin the harvest is determined by factors such as labor availability, market demand, consumer preferences and shipping time and schedule if shipping of the fruit is required (Yahia, 2011). It is desirable that the fruits are harvested during the cooler parts of the day to reduce the risk of heat injury and sunburn (Yahia, 2011). This also reduces the costs for cooling the fruits. It is important that the fruits are handled gently; rough handling can lead to internal fractures, bruises or skin injuries on the fruit. As mentioned above harvesting is conducted by hand in most countries; fruits from the lower part of the tree can be harvested by hand while a picking pole is used for the fruits higher up in the tree (Crane et al., 2009). Pickers reach the fruit by climbing the trees or using ladders or hydraulic lifts. The fruit should never fall straight to the ground and therefore the picking pools should have attached baskets or bags or other attachment by which the picker can grip the fruit stem (Yahia, 2011). The fruit is harvested at different stages of maturity depending on how far the fruit will be

transported, how long it will be kept in storage and the requirements for the specific market (Crane et al., 2009). When the stem is taken away from a mango fruit, latex sap spurts out from the cut stem. The latex sap has high oil content and low pH and can cause peel damage on the fruit (Johnson & Hofman, 2009). However, the latex may protect the fruit against diseases and fruit fly infestation. It depends on the cultivar how sensitive the fruit peel is to the sap and the concentration of latex also differs among the cultivars. To prevent peel damages, so called sap burn, from the latex sap 10-20 mm of the stem can be left on the fruit during harvest. Another practice to prevent sap burn is to drain the latex sap from the fruit and dip it into alkaline detergents. After harvest the fruit should not be exposed to sunlight (Johnson & Hofman, 2009). The fruit should be kept in the shade or removed from the field to a pack house as soon as possible. The roads to the pack house should be smooth to prevent mechanical damages on the fruit caused by vibration and bouncing. At the pack house the procedures can differ. According to Johnson & Hofman (2009) the mangoes should be washed and then undergo a hot water treatment. Furthermore fungicides can be applied to prevent diseases. After this the fruits are graded and disinfested against pests before the fruits are packed. After packing it is important to cool the mangoes as soon as possible. An effective and uninterrupted cold-chain is of high importance to delay the ripening and to extend the shelf-life of mango (Prusky et al., 2009). Mango is sensitive to chilling injuries so it is important that the fruits are not stored a longer period under 13ºC (Singh et al., 2013). Storage life of mango differs depending on handling of the fruit and storage temperature. If the fruits are stored airy at a temperature at 10°C−15°C the storage life can be up to 2-3 weeks but it is often shorter (Yahia, 1998). 2.4 Post-Harvest Technology of Mango Post-harvest technology is interested in the application of technology/processing mainly after food products are harvested. However, the qualities of the food products are affected by the treatments done at both pre-harvest and postharvest stages. Post-harvest technology involves de-sapping, cleaning and washing, sorting/grading, hot-water treatment and packaging labeling post-harvest operations.

2.4.1 De-sapping De-sapping is a process of removing the sap from mango fruit. The sap from the fruit is removed by cutting the stalk of the fruits at a length of 5-10 mm from the base of the fruit with the help of a sharp edged scissor/harvester, at the time of stalk cutting, the fruit should be held upside down 15

so as to avoid the flow of sap on the skin of fruit. It is advisable that whole sap from the fruit should come out during the de-sapping process. However, to reduce the process time, fruits should be placed upside down at least for 45 minutes. This process should be undertaken by only trained/skilled workers of the packhorse so that skin of the fruits is not damaged .It would be appropriate if fruits are washed with water by applying a forced jet system of spraying. This will considerably hasten the process of de-sapping and ensure proper coverage of the fruit by the spraying water (Johnson et.al, 2009).

2.4.2 Cleaning and washing of fruit After de-sapping, the fruits should be washed carefully for 2-3 minutes to remove any patches of sap. During washing, fruits should also be cleaned with soft brushings. The washing is recommended to be done with only fresh potable water of temperature lower than that of the fruit. Usually, the temperature of water is maintained at 27oC (Johnson et.al, 2009). Neutral detergents like Teapol, Sandovit or Indtron at 0.1% (1 ml of detergent per litre of water) may be mixed with water to help remove latex (sap). The process of cleaning and washing will take 3-5 minutes (Yahia.E.M, 1998).

2.4.3 Hot water-treatment (HWT) Hot water (HW) is an effective heat transfer medium and, within a short time a uniform temperature profile will be maintained (Couey, 1989). The additional benefit of HWT is that it can control postharvest diseases such as anthracnose and stem end rot (Couey 1989; McGuire 1991), HWT also with controlled atmosphere storage also alleviated Chilling injuries (Forney and Lipton, 1990). This treatment is commonly used for disinfestation of mango from fruit flies (Sharp et al.). This treatment is cheaper than any other heat –treatment and is also effective on commercial scale in the USA. Thus, after de-sapping and washing, mango fruits should be passed through hot water treatment tanks fitted with thermostat control sensors to maintain the desired temperature of 52oC. The hot water should be treated with disinfectant such as sodium hypochlorite/procloraz etcat 200 ppm concentration for 3-4 minutes.

2.4.4 Sorting/grading Mango fruits are graded /sorted according to their size, weight, color and maturity. Packaging of smaller fruits with larger ones should be avoided, to achieve uniform ripening. Immature, overripe, damaged and diseased fruits should be discarded. Thus, the export quality mangoes are categorized

into three grades according to the fruit weight viz., Category-I (200-250 g), Category-II (251-300 g) and Category-III (300-350 g) (Yahia, E.M, 1998)

2.4.5 Packaging and labeling Each graded mango is placed into soft, white expandable polystyrene, netted sleeves to prevent bruising before placing it in compressed fiberboard cartons. The sleeved mangoes are packed in a single layer in compressed fiberboard cartons of interlocking type preferably having a water proof coating to prevent damage due to high humidity during cold storage. All the holes (ventilator openings of the cartons (packages) are covered with insect- proof screen of a minimum of 30 meshes per linear inch. Only packing material of food grade is used for packing mangoes at the pack house facility and the following standard size of packages are used for packing mangoes for export viz., 370 X 275 X 90 mm. All the sides of each package are then sealed with adhesive tape to prevent entry of target or non-target quarantine pests (Johnson et.al, 2009).

2.4.6 Loading and Transportation Process of shipping shall be carried out within 48 hours of harvesting. In this regard it is advisable that a complete plan preferably by a pert chart should be made as per the expert guidance, in advance of export. Before loading the consignment, temperature of the fruit should be brought down to 12oC.Temperature of the loading bay should also be maintained at 12oC. Air flow movement should be provided by stacking the cartons properly. The temperature of the container should be maintained at 12oC and The Relative Humidity (RH) should be 90-95 %( Johnson et.al, 2009). The temperature during transport should be monitored meticulously. The temperature of 12oC shall be maintained throughout the transit period. It would always be advisable if data loggers are placed inside the container to monitor the temperature and RH throughout the transit period. This will provide information in case of any spoilage of fruit during transportation. To avoid the breaking of cool chain at destination, consignment should be immediately transferred to the cold store (maintained at 12oC.) till fruits are supplied to the market (Yahia. E.M, 1998).

2.5. Storage of Fruit The basic concept of storage is to extend the shelf life of products by storing them in appropriate conditions to maintain their availability to consumers and processing industries in their usable form. They can either be stored naturally in the field, or in built storages (Raghavan and Gariépy, 1985 and Pantastico et al., 1975). In natural storage the product is left in the field and harvesting

is delayed, while in artificial storage favorable conditions are provided which help to maintain product freshness and nutritional quality for a longer period. During storage, the mango physiology and its ripening involves many physiochemical activities, such as cumulative physiological loss in weight (CPLW), pulp and skin color change, acidity, loss in firmness, increase in total solids and sugar concentration. There are various techniques, which have been developed to improve the storage life and maintain the quality of fresh horticultural commodities. 2.5.1 Storage at low temperature International trade of fresh mango has been limited because of its highly perishable nature and susceptibility to postharvest disease and injury and hence mangoes are still considered as luxurious and expensive item in the markets of many industrialized countries. While storing the commodities there are many factors which influence product quality; temperature is one of them. For successful storage it is necessary to efficiently control the temperature throughout the storage period.

The principle behind cold storage is to delay the period of ripening of a product by slowing down its physiological activities. While storing fruits the first priority is to maintain the quality of the product. Many commodities when stored at low temperature are subjected to damage caused by chilling which will promote fungus and diseases. Mangoes are tropical fruits and are therefore sensitive to chilling when stored below a critical minimum temperature (Chaplin et al., 1991; Lizada, 1991). If stored at low temperatures for prolonged time, storage could have an effect on ripening. It has been reported that cvs. Langra and Dasheri can safely be stored at 7-8°C for up to 25 days (Mann and Singh, 1976). However, recommended temperatures are in the range of 10-15 °C and lead to storage life of 2 to 3 weeks. The best ripening temperature ranges from 21- 24°C. But at high temperature of 32°C, the ripening process is retarded. Other essential factors are 98 % to 100 % relative humidity, and atmospheric pressure of 76 or 152 mm of Hg.

