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SudanAcademy of Sciences,SAS Agricultural ResearchCouncil
Preliminary Studieson the Popping Characteristicsof SorghumGrains
By
RabiaaMoharnmed El-khalil Hamad B.Sc (Honour) Al-Zaiem AI- Azhari University Food Scienceand Technology
A ThesisSubmitted to the SudanAcademy of Sciencesin FulfiIlment of the Requirementfor Master Degreein Food Scienceand Technology
Supervisor: Dr. Nourel Huda Abdel Galil Kheiri AssociateProfessor .Food Research Center Agricultural Research&Technology Corporation
October -2006 PreliminaryStudies on the Popping Characteristicsof SorghumGrain
By
Rabiaa Mohammed El-khalil Hamad
Examination committee
Name Title ".ffkp&il Dr. Khogali E. Ahmed Chair / Externalexaminer Prof. Abdel Halim .R .Ahmed Internalexaminer W Dr. Nourel Huda A. G. Klreiri Major Supervisor
Date of examination l4ll/2007 Uedlcatlofi
Y to ryt tutotfrerQggia A6[ Et - I{afi anf to mysister Eg6a[EfKfiafit. Acknowledgemenl
Thanksand gratefulnessfirstly and lastly to "Allah" who gave me determination and patience to finalize this study successfully.
I would like to expressdeep thanks and gratitudewith special respectto Dr. Nour el Huda Abdel Galil for her kindness , unlimited help and personal guidance during the research period.
I am gratefulto Dr. OsmanEbide and Dr Ibrahim Nour Aldin and their sorghum breederscolleagues (FRC) who provided me with the testedsamples .
I am grateful to Prof. Bahi El Din Ibrahim Magboul for his assistanceand help .
* I am also very grateful to all thosehelped me during this work ABSTRACT
The aim of this study was to specify and describethe appropriatestages of pop processing of three sorghum varieties (Safra,Engaz and Edo) then selection suitable variety for pop production and the associationbetween its chemicalcomposition and the ability of popping. The proximatechemical composition of the threetested sorghum varieties during the stagesof processingto pop the poly phenols(phytic acid and taunins) besidestarch and someminerals (the macro elementspotassium, calcium and the microelements,iron and zinc) were determined. The range of chemical composition of raw sorghum varieties were as follows: Moisture 8.57 -9.13o/o;ash l.5l-2.l6oh; crudefat 3.39-3.62%o;protein 9.06-18.58%;carbohydrates 67.41-76.58:" starch 65.23-74.66;tanninsO.33- 0.28mg/100g;phytic acid 2.90-4.93mgl100g;iron 3.43-4.58mg/I00g; calcium 5.17-11.26mg/1009;zincl.48-2.78m9l1OOg;potassium198.80-387.78mgll00g.The resultsshoweci significant difference between the threesorghum varieties. The chemicalcomposition of the boiled stagewere : moisture 11.80- 13.06%;ash 1.49-2.12%o;crude fat 3.63-3.79%o;crude protein 10.32-18.50o/, : carbohydrate62.86-71.68; starch 64.14 -74.10; tannin 0.12-0.18 rng/I00g; phytic acid2.39-3.69 mgll}}g; iron 4,44-5.45mg /100g;calcium 9.26-20.19mg /100g: zinc 1.33-2.43m9/1009; potassium 184.62-266.08 mg /100g The chemicalcomposition of pop sorghumproducts gave: moisture3.66-
4.93%; ash 1.49-2.35%; crude fat 3.61-3.9loh; crudeprotein 9.13-15.82%o : carbohydrates74.56-81.06Yo; starch 70.14-77.5802;tannins 0.29-0.34mgl100g; phyticacid0.93-2.23m911009; iron 3.65-3.79mgl100g; calcium 18.72-23.09mg /100g;zinc 1.45-2.48mg /100g; potassium190.53-322.44 mg/l00g . The variety Engaz was most acceptablein organoliptic evah-rationin all the testedcharacters: color, flavors (odor and taste)and texture taking pop corrr as the control followed by the variety Edo wbile Safra was least acceptablein poppingThe ability of the varietiesfor popping correlatedwell with organoliptic, the best variety was Engaz, followed by Edo andlast was Safra.
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Eai.Il ".,^tt i-ti^-,ri .'.L.1 lrL dl:l elJi,-ef.!,ll L* 3r!i.i;,.J|j l.6;helylt: ( UUr +I ) 4{S$t a1l i+l+li.4;.till e$*j uJl ;_.r.llr-r" _t _lt+s 6rr^tt Jtiill iJ i,p!ilI "+Jl C- fuJtiltJ Jt iill gr. el-!*$ i+.lr -+{ f{+E3ti{ *l;sJl A""rl ditS3 .,,,alt dJfiXdl:i 6. 4!tLt c&l+ Jt^iill .r.irl . Jl es,'!- lv List of content Dedication i Acknowledgement ii Abstract lll Arabic Abstract iv List of Content V List of Table vii List of Figure vii List of Plate vii Chapterone Introduction l.Inhoduction Chapter Two Literature Review 2.I Sorghumclassification:- 5 2.2 Sorghumcommon names: 5 2.3 Sorghumhistory 5 2.4 Sorghumstructure:- 7 2.4.1Pericarp; 7 ., 2.4.1.1Epicarp:- 2.4.1.2Mesocarp 8 2.4.1.3Endocarp 8 2.4.2 Seed-coator Testa I 2.4.3Endosperm: 8 2.4.4Thegenn: 9 2.5 Nutritive valueof sorghum 9 2.6.1 Carbohydrate 9 2.5.1.1Carbohydrate defi nitions l0 2.5.1.2Sorghum Starch: l0 2.5.1.2. I Starchcomposition and structure l0 2.5.1.2.1.1Amylose 2.5.1.2.1.2Amylopectin 2.5.t.2.1.3Cereal lipids 2.5.1.2.1.3Resistant starch l3 2.5.2Protein t3 2.5.3-Lipidsin sorghum l4 2.5.4 - DietaryFiber l5 2.5.4.IThepentosans l6 2.5.5-minerals t7 2.5.6-SorghumVitamins l8 2.5.7-Sorghumphenolic compounds 20 2.5.7-I SorghumTannins 20 2.5.7-2Phytic acid 22 Chapterthree materialsand methods 3. I Materials 24 3.2Methods 24 3.2.1Preparation of the samples 24 3.2.1.1Rawgrains 24 3.2.1.2Treated grains 24 3.2.1.3Popping technique 24 3.3Proximate chemical composition 25 3.3.1Moisture content 25 3.3.2Ash content 25 3.3.3Protein content 26 3.3.4Fat content 26 3.3.5 TotalCarbohydrate content 27 3.3.6Crude fiber content 27 3.4 Determinationof Starch 28 3.4.1Preparation of the samplesolution 28 3.4.2Reducing sugar 28 3.4.3Total sugars 29 3.5 Determinationof mineralscontent 29 3.5.1Preparation of standardcurve for eachmineral 30 3.5.2heparationof the sample 30 3.6Phytic acid determination 3l 3.6.1Standard curve of phyticacid 32 3.7Tannic acid 32 aa 3.7.1Tannic acid standard solution JJ 3.7 .2 Tannicacid standardcurve JJ 3.7.3Test sample preparation 53 3.8 Statisticalanalysis 34 3.8.I Statisticalanalysis 34 3.8.1The ranking test 34 Chapterfour Resultsand Discussion 4.1Moisture content 35 4.2. Ashcontent 36 4.3.Fat content 39 4.4.Protein content 39 4.5 Total Carbohydratecontent 40 4.5.Crude fiber content 48 4.6. Starchcontent 48 4.7.Tannininsorghum 55 4.7. Phyticacid sorghum 57 4.7. Mineralsin sorghum 59 4.7.l.Ironin sorghum 59 4.7.1Calcium in sorghum 6l 4.7.1Zincin Sorghum 63 4.7.1Potassium in sorghum 65 4.8 Sensoryevaluation of color in pop sorghumproduct 67 4.8.lSensoryevaluation of flavorin pop sorghumproduct 67 4.8.2Sensoryevaluation of texturein pop sorghumproduct 67 4.8.3Sensory evaluation of overall qualityin popsorghum product: 68 Chaptersix Conclusion and Recommendation 6.1Condlusions 72 6.1Recommendations 72 Reference 73 Appendix 90 vl List of Table Table(2.1) Estimates of origin and early cultivationof cereals 6 Table4. l: chemicalcomposition of raw sorghumgrain 45 T able4.2: Chem ical compositionof boiled sorghum 46 Table4.3:chemical composition of poppedsorghum 47 Table 4.4: Starch content of raw sorghum 50 Table 4.5: Starchcontent of treatedsorghum 5l Table 4.6: Starchcontent ofpopped sorghum 52 Table4.7:Tannin contentof sorghummgll00g 56 Table4.8:Phytic Acid contentof sorghummg/100g 58 Table 4.9: Iron contentof sorghummgll00g 60 Table4.10: Calcium contentof sorghummgl100g 62 Table4.1 l: Zinc contentof sorghummgi 100g 64 Table4.l2: Potassiumcontent of sorghummg/100g 66 Table4.13: Sensoryevaluation ofpop sorghum 68 List of Figures Figure(i). Diagramof sorghum 7 Figure(ii) Amylosestructure l2 Figure(iii) Amylopectinstructure t2 Fig (l): Themoisture content of sorghum )l Fig (2): Thepercentage ash content ofsorghum 38 Fig (3): percentageThe Fat contentin sorghum 42 Fig (a): Thepercentage crude protein content of sorghum 43 Fig (5): The percentagetotal carbohydrate 44 Fig (5):The percentage crude fiber in sorghum 53 Fig (6):): PercentageStarch content of sorghum 54 Fig (7):Tannins in sorghummgl100g 56 Fig (8) : Phyticacid in sorghummg/100g 58 Fig (9): Iron in sorghummg /100g 60 Fig (10):Calcium in sorghummg /100g 62 Fig:(11): Zinc in sorghummg/I00g 64 Fig (12):Potassium in sorghummg/l00g 66 List of Plate Plate (l) EngazRaw 69 Plate (2) Engaz Pop 69 Plate (3) Edo Raw 70 Plate (4) Edo Pop 70 Plate(5) SafraRaw 71 Plate (6) Safra Pop 7l vtl CHAPTER ONE 1. INTORDUCTION The global importanceof cerealcrops to the human diet and moreoverto the written history of man and agriculturecan not be over stated.Cereal grains are the fruits of plants belonging to the grassfamily (gramineae).The sustenanceprovided by cerealsis frequently mentioned in the Quran and Bible, and they are by many other criteria the most important group of food crops producedin the world (Chavenand Kadam, 1989). In general,carbohydrates constitute about 75 percentof the solid contentof cereals(FAO, 1999).Dietary carbohydrates have beengiven an energyvalue of 4 Kcal lg or lTKJlg, althoughwhere carbohydratesare expressedas mono-saccharides, the value of 3.75 KcaI lg or 15.7KJlg is used(FAO, 1998).Cereal grains and their milled derivatives contain only 0.5-2.syo freely available disaccharides(Becher and Hanners, 1991). Sorghum (Sorghum bicolor) is an important cereal crop grown in the semi _ arid tropics of Africa and Asia due to its droughttolerance. It is a staplefood crop cultivatedon subsistence level by the farmers(Murty and Kumar, 1995),therefore plays an importantrole in food security. The world annual sorghum production is over 60 million tonnesof which Africa producesabout one- third (Taylor, 2002). This productionmakes sorghum the leadingcereal in someAfrican countriesand Nigeria is the world secondlargest producer of the grain (ICRISAT,2002). The major sorghum producing countries in Africa are o Nigeria (33.8 %), Sudan (21.4 ), Ethiopia (7.4 %) and Burkina Faso (6.60/o) accounting for nearly 70o/o of Africa's production (Taylor,2002). In westernand centralAfrica, sorghumis grown throughout the belt betweenthe sahra desert in the north and the equatorial forestin the south(FAO.l996). Growthrate in the agriculturalsector has noticeably declined from7.3 percent in2002to 5.2 percentin 2003and to 4.5 percent in2004.The decline in 2003was mainly due to thedeterioration in the traditionalrain-fed agriculture while furtherdecline in 2004 is attributedto the poor performanceof the mechanizedrain-fed agriculture.