J. Trop. Agric. and Fd. Sc. 28(2)(2000): 183–188 S. Y. Lee

Physico-chemical characteristics of calamansi juice, agglomerate and drink (Ciri fizikal dan kimia jus calamansi, aglomerat dan minuman calamansi)

S. Y. Lee*

Key words: calamansi, agglomerate, juice, carrier, additives, process variables

Abstrak Jus calamansi boleh dijadikan serbuk atau aglomerat dengan menggunakan proses pengeringan ‘fluidized bed’ dan pengaglomeratan. Gula kisar digunakan sebagai pembawa manakala bahan tambahan seperti asid sitrik, perisa dan warna diperlukan untuk menambah perisa dan mengimbangkan asid-gula serta untuk kelihatan menarik. Parameter proses yang optimum yang digunakan ialah suhu 45 °C, kadar aliran udara 20 m3/jam yang menghasilkan had laju 1.5 m/s, tekanan pengabus 3 bar dan kadar alir pam 6 g/min. Kadar perolehan jus ialah 35.8% dengan kelembapan buah 83.8% dan warna kulit calamansi L* = 45.6, a* = Ð9.8, b* = 26.7. Ciri-ciri jus yang dianalisiskan ialah nilai warna L* = 7.5, a* = 1.3, b* = 12.8, TTA = 5.8%, pH = 2.4, TSS = 8.5 dan kelikatan = 5.1 cP. Analisis produk aglomerat seperti saiz-zarah, warna L* = 91.8, a* = Ð7.1, b* = 20.1, ketumpatan pukal = 0.6 g/mL dan kelembapan = 3.2%. Ciri-ciri produk minuman calamansi seperti warna ialah L* = 87.3, a* = Ð3.3, b* = 18.5, TTA = 0.6%, pH = 3.1, TSS = 12.8 dan kelikatan = 2.7 cP. Minuman calamansi dibandingkan dengan jus calamansi yang dicairkan yang mempunyai indeks warna L* = 23.1, a* = Ð1.1, b* = 20.9, TTA = 1.5%, pH = 2.9, TSS = 11.4 dan kelikatan = 3.5 cP. Minuman calamansi mendapat nilai lebih tinggi daripada jus calamansi asli apabila diuji nilai rasa.

Abstract Calamansi fruit juice can be converted into powder or agglomerate by the process of fluidized bed drying and agglomeration. Ground sugar was used as a carrier for the process whereas essential minor additives i.e. citric acid, flavour and colour were used to boost up flavour, acid-sugar balance and eye appeal of the product. Optimum process variables used were 45 °C as the process temperature, 20 m3/h as the airflow rate which resulted in an air velocity of 1.5 m/s, an atomization pressure of 3 bar and a pump flow rate of 6 g/min. The juice recovery was 35.8%, the fruit moisture content was 83.8% and the fruit skin colour was L* = 45.6, a* = Ð9.8, b* = 26.7. The characteristics of the juice analysed were colour with values L* = 7.5, a* = 1.3, b* = 12.8, TTA = 5.8%, pH = 2.4, TSS = 8.5 and viscosity = 5.1 cP. Product analysis of the agglomerate showed a good range of particle size distribution, the colour of the agglomerate was L* = 91.8, a* = Ð7.1, b* = 20.1, bulk density = 0.6 g/mL and moisture content = 3.2%. Product characteristics of the calamansi drink analysed were L* = 87.3, a* = Ð3.3, b* = 18.5 for colour, TTA = 0.6%, pH = 3.1, TSS = 12.8

*Food Technology Centre, MARDI Headquarters, P.0. Box 12301, 50774 Kuala Lumpur, Malaysia Author’s full name: Lee Siew Yoong @Malaysian Agricultural Research and Development Institute 2001

183 Physico-chemical characteristics of calamansi juice, agglomerate and drink and viscosity 2.7 cP. The calamansi drink was compared to the diluted calamansi juice which had colour values of L* = 23.1, a* = Ð1.1, b* = 20.9, TTA = 1.5%, pH = 2.9, TSS = 11.4 and viscosity = 3.5 cP. The calamansi drink had higher scores than the diluted calamansi fruit juice when organoleptically evaluated.