2.5.2 Storage at low pressure Low pressure storage, also called hypobaric storage, deals with the control of air pressure, temperature and humidity. The main principle of low pressure is that the pressure of the chamber is directly proportional to the O2 level. With a pressure decrease, the amount of O2 decreases reducing the respiration rate of the product. This system easily maintains O2 and relative humidity. The advantage of this system is that it can easily remove the metabolites. But this system cannot be used commercially as it has certain construction disadvantages with airtight chambers being

costly. Furthermore, this storage provides unsatisfactory ripening and poor aroma and flavor to the fruits (Ramachandra, 1995). Spalding and Reeder, 1997 noted that when cvs. Tommy Atkins and Kent were stored at 13°C at a pressure of 76-152 mm Hg with a relative humidity of 98-100 % for up to 3 weeks, a greater percentage of market acceptable fruits were obtained; and when they were placed under normal pressure they took a longer time for ripening as compared with those stored at 760 mm Hg. The fruits were more greenish in color compared to those stored at normal pressure.

2.5.3 Storage by use of coating Waxes are commercially used to reduce the moisture loss from the fruits. Aqueous wax emulsion consisting of mineral petroleum like paraffin and vegetable waxes with or without emulsifier are commonly used to increase the storage life of mangoes (Dalal et al., 1971). However, coating of mango with refined mineral oil resulted in fruit injury (Mathur and Srivastava, 1955). Oil coating decreased the respiration more than wax coating and results in severe anaerobic condition that injured the fruit. Fungicidal wax, emulsion containing hydrazide, maleic and polysaccharide based coating also delays ripening process. Selective films like Polyvinyl chloride (PVC) films also prolong shelf life of mango fruit (Ketsa and Raksritong, 1992). The wax can be applied by roller brushes in a specifically designed wax applicator or by hand. Dipping in wax is to be avoided, and a uniform application of wax is necessary otherwise some fruits receive too much wax and others too little. Before application of wax fruits must be dried, otherwise foaming of water-emulsion waxes may occur.

2.5.4 Storage by using chemicals Treatment efficiency varies with infection level and storage regime. The length of shelf life depends on cultivar, injury, maturity at harvest, calcium spray, and exposure to ethylene (Anonymous, 1988, Coates et al, 1995). A dip in 4-6 % calcium chloride can increase the shelf life of some cultivars (Singh et al., 1993). Ethylene is used to reduce time for ripening initiation and it can also enhance skin color of the fruit (S. P. Burg and Burg, 1962). Prochloraz provides good protection from anthracnose and Alternaria rot in mango (Johnson and Coates, 1993). Prior to harvest Gibberellic acid (GA3) spray can retard mango ripening at ambient temperature for up to six days of storage (Khader, 1991). Calcium chloride treatment resulted in low ethylene production, low respiration, and helped to reduce the occurrence of storage decay (Eeden, 1992).

2.5.5 Modified Atmosphere Packaging (MAP)

MAP involves the use of polymeric films to create a modified atmosphere that is high in CO2 and low in O2 around the fruit. There is a large range of polymeric films available in the market with greater flexibility in gas permeability. Fruit are stored in sealed polythene film (40 μm thick low density polyethylene) bags at a suitable temperature. The fruit are removed from the bag to achieve normal ripening (Wills et al., 2007). MAP delays mango fruit ripening mainly due to increased levels of CO2 and reduced concentrations of O2, which reduce respiration rate and inhibit ethylene production. The plastic film also acts as a barrier to minimize water loss from the fruit ( Castro et al., 2005). It also refers to the technique of sealing actively respiring produce in polymeric film packages to modify the O2 and CO2 levels within the package atmosphere. In addition, MAP vastly improves moisture retention, which can have a greater influence on preserving quality than O2 and CO2 levels (Beaudry, R.M., and C.D. Gran. 1993).

2.5.6 Controlled Atmosphere Storage Technology

Controlled Atmosphere (CA) storage usually involves regulating the concentration of oxygen (O2) and carbon dioxide (CO2) usually using nitrogen gas, storage temperature, as well as relative humidity in the storage environment. Various advantages of CA storage have been reported to reduce respiration rate, ethylene production and its action, delay fruit ripening, prolonged storage life, delay breakdown of chlorophyll, retard fruit softening and disease development in horticultural commodities (Thompson, 2001). This storage method has also been coupled with some disadvantages such as poor color development, modification in the metabolism of some organic acids, alteration of texture, formation of undesirable flavor and odors, development of physiological disorders, high establishment, maintenance, operational costs as well as health and safety issues (Thompson, 2001). CA storage seems to be promising for extending storage life, maintaining fruit quality of mango fruit consequently offers opportunities to export mangoes to distant markets using sea freight.

2.6 Application of CA storage Mango is a climacteric fruit and shows respiration and ethylene production peaks during ripening. So that, the application of CAS for mango fruit is reducing the rate of physiological and biochemical changes, ethylene sensitivity and incidence of decay development as result of senescence are delayed. It also play great role in managing chilling injuries and post-harvest diseases. Singh et al. (1937) reported that mango can be stored in CAS containing 9.2% O2 to prolong their ripening period. Later on, various researchers in different parts of the world have attempted to optimize the composition of CAS for extending storage life and maintaining fruit quality in different mango cultivars (Table 2.2).

The composition of gases of CAS required for extending storage life varied among different cultivars of mango and is also influenced by the harvest maturity. CAS suppresses respiration rate and ethylene production during storage and ripening period in mango (Lalel et al., 2003a, 2005;

Rao and Rao, 2008). Reduced concentrations of O2 and elevated levels of CO2 in CA storage also lead to anaerobic respiration and poor quality of ripe mango fruit in cultivar ‘Tommy Atkins’

(Bender et al., 2000c).. CA storage comprised of 3% O2 and 6% CO2 at 13°C proved to be beneficial for maintaining quality, extending the shelf life of the ‘Kensington Pride’ (35 days) and ‘Delta R2E2’ (38 days) Australian mangoes (Lalel and Singh, 2006, 2004; Lalel et al., 2003a, 2005).

Major research work has been reported on use of CAS in extending storage life of hard mature green mangoes. However, only little research work has also been reported on role of CA storage in extending storage life of ripe mango fruit. Bender et al. (2000b) reported that CAS composition comprising of 3-4% O2 and 25% CO2 at 8°C or 5% O2 plus 10% CO2 at 5°C improved storage life of tree ripe fruit up to 21 days without any chilling in ‘Tommy Atkins’, ‘Haden’, ‘Keitt’ and ‘Kent’ cultivars of mango.

Table: 2.2 Storage life and fruit quality in different varieties of mango influenced by CA storage compositions temperature and period. Varieties Temperature Concentration Inferences References o ( C) O2/CO2 Keitt 20 2/50 Stored for 12 days, delayed Yahia.et.al.1993 ripening, reduced respiration, color development, maintained firmness. 13 5/5 Extended storage life up to 35 days, deteriorates quality Palding and Reeder 1977

Tommy 10 3/10 Stored for 14 days, delayed Kim.et.al.2007 Atkins color development and high Titric Acid(TA) 12-13 10/5 Stored for 31 days and with good marketable fruit Lizana.et.al 1997 Kent 13 5/5-10 No significant effect on TA, Trimidel. et .al 1996 firmness, fruit color, following 21 day storage. 12-13 5/5 Stored for 29 days with good marketable fruit. Lizana.et.al 1997

2.6.1 CA in Managing Chilling Injury (CI) Mango fruit are susceptible to CI when stored below 13°C. Visible CI symptoms on mango fruit included dark skin color, prominence of lenticels, uneven ripening, and development of off-favors and poor fruit quality (Nair et al., 2004). Previously, adverse effects of CI on mango fruit quality have been reported (Lederman et al., 1997). The severity of CI depends upon the storage type and temperature, duration of exposure, maturation stage, cultivar and pre-storage conditions (Medlicott etal., 1990). The effects of CA storage on reduction of CI in different mango cultivars have been summarized in Table 2. 3. CA has also been found helpful in alleviation of CI in mango (Pesis et

al., 1997, 2000). CA containing 5-10% CO2 alleviated chilling symptoms in ‘Kensington Pride’ mangoes stored at <10°C, but higher concentrations were injurious (O’Hare and Prasad, 1993).

Short treatments to ‘Tommy Atkins’ fruit with low O2 induced higher CO2 levels and were effective in reducing CI symptoms at 5°C (Pesis et al., 1997).

Table 2.3: CI influenced by compositions of CA storage temperature and period in mango Varieties Temperature Concentration Inferences References o ( C) O2/CO2 Keitt, Kent and 5 5/10 No CI following 21 days Bender.et.al 2000c tommy Atkins storage Kensington 7 5/5-10 Alleviated CI after 35 days O’Hare and Prasad, pride storage 1993 Tommy Atkins 12 10/5 Reduced CI during 21 days Pesis.et.al 2000 and Keitt storage

2.6.2 CAS in Managing Postharvest Diseases Anthracnose, stem-end rot and Alternaria rot are the major postharvest diseases of mango fruit as it becomes highly susceptible during storage and ripening. Anthracnose (Colletotrichum gloeosporioides Penz. and Sacc.) and stem-end rot (Dothiorella dominicana Petrak and Cif. and Lasiodiplodia theobromae Griff. and Maubl.) have been known to cause highest losses during postharvest handling of mango fruit. Various pre and postharvest approaches such as application of fungicides, biological antagonists and heat treatments alone and combined with fungicides have been used to control postharvest diseases of mango fruit.. CA storage has been reported to suppress and delay development of postharvest diseases in mango depending upon other pre- and postharvest practices used to control the pathogens. For instance, the effects of composition of CA storage temperature and period on management of postharvest disease for Tommy Atkins mango o o fruit with temperature of 10 C, and 3% O2, 10% CO2 respectively treated with hot water at 46.1 C for 75 min followed by CA storage inhibited anthracnose for 14 days (kim.et.al 2007).

