Effect of Edible Coating on Quality Parameters of Jaggery During Storage. Khan Chand, A. K. Verma, Anil Kumar & N. C. Shahi

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1 Effect of Edible Coating on Quality Parameters of Jaggery During Storage Khan Chand, A. K. Verma, Anil Kumar & N. C. Shahi An International Journal of Sugar Crops and Related Industries ISSN DOI /s

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3 DOI /s RESEARCH ARTICLE Effect of Edible Coating on Quality Parameters of Jaggery During Storage Khan Chand A. K. Verma Anil Kumar N. C. Shahi Received: 17 April 2013 / Accepted: 4 July 2013 Ó Society for Sugar Research & Promotion 2013 Abstract The study was conducted to see the effect of edible coating of whey protein concentrate (WPC) on quality characteristics of jaggery stored in drying cum storage bin for 4 months. Edible coating solution (4 and 8 % (w/v) WPC) was prepared in distilled water with 5 ml glycerol as plasticizer. Moisture content, ash content, ph, reducing sugar, sensory characteristics were taken as parameters to observer the jaggery quality. The colour of coated jaggery was retained during storage however the acidity of jaggery increased slightly under storage. The moisture content was found decreasing in 8 % WPC during the storage. Sensory attributes of jaggery with a thick coating i.e., 8 % WPC was found the best. Total effects of edible coating during storage was good in comparison to uncoated jaggery. Keywords Jaggery Whey protein concentrates (WPC) Glycerol Reducing sugar ph and moisture content K. Chand (&) N. C. Shahi Department of Post Harvest Process & Food Engineering, College of Technology, Pantnagar, India kcphpfe@gmail.com A. K. Verma Department of Biochemistry, College of Basic Sciences and Humanities, G. B. Pant University of Agriculture & Technology, U.S. Nagar, Pantnagar , Uttarakhand, India A. Kumar Department of Food Science and Technology, College of Agriculture, Pantnagar, India Introduction Jaggery (gur) industry is one of the old and large agroprocessing cottage industries in India. In India, production of gur starts from October and continues up to May, depending on the location. Jaggery production in India is about 7 10 million tons/annum, while its per capita consumption is about 5 kg. As the total gur produced is not consumed immediately after production, it is stored for a period of months. However the major limitation associated with gur storage is the change of colour due to non-enzymatically oxidation of polyphenols and other minerals. Beside, these impurities, invert sugars and mineral salts being hygroscopic in nature, absorbs moisture particularly during monsoon season when ambient humidity is high, leading to spoilage. High moisture content also invites microbial contamination (Singh et al. 2009; Verma et al. 2012). It has been estimated that more than 10 % of gur produced in the country worth Rs. 40 crore is lost every year due to these problems. Browning of jaggery is a major problem for the jaggery industry. The normal approach to inhibit both enzymatic and non-enzymatic oxidative browning in foods has been the application of sulfites. An extensive use of sulfite for clarification of jaggery is affected to change the colour of jaggery during storage (Pérez-Gago and Krochta 2002). Another approach is the use of anti-browning agents based on citric acid or ascorbic acid. Although ascorbic acid can reduce enzymatic browning, it can increase nonenzymatic browning due to its own oxidation into dehydro-ascorbic acid (DHAA) which then reacts with amino acids to yield brown colors by the Mallard reaction or other non-enzymatic processes. For the most part, the development of edible films and coatings has focused upon creating barriers containing