(FAO/WFP, 2006u) Aggregate2005/06 cereal production in Sudanis estimated at 5.46million tonnes,about 59 percenthigher than the previous yearswith very poor crop and 17 percentabove the averageof the previousfive years(FAO/WFP, 2006b) The traditionallyproduced fermented Sudanese sorghum or millet productsare: Kisra which is a thin pancake-typeleavened breadmade from fermentedsorghum flour which is bakedon a hot plate to form thin sheetsof bread having 52-53o/o rnoisture when freshlyprepared and 60-6IYo starch,l}-|2 o/oprotein and 3.8-3.9o/o crude fiber on dry weight basis(El Tinay et al, 1979).Aceda or Porridgeis the major food in severalAfrican countries.It is either thick or thin in consistency and carries different local nalnes. Thick porridge is called uguli (Kenya, United Republic of Tanzania,Uganda), tuwo (Nigeria), aceda(the Sudan),bogobe, jwa ting (Botswana) and sadza (Zimbabwe). In Sudan traditional porridge is consumedwith one of variety of Sudanesecooks. (FAO, 1995).Nasha is a traditionalsour thin porridgemade fiorn sour dough preparedfor acedaand/or kisra; also it is used as a weaning food, preparedby fermentationof dough and sorghum flour (Grahamet al, 1986).Jiryais the most refined sorghurnand millet porridge of Sudan, consisting mainly of starch (Dirar, 1993).Husuwais a traditional Sudanesefermented sorghun-r food, made from Sorghum bicolor variety .feterita. It is rnade of a mixtureof malt and sorghumflour rnixedwith water,the dough is friedin oil, eitherstored or eatenimmediately or dilutedwith water anddrank . It's non-alcoholicbeverage (El Nour et al, I999).Hulu- mur is an importanttraditional refreshing drink during the month of Ramdan.It is prepared from a mixture of malt and sorghurn flour (Burenget al ,1987),in the form of brownishflakes or sheets, soaked in water for a suitable time and then strained and sweetenedwith sugarto taste (Agab, 1985). Folk medicine: Severaluses of sorghumwere observedin traditional medicine, cyanogenetic, demulcent, diuretic, emollient,detoxicant , and depoisonious.Sorghurn is a folk remedyfor cancer,epilepsy, flux, and stomachache(Duke and Wain, 1981).The root is usedfor treatmentof malaria,the seed has been used for breast diseaseand diarrhea;the stenr for tubercularswelling, (Watt and Breyer-Brandwiik,t 962). The maize (Zea mays):Maize is the AmericanIndian word for corn,means literally "that which sustainslife". It is the first crop in Africa (Taylor, 2002), successfullygrown in southernand eastern Africa (FAO, 1996). It is the third cerealgrain in the world after wheatand rice (FAO, 1992). Botanically, maize (Zea mays) belongs to the grass family (gramineae). It is a tall annual plant with an extensive fibrous root system,a cross pollinating species,with the female (ear) and male (tassel) flowers in separate places on the plant.(Henry and Earl, re37). Differenttypes of maizeare classifiedon the basisof protein contentand the hardnessof the kernel. These include pop, flint, flour, Indian and corns (FAO, 1999).Maizeis usedas food, feed and as raw material for industry. The by-productsof dry milling includethe germ and the seed-coat,the former is used as a source of high qualityedible oil. The seed-coator pericarpis usedmainly as a feed,in recentyears an interesthas developedin it as a source of dietaryfiber (Earll et al., 1988;Burge and Duensing, 1989). Pop corn: Popcorn,a productof whole maizegrain, is one of the best all-round foods made from a special kind of flint corn with popping characteristicsoriginally selected by Indians in early westerncivilizations (Carter s! al, 1989). Objectivesof the study:- o To investigatedthe suitability of sorghum grains for popping. i To assesscompositional variations with respect to nutritive value CHAPTER TWO z.LITERATURE REVIEW 2.1Sorghum classification:- Sorghum(Sorghum bicolor (L) Moench)belongs to the tribe andropogonaeof the grass family gramineae. The genus sorghum is characterizedby spikeletsborne in pairs (FAO, 1995).Sorghum is classifiedby Snowden(1936). Other classificationssince that time area modificationsor adaptationsof the Snowdensystem. Sorghumis divided into five basic groups or races: bicolor, guinea, caudatum,kofi, and durra. The wild type and shatter cane areconsidered as two other spikelet types of S. tricolor (Harlan and de Wet, 1972). The chief races or varieties of sorghum in the UnitedStates are termedsorgo, kafir, durra,milo, feterita,kaoliang andbroomcorn (Hitchcock, l97I). 2.2 Sorghum common names: Sorghumcommon names are greatmillet and guinea corn in WestAfrica, kafir corn in South Africa, durra in Sudan,mtama in easternAfrica, jowar in India and kaoliang in China (Purseglove, re72). 2.3 Sorghumhistory: Sorghumwas detectedat an ancientsite 8000 B.C, "Nabta playa" Sudanesecivilization close to in southern Egypt they found sorghumseeds remain were similar is size and structureto modern wild type. Table 2.1 shows that sorghum was known in "Nabta playa"before others civilization (Wendorf et al,1992) Table(2.1) Estimates of origin and early cultivation of cereals LOCATION NearEast 4 500BC 4 s00B.c CentralAmerica 4 000BC ll Africa 100AD ll Europe 1930A.D. USSR,Europe Sources(McGee, 1984, Meikle, Scarisbrick1994.) 2.4Sorghum structure:- The kernelconsists of threedistinct anatomical components Fig.1.:Pericarp(outer layer) originates from the ovary wall endosperm(storage tissue), and germ (ernbryo). AI ('orrreous E I T $ Ccrnr rVlr f.v, s I rr rrt Figure (i). Diagram of sorghum,(source; Rooney and Miller tgB2) 2.4.1Pericarp:- Pericarpconsists of three histological tissues; epicarp , mesocarpand endocarp(Earp and Rooney, 1982). 2,4.l.lBpicarp:- The epicarpis generallycovered with a thin layer of wax andis furtherdivided into epidermisand hypodermis.The epicarp consistsof two or threecell layersthick andconsists of rectangular cellsthat often containpigmented material (Blakely et al,, lgTg). Thepigments are concentrated in the pericarpand /or inthe glume (modifiedleaves partially enclosingthe grain and may extendto the endosperm).Thesepigments color the sorghumfood products. However,recently, attention has beendrown to the possibility that suchpolyphenolic compounds may have a beneficialfunction as an anti-oxidant (Armad et al, 1998). Also the epiderrnis is composedof thick, elongated,rectangular cells which have a coatingof cutin on the outersurface (FAO,1995). 2,4.1.1Mesocarp:- The pericarpusually containsabout three or four layers of mesocarpfilled with small starchgranules (Blakely et a.L 1979). 2,4.1.2Endocarp:- Theendocarp is composedof crosscells and tube cells (Earp andRooney,1982). 2.4.2Seed-coat or Testa:- The seedcoat or testais derivedfrom the ovule integurnents. The thicknessof the testaranges from 8 prn to 40 pm and varies within individual caryopses(Blakely et al, 1979). 2.4.3Endosperm:- The largestcomponent of the cerealkernel is the endosperm, which is the major storagetissue. It is composedof the aleurone layer, peripheral,corneous and floury areas (Earp and Rooney, 1982). Thealeurone is the outercover and consistsof a singlelayer of rectangularcells adjacentto the testa or tube cells. The cells possessa thick cell wall, largeamounts of proteins(protein bodies, enzymes),minerals, phytin bodies, oil and spherosomes.The peripheralarea is composedof several layers of dense cells containingprotein and smallerstarch granules than the corneous area.Both the peripheraland corneousareas appear translucent or vitreousand they affect processingand nutrient digestibility. waxy sorghumscontain larger starch granules and less protein in the peripheralendosperm than regular sorghums(sullins and Rooney 1974;1975). The corneous and floury endosperm cells are composedof starch granules,protein matrix and protein bodies. Their cell walls are rich in cellulose,B-glucans, and hemicellulose. starchgranules and protein bodiesare embeddedin the continuous proteinmatrix in the peripheraland corneousareas (seckinger and Wolf 1973;Hoseney et a!, 1974). The protein bodies are largely circular,0.4-2.0 pm in diameter(Taylor et al,l984). 2.4.4The germ:- The germ embryonic axis and the scutellum are the two major parts of the germ. The scutellumis the storagetissue rich in lipids, protein, enzymesand minerals. In pearl millet the ratio of germ to endospermis larger than in sorghum and other millet kernels.The oil in the sorghum germ is rich in polyunsaturated fatty acidsand is similar to corn oil (Rooney, I97B). 2.5Nutritive value of sorghum:- The chemical composition of different sorghum varieties reportedby singh and Axtell(1973),protein (l0.cl g.syo),starch (55.G75.2o/o),crude fiber (1.0-3.4yo), fat (2.1-7.6%) and ash (1.G3.3%). 2.S.l.Carbohydrates:- carbohydratesconstitute the major part of the chemical compositionof cerealsand cerealproducts (Sukkar et al, lg75) 2.5.l.lCarbohyd rates defi n ition s:- Carbohydratesare polyhydroxy aldehydes,ketones, alcohols andacids. Their simplederivatives and polymerlinkages are of the acetyl type. They may be classified according to their degree of polymerization into three principal groups, namely sugars, oligosaccharidesand polysaccharides(Pigman and Horton, 1972). 