CHAPTER III 3. MATERIALS AND METHODS

The experimental work has been carried out in the Addis Ababa University, Addis Ababa Institute of Technology, School of Chemical and Bio Engineering Laboratories, Addis Ababa, Ethiopia.

3.1 Materials

3.1.1 Chemical and Reagents Used The following analytical grade chemicals and reagents were used for chemical analysis of the fruit. These include sodium hydroxide (NaOH), phenophentalaien indicator, ethanol and distilled water. All chemicals were used from research center chemical storage.

3.1.2 Equipment Required The major equipment used for the research works are: Model V2P-L CA storage controller , Model-FACCHINI-48011 penetrometer with + 0.2 precision, Model-RF18-hand refractometer with + 0.1 precision, one-wire I button, laptop computer, pH meter, digital weight balance, conical flask, beakers, burette, funnel, measuring cylinder, plastic bags, water bath and syringe.

3.2 Methods 3.2.1 Raw Material Collection and Preparation The mango market in Addis Ababa and other areas of Ethiopia is mainly dominated with the local mango varieties. Keitt mangoes (288kg-380kg) brought from Addis Ababa Et- fruit and then transports to AAiT Chemical Bio Engineering laboratories through plastic bag. After that fruits were sorted according to their size, weight and color. Finally the sorted fruits were washed by tape water, and dry through blowing dry air then stored in CA storage, and ambient storage was done.

3.3 Method of analysis for quality attributes of mango

3.3.1 Color determination Evenly, the color chart below (Fig 3.1) represents for repining stage of Keitt mango. Colors displays during repining/maturity are as follow: 1-deep green 2-light yellow-green, 3-yellow-light green,4-yellow-orange5-golden orange. According to Mitcham.al.et, 2015 as the ripening stage increased, the skin color of fruit changed and firmness of Keitt mangoes decrease from 16 to 2kg/mm2 and also increased TSS from 8 to18 o brix.

Fig: 3.1: Color indicator chart for Keitt mango during ripening

3.3.2 Titratable Acidity determination TTA analyzed by following AOAC (2002) method 942.15. Ten grams of juice or fruit will be diluted to 250 ml using neutralized or boiled distilled water. An aliquot (50 ml) was mixed with 0.2ml phenolphthalein indicator and titrated it with 0.1 N NaOH to the first appearance of pink endpoint. TTA will be expressed as g citric acid per 100 g fruit using the following equation:

TAA (%) = 0.1×Equivalent Weight of Acid×Titer×100 (3.1) Weight of Sample

3.3.3 Total soluble solids content (TSS)

TSS was analyzed by using AOAC (2002) method 932.12. Model-RF18 handheld sugar refractometer (India) was used to measure total soluble solids of the fruit at 20°C. One cheek of the mango will cut off and a few drops of juice squeezed by hand directly onto the reflecting mirror of an automatic refractometer and read the obrix with intermediate point between the light and dark color of graded scale measuring device.

AOAC (2002) method 981.12 also used for determining pH of the fruit. A table top pH meter with a calomel electrode was used to measure the pH of the fruit at 25°C.

3.3.4 Weight loss By randomly selecting fruits which were delegates’ population in each treatment for weight loss test. Weight loss calculated by standard procedure as mentioned AOAC (1994).

(%) Weight loss = Weight of the 1st interval – weight of 2nd interval × 100 (3.2) Weight of 1st interval

3.3.5 Firmness measurement FACCHINI-48011-Model (Italy) penetrometer were used for measurement of the Fruit Firmness, the outer flesh from both cheeks was cut from each fruit it measured the force applied per unit area of the fruit surface. Using an 8 mm Magness–Tayler type probe (Abbott, 1998)

3.3.6 Sensory evaluation The sensory evaluation were conducted with a group of semi-trained panelists consisting of 10 peoples who are selected to evaluate the effects of CAS and temperatures in terms of the sensory attributes. Five of them panelists were asked to give their individual ratings on all quality attributes of stored fruits including color, aroma, taste, flavor, firmness and overall acceptability of the stored fruits with different conditions and the remained five panelists were asked to evaluate quality of the effects of temperatures with a 9-point structured hedonic scale( Ranganna 1994) was used to conduct the preference test as showed in appendix table D5 and declaration about the sensory quality attributes(Color, Taste ,Flavor, Firmness and over all acceptance) and how they scored their preference and feeling of the product was given for all of panelists.

3.3.7 Experimental Design and Statistical analysis In this research cv. Keitt mango were used to study the effects of temperatures and controlled atmosphere storage on quality attributes of Keitt mangoes. To determine the effects of temperature and CAS, Completely Randomized Design (CRD) was used with below treatments:

1- Storing fruits at 7°C under CAS conditions of A-(6% O2 + 10%CO2).

2- Storing fruits at 7°C under CAS conditions of B-(6%O2+ 8% CO2) o 3- Storing fruits at 7 C under CAS conditions of C-(5%O2+ 5% CO2) 4- Storing fruits at ambient atmosphere D-(Control). Moreover, the effect of temperatures without considering CAS effect also studied through different temperature treatments such as, 7°C, 10°C, 13°C and ambient temperature (Control).

About 112 uniform cv. Keitt mangoes fruits were used for studying 42 of these mango stored at CAS with gas tight plastic bag in order to control the atmosphere by using closed system, 14 mangoes stored in ambient atmosphere and the remained 56 mangoes used for studying the effect of different temperatures. Samples of each treatment were randomly taken within five day intervals to evaluate the effect of Controlled Atmosphere conditions (CA). CAS chambers were calibrated to establish the specified gas composition by a gas blending flow system. The gas blending system generated CA conditions using external supplies of gases from Pressurized gas cylinders fitted with double-stage regulators and outlet controlling devices. These outlets were connected to the inlet flexible pipes that were inserted into the gas tight plastic containers in which the mangoes were stored. Fruits were then stored at specified temperature with different controlled atmosphere which were evaluated every 5 days for total soluble solids (TSS), titratable acidity (TA), pH, weight loss, firmness, and skin color. For the effects of different temperatures sample were taken within 7 days interval by using I Button. The One-Wire Viewer is a Java™-based software package to explore Maxim's 1-Wire and I Button devices with a personal computer. The 1-Wire and I Button devices communicate over a single data line plus ground reference, using the 1-Wire protocol. One way of Analysis of variance (ANOVA) was performed on the data collected using Microsoft excel and Origin Pro 8 soft wares. Comparison between treatment means at 5% level of significance was calculated.

CHAPTER IV 4. RESULTS AND DISCUSSION The effects of controlled atmosphere storage (CAS) and low temperatures, analysis for quality attributes of cv. Keitt mango and the optimum conditions for long storage were studied. In addition, sensory analysis for the final product by using nine hedonic scale also carried out. The results of samples analyzed in this work are presented in different tables and figures.

4.1 The Effect of CAS on Quality Attributes of cv. Keitt Mango

Skin color of fruits stored at ambient atmosphere changed their color from deep green to yellow orange after 15 days and to golden-orange after 30 days of storage (Table 4.2).whereas the skin color of fruits stored at controlled were changed their color after 25 days from deep green to yellow orange and to golden orange colors after 40 days of storage were changed (Table 4.1). The loss of green color was the most obvious change in mango which was probably due to the physiochemical change by degradation of the chlorophyll structure and increased in carotenoids pigments during storage. The principal agents responsible for this degradation might be oxidative system, pH change, and enzymes like chlorophyllase (wills et.al. 1982). In addition, Doreyappa-Gowda and Huddar ,2001 reported the concentration of carotenoids were increased due to a series physicochemical change in green mature mango stored at 18-34oC during ripening and peel color turned from dark green, green, light green to light yellow ,yellow, orange yellow due to break down of chlorophyll leading to disappearing of green color. Similarly the experimental result was observed effect of CAS on skin color not significant (new LSD at 0.05=1.36) between fruits sored in CAS and ambient atmosphere as showed in (Fig 4.1) and the effect of CAS and ambient atmosphere had similar mean result(5-golden orange) after 40 days storage time. Further, Yahia and Hernandez, 1993 also observed that fruits stored in open atmosphere (in air) lost their green color while those stored in control atmosphere remained green and when transfer to air for normal ripening turned to yellow ,but they were still more green than fruits stored continuously in air. That means fruits stored at low oxygen concentration atmosphere showed decreased in respiration rate, ethylene production, flesh firmness and color loss.

Fig 4.1: Skin color of mangoes at 7oC after storage under controlled atmosphere Regarding the firmness, mangoes stored in CAS represented the excellent results by retaining the maximum firmness as compared to air that means, fruits exposed to CAS used in this work remained greener and more firm than those stored in ambient atmosphere, (Fig 4.2). The current investigations confirm the view that CAS conditions delay fruit ripening and softening (Kader, 1986). Ripening and senescence rates in many climacteric fruits like mangoes, can be affected by control of the availability of O2 and CO2 to the fruit during respiration and that these two compounds can have a significant inhibitory effect on ability of ethylene to initiate ripening (Ben- Yehoshua et al., 2005). Thus, flash firmness of fruits kept in air was significant decrease very rapidly from 14.1kg/mm2 to 0.099 kg/mm2 after 35 days of storage (Table 4.2) and new LSD at 0.05=1.708. The flesh firmness of fruits which were kept under (CAS) with treatment of (10%

CO2 + 6%O2) had high firmness than of other treatments after 6 weeks storage mean firmness result was 5.541 kg/mm2 (Fig 4.7) . However, the mean result of all quality attributes fruits stored at ambient condition (control) was after 35days storage time. The firmness of the stored fruits was decreased as the time of storage increased, but it was in the air higher than them.