4 proteins, polysaccharides and lipids for prevention of spoilage of food which increased shelf life of fruits (Guilbert et al. 1996; Pérez-Gago and Krochta 2002). The formation of edible films and the coating from whey proteins can increase the utilization of whey, improve the nutritional values of foods and prolong shelf life (Ozdemir and Floros 2008). Edible films and coatings may extend the shelf life of jaggery produce by providing a semi-permeable barrier to gases and water vapor. This barrier would reduce respiration, enzymatic browning and the loss of water from the product. However this technology is not developed for protection of jaggery from spoilage. Hence it is essentially required a techniques for improvement of jaggery quality during storage. Application of edible films on the food products could also be used as a protective coating to extend the shelf life. An edible film coating can simply be defined as a thin continuous layer of edible material formed on or placed between food and food components (Guilbert et al. 1996). Edible film/coating has been successfully used in various food applications e.g. in maintaining purity of fruits, providing functionality (e.g. glaze to chocolate), controlling adhesion, cohesion, barrier properties, extending shelf life and providing mechanical integrity, etc. to the product. Whey protein concentrate (WPC) based films and coatings are generally made from water based materials and are flavourless, tasteless and flexible. Hence this study was conducted for improvement of jaggery storage quality by applying edible coating (WPC) to the jaggery which may prevent the undesirable changes and increase the shelf life of jaggery and its products. Fig. 1 Jaggery samples kept for drying (3 h) before storage study denaturated at 90 C in water bath for 30 min to provide functionality to edible film. The denaturated WPC was cooled down to room temperature in water. Five percent glycerol was added as a plasticizer and mixed thoroughly. The prepared content was reheated at 50 C for 10 min and then cooled to room temperature. The content was mixed in a mixer for 2 min. Application of Edible Coating on Jaggery Jaggery samples were placed on a table in the cleaned tray and edible coating solution was applied evenly using a brush. The samples were left for drying at ambient conditions for 3 h in the jaggery laboratory (Fig. 1). The edible coated jaggery samples were stored in drying cum storage bin for 4 months. Materials and Methods Fresh concentrate jaggery was prepared as described by Javalekar et al. (1985) from the sugarcane variety HD2824, in the jaggery laboratory, Department of Post Harvest Process and Food Engineering, Pantnagar and it was poured into the iron frame of size (1 inch 3 ) to get desired jaggery blocks, hold it min for cooling, after then cubes were taken out from the frame for edible coating. The storage conditions used in the study were selected keeping in mind their availability in the rural and semiurban areas as well as their low cost so as to fit the farmers pocket. Drying cum Storage Bin Modified drying cum storage bin was used to store edible coated jaggery cubes. The bin is made of galvanized iron (GI) sheet. It has four compartments each equipped with a Preparation of Edible Coating Material Whey protein concentrate (WPC) 4 and 8 % was prepared in distilled water and mixed thoroughly to form uniform solution (Motalebi et al. 2010). The solution was Fig. 2 Storage of coated and uncoated jaggery samples in bin

5 lid at the top centre. Each compartment is provided with two holes at the bottom side for aeration (Chand et al. 2011). A perforated sheet or wire mesh is placed at the bottom of the each compartment over a cross wooden frame and edible coated jaggery cubes were stored above the mesh in storage bin (Fig 2). Quality Parameter Analysis Moisture content Jaggery (5 g) with few drops of absolute alcohol was dried to constant weight at 70 C in a hot-air oven (Mandal et al. 2006). ph ph of jaggery was determined by using a digital ph meter. Ten grams of sample was blended with 10 ml of distilled water and the ph of the suspension was determined by dipping the electrode in the suspension Reducing sugar Using colorimeter, the reducing sugar of jaggery in terms of glucose per cent was determined by plotting the optical density of 100 ppm jaggery solution against the standard glucose curve. The standard curve for glucose was obtained by plotting the optical densities of pure glucose solution of known concentrations. Colour development was done with Anthrone s reagent, which reacts with invert sugars to yield hydroxymethyl furfural imparting a green colour. Before addition of Anthrone s reagent, jaggery solution was decolorized using phosphate free activated charcoal and filtered through Whatman No. 1 filter paper (Mandal et al. 2006). Total ash content Five grams of sample taken in silica crucible was ignited on a heater until fumes ceased. The silica crucible was later shifted to a muffle furnace and temperature of furnace was raised to 550 ± 15 C until clean ash was obtained. The weight of residue was noted and ash content was measured using following expression: % Ash content ¼ Weightofresidue Weight of Sample 100 Colour Using colorimeter, the percentage transmittance of N/2 solution of jaggery was recorded at 540 nm (Mandal et al. 2006). Table 1 Variation in moisture content of edible coated jaggery sample during storage May, June, July, August, Sensory evaluation The sensory evaluation was done on 9 point Hedonic scale as per IS standard (Anonymous 1971).The sensory evaluation was done for liking of jaggery samples on the basis of colour, taste, flavor, texture, aroma and overall acceptability score (OAA) was calculated. A panel of 10 sensory panelists drawn from amongst the student and staff of Post Harvest Engineering Department were selected to evaluate the samples. The score was averaged to determine the OAA. Results and Discussion The freshly prepared jaggery was analyzed for its quality characteristics at monthly intervals from May to August. The initial moisture content of jaggery was % (db) which was much higher than the requirement of 5 7 % as per Bureau of Indian Standards (Anonymous 1990). Soft jaggery is preferred over the semisolid in Uttarakhand and Uttar Pradesh which aggravates the problem of deterioration in storage as large amount of moisture effects the keeping quality of jaggery. Usually low initial moisture content and high solids in jaggery do not help in the growth and multiplication of microorganism. Moisture Content The changes in moisture content of 8 % WPC coated jaggery samples was % (Table 1). It was observed that the moisture content followed same trend in 4 % WPC and in control. This may be due to forming a thick protein-based film at 8 % WPC which lowers oxygen Table 2 Variation in ph of jaggery sample during storage May, June, July, August,