2.5.1.2Sorghum starch :- The major component of cereal flour is starch. The propertiesof starchare very important in bakedproducts (Floseney et sl, 1987).Cereals grains including sorghum are valued for their contentof energyin the form of starch(Wall and Blessin, 1970). The value of sorghumstarch ranges (56 -73%); the averagestarch contentof sorghumis 69.5 percent(Jambunathan and Subramanian re88). 2.5.1.2.1Starchcomposition and structure: - The principal carbohydrate of all cereals is starch, representing56 percentin oat and 80 percent in Maize of their dry matter content (E,liassonand Larsson, 1993) . All cereal starchesare similar in their composition, having 74-79 percent amylopectin,25-30percent amylose and 1 percentlipids. Starchgranules are composedof trvo typesof alpha- glucan, amyloseand amylopectin, which representapproximately 98-99 percentof the dry weight (Testeret gL 2004).About 70 -80 percent of the sorghum starch is amylopectin and the remaining 20-30 percentis amylose(Deatherage et al, 1955). Both genetic and environmentalfactors affect the amylose content of sorghum (Ring4 al ,1982). t0 2.5.1.2.1.1Amylose:- Amylose is a relatively long linear alpha- glucan (Fig.2) containingaround 99 percento (l-4) and a (l- 6) linkagesdiffer in size and structure dependingon botanical origin . Amylose has a molecularweight of approximatelyI x 105-lx 106(Biliaderis,l998). The degreeof polymerization (DP) by number is 324 -4920 with round9-20 branchpoints equivalentto 3 -l l chaingper molecule (Yoshimatoet al ,2000; Yoshushi et al ,2002). 2.5.1,2.1,2Amylopectin :- Amylopectin (Fig .3) a much larger molecule than amylose1x 107-lx l0e (Morrisonand Karkallas, 1990;Biliaderis, 1998)a heavily branchedstructure built from about 95 percent a (1-a) and 5 percent or(l-6) linkages.the DPnis typically within therange 960f 15,900but thereare three major specieswith DPn 13,40U26,500,4400-8400 and 700-2100 (Takeda et a1,2003) . 2.5.1.2.1.3Cereal lipids : - Cerealstarches contain integral lipids in the form of lyso- phospholipids(LPL) and free fatty acids (FFA) which are positively correlatedwith the amylosefraction and the LPL may accountfor up to 2o/oof starchweight in high amylosecereal starches(Morrison, 1988 ,1995). The moisture content of air-equilibratedstarches rangesfrom about lU-l2yo in cerealsand about l4-l9yo in some rootsand tubers (Tester et aL,2004). Figure(ifl Amglosestruchtre ffester et a1.,2000) Figure (iii) Amylopectinstructure (Tester et g!.,2000) t2 2.5.1.2.1.3Resistant starch :- One of the major developmentsin our understandingof the importanceof carbohydratesfor health in the past years has been the discoveryof resistantstarch. Resistant starch is defined as starchand starchdegradation products which are not absorbedin thesmall intestine of healthyhumans (FAO,1990).The main forms of resistantstarch are physically enclosed starch, €.g. within intact cell structures(RSr), some raw starch granules (RSr) and retrogradedamylose (RS:) (Woolfe, 1987). 2.5.2Protein:- The secondmajor componentof sorghumand rnillet grains is protein.The geneticand environmentalfactors affect the protein contentof sorghumand millets. In sorghumthe variability is large, probablybecause the crop is grown under diverse agroclimatic conditionswhich affect the grain composition(Deosthale et al ,1972). Grain proteins are broadly classified into four fractions accordingto their solubility characteristics:Albumin soluble in water. Globulin soluble in dilute salt solution .Albumin and globulin are the best in nutritional value. Prolamine (kafirin) Prolamineis soluble in ethyl alcohol and is the poorest in nutritionalvalue. Glutelins are soluble in dilute alkali or acid solutionsand are intermediate in nutritionalvalue (Virupaksha and Sastry,1968). Sorghumprotein is predominatedwith prolamine,which is responsible for its low nutritional value (Virupakshaand Sastry, 1968).Prolamine and Cross-linkedprolamine fractions are very l3 low in lysineconcentration. In high-lysinesorghum, the proportion of thesetwo fractionsis lower andthat of the alburninand globulin fractionsare higher than in normal sorghum,,thus improving its overallprotein quality (Jambunathan, 1980). Studies on the arnino acidscomposition of the proteinfractions showed that the albumin and globulin fractions contained high amounts of lysine and tryptophanand are well balancedin their essentialamino acids composition.On the otherhand, the prolaminfraction is extrernely poor in Lysine,arginine, histidine and tryptophanand contained highamounts of proline,glutamic acid and leucinepresent in the formof proteinbodies. Prolamine is a predominantprotein fraction directlyassociated with the proteincontent of the grain.Glutelin is the secondmajor protein fraction,it is a structuralcomponent of the proteinmatrix in the peripheraland inner endospermof the sorghumkernel (Ahuja, et al ,1970) chemical and amino acids compositionsgive only an approximationof the proteinquality . Actual biologicalutilization of the proteinmust be determinedusing animalsand, if possible, children.(Maclean et al, 1981).Sorghurn proteins differed in their essentialamino acids content lvsine I .06-3.64,threo nine 2.12-3.g4, valine 3.84-6.93, Methionineand cystiner.80-2.69, Isoleucine 2.85-5.05, Leucine r0.12-17.60,phenylalanine and tyrosine 6.1 I - 10.72gll6gN (Jambunathan,et al , 1984) 2.5.3Lipids in sorghum: - In mostcereals the lipid fractionis concentratedin the germ. oats and maizeare unique a.mongstthe cerealsthat is they rnay containa relativelyhigh lipid contentmore than 10 percentfor t4 oatsand as high as 17 percentfor some maizecultivars compared to about2-3 percentfor wheat and most other cereals(Morrison, 1978).The crude fat content of sorghumis 3 percent,which is higherthan that of wheat and rice but lower than that of maize.The germ and aleuronelayers are the main contributors to the lipid fraction.The germ itself provides about 80 percentof the total fat (Rooneyand Serna-Saldivar,1991).The kernel fat is mostlylocated in the gern, in sorghummutants with a large embryo fraction the fat contentis higher 5.8 -6.6 percentthan normal (Jambunathan, le80). Themajor fatty acidsin cerealgrain lipids are linoleic,oleic andpalmitic (Haard and Chism 1996).The fatty acids content is significantlyhigher in kafir, caudatumand wild sorghum than in thebicolor, durra and guineagroups. On the other hand, caudatum typeshave the lowest linoleic acid content.Bicolor, durra and guineavarieties have more than wild and kafir sorghum.Oleic and linoleicacids are negatively correlatedwith each other. The fatty acidcomposition of sorghum fat is similar to that of corn fat but with more unsaturated fat, linoleic acid 49 percent, oleic 31 percent,palmitic 14 percent,linolenic 2.7 percentand stearic2.1 percent(Rooney, 1978). 2.5.4Dietary Fiber:- Dietaryfiber content is one of the most interestingnutritive parameters.It is the portion of food from the cellular walls of plantswhich is digested very poorly by human (Holland et al, leel). 15 Dietaryfibers. is usedto describea variety of indigestible plantpolysaccharides including cellulose,hemicelluloses, pectin, oligosaccharides,gums and various lignified compounds. Accordingto the modified definition of Trowell, (1976), dietary fiber is definedas the sum of the lignin and polysaccharidesthat are not hydrolyzed- by the endogenousenzymes of the human digestivetract. The major insolublefiber componentof sorghumis cellulose,its contentvary from 1.19 to 5.23 percentin sorghum varieties.In any seed material there are two sourcesof dietary fiber, namelythe hull or the pericarp and the cell wall structural components.The plant cell walls contain many non-carbohydrates componentsin addition to lignin, such as protein, lipids and inorganic materials and they modify the properties of the polysaccharides.Several approaches have been suggestedfor the measurementof total dietary fiber in foods, eachof thesemethods have certain limitations which may contribute to the observed variationsin dietary fiber content reported for various foodstuffs. (Kamathand Belavady, 1980) The commonly consumed low-tannin Sudanesesorghum varietyis dabar.Its total fiber contentis about 7.6 percentwhile the high-tanninSudanese variety, feterita, contains 9.2 percent.The totaldietary fiber in both varietiesis water insoluble(6.5 percentin dabarand 7.9 percentin feter:ita).The acid detergentfiber in the two varietiesis 2.9 percentin dabar and 3.6 percent in feterita (Knudsenand Munck 1985). 2.5.4.1ThePentosans : - The pentosans are a heterogeneous mixture of polysaccharides, many of which contain proteins.It occurs in the t6 cell walls of cerealgrains. The contentof sorghumis 2.5r-5.s7 percent(Karim and Rooney,1972). 