Introduction The key to any soft drink success today Beverage products cover alcoholic is refreshment and taste (Thorpe 1995). beverages, hot beverages, soft drinks and Besides fresh fruit beverages, there is an juices. Consumption of these beverage untapped market for ready-to-drink fruit products is always on an increasing trend beverages. The ready-to-drink fruit due to continuous emergence of innovative beverages available in the market are mostly products in the market. The beverage processed from temperate fruits. These innovation attributes in the 1990s are ready-to-drink fruit beverages can be convenience, multipleasure, healthy and processed using the fluidized bed functional (Sinki and Buco 1994). In agglomerator or spray dryer by Europe, the per capita consumption of non- agglomeration (Lee 1999). Agglomeration is alcoholic beverages has increased from 122 a process whereby several particles are litres to 190 litres, a 35% increase, over the caused to adhere to each other in random past ten years (Bussien 1998). fashion, resulting in a porous, open structure The production of fruit juices and fruit aggregate of greater size than the original beverages is established and there is always individual particle (Pintauro 1972). It is market for it. Fruit beverages offer a whole primarily a mixing-drying process in which range of exciting tastes and flavours, it is both the powder and liquid ingredients are not surprising that consumers never fail to sprayed into a mixing chamber. The resist them. The general perception of objective of the process is to obtain a consumers towards these fruit beverages is homogeneous mixture with liquid evenly the benefits to health. Variety is the distributed throughout the powder (Anon. predominant factor in which the fruit 1981). There is very little information on the beverage market thrives. Exotic fruit ready-to-drink fruit beverages using the flavours such as guava, papaya, kiwi and fluidized bed agglomeration process mango, once foreign to beverage ingredient especially on tropical fruits. This study was labels, are now becoming popular in fruit undertaken to study the use of calamansi beverages. They impart a more sophisticated juice to produce agglomerate as a ready-to- image to fruit beverages. Besides showing a drink fruit beverage. growing preference for fruit drinks over fruit juices, consumers also tend to purchase Materials and methods those fruit beverage types that are Fruit and juice convenient and easy to consume. As life Calamansi (Citrus microcarpa) was becomes more and more hectic, the time and purchased from a local market and stored at effort required to make fresh fruit juice 30 °C for 24 hours before processing. The becomes less practical. Hence, newer, more fruits were manually washed and crushed in convenient forms like chilled, ready-to-serve the hydraulic press (Associated Instrument and shelf stable products have grown in Manufacturer Sdn. Bhd., Kuala Lumpur, popularity. Typically, consumers cannot Malaysia). The extracted single strength differentiate between fruit juices and juice was strained using a muslin cloth to flavoured drinks, especially when a fruit remove any trace of fibre. flavoured drink can easily be mistaken as a fruit juice (Sfiligoj 1996).