Fig 4.2: Flesh firmness of mangoes at 7oC after storage under controlled atmosphere

The total soluble solid (TSS) was observed that fruits stored in ambient atmosphere were increased from 4.1 to 18.86oBrix after 30 days and decreased to 14.8oBrix after 35days storage ( Table 4.2). The increased in TSS might be due to alteration in cell wall structure and break down of complex carbohydrates into simple sugars. This increase and decrease in TSS are directly correlated with hydrolytic changes in starch and conversion of starch to sugar being important index of ripening process in mango fruits and other climacteric fruits and further hydrolysis decreased the TSS during storage (kittur et.al. 2001).Beside, fruits stored at controlled atmosphere storage also increased the TSS content from 4.1 to 18.25oBrix after 45 days of storage (Table 4.1). As the result showed, it would stay in CAS further days without significant quality effects. From the CAS o treatments; treatment- A (10%CO2+6%O2) had less TSS content with average (13.5 Brix) than of the other treatments as shown in Fig 4.2. Hence, this treatment have a potential to extend the storage life of fruits beyond 45 days of storage time. The TSS no significant change between fruits kept at ambient atmosphere and CAS were observed (new LSD at 0.05=4.406)

The change in titratable acidity of the mango (cv. Keitt) recorded during storage at ambient temperature of (21-24oC) is presented in Table 4.2. The results revealed that percent titratable acidity of treated cv. Keitt mango ranged from 1.665% to 0.0234% with an average means of 0.52% (Fig 4.7) during storage and the pH also increased from 2.4 to 5.16 after 35 day of storage. So that, the result was observed that percent of titratable acidity had decreasing trend during 35 days of storage period that might be due to the degradation of citric acid which could be attributed ripening or reduction in acidity may be due to their conversion into sugars and their further utilization in metabolic process in the fruit. These results coincided with those Doreyappa-Gowda and Huddar (2001) who reported the similar pattern in different varieties of mango fruit stored at 18-34oC under gone a series of physico-chemical changes during ripening and the major changes were considerably increased in pH from 2.85 to 4.38 and decreased in acidity from 2.71 to 0.04% during ripening. Thus, no significant change in TAA and pH; between fruits kept at ambient atmosphere and CAS were observed (new LSD at 0.05=0.536 and 1.118) respectively.

Fig 4.3: Total soluble solid content of mangoes at 7oC after storage under controlled atmosphere.

Fig 4.4: Titrable acidity of mangoes at 7oC after storage under controlled atmosphere

Fig 4.5: pH of mangoes at 7oC after storage under controlled atmosphere

The reduction in weight is attributed to the physiological loss in weight (PLW) due to respiration, transpiration of water through peel tissue and other biological changes taking place in the fruit. The effect of CAS was highly significant on weight loss of stored fruit. It had a significant less weight (moisture) loss (new LSD at 0.05 =3.12) than fruits which were kept in the ambient atmosphere (Fig4.6). The mean weight loss percentage of fruits stored with treatment A (10%

CO2+ 6%O2) was less (0.75%), whereas fruits stored at ambient atmosphere was high loss (5.87%) after 4-6 weeks of storage (Fig4.7).

Fig 4.6: Weight loss of mangoes at 7oC after storage under controlled atmosphere

Fig: 4.7 over all Mean result of mango quality attributes stored at CAS. Table 4.1: Mean results of mango quality attributes stored in CAS for 0- 45 days

Days Firmness TSS(o TAA pH Weight loss Skin (kg/mm2) Brix) (%) (%) color 0 14.13 4.1 1.66 2.40 0 1 5 12.16 8.8 1.151 2.45 0.0869 1 10 9.43 13.13 0.754 2.46 0.603 2.6 15 6.33 14.36 0.373 2.79 0.533 3.3 20 4.8 15.03 0.293 3.43 0.457 3.6 25 2.6 15.46 0.198 3.42 0.623 3.6 30 1 16.36 0.127 5.01 1.452 4 35 0.67 17.23 0.091 5.08 1.457 4.6 40 0.48 17.86 0.056 5.15 1.475 5 45 0.29 18.33 0.0391 5.16 1.491 5 NB: 1-deep green, 2-light yellow-green, 3-yellow-light green, 4- yellow orange,5-golden-orange

Table 4.2: Mean results of mango quality attributes stored in ambient atmosphere for 0-35 days

Days Firmness TSS(oBrix) TAA pH Weight Skin (kg/mm2) (%) loss (%) Color

0 14.1 4.1 1.665 2.40 0 1

5 12.1 8.9 1.152 2.83 6.289 2

10 9.2 14 0.7541 3.24 5.370 3

15 5.4 16 0.3328 3.54 3.272 4

20 1.2 17 0.128 4.56 4.384 4

25 0.25 18 0.0828 4.96 3.144 5

30 0.1 18.5 0.0256 5.27 12.182 5

35 0.099 14.8 0.0234 5.48 12.234 5

NB: 1-deep green, 2-light yellow-green, 3-yellow-light green, 4- yellow orange,5-golden-orange

4.2 Effect of Temperatures on Quality Attributes of Stored cv. Keitt Mango

Significant increase in sucrose content of mango has been observed during ripening and this has been attributed to an increase in total soluble solids during ripening. This is due to transformation of starch into soluble sugars as the carbohydrates in the fruit are broken down under the action of phosphorylase enzyme during ripening into simple sugars (Mitra S et.al., 1997). On the other hand, hydrolysis of starch in the ripening mango fruit has been associated with amylase activity (G Zauberman et.al.1980). The increase in total soluble solids during ripening was expected and this suggests the extent of sweetening (Chopra S et.al.2005). Storage temperature significantly (new LSD at 0.05=0.317) affected the TSS of fruits. As the mean storage temperature decreased from 13 to 7oC, the TSS also decrease from 12.87 to 9.875oBrix. As shown in (Table 4.3) after three weeks storage. TSS was high in fruits stored with ambient temperature with mean result of it was 14.07oBrix, next fruits stored at 13oC, mean result was 12.87oBrix and minimum TSS was observed fruits sored at 7oC was 9.87oBrix after three weeks storage (Fig4.8) Titrable Acidity of the stored fruit were significantly decreased as the temperature of the storage increased (new LSD at 0.05=6.58) after three weeks of storage (Table4.3) , the mean results from

1.2865 to 0.937 mg/10mg juice at temperatures of 7oC to ambient temperature(21-24oC) respectively after 3 weeks storage. The decline in acidity could be due to susceptibility of citric acid to oxidative destruction as impacted by the ripening environment, and also it is a consequence of starch hydrolysis leading to an increase in total sugars and a reduction in acidity (Aina JO, 1990).

Table 4.3 Mean effect of Temperatures on mango quality attributes after 3 weeks storage.

Temperatures Firm(kg/mm2) TAA (%) TSS(oBrix) Wet loss (%) pH Skin color 7 o C 11.5 1.2865 9.875 2.6 3.18 1 10 o C 10.125 1.202 11.125 2.9 3.3975 2 13 o C 8.2 0.98975 12.875 4.25 3.81 3 Control 6.255 0.9374 14.075 4.44 4.015 4 NB: 1-deep green, 2-light yellow-green, 3-yellow-light green, 4- yellow orange

Increase in pH during ripening of mango fruits has been reported by other authors (Tovar B.et.al.2000) and was similar to what was observed in the present study. According to the authors, there is an inverse relationship between titratable acidity and pH. The increase in pH (decline in acidity) could be due to utilization of acids as respiration substrates (Dadzie BK et.al.1997).

The pH of the fruits also significantly affected by storage temperatures (new LSD at 0.05=3.46).as the storage temperature increased from 7oC to ambient temperature(21-24oC) the pH of the fruits also increased from 3.18 to 4.01 after three weeks storage as shown in( Table 4.3).

According to the result, the effect of temperatures on skin color of the stored fruits was not significance changes fruits which was exposed to 7, 10, and 13oC, whereas fruits stored in between 7 oC and ambient temperature was significant (new LSD at 0.05=2.41). The average skin color fruits stored at 7oC was light yellow green, 10oC light yellow green ,13oC yellow-green and 21- 24oC yellow orange ( Table 4.3).

The effect of storage temperatures on firmness of cv. Keitt was significantly affected, only between fruits stored at temperature of 7 oC and ambient (21-24oC) temperature with new LSD at 0.05=6.50 and weight loss percentage of fruits stored between the treatments of storage temperatures were

significantly (new LSD at 0.05=4.148) affected. As showed (Table4.3) the maximum average weight loss percentage was fruits stored at ambient temperature (4.44%) after three weeks storage. As temperature of storage increased the average weight loss also increased.

Mangoes stored at low temperature leads to certain physiological disorder have been observed such as Chilling Injuries (CI). The primary cause of CI is thought to be the damage of cell membrane that initiates a cascade of secondary reaction. CI is a time and temperature problem. Mango fruits are subjected to CI when stored below 10°C. The symptoms include grayish scald- like discoloration of the skin, skin pitting, uneven ripening, and reduction in the level of carotenoids, aroma and flavor during ripening (Thomas,. P et.al a1983).