2.5.5-Minerals:- Phosphorous,potassium, magnesium, calcium and tracesof iron andother minerals are found in cereals(Bowers, lgg2).Barley and wheatgrains provide 50 and 36 mg ca/100 g respectively. Barleyprovides 6 mg of iron per 100 g; millet provides6.g; oats, 4.6 andwheat, 3.1 mg ll00g. Soybeansprovide more of these nutrients,calcium 210 mg/100g and iron 7 mg/100g, (Haard and Chism1996). The sorghumkernels mineral are unevenly distributed and aremore concentrated in the germ and the seed-coat(Hubbard, et al 1950).In milled sorghumflour, mineralssuch as phosphorus, iron, zinc and copper decreasedwith lower extraction rates (Pedersenand Eggum,l983). The mineralcomposition of sorghum grain, Phosphors352mgl 1 00 g,Magnesiu m,r7 | mg/r00g,calcium 15 mg /1009,Iron 4.2mg/100g,Zinc2.5 mgllOOg,Copper 0.44 mgl 1009,Manganesel.15 mg/ r00g, Molybdenum0.06mg/ 1009 chromium 0.017 mgllO0g (Sankaraand Deosthale,19g0) while the potassiumcontent of sorghum grain was reporled 323.g mg/l00g by Jambunathan(I 980) Most plant-based foods contain some phytase enzymes, althoughin dry or dormant seedsits activity is negligible. The amountsofphytase activity dependon the speciesand the varieties, tropical cereals such as maize and sorghum have a lower endogenousphytase activity. phytase enzymeshydrolyze phytic l7 acid.Only the higher inositol phosphatesinhibit zinc andnon heme iron absorption(Lonnerdal et al, 1989).Certain amino acidsand a cysteine- containingpeptides released during the digestion of cellular animal protein and organic acids produced during fermentationenhance zinc absorption(Desrosiers and Clydesdale ,1989) A studyin Indian women reportedthat the absorptionof iron was higher from tannin-free than fi'om high-tannin sorghum cultivars(Gillooly et a1,1984).The bioavailabilityof iron in normal andanaemic persons was studiedin subjectsfed diets basedon two varieties of sorghum containing 20 and 136 mg of tannins respectivelyand 160.273mg of phytin phosphorusrespectively per 100g. It was found that in normal subjectsiron absorptionfrom low- and high-tanninsorghum were essentiallysimilar. However, in anaemicsubjects it was significantly lower with high-tannin sorghum.On equalization of the phytate content of the two sorghummeals the difference in iron absorption disappeared.It was concludedthat at the levels of tannins present in the two varietiesof sorghum,tannins had a minor role in determiningthe iron bioavailability(Radhakrishnan and Sivaprasad; I980) 2.5.6-SorghumVitamins :- Sorghumgenerally is a rich sourceof B-complexvitamins. Someyellow-endosperm varieties of sorghum contain B-carotene which canbe convertedto vitamin A by the human body (Blessin, et al, 1958).Isolated carotenoids of sorghumcompose of lutein, zeaxanthinand Bcarotene.Suryanarayana et al, (1968) analyzed severalvarieties of sorghum for their B-carotenecontent. the 18 acid.only the higher inositol phosphatesinhibit zinc andnon heme iron absorption(Lonnerdal et a\,1989). Certainamino acids and a cysteine- containing peptidesreleased during the digestion of cellular animal protein and organic acids produced during fermentationenhance zinc absorption(Desrosiers and Clydesdale ,1989) A study in Indian women reportedthat the absorptionof iron was higher from tannin-free than fiom high-tannin sorghum cultivars(Gillooly et a|,1984).The bioavailabilityof iron in normal andanaemic persons was studiedin subjectsfed diets basedon two varietiesof sorghum containing 20 and 136 mg of tannins respectivelyand 160.273mg of phytin phosphorusrespectively per 100g. It was found that in normal subjectsiron absorptionfrom low- and high-tanninsorghum were essentiallysimilar. However, in anaemicsubjects it was significantly lower with high-tannin sorghum.on equalization of the phytate content of the two sorghummeals the difference in iron absorption disappeared.It wasconcluded that at the levels of tannins present in the two varietiesof sorghum,tannins had a minor role in determiningthe ironbioavailability (Radhakrishnan and Sivaprasad; I980) 2.5.6-SorghumVitamins :- Sorghumgenerally is a rich sourceof B-complexvitamins. Someyellow-endosperm varieties of sorghum contain B-carotene whichcan be convertedto vitamin A by the humanbody (Blessin, et al, 1958).Isolated carotenoids of sorghumcompose of lutein, zeaxanthinand Bcarotene.Suryanarayana et al, (1968) analyzed severalvarieties of sorghum for their B-carotenecontent, the l8 variationswere very largewith valuesranging from 0.00-0.097ng /100 g of grain sample.In view of the photosensitivenature of carotenesand the variability due to the environmental factors, yellow-endospermvarieties of sorghumare likely to be of little importanceas a dietary sourceof vitamin A precursor.Detectable amountsof other fat-soluble vitamins, namely D, E and K have alsobeen found in sorghumgrain. Sorghumis not a sourceof vitamin C, on germinationvitamin C is synthesizedin the grain and on fermentationthere is a further rise in the vitamin content (Tauret al, 1984).Feeding trials in guineapigs on diets basedon wheat, rice, maize or pearl millet suggestedthat vitamin C requirementof the animals for optimal growth was five times higherthan that of animalsfed caseinin their diets (Klopfenstein, et al a 1980a;Klopfenstein, et al, 1981b;.Among B-groupof vitaminsthe concentrationsof thiamine. riboflavin and niacin in sorghumwere comparableto those in maize,wide variationshave beenobserved in the valuesreported, particularly for niacin (Hulse et al , 1980).The highestniacin contentof sorghumgrain reported by Tanneret al , (1947) was 9.16 mg per 100 g .Ethiopianhigh- lysinesorghum varieties have also very high niacin content 10.5 mg in IS I I 167 and I I .5 mg in IS 11758 /1009, as against2.9 to 4.9mg in normalsorghum (Pant, 1975). Niacinin cerealgrains exists in a boundform which is alkali soluble but considered biologically unavailable to humans (Goldsmithet al,1956; Ghosh,et al, 1963).Itwas observed that 80 -90 percentof the niacin in sorghumgrains was in a bound form and was availablefor the growth of the rnicroorganismused for niacin assay only after alkali treatment. (Adrian et al, 1970) t9 following differentextraction procedures found that in sorghum20 -28 percentof the niacin was cold-water extractableand thus biologicallyavailable, compared to about 45 percent in maize. (Belavadyand Gopalan, 1966)in their studiesin dogs observed that niacin in sorghumgrain was completelycold-water soluble and thus available,an observationthat was quite different from thoseof ( Ghosh,et al 1963; Adrian, et al (1970).Other studies (Carterand Carpenter1981,1982) showed that niacin in sorghurn grainwas presentas a high-molecular-weightcomplex and was biologicallyavailable to rats after alkali treatmentof the grain but not afterboiling in water. In boiled grainstotal niacin per 100 g was7.07 mg in rice,5.73mg in wheat,4.53 mg in sorghumand 1.88mg in maize.The proportionof total niacin availableto rats was41 percentin rice, 31 percentin wheat,33 percentin sorghum and 37 percentin maize. Thus niacin bioavailability in cereal grainswas found to be limited (Wall andCarpenter, 1988). OtherB-complex vitamins present in sorghumin significant amountsare vitamin 86 0.5 mg, folacin 0.02 mg, pantothenicacid 1.25 mg and biotin 0.042 mg/100g (United StatesNational ResearchCouncil/\lational Academv of Sciences.1982). 2.5.7Sorghum phenolic compounds:- 2,5.7.l Sorghum Tannin :- The majorpolyphenols fbund in high tannin sorghumgrains arecondensed tannins made up of Oligomersof flavan-3-olsand flavan-3,4-diols,called condensed tannins, occur widely in cereals andlegumes (Haard and Chism 1996)referred to sorghumtannins 20 asprocyanidins because they thoughtthat cyanidinwas usuallythe soleanthocyanidin involved. During grain development,flavonoid monomersare synthesizedand then condenseto form oligomeric proanthocyanidinsof four to six units.(Guptaand Haslam, 1980) All sorghumscontain phenols and most containflavonoids; however,only pigmentedcultivars produce condensed tannins or pro-anthocyanidins.Most cultivated sorghums do not contain condensedtannins even though non-tannin,phenolic compounds areoccasionally reported as tannins. Sorghums without tanninsare classifiedas type I and those with tanninspresent in pigmented testaas type II while sorghurnwith tanninspresent in pigmented testaand pericarp as type III. Tanninshave antioxidantproperties andare currently being considered as nutriceuticals (Hagerman and Butler,1989).The role of tannins in plant generallyprotects the grainagainst insects, birds, fungi, and weathering(Waniska et al- 1989).The antinutritionaleffect of tanninsin sorghurnhas been demonstratedclearly that is high-tanninsorghum varieties form indigestibleprotein-tannin complexes which is a major limiting factorto proteinutilization (Chibberet al, 1987).Tannin-protein interactions in sorghum involve hydrogen bonding and hydrophobicinteractions (Butler et al 1984).The tanninsbind both theexogenous and endogenousproteins including enzymes of the digestivetract thus affect the utilization of protein (Asquith and Butler1986; Griffiths (1985). The contentof tannin in high tannin sorghumis 2-3 oh (Hagermanand Butler, 1989).Sorghum containing tannin is called tanninor brown sorghum even though the pericarp color rnay be white,yellow, or red. The brown -seed sorghumcontent of tannic 2l acid is I.3-2 o/ocompared to 0.1-0.4 in other common varieties (Wall and Blessin, 1970). Grain appearanceis not necessarily relatedto its contentor presenceof tannin. Phenoliccompounds and tanninshave been reporledin much higher levels (10- 100 fold) in pericarp,glumes, and leaf sheathsthan in the endosperm. Phenolsisolated from the leaf sheaths(Sereme et al, 1993) and stems(Rey e/ a1,,1993) can be used as pigmentsfor clothes,pots, etc. Tannins (proanthocyanidins)apparently occur only in the pericarp,pigmented testa layers (Hahn and Rooney 1986) and glumes(Doherty et al, 1987)of sometype II or type III sorghums butnot in glumesof type I sorghums. 