184 S. Y. Lee

Carrier used was 6 g/min. The total drying and Granulated sugar was purchased from a agglomeration duration was 2 hours 10 local market. The sugar was ground using minutes. The amount of juice sprayed during the disk mill (Model FFC-15, ROC) and the process was 452 g. sieved through ASTM mesh no. 20, 30, 40 and 60 on a Rotap device (Endecott Test Instrumentation Sieve Shaker, England) for 5 min to ensure Inlet temperature of the fluidizing air, consistent particle size. One kilogramme of product temperature in the drying chamber this ground sieved sugar was used as a and exhaust temperature were displayed by carrier in the fluidized bed dryer and LEDs on the control panel. The product and agglomerator. filter differential pressures, airflow rate, and atomization pressure were displayed on the Minor additives control panel. These variables were recorded The minor additives used in this study were and printed on paper at 60 second intervals. calamansi flavour, anhydrous citric acid and permitted food colour. From preliminary Fluidized bed drying and agglomeration trials it was found that 1% of calamansi process flavour (Bayer Malaysia Sdn. Bhd.) based The process variables of the fluidized bed on 1 kg of sugar, a solution weight of 1 g dryer and agglomerator were set before taken from 1% stock solution of tartrazine loading. Preheating of the drying chamber (Boustead Engineering Sdn. Bhd.) and 0.1 g was carried out for 15 minutes on empty taken from 1% stock solution of brilliant load until equilibrium had been attained. blue (Boustead Engineering Sdn. Bhd.) were One kg of ground sugar was used as the adequate for the product. The minor carrier and loaded into the retaining bowl. additives were added to 40 g of fresh After loading, the heating was continued for calamansi juice to be sprayed at the 15 minutes to ensure the ground sugar was beginning of the fluidized bed drying and thoroughly heated or until equilibrium had agglomeration process. been attained. The shaking device was activated at 10 second interval for a duration Process variables of 5 seconds to prevent product from The fluidized bed dryer (Glatt model sticking to the filters. GPCG1, Germany) has a vertical column as When the operating conditions were at the drying chamber at the bottom of which equilibrium, spraying of the juice (to which is the retaining bowl. The capacity of the minor additives were added) commenced at equipment is 1Ð1.5 kg bed load. The process the beginning of the agglomeration process variables were determined after several to ensure uniform blending of the trials. They were found to produce ingredients. This was immediately followed reproducible results. The spraying process by spraying of fresh juice. The spraying of was carried out by an atomized top spray fresh juice continued until the product was consisting of a pneumatic nozzle of 1.0 mm well agglomerated or until the product diameter fixed at the upper position. The appeared to be heavy and not able to be bed load used was 1 kg of ground sugar as a fluidized by the air velocity. At this point carrier. The inlet temperature used was 75 spraying was terminated and drying °C and the process temperature was 45 °C continued for another 30 minutes. At the end in the drying chamber. The fluidizing of the run, the product was discharged from airflow rate used was 20 m3/h which the product container and was cooled for 2 h resulted in an air velocity of 1.5 m/s. The at room temperature before product analysis atomization pressure at the spray nozzle was were carried out (Figure 1). 3 bar. The flow rate of the peristaltic pump

185 Physico-chemical characteristics of calamansi juice, agglomerate and drink

Single strength calamansi juice Product analysis

M The calamansi agglomerate was sieved Drying and agglomeration through ASTM mesh no. 20, 30, 40, 60 on a

M Rotap device to determine the particle size Agglomerated calamansi powder distribution. The colour of the agglomerated M Cooling calamansi powder was determined for L*, a*, b* values. Triplicate readings of the M Product analysis moisture content (wet basis) of the agglomerate were determined by using the M Packaging AOAC official method (1990). Triplicate