Most of mangoes cultivars show injury below 10°C (50 °F), especially if fruit have just reached maturity. Tolerance to chilling increases during ripening (Medlicott et al. 1990). Chilling injury (CI) has been reported to occurs in mango fruit at temperatures below about 10-13°C, although some cultivars (Dasheri, Langara) were reported to be safely stored at 7-8°C for up to 25 days. Storage at 10 to 13°C (50 to 55°F) with 85 to 90% relative humidity should give a shelf-life of 14 to 28 days for mature green fruit, depending upon variety (Jobin Decor 1988).

The result of the experiment was showed that fruits stored at temperature of 7oC, after three weeks storage time, fruits were exposed to CI started from 7 days storage mainly for the fruit stored at 7oC and its symptoms was unripening, skin pitting, discoloration, poor aroma and flavor during ripening and is in agreement with Jobin Decor result (Fig4.9).

Fig 4.8: Photograph of Keitt variety mango fruit before storage

Fig 4.9: Photograph of Keitt type mango fruits stored at temperatures of 7oC.

4.3 Effect of CAS and Temperatures on Sensory Quality Attributes (SQA)

Color changes in mango fruit are due to the disappearance of chlorophyll and appearance of other pigments. Chloroplasts are transformed to chromoplasts containing yellow or red pigments (Lakshminarayana at.el.1980). The result of the experiment was observed skin color of fruits stored with treatment (10%CO2 + 6%O2) had maximum preference with it mean and standard deviation result was 8.4+0.89 (Table4.4). Fruit flavor depends upon taste (balance between sweetness and sourness or acidity, and low to no astringency) and aroma (concentrations of odor-active volatile compounds). Although taste and aroma are well integrated in their contribution to the overall flavor, aroma is often considered to play a dominant role in flavor. Taste development is due to a general increase in sweetness, which is the result of increased gluconeogenesis, hydrolysis of polysaccharides, especially starch, decreased acidity, and accumulation of sugars and organic acids resulting in an excellent sugar/acid blend (Grierson et al., 1981) Sourness or acidity is determined by the concentrations of the predominant organic acids, which are citric acid, malic acid, and tartaric acid. Some amino acids, such as aspartic and glutamic acid may also contribute to sourness. Several factors affect sugar and acid contents in mango, including cultivar (Kapse et al., 1989) The experiment was showed flavor of stored fruits had highly preference by panelists was mangoes stored with treatments A (10%CO2 + 6%O2) and B (8%CO2 + 6%O2) with average results for both of them was 7.4 (Table 4.4). But, the overall acceptance was high for fruits stored with treatment A (10%CO2 + 6%O2) mean result was 8.0 (Table4.4)

Table 4.4: Effect of CAS on Sensory Quality Attributes of stored fruits (Means + SD)

SQA A B C D Color 8.4 + 0.89 7.8 + 0.83 7.6 + 1.14 7.8 +1.09 Flavor 7.4 + 1.14 7.4 + 0.89 6.8 + 1.30 7 + 2.00 Taste 8 + 0.70 8.6 + 0.54 6 + 1.58 5.8 + 2.38 Firmness 7.4 +1.14 7.4 + 0.54 7.4 + 0.54 8 + 0.00 Over all 8 + 0.70 7.8 + 0.44 7.2 + 0.83 6.8 + 1.78 acceptance

NB: A (10%CO2+6%O2), B (8%CO2+6%O2), C (5%CO2+5%O2) & D (Control)

Similarly, the effects of temperatures on quality of stored fruits was evaluated by sensory panelists, the color of the fruits stored at temperature of 13 and ambient (21-24oC) had high preferences with their mean values for both of them were 7.6 (Table 4.5). When fruits stored at temperature of 13oC had maximum overall acceptance, while fruits stored at temperature of 7oC got minimum overall acceptance (Table 4.5).

Table 4.5: Effect of Temperatures on Sensory Quality attributes (Means + SD)

SQA 7oC 10oC 13oC Control(21-24oC) Color 4 + 1.58 6.4 + 1.51 7.6 + 1.14 7.6 + 1.14 Flavor 3.2 + 1.48 5.8 + 0.83 8 + 0.70 7.2 + 0.83 Taste 3.4 + 0.89 5.2 + 0.83 7.6 + 1.14 5.8 + 0.83 Firmness 3.8 + 3.8 6 + 1.22 7.2 + 0.83 5.6 + 1.14 Over all 3.6 + 3.6 6.4 + 0.54 8 + 0.70 6.4 + 0.54 acceptance

CHAPTER V 5. CONCLUSION AND RECOMMENDATION

5.1 Conclusions

Mangoes are highly nutritious and best fruit of the world. Approximately 50% of all tropical fruits produced worldwide are mangoes and its demand in the market is high due to its nutritional and medicinal benefits. But, it is expose to a number of diseases (Anthracnose) at any stage of development and attack by pest (fruit fly) to damage its physiological disorder. Moreover, Mangoes are highly susceptible to pre-harvest and post-harvest handling. In Ethiopia, the postharvest loss (transporting, handling and storage) of mango is 23.6%. Thus, study was carried out by using CAS technology which is constantly monitor and adjust the CO2 and O2 levels within gas tight stores or containers to reduce storage loss and extending the storage life of mangoes for better duration without loss of its quality.

The experiment was designed using randomized block design for both factors (temperatures and CAS) with each four treatments. As the result showed that Controlled atmosphere storage technology (CAS) has a great role in extending storage life of cv. Keitt mangoes for up to 6 weeks without significant quality loss. CAS treatment at 7°C with 10%CO2 + 6%O2 considered to be the best condition for storing long duration (6 weeks) without significant quality loss of cv. Keitt mango.

With regard to temperature, the study showed that cv. Keitt mangoes stored at 13oC was good quality after 3 weeks storage time as confirmed by sensory analysis which had high over all acceptances than of fruits stored with other treatments. Therefore, the optimum conditions for better quality and prolong storage duration is storing cv. Keitt mangoes at temperature of 7oC and

10%CO2 + 6%O2 and could store up to 6 weeks and beyond without significant quality loss of the fruit. Extending storage duration more than 6 weeks is extending marketing period and maintained fruits availability. But, the study was limited to Cv. Keitt mangoes because of limited time constraint and having limited CAS resource.

5.2 Recommendations The following recommendations can be made based on coverage of the work:  Further study needs to be carried out on the effects of CAS and temperatures with other varieties such as cv. Kent, cv. Tommy Atkins and cv. Apple of mangoes to check whether the same optimum condition can be used for all varieties using CAS technology.  Study on optimization of controlled atmosphere storage conditions and temperatures using various CAS is necessary.  Further study needs to be done on the maturity index of harvested fruits.  Study on feasibility analysis of the CAS technology is indispensable.

REFERENCES

Aina JO Physico-chemical changes in African Mango (Irvingia gabogensis) durin normal storage ripening. J. Food Chem., 1990; 36: 205 – 212.

Alexandratos, N., and J. Bruinsma. 2012. “World agriculture towards 2030/2050: the saving water. From Field to Fork-Curbing Losses and Wastage in the Food Chain 2012 revision.” Working paper: FAO: ESA No. 12-03, p.4

Amer, M.H. 2002. Ethiopia, the Sudan, the Libyan Arab Jamahiriya and Somalia: Status of irrigation and drainage, future developments and capacity building needs in drainage. IIPTRID capacity building report. FAO, Rome. March 2002. Pp. 121-143 Annonymous (2000).National coordinated research project on mango crisis. First annual Report Dept. of Hort.Univ.Agric. Faisalabad, pp: 240 Anonymous. 1988. Conditions for importation of fruit and vegetables. In: Plant Quarantine Manual section E. Australian Quarantine Inspection Service, Canberra, pp. 1-59. Antonio and Ochagavia, 1998. Controlled atmosphere storage of mango fruits. (Mangifera indica.L)cvs Tommy Atikns and Kent IDESIA(chile) vol. 15,77-83

Aragaki, M., and M. Ishii. 1960. Anthracnose control in Hawaii,Plant Disease Reporter 42:474 475.3 Arauz, L.F. (2000). Mango anthracnose: Economic impact and current options for integrated management, Plant Dis., 84, 600-611. Baldwin, E.A. 2002. Fruit flavour, volatile metabolism and consumer perceptions.p.89-184 106. In:M. Knee (ed.), Fruit Quality and Its Biological Basis. Sheffield Academic Press, Sheffield, UK. Beaudry, R.M., and C.D. Gran. 1993. Using a modified-atmosphere packaging approach to answer some post-harvest questions: Factors influencing the lower O2 limit. Acta Hortciulturae 326: 203–212. Bender, R.J., Brecht, J.K., Sargent, S.A. and Huber, D.J. 2000c. Mango tolerance to reduced oxygen levels in controlled atmosphere storage. J. Amer. Soc. Hort. Sci. 125:707-713 Carrillo, L.A., F. Ramirez-Bustamante, J.B. Valdez-Torres, R. Rojas-Villegas and E.M. Yahia 2000. Ripening and quality changes in mango fruit as affected by coating with an edible film J. Food Qlty., 23: 479-486.