2.5.7.2Phytic acid :- Phyticacid is the 1,2,3,4,5,6-hexaphosphate of myoinositol thatoccurs in discreteregions of cerealgrains and accountsfor as muchas85Yo of the total phosphorouscontent of thesegrains. The phytatemolecules contain six phosphategroups and are highly charged.This makes it an excellent chelater and it can form insoluble complexes with protein (Ryden and Selvendran, 1993).Phyticacid in whole grain flour can be decreased considerablyby removingits hull (Reddyet al, 1982). In several varietiesof sorghumwhole grain, the phytin phosphorusrarlge was 1.7-3.8 mg per 100g. Over 85 percentof the totalphosphorus in the whole grain is bound as phytin phosphorus(Doherty g! al, 1982).The phyin phosphorusin sorghurngrain is found in greater percentagein the genn than in the bran and the leastis found in the endosperm.De-hulling can remove40 -50 percentof both phytate and total phosphorus.It was observedthat phytin phosphorus constituted82 - 91 percentof total phosphorusin the whole grain, 22 &4 percent in the de-hulled grain and 85 -95 percent in the {Wang et al, 1959). Phytates reduce the bioavailability of and the solubility, functionality and digestibility of and carbohydrates(Reddy et al, 1989).Bioavailability of sorghumfor human subjectswas found to be affected more phosphorus than by tannin content of the grains , ffid Sivaprasad,1980). On pealing of sorghum is a signification irrcreasein ionizable iron and soluble is an indication of the improvement of the ity of these two micro-nutrients as a result to the of phytate, fiber and tannin along with the bran portion (Sankaraand Deosthale,(1980). 23 CHAPTER THREE 3.MATERIALS AND METIIODS 3. I Materials: Threelocal cultivars of sorghum bicolor (L) Moench grains namelysafra, Engaz and Edo (season2003/2004) were brought fromAgricultural Research corporation (ARC), wad Medani. The grainswere manually cleaned from impurities,and subjectedto the followingprocesses. 3.2Methods:- 3.2.1Preparation of the samples:- Three samplesof each cultivar were prepared,raw grains, boiledgrains, popped grains and the threesamples were milled and subjectedto chemicalanalysis . 3.2.1,1Rawgrains:- The grains of each cleaned cultivars were milled and chemicallyanalyzed. 3,2.1.2Boited grains :- The grains of each cultivar were boiled in distilled water (100"c) for a minute,dried at room temperature(25-30oc) , milled andsubjected to chemicalanalysis. 3.2.1,3Popping technique :- The boiled grains were roasted in a covered hot plate for popping and the popped sorghum of each cultivar was organolepticallyevaluated. 24 3.3Proximate chemical composition: 3.3.LMoisture content: The moisturecontent was determinedaccording to the methoddescribed by AOAC the (2000). Two grams of the sample were weighed into a pre -dried aluminumdish, with a lid then placed in a temperaturecontrolled ovenat 103'C+2 over night (about 8 hours).The coveredsample wastransferred to a desicatorand cooledto room temperature,and thenweighed .The moisture content was calculatedas percentage ofthe originalweight of the sample: Moisture content {o/ol= Wz - Wg x lOO Wz-Wr Where W1=Weight of dish+ lid Wz= Weightof dish + lid * sample W3= Weightof dish + lid sampleafter drying 3.3.2Ash content: The ash content of the samplewas measuredaccording to the AOAC the (2000). A 2e of the sample were weighed into a cleandry porcelaincrucible and placed in muffle furnace (model TipofomoZ A No. 18203 Get Ran 1002) at 600'C for 6 hours. The crucible was transferred to a desicator, cooled to rooln temperatureand weighed. The ash content was calculated as follow: -- Ash content {%l wr -wz x too Weight of sample Where Wr : weightof cruciblewith ash. W2= Weightof emptycrucible. 3.3.3Protein content: The proteincontent of the sorghumsamples was determined by the micro-kjeldahlmethod (AOAC, 2000).4 0.2 e samplewas weighedaccurately into a micro-Kjedahl flask, 0.4g of catalyst mixtureand 3.5 ml of concentratedsulphuric acid were added,the flask was then placed into the Kjedahl digestion unit for about 2 hoursuntil a colorlessdigest solution was obtained. The flask was left to cool to room temperature.20 ml of 40% sodium hydroxide solutionwere addedto the digestedsolution and the mixture was heated.The ammoniaevolved was trappedintolOmls of 2o/oboric acidsolution, then titratedagainst 0.02N hydrochloricacid using universalindicator (methyl red + bromo cresol green. The total nitrogenand protein were calculatedusing the following formula: Nitrogenlo/ol = Volumeof HCI x Nx 14 x 100 Weightof samplex 1000 Proteinlo/ol= Nitrogen l%l " A.ZS Where: Nitrogenlo/ol = crudenitrogen. Protein lo/ol= crudeProtein. N = normalityof HCl. 14= equivalentweight of nitrogen. 3.3.4Fat content: Crude fat was determinedaccording to the AOAC (2000) method.A 2g sorghum samplewere extractedwith hexanefor 8 hoursusing Soxhlet apparatus. The solventwas evaporatedand the remainingcrude fat was determined. Fat %o= Wz:\ilr x 1OO trIeight of sample 26 Where Wr: Weightof emptyflask. Wz = Weightof flask with oil 3.3.5Total Carbohydrate content: Total carbohydratewas calculatedby differenceaccording to Pearson,(1976) using the following formula: Total carbohydrateo/o: 100- (moistureo/o-tcrude fat o%* crude protein%+ ashYo). 3.3.6Crude fiber content: Crudefiber contentwas determinedaccording to the AOAC (2000).42.7 g dried, defattedsample were transferredto a 600m1 beaker,anti- bumping granuleswere added and the sample was digestedusing 200 ml 0.25N sulphuricacid for 30 minuteswith periodicalswirling. The contentswere filtered through a Buchner funneland washed with boiling water. The digestionwas repeated using200 ml of 0.3 N sodium hydroxide for 30 minutes,then filteredimmediately through ashlessfilter paper and washedwith boilingwater, followed by anotherwashing with I o/ohydrochloric acid and finally with boiling water until free from the acid,then washedtwice with 7}o/oethanol.The residue in the ashlessfilter paperwas transferred to a crucible,dried at 103'C over night then transfenedto a desicator,cooled to room temperatureand weighed. Theashless filter paper with its contentwas ignited in the muffle furnaceat 500oCfor 2 hours, transferredto a desicator,cooled to roomtemperature and re-weighed. The crude fiber was calculated usingthe following equation: Crude Fiber = tvr -We x loo Weight of sample 27 Where: Wl : Weightof sample. W2=weight of crucible with sample W3=weight of crucible with ash 3.4Determination of Starch: Starchwas calculatedby differenceaccording to Ranganna (1986)using the following formula: Starch:100- (crude fatYo+ crudeprotein Yo+ashYo+ crude fiber o/o +reducingsugar *non reducingsugar). 3.4.1Preparation of the sample solution:- Sample (about 2.59 was weighed, and transferred to a 250m1beaker containing about 50ml water,heated to boiling then. Lead acetatesolution (45o/o)was added and the solution was shakenand left to stand for l0 minutes. Excesslead acetatewas precipitatedusing 22Yo potassiumoxalate solution, filtered and madeup to volume in a 250 ml volumetric flask. 3.4,2Reducing sugars:- 5ml samplesolution were pipettedinto a 25x200 mm test tube5 ml of the Shaffer-somogyi reagent was added (dissolve 259 of anhydroussodium carbonate and 25g potassium sodiurn tzrtaratein 50 ml water in a beakerwith stirring+75mI( lOTocopper sulphatesolution) was added+ 20g sodium bicarbonate +5g potassiumiodide (3.5679of potassiumiodate in 1 liter) then the solutionwas transferred to a 250 ml volumetric flask, completedto volumewith 0.1N potassiumiodate , filteredand stored overnight beforebeing used).A blank was concurently run. The test tube was capped with a funnel and placed in a boiling water bath for 15 minutes, then cooled carefully without 28 disturbing in running water for 4 minutes. 2 ml of lodide- potassiumoxalate solution and 3ml of 2N sulphuric acid concentrationwere added to the tube. The funnel was removed withoutagitating the solution, mixed thoroughly to ensurethat all the cuprousoxide was dissolved and left to stand in cold water bathfor 5 minutes,mixed twice during that time then titrated with 0.005Nsodium thio-sulphatesolution using starch as indicator. Thetiter value of the test solution was subtractedfrom the blank andits dextroseequivalent was calculatedfrom the Ranganatable. 3,4.3Total sugars: 50 ml of samplesolution was pipettedinto a 250 ml conical flask,59 of citric acid and 50 ml of water were added then the solutionwas boiled for 10 minutes to completethe inversion of sugars,the solution was l:ft to cool at room temperature, transferredto a 250m1volumetric flask and neutralizedwith lN sodiumhydroxide using phenolphthaleinas indictor then made up to volumeand titrated as describedbefore for the reducingsugars. Calculation Reducingsugar- ms of dextrosexvolume made upxlo0 Sxweight of samplex 1000 Total sugar= mg of invert sugar x volume made upx 1OO Sxweightof samplex 100 3.5Determination of mineralscontent: Mineralscontent were determinedby the Atomic Absorption Spectrometer(A.A.S model GBC 932 plus). Composedof: I Hollowcathode lamp as source of electromagneticrays. r Monochromater. 29 r Nebulizer. t Spraychamber. I Burner. This apparatus was connected with an air compressor acetylenecylinder. A softwareprogram control the whole analysisprocesses. 3.5.1Preparation of standard curve for each mineral: A standardsolution was preparedfor each element using differentconcentrations (pp-). 