M readings of bulk density of the agglomerate Storage were determined (Kim and Toledo 1987). This was measured as the weight of the Figure 1. Drying and agglomeration of agglomerate per unit volume of the calamansi juice graduated cylinder which contained the agglomerate. Physico-chemical properties of calamansi fruit and its juice Calamansi drink Twenty fruits were randomly selected and Calamansi drink was obtained by dissolving colour readings of the fruit skin were 20 g of the agglomerate in 200 mL of water. determined using a Minolta Chroma CR-200 L*, a*, b* values, TTA, pH, TSS and (Japan) for L*, a*, b* values. Triplicate viscosity in triplicate readings were readings of the moisture content (wet basis) determined from the calamansi drink. of the macerated calamansi fruit was Organoleptic acceptability of the determined according to Pearsons Chemical calamansi drink compared to the diluted Analysis of Food (Egan et al. 1987). The calamansi juice was carried out. Twenty juice recovery was determined from experienced panelists were asked to rate the triplicate samples obtained at different flavour, sweetness, sourness, colour and batches of processing by subtracting the overall acceptability using a 9-point hedonic weight of extracted juice from the weight of scale where 1 = dislike extremely and 9 = the fruit. like extremely. The juice pH was determined using the WTW pH meter (Werkstatten, Germany). Sampling Total soluble solid (TSS) of the juice was Twelve batches of calamansi processing determined using the refractometer (Atago (from raw fruits until product and drink NI, range 0Ð32%, Japan). The juice analyses) were carried out over a period of viscosity was determined using the 12 months. Out of these 12 batches, 3 viscotester (Haake Ð Type VTO1, Germany) batches were randomly selected for the using spindle no. 4 at room temperature. purpose of this paper. The results presented Total titrable acidity (TTA) of the juice was in this paper are the average values of 3 determined by titrating a known weight of batches. juice to pH 8.1 with 0.1N NaOH and the results expressed as a percentage of citric Results and discussion acid (AOAC 1990). Triplicate readings of A carrier or nucleus used in the fluidized the juice colour were determined for L*, a*, bed agglomerator is a substance which b* values. causes the particles to adhere to each other with the help of a wetting agent. In this study, the wetting agent used was the single strength calamansi juice. Usually, the carrier

186 S. Y. Lee forms a major portion of the product. From under the category of milk powder which preliminary trials using different types of has moisture content of 2Ð4% (Peleg and carrier e.g. malto dextrin, lactose, starches; Bagley 1983). sugar was found to be the most suitable Juice recovery was moderately low at carrier for this product. 35.8% and the moisture content of the fruit Minor additives are considered was 83.8%. The skin colour of L* = 45.6, a* essential elements in beverage products. = Ð9.8, b* = 26.7 indicated that the They make up of less than 2Ð3% of the calamansi fruit was yellowish green. The weight of any beverages. They are the most characteristics of calamansi juice (Table 2) important components because they add showed that the colour was light orange, definition and character through flavour and high TTA, low pH, moderately low TSS, a acid-sugar balance (Giese 1995). Taking into non-viscous fluid. These properties are consideration that natural fruit flavour and generally acceptable in citrus fruits. From colour are unstable especially after preliminary trials, diluting fresh calamansi processing, these minor additives were juice with 50% w/w water and 10% w/w added to boost up the flavour, acid-sugar sugar produced the most acceptable diluted balance and eye appeal of the product. juice. The colour of the diluted juice was Particle size distribution of light greenish yellow, the TTA was relatively agglomerated calamansi powder (Table 1) low, the pH was low, a moderately high showed that there was a big percentage of value of TSS and a non-viscous fluid. The the particles on mesh no. 60 due to the reconstitution of calamansi agglomerate in effect of agglomeration. About 23% of the either cold or warm water is known as particles were finer than 250 mm and the dissolution. From preliminary sensory rest of the relatively bigger particles were evaluation trials, a dissolution rate of 20 g found in smaller percentages. Particle size of agglomerate in 200 mL of water produced distribution of such nature is desirable for acceptable flavour, sweetness, sourness and rapid dispersion or solubility. colour of the calamansi drink. The colour The colour of the agglomerated calamansi powder was L* = 91.8, a* = Ð7.1, b* = 20.1 indicating that it was pale Table 1. Particle size distribution* of agglomerated calamansi powder greenish yellow which is the perceived colour of the calamansi skin. The bulk Mesh no. Size (mm) % Retained density of the calamansi powder was 20 840 3.49 0.6 g/mL which falls under the category of 30 590 1.18 food powders which have densities in the 40 420 4.05 range of 0.3Ð0.8 g/mL (Peleg and Bagley 60 250 68.88 1983). The moisture content of the Pan Ð 22.40 calamansi powder was 3.2% which falls *Average of three batches

Table 2. Mean values* of colour, TTA, pH, TSS and viscosity of calamansi juice, diluted calamansi juice and calamansi drink