Castro, J. V., Pfaffenbach, L. B., Carvalho, C. R.L., and Rossetto, C. J. 2005. Effect of film packaging and cold storage on postharvest quality of ‘Tommy Atkins’ mangoes. Acta Hort. 682: 1683–1687. Chaplin, G.R., S.P. Cole; M. Landrin; P.A. Nuevo; P.F. Lam; and D. Graham. 1991. Chilling injury and storage of mango (Mangifera indica L.) held under low temperature. Acta Horticulture. 291: 461-471 Coates, L. M., Davis, R. D; and A. W. Cooke. 1995. Postharvest disease control in mango potential options for reducing chemical use. Proceedings Mango 2000 Production.Workshop, Townsville Coates, L. M., G. I. Johnson; and A. W. Cooke. 1993. Postharvest disease control in mangoes using high humidity hot air and fungicide treatments. Annals of Applied Biology 123: 441- 448. Couey, H.M. 1989. Heat treatment for control of postharvest diseases and insect pests of fruits. Hort Science. 24(2):198-202. Crane, J.H. and C.W. Campbell. 1991. The Mango. Fruit crops fact sheet FC-2, Florida cooperative extension service, Gainesville, FL Crane, J.H., Salazar-Garcia, S., Lin, T.S., de Queiroz Pinto, A.C. & Shu, Z. H., 2009. Crop Production: Management (432- 483) in Litz, R. E. (eds). The mango: botany, production and uses, 2nd edition. CABI, Oxfordshire.

CSA, (2009): Agricultural sample survey: report on area and production for major crops, stastical bulletin 427. Addis Ababa, Ethiopia CSA, (2013): Agricultural Sample Survey 2012 / 2013; Volume I, Report on Area and Production of MajorCrops, Statistical Bulletin 532; Addis Ababa, Ethiopia CSA, (2013): Agricultural Sample Survey 2012 / 2013; Volume I, Report on Area and Production of Major Crops, Statistical Bulletin 532; Addis Ababa, Ethiopia Dadzie BK and J Orchard Routine Post Harvest Screening of Banana/Plantain Hybrids: Criteria and Methods. INIBAP Technical Guidelines 2, Wageningen, The Netherlands, p 63, 1997.

Dalal, V.B., W.E. Eipeson; and N.S. Singh. 1971. Wax emulsion for fresh fruits and vegetables to extend their storage life. Indian Food Packer. 25: 9-15.

Desta H, (2005). Export potential of Ethiopia processed fruit and vegetables, export promotion department of English, P., S. Jaffee and J.J. Okello.2006. “Exporting out of Africa: The Kenya Doreyappy-Gowda, I.N.D and A.G. Huddar, 2001 ,Studies on ripening changes in mango (Mangifera indica L.) fruits. J. Food Sci. Tec. Mysore, 38: 135- 137 Eeden, S. J. 1992. Calcium infiltration as a possible postharvest treatment to increase storage potential of mango fruit. Yearbook South African Mango Growers’ Association. 12: 26-27. Elias. A, 2007: Technical Assessment on Viability of Integrated Fruits Processing in Ethiopia; Master of sciences Thesis, Addis Ababa, Ethiopia Esguerra, E.B. and M.C.C. Lizada. 1990. The postharvest behavior and quality of ‘Carabao’ mangoes subjected to vapor heat treatment. ASEAN Food Journal 5: 6-11. FAO, 2010: Technical guidelines on tropical fruit tree management in Ethiopia; Giuseppe De Bac Project GCP/ETH/073/ITA FAOSTAT. Preliminary 2009 Data Now on Mango, FAO Rome, 2010. (http://faostat.fao.org/site/567/DesktopDefault.aspx?PageID=567#ancor) (Accessed 7th November, 2010)

Fitzell, R.D. and C.M. Peak. 1984. The Epidemiology of anthracnose disease of mango: inoculum sources, spore production and dispersal. Annals of Applied Biology 104: 53-59. Food and Agricultural Organisation (1981). Food Loss Prevention in Perishable Crops. M–15, ISBN 92-5-101028- 5, Rome, Italy. Food and Agricultural Organisation (2012) Current situation and medium term outlook for tropical fruits. http://www.fao.org/es/esc/common/ecg/108849_en_Sit_web _e.pdf Gomer-Lim, M.A. 1997. Post harvest physiology. In: The Mango: Botany, Production and Uses (Es.): R.E. Litz. pp. 425-446, CAB International, New York. Grierson, D., Tucker, G. A., and Robertson, N. G. 1981. The molecular biology of ripening. In Biochemistry of Fruit and Vegetables, pp.179–191. Friend, J., Ed., Academic Press, London

Gustavsson, J., Cederberg, C., Sonesson, U., van Otterdijk, R., Meybeck, A. 2011.“Global Food Losses and Food Waste: Extent Causes and Prevention.” Rome, Food and Agriculture Organization (FAO) of the United Nations

Herianus, J.D., L.Z. Singh and S.C. Tan. 2003. Aroma volatiles production during fruit ripening of Kensington Pride mango. Postharvest Biol. Technol., 27: 323-336.

Hussen, S. & Yimer, Z., 2013. Assessment of Production Potentials and Constraints of Mango (Mangifera indica) at Bati, Oromiya Zone, Ethiopia. International Journal of Sciences: Basic and Applied Research (IJSBAR), 11, 1:1- 9

ILRI, 2011. Fruits - A synthesis of IPMS value-chain development experiences. ILRI, Nairobi.

Issarakraisila, M., J. A. Considine; and D. W. Turner. 1992. Seasonal effects on floral biology and fruit set of mangoes in warm temperature region of Western Australia. Acta Horticulture 321:626. Jha SN, Chopra S and ARP Kingsly Determination of Sweetness of Intact Mango using Visual Spectral Analysis. Biosys.s Eng., 2005; 91 (2): 157-161.

Jobin-Decor, M.P. 1988. Mango ripening guide. Queensland Agric. J. 114:369–371.

Johnson, G. I. And L. M. Coates. 1993. Postharvest diseases of mango. Postharvest News an Information 4: 27N-34N Johnson, G.I. & Hofman, P.J., 2009. Postharvest Technology and Quarantine Treatments (530- 569) in Litz, R. E. (eds). The mango: botany, production and uses, 2nd edition. CABI, Oxfordshire.

Joosten F (2007). Development Strategy for Export Oriented Horticulture in Ethiopia. http://library.wur.nl/way/bestanden/clc/1891396.pdf Kader, A.A. (1986). Biochemical and physiological basis for effects of controlled and modified atmospheres on fruits and vegetables. Food.Technol. 40: 99-104. Kader, A.A. (1994). Modified and controlled atmosphere storage of tropical fruits. ACIAR Proceedings No. 50: 239-249. Kader, A.A. (2003). A Summary of CA Requirements and Recommendations for Fruits Other than Apples and Pears. Acta Hort. (ISHS) 600: 737-740. Kader, A.A. (2008). Mangoes Recommendations for Maintaining Postharvest Quality. In: Fruit Ripening and Ethylene Management. 50-51. Univ. Calif. Postharvest Technology Research and Information Center Publication Series #9. Kader, A.A. and Mitcham, B. (2008). Optimum Procedures for Ripening Mangoes. In: Fruit Ripening and Ethylene Management: 47-48. Univ. Calif. Postharvest Technology Research and Information Center Publication Series #9.

Kadman, A., S. Gazit; and G. Ziv. 1976. Selection of mango rootstocks for adverse water and soil conditions in arid areas. Acta Horticulturae. 57: 81-88. Kapse, B. M., Rane, D. A., and Khedkar, D. M. 1989. Correlation between biochemical parameters and organoleptic evaluation in mango varieties. Acta Hort. 231:756–762.

Ketsa, S. and T. Raksritong. 1992. Effect of PVC film wrapping and temperature on storage life and quality of Nam Dok Mai mango fruits on ripening. Acta Horticulturae 321: 756-763 Kim, Y., Brecht, J.K. and Talcott, S.T. 2007. Antioxidant phytochemical and fruit quality changes in mango (Mangifera indica L.) following hot water immersion and controlled atmosphere storage. Food Chem. 105:1327-1334. Kittur, F.S., N. Saroja, Habibunnisa and R.N. Tharanathan, 2001. Polysaccharide-based composite coating formulations for shelf-life extension of fresh banana and mango. Eur. Food Res. Tec. 213: 306-311 Kosiyachinda, S., Lee, S. K., & Poernomo, E. (1984). Maturity indices for harvesting of mango. In D. B.Jr., & R. B. H. (Eds.), Mango: Fruit development and postharvest physiology (pp. 33−38). Kuala Lumpur, Malaysia: ASEAN Food Handling Bureau. Lakshminarayana, S., M. Subbiah Shetty; and C. A. Krishnaprasad. 1975. Accelerated ripening of Alphonso mangoes by the application of ethrel. Tropical Science. 17: 95-101. Lakshminarayana, S., N. V. Subhadra; and H. Subramanyam. 1970. Some aspect of developmental physiology of mango fruit. Journal of Horticultural Science 45: 133-142. Lalel, H.J.D. and Singh, Z. 2004. Biosynthesis of aroma volatile compounds and fatty acids in ‘Kensington Pride’ mangoes after storage in a controlled atmosphere at different oxygen and carbon dioxide concentrations. J. Hort. Sci. Biotechnol. 79:343-353. Lederman, I.E., Zauberman, G., Weksler, A., Rot, I. and Fuchs, Y. 1997. Ethylene forming capacity during cold storage and chilling development in ‘Keitt’ mango fruit. Postharvest Biol. Technol. 10:107-112 Lizana, L.A. and Ochagavia, A. 1997. Controlled atmosphere storage of mango fruits (Mangifera indica L.) cvs. ‘Tommy Atkins’ and ‘Kent’. Acta Hort. 455:732-737. Leon DM, De la Cruz J, Parkin KL, Garcia HS, 1997. Effect of controlled atmospheres containing low O-2 and high CO2 onchilling susceptibility of Manila mangoes. Acta

Horticulturae. 455, 635-642.