6 Table 3 Variation in ash content (in%) of jaggery sample during storage May, June, July, August, Table 4 Variation in reducing sugar content (in lg/ml) of jaggery sample during storage May, 2012 Discarded Discarded Discarded June, ,463 1,223 1,296 July, ,710 1,068 1,368 August, , ,230 2, permeability and reduces the moisture content (Hong and Krochta 2003). The rate of moisture loss was found maximum in case of uncoated sample but 8 %WPC has minimum moisture content. This showed that coating of jaggery samples could helped in retaining desirable moisture up to some extent while ambient conditions lead to excessive moisture loss from jaggery rendering jaggery samples to almost a dry and granular structure. The statistical result for moisture content of edible coating was found significant at 5 % level of significance with F cal (8.0325) [ F tab (5.14). ph Content The changes in ph content of jaggery samples followed a decreasing trend (Table 2). It may be due to the fact that a fall in ph is directly proportional to absorption of moisture and vice versa. The ranges of ph during storage were found to be The statistical result for ph of edible coating was found non-significant at 5 % level of significance with F cal (4.809) \ F tab (5.14). Table 5 Variation in colour score of jaggery sample during storage May, June, July, August, Table 6 Variation in taste score of jaggery sample during storage May, June, July, August, comparatively less ash content and increasing the shelf life of jaggery samples. The statistical result for Ash content of edible coating was found significant at 5 % level of significance with F cal (7.581) [ F tab (5.14). Reducing Sugar The changes in reducing sugar content of jaggery samples are shown (Table 4). It was observed that reducing sugar increased as the storage period increased, but there was least increasing in coated samples with 8 % WPC and maximum increment in uncoated samples. The increase in reducing sugar content in jaggery may be due to inversion of sucrose into glucose and fructose. The statistical result for reducing sugar of edible coating was found significant at 5 % level of significance with F cal (63.12) [ F tab (5.14). Sensory Characteristics Colour The sensory analysis of coated and uncoated jaggery samples were carried out in the jaggery Laboratory of Department of Post Harvest Process and Food Engineering Ash Content The ash content of coated and uncoated jaggery samples changes during storage is shown (Table 3). The ash content was in the range of % in 4 %WPC to % in uncoated sample. This might be due to relatively more increase in mineral salts in uncoated sample than other samples. This could be the reason that edible coating may helped in prevention of more ash formation thereby having Table 7 Variation of texture score with time during storage May, June, July, August,