3.5.2Preparation of the sample: Onegram of the samplewas weighedin a porcelaincrucible. Thecrucible was ignited in a muffle furnaceat 550'C for six hours thencooled in the desicator. The ash obtained was treated with l0 mls of concentrated hydrochloricacid then transferred quantitatively to a 100 ml volumetricflask and completed to volume with distilled water, ttrenwell shaken.The hollow cathodelamp was selectedaccording to theselected element, and the acetyleneand air ratio was 2:8. The soft ware was provided with the required data such as the specificelement, its wavelength and the number of samples with labels.The burnerwas ignited to createa suitableflame of air andacetylene. Through this flame, electromagneticrays from the hollowcathode lamp passedthe sample solution in the capillary fubeand changedit to the gaseousstate. The free atoms absorb partof the electromagneticrays from the sourceand the intensity of whichwas calculated. 30 Phyticacid determination: Phytic acid was determinedby the method of Wheelerand , (1971); Reddyet al (1989), the principleof the methodis on the extractionof phytic acid in low acid media, then as ferric phytate by the addition of ferric chloride converted to ferric hydroxide by addition of sodium ; the ferric hydroxide is concentrated to as ferric by addition of nitric acid. Ferric nitrate is measured ly; the phytatephosphorus is calculatedassuming 4:6 Iron: ratio. Two gramsof milled sample, were weighed in a 125 ml flask, 50 ml af 3 ohtrichloro aceticacid (TCA) were added shaken in a mechanical shaker for 3 hours (Griffin flask ), Th. suspensionwas centrifuged for 5 minutes. l0 ml of supernatantwas transferredto a 40 ml tube and 4 ml of chloridewas added by pipetting { ferric chloride solution 2mg Fe*3 ions/ml TCA) . The tube was then heatedin a waterbath for 45 minutes,cooled and centrifugedfor l0-15 The clear supernatant was decanted, the precipitate was twiceby 25ml 3%TCAthen heatedfor l0-15 minutesin a wster bath, followed by centrifugation. The washed was dispersedin water and 3ml of 1.5N of NaOH was ith mixing, then the volume was madeto 30 ml with water, was heatedin a boiling water bath for 30 minutes using No 2. Filter paper, precipitatewas washedwith hot water, the washing was and the precipitatewas dissolvedin 40 ml hot 3.2 N 3l nitric acid into a 100m1volumetric flask ,the filter paper was washedwith water and the washingswere collected in the same flaskthen completedto volume. 0.5 ml aliquot was transferredinto a 10ml volumetricflask ,2 ml of 1.5Npotassium thiocyanate was addedand completedto volume by water,then immediatelyread a in,spectrophotometer(JENWAY-6400spectrophotometer)within I minuteat 480 nm . 3.6.1.Standard curve Standard curve of different concentrationsof Fe*3 was prepared; the phytate phosphorus was calculated from Fe*3 rd curve of phytic acid: K:2.7241 opticaldensity )n: sample=6 x Ax meansx 20x10x50x100 4 1OOOx2 adld= {mg P/ lOOx 6661 194 nnic acid ,Tannic acid was determinedbv the method describedbv (1986).Colorimetricestimation of tannicacid is basedon of the blue color formed bv the reduction of acidby tanninlike materialsin alkaline solution. 32 3.7.1Standard solutions:- {A}Folin and Dennis Reagent:- Sodium tungstate (100 g) was added to 750 ml distilled waterfollowed by 20g phosphomolybdicacid. Then 50 ml of 85Yo of acid were added and the mixture was refluxed for 2 hours, cooledto 25oC madeup to volume in a 1000ml volumetric flask. {B} Standard anhydrous sodium bicarbonate: Anhydroussodium bicarbonate(3509) was dissolvedin 750 lnl distilled water, heatedat 70-80Coand cooled over night then to one liter, the solution was filtered beforeuse. Tannicacid standard solution: Tannicacid (0.1 g) was dissolvedin lZ distilled water, freshlyfor eachdetermination {0.lmglml}. 7.2Tannic acid standard curve:- Standardtannic acid solution (0-10 ml) was pippeted into a of 100ml volumetric flasks containingT5 ml distilled water. flask was added5 ml of Folin and Dennis reagentand l0 anhydroussodium bicarbonate then made up to volume in a volumetricflask. mixed well and left for 30 minutes then in,spectrophotometer(JENWAY-6400spectrophotometer)at Testsample preparation: le (1g) was addedto 40 ml water boiled for 30 minutes to a 100ml volumetric flask, completedto volume, and filtered. = mg tannic acid x dilution MlTaken for (colordevelopment)x Wx 1000 55 Weightof Sample = standardtannic acid from curye Statisticalanalvsis: I Statisticalanalysis of datawas doneusing Duncan'smultiple ing tests(DMRT) The ranking test was used for sensory evaluation re77) 34 CHAPTER FOUR 4. RESULTS AND DISCUSSION 4.lMoisturecontent:- Moisturecontent of the raw sorghumvarieties is shown in 'Table4.1. It was in the range 8.50-9.n%. Generallysorghum rangeis 6.50-8.80% as reportedby El Tinay et gl_0979). moisturecontent of Engaz is higher than the reported range Safra and Edo are within the reported range of sorghum content, the moisture content of Engaz is significantly thanSafra and Edo (PS0.05). Moisture content of the boiled sorghum varieties which after boiling is shown in Table 4.2. Safra, Engaz and increasedby boiled from raw to process.The moisturerange boiled sorghumvarieties is 11.80-13.06%.Neucere and (1980) reporteda higher moisture range 12.07-13.36 % reportedby El Tinay et al (1979) on endogenousvarieties moisture content of boiled Edo is significantly lower andEngaz (PS0.05). moisturecontent of pop sorghumTable .3.shows.The moisturerange is 3.6G4.83 %.The moisture content Safra is significantly lower than Engaz (PS0.05). y, observedmoisture content increased from raw to but decreasedin pop stageas illustratedin Fig .1. Foisture content varies even within the same variety on the environmental condition especially relative 35 humidity and temperature, as well as the stage of maturity, iconditionand duration of storage. Ash content:- The percentageash content of raw sorghum varieties are in Table.1. The ashrange is 1.50-2.05% comparablewith findingsof Hoseneyet al (1982) 1.2V2.2 %. There is ificant difference between Engaz, Edo and Safra in their ash (Ps0.os). The percentageash content of boiled sorghum varieties are in Tabte 4.2. The ash content range is 1.49 -2.12oh. et al (1982) findings were 1.2U2.2 Yo,that meanthe ash of the tested samples are within the range. There is a differencein ash content betweenEngaz, Edo and Safra varieties(PS0.05). The ash content percentage of pop sorghum varieties are in Table 4.3. The ash content range 1.49 -2.35 is with Hoseney et al (1982) range 1.20-2.2% . Both and Edo results are within the range but the ash content of higher than the reported range. There is a significant betweenthe ash content of the other two tested sorghum (PsO.os1. ash content of the tested samplesat the three stagesof to pop sorghum. The ash content of Safra increased during the three stagesof processing,while Engaz and decreasedfrom raw to treated stagebut increased ing stageas illustrated Fig .2. 36 15 10 Moisture% 5 0 ): The moisture content of sorghum grain 37 Fig(2): The ash contentof sorghumgrain X'atcontent: Theoil contentof the raw sorghumvarieties is illustratedin .l.The oil rangeis 3.39-3.6lyo comparablewith that reported Jamburiathan(1980) 2.l-7.6 %.The oil content of safra is lower thanEngazand Edo, which are not significantly in theiroil contentat (P<0.05). Theoil contentof the boiled sorghumvarieties are shown in 4.2.thereis no-significantdeference between Engaz andEdo contentbut there is significant difference in both Engaz and, varietiesand Safra at (P<0.05). The oil content of the pop sorghum varieties are shown in ,4.3.There is no-significant different betweenEngaz and Edo contentbut there is significant difference in both Engaz and varietiesand Safra at (P<0.05). The oil content increased in both varieties safra and Edo to boiled stage but decreasein pop stage. In Engaz the oil content increasedfrom raw to boil to pop stage.Fig the fat content of the tested sorghumvarieties in the raw, ,ind pop stages. oil contentof sorghum grain is less than in corn this r, with the finding reportedby Klein et at (1971) andBadi (1987) that the oil content of corn grain was higher with other cerealsdue to its large germ which is rich in content: percentage crude protein content of raw sorghum shownin Table4.1. Was in the range9.06-lg.5g%. Mo and safra protein contentsare within the reported 39 rangeof Subramnianet al (1990)6.8-19.6%. There is a significant difference between the tested varieties in their protein content (PsO.05). The percentage crude protein content of boiled sorghum varietiesare shown in Table 4.2: The protein range is 10.32- l8.50%comparablewith subramanian et ar (1990) 6.urg.6%. Thereis a significant difference in the crude protein content of the testedvarieties (PS0.05). The percentage crude protein content of pop sorghum varietiesare shown in Table 4.3: the protein range is 9.13 -ls.g2 le with Subramanianet al (1990) 6.8-19.6% . Thereis a ificant difference betweenthe testedvarieties (p<0.05). The protein content of safra decreasedsuccessively during threestages of processingraw, boiled and pop. Engaz andEdo in content increasedfrom raw to boiled but decreasedin pop Fig .4. shown the percentagecrude protein content of the samplesduring processing. Total Carbohydratescontent: The percentagecarbohydrate content of raw sorghum are shown in Table 4.1. Carbohydratesrange 67.41 _ is comparablewith that of Inamdor et al (19g4) who range7r.19-78.70%. Engaz andEdo total carbohydrates are within the range but safra is not within the reported of the total carbohydratescontent. There is a significant betweenthe tested varieties in their total carbohydrate (Ps0.0s). The percentage carbohydrate content of boiled sorghum ies are shown in Table 4.2. carbohydraterange 62.g6 -71.67% 40 is comparablewith Neucere and Sumrell (1980) who reported range67 .61-73.70yo , i.e Engazand Edo total carbohydratecontent arewithin the reported range but Safra is not within this range . Thereis a significant difference betweenthe varieties(P<0.05). The percentage carbohydrates content of pop sorghum varietiesare shown in Table4.3.carbohydraterange is 74.56 - 81.06%.Edo gavethe highest total carbohydratescontent. There is a significantdifference betweenthe tested samplesin their total carbohydratescontent (P<0.05). Generallythe carbohydratecontent decreasedsuccessively processingfrom raw to boiled and increasein the pop stage. shows the effect of processing on the total carbohydrates of the testedsamples. Carbohydratesprovide the majority of energy in the diets of people.It is a desirablesource of energybecause it provides available energy for oxidative metabolism.Carbohydrate often contain vitamins and mineralsplus other compounds, asphyto-chemicals and antioxidants,which may have health ion (Burke et al ,1993) 4I 4 3.8 3.6 @ Raw Fat o/o 3.4 I Boiled 3.2 tr Pop a J Fig (3): The fat content of sorghum grain 42 F'ig(4): The protein content of sorghumgrain 43 100 80 Carbohydrate60 40 20 0 Safra Engaz (4): The carbohydratecontent of sorghumgrain q) .