Mann, S.S. and R.N. Singh. 1976. The cold storage life of Dashehari mango. Scientific Horticultureae 5, 249-254. McCollum, T.G., S. D’Aquino; and R. E. McDonald. 1993. Heat treatment inhibits mango chilling injury. HortScience. 28:197-198.

Medlicott, A.P., Sigrist, J.M.M. and Sy, O. 1990. Ripening of mangoes following low temperature storage. J. Amer. Soc. Hort. Sci. 115:430-434. Mizrach, A., Flitsanov, U., Schmilovitch, Z., & Fuchs, Y. (1999). Determination of mango physiological indices by mechanical wave analysis. Postharvest Biology and Technology, 16, 179−186. Nair, S. and Singh, Z. 2004. Chilling injury in mango in relation to biosynthesis of free polyamines. J. Hort. Sci. Biotechnol. 79:515-522. Narayana, C.K., R.K. Pal and S.K. Roy. 1996. Effect of pre-storage treatments and temperature regimes on shelf-life and respiratory behaviour of ripe Baneshan mango. J. Food Sci. Tech., 33: 79-82. Niranjana, P., Gopalakrishna, R.K.P., Rao, S.D.V. and Madhusudhan, B. 2009. Effect of controlled atmosphere storage (CAS) on antioxidant enzymes and DPPH-radical scavenging activity of mango (Mangifera indica L.) cv. Alphonso. African J. Food Agri. Nutr. Dev. 9:779-792. O’Hare, T.J. and Prasad, A. 1993. The effect of temperature and carbon dioxide on chilling symptoms in mango, acta Hort. 343:244-250. Pantastico, Er. B., T.K. Chattopadhya; and H. Subramanyam. 1975. Storage and commercial storage operation. In, Postharvest Physiology, handling and utilization of tropical and subtropical fruits and vegetables. AVI Publishing Company. Pp.560. Paull, R.E. and Chen, C.C. (2004). Mango. In: Gross K.C., Wang C.Y. and Saltveit M. (eds), The Commercial Storage of Fruits, Vegetables and Florist and Nursery Stocks. A draft version of the forthcoming revision to USDA, Agriculture Handbook 66 on the website of USDA, Agricultural Research Service Pesis, E., Aharoni, D., Aharon, Z., Ben-Arie, R., Aharoni, N. and Fuchs, Y. 2000. Modified atmosphere and modified humidity packaging alleviates chilling injury symptoms in mango fruit. Postharvest Biol. Technol. 19:93-101.

Pesis, E., Faure, M. and Arie, R.M. 1997. Induction of chilling tolerance in mango by temperature conditioning, heat, low O2 and ethanol vapours. Acta Hort. 455:629-634. Popenoe, J. and W.G. Long. 1957. Evaluation of starch contents and specific gravity as measure of maturity of Florida mangoes. Proceedings of the Florida state Horticultural society 70: 272-274. Proceedings of the Florida State Horticultural Society 78, 369-375. Prusky, D., Kobiler, I., Miyara, I. & Alkan, N., 2009. Fruit Disease (210-224) in Litz, R. E. (eds). The mango: botany, production and uses, 2nd edition.

Raghavan, G.S.V. and Y. Gariépy. 1985. Structure and instrumentation aspects of storage systems. Acta Hortic 157 : 5-30. Ramachandra, M. 1995. Diffusion channel for broccoli storage. M. Sc Thesis. Department of Agricultural and Biosystems Engineering. McGill University. Ravindra Rekha Menon and Goswami, T.K. (2008). Comparative performance of precooling methods for the storage of mangoes (mangifera indica l. Cv. Amrapali). Journal of Food Process Engineering, 31 (3) 354 – 371. Richardson, D.G.and Meheriuk, M. (Eds.). (1982).Controlled Atmospheres for Storage and transport of Perishable Agricultural Commodities, Timber Press, Beaverton, Oro Salim AS, Simons AJ, Orwa C, Chege J, Owuor B and Mutua A. 2002. Agroforestree database: a tree species reference and selection guide. Version 2.0 CD-ROM. Nairobi, Kenya: International Centre for Research in Agroforestry Sauco, V. G. (2004). Mango production and world market: Current situation and future prospects. Acta Horticulturae, 1, 107−116. Schouten,S.2008. Controlled atmosphere of fruits and vegetables. CAB.international.UK.

Seyoum T; Woldetsadik K (2000). Natural ventilation evaporative cooling of mango. Journal of Agriculture Biotechnology Environment, 2, 1–2 Singh, B.P., D. K. Tandon; and Kalra, S. K. 1993. Changes in postharvest quality of mangoes affected by preharvest application of calcium salts. Scientia Horticulturae. 54,211-219 Singh, L. B. 1960. The Mango. Leonard Hill, London.

Singh, Z., Lalel, H.J.D. and Nair, S. 2004. A review of mango fruit aroma volatile compounds- state of the art research. Acta Hort. 645:519-527.

Singh, Z., Singh, R. K., Sane, V. A. & Nath, P., 2013. Mango-Postharvest Biology and Biotechnology. Critical Reviews in Plant Sciences, 32, 4:217-236

Spalding, D.H. and W.F. Reeder, 1977. Low pressure (hypobaric storage) of mangoes. Journal of the American Society for Horticultural Science 102: 367-369 Tadesse F (1991). Postharvest losses of fruits and vegetables. Journal of Horticulture, 270, 261- 27

Tharanathan, R. N., Yashoda, H. M., & Prabha, T. N. (2006). Mango (Mangifera indica L.), “The King of Fruits” An overiew. Food Reviews International, 22, 95−123 Thompson, A. K. 1987. The development and adaptation of methods for the control of anthracnose. In Prinsley, R. A. and Tucker, G. (Editors), Mangoes- A review. Commonwealth Science Council: 29-38. Thompson, A.K. 2001. Controlled Atmosphere Storage of Fruits and Vegetables. CABI Publishing, Wallingford, UK, p.278 Wenkam, N. S. 1990. Food of Hawaii and the Pacific Basin. Fruits and fruit products. Research Extension Series 110. College of Tropical Agriculture and Human Resources, University of Hawaii, Honolulu. Wills, R. B. H., McGlasson,W. B., Graham, D., and Joyce, D. C. 2007. Postharvest; An introduction to the Physiology and Handling of Fruit, Vegetables and Ornamentals. pp. 83– 99. UK: CABI Pub. Yahia, E. 1998. Modified and controlled atmospheres for tropical fruits. Hort Rev 22: 123-128 Yahia, E. M. 1998. Postharvest handling of mangoes. Technical Report. Agricultural Technology Utilization and Transfer Project, Giza, Egypt

Yahia, E.M. and Vazquez-Moreno, L. 1993. Tolerance and responses of mango to insecticidal oxygen and carbon dioxide atmospheres. Food Sci. Technol. 26:42-48. Yahia, E.M., 2011. Mango (Magnifera indica L.) 492- 550 in Yahia, E.M. (eds.). Postharvest Biology and Technology of Tropical and Subtropical Fruits Cocona to Mango (vol. 3). Elsevier, Amsterdam. Yahia, E.M., Rivera, M. and Hernandez, O. (1992). Response of papaya to short-term insecticidal oxygen atmosphere. Journal of the American Society for Horticultural Science, 117(1): 96-99.

Yashoda, H.M., Prabha, T.N., Tharanathan, R.N., 2006. Mango ripening: changes in cell wall constituents in relation to textural softening. J. Sci. Food Agric. 86, 713–721. Yashoda, H.M., Prabha, T.N., Tharanathan, R.N., 2006. Mango ripening: changes in cell wall constituents in relation to textural softening. J. Sci. Food Agric. 86, 713–721. Yeshitela, T., Robbertse, P. J. & Stassen, P. J. C. 2005. Potassium nitrate and urea sprays affect flowering and yields of ‘Tommy Atkins’ (Mangifera indica) mango in Ethiopia. South African Journal of Plant and Soil, 22, 1:28-32.

Young TW and Sauls JW. 1979. The mango industry in Florida. Florida, USA: Institute of Food and Agricultural Sciences, University of Florida.