Characteristics Juice Diluted juice Drink Colour (L*, a*, b*) 7.5, 1.3, 12.8 23.1, Ð1.1, 20.9 87.3,Ð3.3, 18.5 Total titratable acidity (%) 5.8 1.5 0.6 pH 2.4 2.9 3.1 Total soluble solids 8.5 11.4 12.8 Viscosity at 30 °C (cP) 5.1 3.5 2.7 *Average of three batches

187 Physico-chemical characteristics of calamansi juice, agglomerate and drink

Table 3. Average scores for colour, flavour, sweetness, sourness and overall acceptability of calamansi drink and diluted calamansi juice

Colour Flavour Sweetness Sourness Overall acceptability Drink 6.4a 6.3a 6.2a 6.3a 6.3a Diluted juice 5.8a 4.8b 4.5b 4.4b 4.4b Mean values with different letters in each column are significantly different (p <0.05) based on t-test Using a 9-point hedonic scale where 1 = dislike extremely and 9 = like extremely was light greenish yellow, the TTA was low, technical assistance in this study. This work the pH was low and the TSS was 12.8 was supported by IRPA grant 01-03-03- which are desirable characteristics of a fruit 0351. beverage. Results of organoleptic evaluation References (Table 3) showed that there was no AOAC (1990). Official methods of analysis of the significant difference in the colour of the association of official analytical chemists, th drink and the diluted juice. However, the 15 ed. Arlington, VA: Association of Official Analytical Chemists flavour, sweetness, sourness and overall Anon. (1981). Spray mix revolution. J. of Food acceptability differed significantly with Manufacture 52(5): 37 higher scores given to the drink. This could Bussien, H. (1998). Beverage trends. The world of be due to the reason that the diluted juice ingredients Journal 4: 10Ð13 prepared from fresh fruits had a slight bitter Egan, H., Kirk, R. S. and Sawyer, R. (1987). after-taste which was not found in the drink. Pearsons chemical analysis of food 8th ed. Essex, England: Longman Scientific and Technical Conclusion Giese, J. (1995). Developments in beverage Calamansi agglomerate produced by additives. Journal of Food Technology 9: fluidized bed agglomeration process using 64Ð72 ground sugar as a carrier produced an Kim, M. H. and Toledo, R. T. (1987). Effect of acceptable ready-to-drink fruit beverage. osmotic dehydration and high temperature fluidized bed drying on properties of The calamansi juice played a major role as a dehydrated rabbiteye blueberries. J. of Food wetting agent for successful agglomeration Science 52 (4): 980Ð4, 989 which produced a range of suitable particle Lee, S. Y. (1999). Fluidizing drying of pineapple size distribution for rapid solubility. juice for the development of agglomerated Optimum process variables were used pineapple powder. Proc. of the National during fluidized drying and agglomeration Horticulture Conference ‘99 Kuala Lumpur, 16Ð17 Nov. 1999, p. 711Ð8. Serdang: MARDI since fresh juice was used. The preceived Pintauro, N. (1972). Agglomeration processes in flavours of the calamansi drink depended food manufacture. Food Processing Review upon several chemical attributes of the No. 25. New Jersey, USA: Noyes Data product, namely TTA, pH and TSS which Corporation were contributed by the calamansi juice as Peleg, M. and Bagley, E. B. (1983). Physical well as the minor additives. characteristics of food powders. In Physical Properties of Foods. Westport, Connecticut: AVI Publishing Co. Inc. Acknowledgement Sfiligoj, E. (1996). Steady as she grows. J. The author is grateful to Ms Hamidah Adam Beverage World 5: 68Ð70 and Mr Samsul Bahri Hussin for their Sinki, G. and Buco, T. (1994). Why consumers want. J. Beverage World 2: 42Ð50 Thorpe, S. (1995). Fruit as a core value. J. Accepted for publication on 22 September 2000 Beverage World 3: 108Ð10

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