{.. G!O c.l rn @ h0 cJ o O o x+ +l ll + EE o -o oo o\ -Eg =q v? rt) fr= f- \o (n ctZ \o f- C- (J - .! GI L a0 .-I a s I o13 oo oo E oJ -t-a E(/) ol A o - h+ o0 Aa + + + L o .o ea @ \o ca (t)o EC) |.n o\ oo F t> o\ GI U L * f- o ca A : rt .-o .-.ar. E(, + +l ll u) 0 :+l o\ c.l l- o co ,l? - 9 - EF co cn ca I E (J) 5g ()c|t .- Fa - \n :f c\ I o q) o o O d E+ - U)a +l +l +l v \o o (l) q ,l? FI 9 !+ o.l -€) ,- clt \o c.l (n F s3 o o E+l -tl +l {{ .2E o c\ co rn 9 sg @ oi oo t-l h.t A 13 FI E € c! TEI a $ ,$ O Fq p F] E 'E -tsa $ F FI N $ tD UJ N) oo a> bo o o\ \o c, 6 FS-a' 5 H- FF l+ I P *9 Fl o b !? O 5 o\ 3E -d (D 5 b,J l..J 5 { 3 \o o @ tD o \o o P-a E l+ FF (D t-t- 5 E ll- I P o -.- o\ - f) D- f) I I u) (JJ t, Y o\ \ o\ (DFt3o Fi \o \o (JJ o o Fla 0 |L -. t+ t-t- t-F F} o I l+(! ts. b (, D' -FI oo Lrr t) -\ F| f-f) FI o o -. >1 (D O oo =tr - l..r) tJ lJl (t) oo N) 8F o El- ll t+ t+ FF r+x oe- w b ca3 - 5 (-.1 AtD r E' - - oq tl p o I { { o\ :2tr !.-, =Ft b\ @ oo NJ o\ sg o tl tr!r t+ rr t+ o o o l+x ir o h ai 5 \o gs F} r! O frl - frl - OO x $ s $a N (D (JJ s (JJ 3_ \c \c b\ t9 (}J o\ ss rl o o D9 l+ t+ t-F t|3 tD L : h 0= o\ oo grd 5 (, NJ c) = it 5 b\ L^) tD \o N) (-fl t! o P H l-F t-F t-F -u) l+ !t f? (rn q a NJ f) H FFI UJ UJ u) o (DFT3o o\ \c o\ F} o D'-- l-t- l+ t-F po A (t) p' t-fl (.,1 tJ Fi FFI o (D >4 I \o p (/r| (t) io r-tr (,1) @ AA" Fl s () tJ FI 'D t+ EI oq t+ tf +; It (/|| -l tJ) NJ O= { N) gj(D I oe Fl o - oo oo { :Z D' i =Ft 5 (.ll o\ NJ o\ sg il=r l-f. FF l+ rrx NJ i.t L^, a; N) s { s3 tD 4.5. Crude fiber content: The percentagecrude fiber contentof raw sorghumvarieties are shown in Table 4.4. The crude fiber contentrange is 1.39- l.2l% comparablewith Jambunathanet al (1984) who reported range 1.0-3.4 o/othat is the crude fiber content of the tested samples are within the range. There is a significant difference betweenthe testedvarieties (PS0.05). The percentagecrude fiber content of boiled sorghum varietiesare shown in Table 4.5. The crude fiber content range 1.42-l.24yo is comparablewith Jambunathanet al(1984) who reportedrangel .0-3.4oA. All the testedsorghum varieties are within the range. There is a significant difference in the crude fiber contentof the testedvarieties (PS0.05). The percentagecrude fiber contentof pop sorghurnvarieties are shown in Table 4.6. Crudefiber contentrange 1.5-1.18%is comparablewith Jambunathanet al Q98\ who reported range 1.0-3.4%. There is a significant difference in the crude fiber contentof the pop varieties(P<0.05). It is observedthat the crude fiber content in Safra andEdo increasedsuccessively from raw to boil to pop while Engazcrude fiber content decreasedsuccessively from raw to treat to pop product. Fig .5. Shows the crude fiber content of the tested sorghumduring differentstages of processingto pop. 5.6.Starch content: The percentage starch content of raw sorghum varieties are shown in Table .4. Starch content range 65.23-74.66is comparable with Jambunathanet al, (1984) who reportedrange 55.60-75.200 . 48 There is a significant difference in the percentagestarch content of the raw sorghumvarieties at (PS0.05). The percentage starch content of the boiled sorghum varieties are shown in Table 4.5. Starch content range 64.14 - 74.10% is comparable with Jambunathanet ol, (1984) who reportedrange 55.6f75.20%. There is a significant differencein the percentage starch content of the treated sorghum varieties (Pso.os). The percentagestarch content of pop sorghum varieties are shown in Table 4.6. Starchcontent range 70.13-77.58% is different from . Jambunathanet al (1984) who reportedrange 55.60-75.20 i.e Safra content of starch is within the range while Engaz andEdo are not within the range reported by Jambunathanet al (1984) , probably becauseamylose and amylopectin tacked into a new structure in pop sorghum product. There is a significant difference in the percentagestarch content of the pop sorghum varieties (PSo.os). The starch content of the tested sorghum decreasedslightly from raw to treated then increasedin the popping stage.Fig .6. Shows the effect of processingon the starchcontent of the tested sorghum. Starch is the most important abundant homo- polysaccharidein pop manufacturing. 49 Table 4.4: Starch content of raw sorghum grain Sample Crude fiber Reduce Non- Reduce Starch Mean + Sd sugar sugar Mean + Sd Mean + Sd Mean + Sd b+ Safra 1.39\ 0.04 4.21 0.00 5.19'+0.03 65.23"* 0.04 Engaz l.3l"b+0.10 4.52u+0.09 5.22b*0.09 74.66"+ 0.23 Edo r.2f+ 0.02 4.45"+0J5 5.36"+0.03 7232b+0.52 Table 4.5: Starch contentof boiled sorghum grain Sampl Crude fiber Reducesugar Non- Reduce Starch Mean + Sd Mean + Sd sugar Mean * Sd Mean + Sd Sofro 1.42"+0.07 4.70b+ 0.00 5.59'+0.06 64.14"+ 0.09 Engaz 1.24"+0.06 4.80"+0.02 5.47b+0.01 74.10"+0.19 Edo 1.34b+0.01 4.69'*0.00 5.33u*0.03 72.54b+0.34 Table 4.6: Starch content of poppedsorghum grain Sampl Crude fiber Reducesugar Non- Reduce Starch Mean + Sd Mean + Sd sugar Mean + Sd Mean + Sd Safra l.5l "* 0.02 3.25b+ 0.02 3.66"+ 0.04 70.13"+ 0.09 Engaz 1.18'+0.00 3.97u+0.03 3.63b+0.04 77.58^ * 0.32 Edo 1.42b+0.02 3.09'+0.00 3.s4%0.03 76.94b*0.51 1.6 t.4 1.2 I Fiber% 0.8 0.6 0.4 0.2 0 Safra Engaz Fig (5): The fiber content of sorghum grain 80 60 I Raw Starch% 40 I Boiled 20 fl Pop 0 Safra Engaz Edo Fig (6): The starch content of sorghum grain 4.7.Tannins in sorghum: The tannins content mg/100g of raw sorghum varieties are shown in Table 4.7. Tannins content range 0.33-0.28 mg/100g is comparablewith Jambunathanet ol Q98Q who reportedrange 0.1- 6.4 mgll0Og. There are significant differencebetween varieties at (Pso.0s). The tanninscontent of boiled sorghumvarieties are shown in Table 4.7.Tanninsrange 0.12-0.18mg/100g is comparablewith Jambunathanet al, (1984) who reported range 0.1-6.4 mg/100g. thus all results are within the range. There are significant differencesbetween varieties (P<0.05 ). The tannins content of pop sorghumvarieties is illustrated in Table 4.7.Tannins content range 0.3+0.28 mg/100g is comparablewith Jambunathanet al (1984) who reportedrange 0.1- 6.4. There are significant differencesbetween varieties (PS0.05). Tannins content decreasedfrom raw to treated stage in all the testedsamples probably due to the loss of somesoluble tannins in the processof boiling. The tannins contentincreased in the pop product in all the testedsamples. Fig .7. showsthe tanninscontent of the tested sorghum varieties and the treatment effect. The polyphenolic compoundsare also known as tanninspresent in the grain of sorghum cultivars which substantially reduce the availability of protein and other nutrients, thus indirectly has a major negativeeffect on the nutritional quality of grain sorghum. 55 Table4.1: Tannin content of sorghum mg/100g Sample Raw boiled Popped Mean + Sd Mean + Sd Mean+ Sd Safra 0.33"*0.01 0.17b*0.oo 0.34"*0.01 Engoz 0.31b*0.00 0.12'*0.00 0.29b*0.00 Edo 0.28'+0.01 0.18%0.00 0.29'*0.01 0.4 0.3 Tannin ; Raw 0.2 mg/100g a Boiled 0.1 E Pop 0 Safra Engaz Fig (7): The tannin content of sorghum grain 4.7.Phytic acid contentof sorghum: The phytic acid contenl mg/I00g of raw sorghumvarieties are shown in Table 4.8. Phytic acid content range 4.93-2.90 mgi l00g is comparablewith Dohertyet al (1982) who reported range 1.70 -3.80 mgl100g i.e Engaz and Safra resultsare not within the reported range but Edo is. There are significant differencebetween varieties (P<0.05). The phytic acid contentof the boiled sorghumvarieties are shown in Table 4.8. Phytic acid contentrange 3.69-2.39 mg/I00g is comparablewith Doherty et al (1982) who reporteda range 1.70-3.80mg/100g hence all the resultsof the testedsamples are within the range.There is significantdifference between varieties (P<0.0s). Phytic acid contentof pop sorghumvarieties are shown in Table4.8. Phyticacid contentrange 2.23-0.93 is comparablewith 'l'he Doherty et al, (1982) reportedrangel.70-3.80. Engaz and Safra results are within the reportedrange of phytic acid content but Edo is outside the range. There are significant difference betweenvarieties (Ps0.05).Phytic acid contentdecreased from raw to boiled to pop stagebecause it is watersoluble. Fig.B. shows the result of the testedsorghum varieties and treatmenteffect.Phytates reducethe bioavailabilityof minerals,the solubility function and digestibilityof protein and carbohydratesas reportedby Reddy et al, (1989).Phytic acid hasthe potentialto bind calcium,zinc, iron and other minerals,thereby reducing their availabilityin the body Davis and Olpin,(1979)Therefore the processof poppingimproves the nutritionalvalue of sorghumby reducingits phytic acid content in Safra to 55.I o/oin Engazto 59o/oand in Edo to 68.8%. 