7 Fig. 3 Variation in colour of coated and uncoated jaggery cubes during the storage Table 8 Variation in overall acceptability score of jaggery sample during storage May, June, July, August, in every month on the basis of score value. The variation in the colour of jaggery samples was obtained during storage period (Table 5). The colour score of jaggery samples ranged from 8.5 to This may be due to darkening of jaggery samples during storage. However, 8 %WPC of samples could help in retaining colour to some extent (Plate 1). The statistical result for colour of edible coating was found significant at 5 % level of significance with F cal (7.077) [ F tab (5.14). Taste The taste score of jaggery samples ranged from 8.05 to 7.1(Table 6). Coated jaggery samples in whole storage period slightly affected taste because in the months of May and August, uncoated samples had a better taste score as compared to coated samples but the score in July and August reduced during storage. However, the taste was maintained in coated samples. It is concluded that 4 % WPC samples were the best for taste as compare to others. But the statistical result for taste score of edible coating was found non-significant at 5 % level with F cal (0.4039) \ F tab (5.14).

8 Texture The texture score of jaggery samples ranged from 7.01 to 4.8 (Table 7). The low score of texture may be due to the hard surface of the sample. In every month the hardness of coated and uncoated sample increased during storage (Fig. 3) but, the best texture scores were observed in the samples with 8 % WPC. The statistical result for texture of edible coating was found significant at 5 % level with F cal (7.159) [ F tab (5.14). Overall Acceptability In this study, the sensory analysis was carried out an expert penal and it was observed that both 4 and 8 % WPC jaggery samples have less affect on overall acceptability and have high sensory score as compared to control sample (Table 8). Control sample had a greater appeal initially but they showed high degradation in quality during storage in the month of August. The properties of coated and control samples were comparable at the beginning but the coated samples were able to retain their quality during 4 months storage period (Fig. 3). But the statistical result for overall acceptability reducing sugar of edible coating was found non-significant at 5 % level with F cal (1.556) \ F tab (5.14). Conclusion Jaggery storage is always a big problem during the summer and rainy seasons. The edible coating may improve the self life of jaggery and retained up to 4 months of storage. From the sensory attribute a thick coating of 8 % WPC was found best with other quality parameters. Hence, edible coating of whey protein concentrate may be helpful to maintain the quality and enhance the shelf life of jaggery. References Anonymous, Ingredients for sweet success. Food Technology 43: Anonymous. (1971). Bureau of Indian Standard IS: 6271, New Delhi. Chand, K., N.C. Shahi, U.C. Lohani, and S.K. Garg Effect of storage conditions on keeping qualities of jaggery. 13(1): Guilbert, S., N. Gontard, and L.G.M. Gorris Prolongation of the self-life perisiable food products using biodegradable films and coatings. Lebensmittel-Wissenschaft Technology 29: Hong, S.I., and J.M. Krochta Oxygen barrier properties of whey proteins isolate coating on polypropylene film. Journal of Food Science 68: Javalekar D.R., B.N. Shinde, and S.J. Randive Use of different clarificants in jaggery making I. effect on physical properties. Indian Sugar 35: Mandal, D., S. Tudu, S.R. Mitra, and G.C. De Effect of common packaging materials on keeping quality of sugarcane jaggery during monsoon season. 8(2&3): Motalebi, A.A., A. Hasanzati Rostami, A.A. Khanipour, and M. Soltani Impact of whey protein edible coating on chemical and microbial factors of gutted kilka during frozen storage. Iranian Journal of Fisheries Sciences 9(2): Ozdemir M., and J.D. Floros Optimization of edible whey protein films containing preservatives for mechanical and optical properties. Journal of Food Engineering 84: 116. Pérez-Gago, M.B., J.M. Krochta, and A. Gennadios In proteinbased films and coatings, Boca Raton: CRC Press. Singh, S., A. Dubey, L. Tiwari, and A.K. Verma Microbial profile of stored jaggery: a traditional Indian sweetener. 11: Verma, A.K., Singh Shubhra, Singh Shalini, and Ashutosh Dubey RDNA sequence based characterization of bacteria in stored Jaggery in Indian Jaggery Manufacturing Units. 14(4):