APPENDIXES Table A1: Effect of CAS on Total soluble solid cv. Keitt mangoes for 0-45 days storage time TSS (oBrix) days A B C D 0 4.1 4.1 4.1 4.1 5 8.9 8.8 8.7 8.9 10 13 13.4 13 14 15 13.6 14.8 14.7 16 20 14.2 15.6 15.3 17 25 14.6 16 15.8 18 30 15.6 17 16.5 18.5 35 16.2 18 17.5 14.8 40 17.1 18.5 18 - 45 18 18.5 18.5 -

NB: A (10%CO2+6%O2), B (8%CO2+6%O2), C (5%CO2+5%O2) & D (Control)

Table A2: Effect of CAS on Firmness of cv. Keitt mangoes for 0-45 days storage time

Firmness(kg/mm2 ) days A B C D 0 14.3 14.1 14 14.1 5 12.2 12.3 12 12.1 10 9.4 9.6 9.3 9.2 15 7.5 6.3 5.2 5.4 20 5.4 4.8 4.2 1.2 25 3.2 2.5 2.1 0.25 30 1.2 1 0.8 0.1 35 0.89 0.67 0.45 0.099 40 0.78 0.34 0.34 - 45 0.54 0.12 0.21 -

Table A3: Effect of CAS on Titrable Acidity of cv. Keitt mangoes for 0-45 days storage time

TAA(mg/10ml juice) Days A B C D 0 1.665 1.665 1.655 1.665 5 1.152 1.15 1.152 1.152 10 0.7544 0.754 0.7542 0.7541 15 0.3845 0.3667 0.3683 0.3328 20 0.3087 0.2848 0.2867 0.128 25 0.2234 0.1857 0.1876 0.0828 30 0.1989 0.0914 0.0912 0.0256 35 0.0989 0.0886 0.0882 0.0234 40 0.0789 0.05543 0.03467 - 45 0.05876 0.02309 0.0356 -

Table A4: Effect of CAS on pH of cv. Keitt mangoes for 0-45 days storage time

pH days A B C D 0 2.4 2.4 2.4 2.43 5 2.43 2.47 2.47 2.8 10 2.46 2.46 2.46 3.2 15 2.83 2.78 2.78 3.5 20 3.43 3.44 3.44 4.5 25 3.19 3.54 3.54 4.96 30 4.87 5.08 5.08 5.2 35 4.96 5.1 5.2 5.4 40 5.1 5.12 5.24 - 45 5.12 5.12 5.25 -

Table A5: Effect of CAS on Weight loss of cv. Keitt mangoes for 0-45 days storage time

Weight loss (%) days A B C D 0 0 0 0 0 5 0.096339 0.07689 0.08765 6.289485 10 0.234411 0.9875 0.5895 7.370339 15 0.265252 0.4567 0.87965 8.272258 20 0.570315 0.34537 0.4567 8.384522 25 0.957068 0.23457 0.6787 9.144499 30 1.333333 1.4563 1.5675 11.18274 35 1.344 1.4653 1.5734 12.234 40 1.3523 1.4876 1.5856 - 45 1.3632 1.507 1.6054 -

Table A6: Effect of CAS on skin color of cv. Keitt mangoes for 0-45 days storage time

Skin color Days A B C D 0 1 1 1 1 5 1 1 1 2 10 2 3 3 3 15 3 3 4 4 20 3 4 4 4 25 3 4 4 5 30 4 4 4 5 35 4 5 5 5 40 5 5 5 - 45 5 5 5 - NB: 1-deep green, 2-light yellow-green, 3-yellow-light green, 4- yellow orange, 5- golden-orange

Table B1: Effect of temperature (7oC) on cv. Keitt mangoes for 0-21 days storage time

7oC Days Firm TSS TAA Wet loss pH skin color 0 14.2 8 1.645 0 2.46 1 7 13.4 9.5 1.325 2.8 2.89 1 14 12.5 10.5 1.153 3.5 3.25 1 21 11.2 11.5 1.023 4.1 4.12 2 Mean 12.8 9.875 1.2865 2.6 3.18 1.25

Table B2: Effect of temperature (10oC) on cv. Keitt mangoes for 0-21days storage time

10oC days Firm TSS TAA Wet pH skin loss color 0 14.2 8 1.665 0 2.46 1 7 11.5 9.5 1.124 3.6 3.12 2 14 8.5 12.5 1.032 3.8 3.45 3 21 6.3 14.5 0.987 4.2 4.56 3 Mean 10.125 11.125 1.202 2.9 3.3975 2.25

Table B3: Effect of temperature (13oC) on cv. Keitt mangoes for 0-21 days storage time

13oC days Firm TSS TAA Wet pH skin loss color 0 14.2 8 1.664 0 2.46 1 7 9.5 12.5 0.987 5.43 3.67 3 14 5.6 14.5 0.765 5.54 4.25 4 21 3.5 16.5 0.543 6.03 4.86 5 Mean 8.2 12.875 0.98975 4.25 3.81 3.25

Table B4: Effect of ambient temperature on cv. Keitt mangoes for 0-21 days storage time

Control days Firmness TSS(o TAA pH Weight skin (kg/mm2) Brix) loss (%) color 0 14.15 8.1 1.5872 2.4 0 1 7 5.23 13.5 1.152 3.86 7.5 4 10 4.14 16.5 0.7544 4.98 11.32 5 21 1.5 18.2 0.256 5.2 12.24 5 Mean 6.255 14.075 0.9374 4.11 7.76 3.75

Table C1: Effect of CAS (10%CO2+6%O2) on SQA of cv. Keitt mango after 6weeks storage time

A(10%CO2+6%O2) Color Flavor Taste Firmness OVA 9 9 9 9 9 8 7 8 7 8 9 6 7 8 7 7 8 8 6 8 9 7 8 7 8 Mean 8.4 7.4 8 7.4 8 SD 0.894427 1.140175 0.707107 1.140175 0.7071

NB: 1=dislike extremely, 2=dislike very much, 3=dislike moderately, 4=dislike slightly, 5=neither like nor dislike, 6=like slightly, 7=like moderately, 8=like very much, 9=like extremely

Table C2: Effect of CAS (8%CO2+6%O2) on SQA of cv. Keitt mango after 6weeks storage

B(8%CO2+6%O2) Color Flavor Taste Firmness OVA 8 8 8 7 8 7 6 9 8 7 9 8 9 7 8 8 7 8 7 8 7 8 9 8 8 Mean 7.8 7.4 8.6 7.4 7.8 SD 0.83666 0.894427 0.547723 0.547723 0.4472

Table C3: Effect of CAS (5%CO2+5%O2) on SQA of cv. Keitt mango after 6weeks storage

C:(5%CO2+5%O2) Color Flavor Taste Firmness OVA

6 5 4 7 6 7 6 5 8 7 8 7 6 7 7 9 8 7 8 8 8 8 8 7 8 Mean 7.6 6.8 6 7.4 7.2 SD 1.140175 1.30384 1.581139 0.547723 0.8367

Table C4: Effect of ambient storage on SQA of cv. Keitt mango after 6weeks storage

Control Color Flavor Taste Firm OVA 8 9 7 8 8 9 9 9 8 9 8 7 6 8 7 6 5 4 8 5 8 5 3 8 5 Mean 7.8 7 5.8 8 6.8 SD 1.095445 2 2.387467 0 1.7889

Table D1: Effect of temperature (7oC) on SQA of cv. Keitt mangoes after 3weeks storage

at 7 o C Color Flavor Taste Firm OVA 2 1 2 3 2 3 3 4 3 3 4 3 4 4 4 5 4 3 4 4 6 5 4 5 5 Mean 4 3.2 3.4 3.8 3.6 SD 1.581139 1.48324 0.894427 3.8 3.6

Table D2: Effect of temperature (10oC) on SQA of cv. Keitt mangoes after 3weeks storage

at 10oC Color Flavor Taste Firm OVA 4 6 5 6 6 6 5 4 7 6 7 6 5 6 7 8 7 6 4 7 7 5 6 7 6 Mean 6.4 5.8 5.2 6 6.4 SD 1.516575 0.83666 0.83666 1.224745 0.547723

Table D3: Effect of temperature (13oC) on SQA of cv. Keitt mangoes after 3weeks storage

at 13oC Color Flavor Taste Firm OVA 9 8 9 8 9 8 8 8 7 8 7 9 8 8 8 6 8 7 6 7 8 7 6 7 8 Mean 7.6 8 7.6 7.2 8 SD 1.140175 0.707107 1.140175 0.83666 0.707107

Table D4: Effect of ambient temperatures on SQA of cv. Keitt mangoes after 3 weeks storage

Control Color Flavor Taste Firm OVA 9 8 6 4 7

8 7 5 6 6

7 6 6 7 7 8 7 5 6 6 6 8 7 5 6 Mean 7.6 7.2 5.8 5.6 6.4

SD 1.140175 0.83666 0.83666 1.140175 0.547723

Table D5: Sensory evaluation score card using nine point Hedonic scale

Panelist name: ………………. Product code: ……………. Date: …………..

Sensory Sensory quality attributes Hedonic perception(score) Color Flavor Taste Firmness Overall scale acceptance Notations a B c d e 1=dislike extremely 2=dislike very much 3=dislike moderately 4=dislike slightly 5=neither like nor dislike 6=like slightly 7=like moderately 8=like very much 9=like extremely NB: a, b, c, d, and e represents for fruits stored at both (CAS & Temperatures) treatment conditions: A (10%CO2+6%O2), o o o B (8%CO2+6%O2), C (5%CO2+5%O2) & D (Control) and [7 C, 10 C, 13 C & control] respectively.

Fig E1: Photograph of cv. Keitt type mangoes to be analyze

a) b)

Fig E2: cv. Keitt mangoes after 4 weeks storage on CAS (a) and ambient atmosphere (b) respectively

Fig E3: One-wire I button integrated with laptop to read temperature and humidity parameters.

Fig E4: Laboratory equipment used such as CAS and Modified storages

Fig E5: Analysis equipment such as Model-RF18 refractometer (India) and Model-FACCHINI- 48011 penetrometer (Italy)

Fig E6: Photograph during measuring Firmness of the fruit within 5 and 7 days storage interval

Fig E7:Photograph during analysis of TSS and sensory evaluation of cv.Keitt mangoes after storage

Fig E8: Photograph analysis of TAA of cv. Keitt mangoes within 5 and 7 days storage interval.

Declaration

I declare that the thesis for the M.Sc. degree at the University of Addis Ababa, here by submitted by me, is my original work and has not previously been submitted for degree at this or any other university, and that all resources of materials used for this thesis have been duly acknowledged.

Name: Zinabu Hailu Siyum

Signature: ------

Date of Submission: ------

This thesis has been submitted for examination with my approval as a university advisor.

Name: Eng. Teshome Worku (Assistant Professor)

Signature: ------

Date: ------