57 Table4.8:Phytic Acid content of sorghum grain mg/100g Sample Raw boiled Popped Mean * Sd Mean * Sd Mean * Sd ^+0.04 Safra 4.93 3.69"+0.05 2.23u+0.04 b*0.00 Engoz 4.42b*0.05 2.95 1.84b0.04 Edo 2.9I'i.0.06 2.39'+0.10 0.93'*0.04 4 Phyticacid 3 [E R"* mg/l00g 2 . ] P"t""".0 ] 1 [I i 0 Safra Engaz Fig (8): Phytic acid in sorghum grain mg/100g 5.7. Minerals in sorghum: Sorghum minerals are concentratedin the genn and the seed coat (Pedersenand Eggum, 1983). 5.7.1. fron in sorghum: The iron content of raw sorghum varieties are shown in Table 4.9. That means iron range 3.43- 4.5gmg/100 g is comparablewith Jambunathan(I980)who reporteda range of 2.60 to 9.60 mg/100 g henceall the resultsare within the range.There are significant differencebetween varieties (pS0.05). The iron content of treated sorghum varieties is shown in Table 4.9.iron range4.43-5.45 mg/r00g is comparable with Jambunathan(1980) who reportedrange of2.60 -9.60 mg/ 100e. All tested sampleswere within the range. There are significant difference betweenvarieties (p<0.05). The iron content of treated sorghum varieties is shown in Table 4.9. Iron range 3.6+3.79 mgl100 g is comparable with Jambunathan(1980) reportedrange 2.6u 9.60 mg/ 100 g. Hence all the tested samples results are within the range. There are significant di fferencesbetween varieties (p<0. 05 ). Iron content of the tested samplesincreased from raw to treatedbut decreasedin pop stage.Fig .9. showsthe iron contentof the three sorghum varieties and treatmenteffect. 59 Table 4. 9zIron content of sorghum mg/100g Sample Raw Boiled Pop Mean * Sd Mean * Sd Mean + Sd Safra 4.59'+0.02 5.45^*0.02 3.71b+0.01 Engoz 3.46b+0.01 4.44"+0.01 3.79"+0.01 Edo 3.43'+0.02 4.44b*0.01 3.65'10.01 6 5 4 Iron a J l-;";1 mg/l00g l; Boiled] 2 [o'.0 ] I Safra Engaz Fig (9): iron in sorghum grain mg/100g 4.7.1 Calcium in sorghum: The calcium content of raw sorghum varieties is shown in Table4.10. calcium range 5.17-11.26 mg/ l00g is comparablewith Jambunathan(l980)who reportedrange 5.5-53.r mgl 100g. i.e that meansall results were within the range.There are significant differencebetween varieties (pS0.05). The calcium contentof boiled sorghumvarieties is shown in Table 4.l0.calcium range 9.26-20.19r mg/ 100 g is comparable with Jambunathan(lg8O)who reportedrange 5.5-53.I md 100 g i.e. all resultsare within the range.There are significant difference betweenvarieties (P<0.05). The calcium content of pop sorghumvarieties is shown in Table 4.10. That meanscalcium range 18.7L23.09 mg/ 100 g is comparablewith Jambunathan(1980) who reportedrange 5.5- 53.1 mgl 100 g i.e. all resultsare within the range.There are significant difference betweenvarieties (pS0.05). Calcium increasedform raw to boiled to pop in the three sorghumvarieties. Fig .10. Shows the result of the three tested sorghum varieties and the treatmenteffect. 61 Table 4.10: Calcium contentof sorghum grain mg/100g Sample Raw Boiled Popped Mean + Sd Mean * Sd Mean * Sd SoJ'ra 11.26%0.01 t7.45b+0.02 23.09u+0.00 Engoz 5.17'*0.00 9.26'+0.01 18.72'+0.00 Edo g.4gb+0.01 20.19"+0.01 22.69b*0.01 25 20 l5 Raw Calcium I mgl100g l0 1 Boiled 5 I PoP 0 Safra Engaz (10)zcalcium in sorghumgrain mg/100g 4.7.1 Zinc in Sorghum: Zinc content of raw sorghum varieties is shown in Table .lt.zinc range 1.4U2.78 mgl 100 g is mostly not comparable with Jambunathan(1980) who reportedrange 1.9-5.7 mg/ 100 g. hence Engaz and Edo results were below the range but Safra was within the reported range. There are significant differences betweenvarieties (PS0.05). The zinc content of boiled sorghum varieties is shown in Table 4.ll . zinc range 1.33-2.42mg/ 100 g is comparablewith Jambunathan(1980) who reportedrange 1.9-5.7 mgl 100 g i.e. Engaz and Edo results are within the range but Safra content is beyond the reported range. Here are significant difference betweenvarieties at (P<0.05). Zinc content of pop sorghum varieties is shown in Table 4.11. Zinc range 1.44-2.48mg1 100 g is comparable with Jambunathan(1980) who reported range 1.9 -5.7 mgl 100 g .Hence Engaz and Edo results are below the range but Safra is within the range There are significant difference between varieties(PS0.05). Zinc content decreasedfrom raw to treatedbut increasedin pop stagein the three sorghum varieties, but Safra has the highest contentof zinc in all stagesof the processingtechniques. Fig .l 1. showsthe result of the threetested sorghum varieties and treatment effect. 63 Table 4.llz Zrnccontent of sorghumgrain mg/100g Sample Raw Boiled Popped Mean * Sd Mean * Sd Mean * Sd Safro 2.78^*0.03 2.43u+0.04 2.48'+0.03 Engaz 1.49'r0.01 1.33'+0.01 1.45"+0.01 Edo 1.5gb*0.01 1.55b+0.01 1.55b*0.02 3 2.5 2 Zinc 1.5 mgil00g I Boiled I 0.5 0 Safra Engaz Fig (11): zinc in sorghum grain mg/100g 4.7.1 Potassium in sorghum: Potassiumcontent of raw sorghumvarieties is illustrated in Table 4.12. Potassium range 198.8G387.79 mg/ l00g is comparablewith Jambunathan(1980) who reportedrange 323.g0- 801.40 mg/ 100 g , henceEngaz andEdo contentof potassiumare below the range but safra is within the range There are significant difference betweenvarieties (p<0.05). Potassiumcontent of boiled sorghumvarieties is shown in Table 4.I2 potassium range 184.62-266.08 mgl 100 g is comparablewith Jambunathanet al (1980) who reported range 323.8G801.40 mgl 100 g i.e. all results are below the range becausepotassium soluble in boiling water . There are significant differencebetween varieties (PS0.05 ). The potassiumcontent of pop sorghumvarieties is shown in Table .l2.potassium range 190.53-322.44 mgl 100 g is not comparable with Jambunathan(1980) who reportedrange 323.80 -801.40 mgl 100 g i.e. all rer;ultsare below the range.There are significant difference betweenvarieties (PS0.05). Potassiumcontent of Engaz , Edo andsafra decreasedfrom raw to boiled but increasedin pop stagei.e. the potassiumcontent of all the testedvarieties decreased in the processof popping may be due to its solubility in water. Fig .12. shows the results of the three testedsorghum varieties and effect of processing. 65 Table4.l2:Potassiumcontentof sorghum grain mg/100g Sample Raw Boiled Popped Mean + Sd Mean + Sd Mean* Sd Safra 387.79u+ 0.06 266.08"*0.05 322.44u+0.03 Engaz 198.86'+0.03 184.62"*0.06 196.47"+0.02 Edo 203.75b+0.03 188.28b+0.03 190.53b*0.02 400 300 Potassium 200 mg/100g 100 0 Safra Engaz Edo Fig (12)z Potassium in sorghum grain mg/100g 66 I 4.8 Sensoryevaluation of color in pop sorghumproduct: Comparingthe color of the control pop corn with the pop of the testedsorghum varieties the following resultswere obtained in Table .13:Engaz 37, Edo 58 when comparedwith Larmond(l977), 19judges and4 treatmentrange 37-58 that meansEngaz andEdo have no- significant difference in color . However there was a significant differenceswith the higher value of safra (75) and the lower value of popcorn(21). Engaz gave the best pop color, followed by Edo, popcorn and lastly Safra. 4.8.1Sensoryevaluation of flavor in pop sorghumproduct: Flavor consistsof taste and odor. In comparingthe control pop corn with that of sorghumvarieties, the following resultswere obtainedin Table .13: Engaz 40, Edo 55 .When comparedwith Larmond (1977), 19 judges and 4 treatmentrange 37-58 that means Engaz and Edo. Acquired no- significant difference in flavor but a significant difference with Safra (68) and the lower value of popcorn (21). Engaz gave the bestpop flaver , followed by Edo , popcorn and lastly Safra. 4.8.2 Sensoryevaluation of texture in pop sorghum product: The textureof the control pop corn againstthe textureof pop sorghum varieties shown in Table .13: Engaz 42, Edo 57 when comparedwith Larmond (1977) having 19judges and 4 treatment range. 37-58 that means Engaz and Edo have no- significant differencesin texture.Significant different occurredwith Safra and popcorn. 67 Engaz gave the best pop texture, followed by Edo, popcorn and lastly Safra. 4.8.3 Sensory evaluation of over all quality in pop sorghum product: Generally pop Engaz gave the best results out of the three sorghum varieties in both chemical analysis and sensory evaluation.Thus the development of the technology of pop sorghum in Sudan can be successfulsnack product analogousto popcorn can be produced.Edo is the secondchoice as determined in this study but Safra failed to give a satisfactorypop. Table 13: Organoliptic quality of pop sorghum Sample Sum of rank Color Flavor Texture Overall quality Engaz 37u 40u 40" 42" Edo 5gu 55u 57u 57u Safro 75" 6g' 72" 72" Pop corn 2rb 27b 2f 2f 68 fllate , 3." E*gaa Kawr * o& " *=' '{ ',, * .* 4' ,.w *rf,E ' :,*: t ''fht{n'd *:o ,'i,i.,%* - 3. t.*d .,ir' ':f .Ii,es...Wi :::1 '. -. ,:- : '. ;j.' . i; , i- ''' ' '; : t :' : :' 'i .. .: - i :_; . ,,,._r,;, : ji "4,, ,.- .i:il,il;. 3r,ffi 4 Plate .3. Edo raw Plate .4, Pop Edo 7A Plate .5. Safra raw ffi,ffi1:' 'i *- *fl**#- :. t.x+ir-{F {r--. "' .': --&"At ffi*tnm ilF 'rtAan (atr:r/Snz ,;/vtk1'0X0)t0) Nf,q{lnnflvwttu \ 13 Lt \v Plate.6. Pop Safra 71 -4, CHAPTER FIVE CONCLUSION AND RECOMMENDATION 5.1 Conclusion: . From three sorghum varieties (Engaz, Edo and Safra ) Engaz variety gave best characteristicin pop sorghum product. ' Pop sorghumis an acceptableproduct. 5.2 Recommendations:- . 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