Quality Evaluation of Jaggery Chocolate Under Various Storage Conditions

Transcription

1 Sugar Tech (Apr-June 2011) 13(2): DOI /s x RESEARCH ARTICLE Quality Evaluation of Jaggery Chocolate Under Various Storage Conditions Khan Chand Anupama Singh A. K. Verma U. C. Lohani Received: 26 April 2011 / Accepted: 24 July 2011 / Published online: 4 August 2011 Ó Society for Sugar Research & Promotion 2011 Abstract Characteristics of developed jaggery chocolate under different storage conditions were investigated. Jaggery chocolates were prepared by standard method and packaged in different packaging materials subsequently subjecting the samples to different storage conditions, viz., incubator (40 45 C), refrigerator (8 10 C) and ambient conditions (25 35 C). Moisture content, hardness, optical density and sensory properties of the stored jaggery chocolates were determined at an interval of 15 days during the 60 days storage period. During different storage conditions, moisture content, optical density and hardness of chocolates varied from 6.09 to 8.42%, 0.12 to and 4.29 kgf to kgf respectively. Results showed an initial increase in moisture content followed by decrease with increasing storage period. However, optical density, hardness and appearance increased gradually with the increase in storage period in all storage conditions. Quality of prepared chocolates was evaluated for its sensory characteristics on 1 10 scale. The colour, taste, texture, flavour and overall acceptability were found to be in range of Keywords Jaggery Jaggery chocolate Moisture Colour Hardness Taste Texture and flavor K. Chand (&) A. Singh A. K. Verma U. C. Lohani Department of Post Harvest Process and Food Engineering, College of Technology, G.B. Pant University of Agriculture and Technology, Pantnagar, U.S. Nagar, Uttarakhand, India kcphpfe@gmail.com Introduction In India sugar consumption is about 23.3 million tones per year (Anonymous 2011). Major companies like Mavana sugar and Dhampur Sugar Mill Pvt. Ltd. etc. are producing and exporting huge amounts of the packaged sugar cubes. These companies have also focused their attention on jaggery and related items because of the growing interest in this sector (Pandey 2007). Jaggery has many other benefits over sugar as it contains many vital vitamins (provitamin, vitamin A, vitamin B 1, vitamin B 2, vitamin B 5, vitamin B 6, vitamin C, vitamin D 2, vitamin E, vitamin PP) and minerals, such as calcium, phosphorus, magnesium and potassium. In fact, jaggery has a mineral content approximately 50 times greater than refined sugar and five times more than brown sugar. It is a wholesome sugar and without doubt is rich in the vitally important mineral salts (28 g per kg compared to 0.3 g per kg in refined sugar) (Gopalan et al. 1991). Chocolates are usually thought of as a source of pleasure with very high calorific value but lacks in carbohydrate and protein composition. It has very less nutritive value as refined sugar is being added as a component and is mainly responsible for various ailments like bad teeth, dental caries, diabetes etc. Thus chocolate needs to be modified and made healthier for consumption by addition of jaggery in place of refined sugar. There are various chocolate based products available in the market which may give a tough competition for jaggery based chocolate. Therefore; to survive and to remain in industry, process needs to be manipulated so that percentage of components added may vary to attain the desired qualities and other textural and sensory properties (Kedari 2005). Texture of the sugar based products is sensed by feeling of touch, usually in the mouth. Therefore, the present investigation was conducted with the following specific objective.

2 Sugar Tech (Apr-June 2011) 13(2): (1) To study the effect of various storage conditions on the quality of jaggery chocolate (2) To study the effect of packaging material in textural properties and sensory characteristics of jaggery chocolate Fresh jaggery Heating upto110 o C Materials and Methods Raw Materials Liquid jaggery was obtained from Department of Post Harvest Process and Food Engineering, Pantnagar. All other ingredients, viz., cocoa powder (Cadbury), skimmed milk powder (Amulya), coffee powder (Nestle) etc. for preparation of jaggery chocolate were procured from the local market of Pantnagar. Chocolate Preparation and Storage The jaggery chocolate was prepared by the method as described by Kedari (2005). The fresh liquid jaggery (400 g) was heated in an iron pan at 110 C for 10 min. All the ingredients were added to it and mixed with the help of a glass rod. The contents were mixed for 2 3 min on a stirrer at 80 rpm. The chocolate mould was prepared by applying a thin layer of melted butter on its surface so that the chocolate did not stuck to the mould and could be easily removed. The chocolate mix was poured in the mould and allowed to cool until it got set. The chocolates were kept for 24 h for setting at an ambient temperature. The chocolates were removed from the mould and kept for conditioning for 24 h at specific temperature (22 C), followed by natural drying at ambient temperature for 24 h (Kadam 2007). The flow diagram for jaggery chocolate preparation is shown in Fig. 1. Prepared jaggery chocolates were packaged in aluminum foils and butter paper for storage. The chocolates were kept in an air tight plastic jar under different storage conditions i.e. in incubators at C, in refrigerator at 8 10 C and under ambient conditions. Same treatments were given to unwrapped and butter paper wrapped chocolates. All the samples were kept in air tight plastic jars to keep them safe from the surroundings. The effect of storage was studied up to 60 days, at interval of every 15 days. Moisture Content The moisture content of the chocolates was measured using the oven dry method Anonymous (1993). For moisture measurements, approx 3.0 g of chocolate samples were taken in petri dishes and kept for oven drying at 90 C for a period of 36 h. The moisture content of Jaggery was calculated as M c ¼ M 1 M M 0 where M c Moisture content of the sample, per cent (wb); M o Initial weight of the sample taken, g; M 1 Weight of the sample before oven drying? weight of dish with cover, g; M 2 Weight of the dish with cover containing dried and desiccated sample, g Optical Density Addition of ingredients Milk powder (150gm) Butter (75gm) Cocoa powder (75gm) Coffee powder (6gm) Mixing in stirrer machine for 2-3 min Moulding in dies Setting at 25 C for 24 h Conditioning at specific temperature 22 C for 24 h Packaging Fig. 1 Process flow diagram for preparation of jaggery chocolate A solution (13.6% w/v) of jaggery chocolate was prepared and filtered through Pall-42 filter paper No. 5 (write company name). The optical density of solution was measured at 540 nm using a spectrophotometer (write company name) by the method described elsewhere (Anonymous 1985).

3 152 Sugar Tech (Apr-June 2011) 13(2): Texture Analysis Textural properties such as hardness and fracturability of jaggery chocolate were analyzed using texture analyzer. The chocolates were taken from their respective storage conditions and kept in desiccators for about 2 h. Texture analysis was carried out as follows: Test mode: Compression, Option: Return to start, Pre test speed: 2 mm per second, Test speed: 10 mm per second, Distance: 3 mm, Trigger force: 10 g, Probe used: P/5 (5 mm), Cell: Heavy duty platform. To test the samples after securing the holed plate into the heavy platform, the position of heavy duty platform was adjusted so that the probe (P/5) was directly above the plate. Later on, calibration of force and probe was done as per the guidelines given in the software. The penetration tests were commenced after the calibrations. Sensory Evaluation Final product was evaluated for its sensory characteristics such as colour, texture, taste, flavour appearance, overall acceptability and quality attributes at regular intervals of 15 days on 9 point hedonic scale (Anonymous 1971). Results and Discussion Moisture Content Moisture content of jaggery chocolate was decreased in storage period from 15 to 60 days with all packaging materials and storage conditions (Table 1). Moisture content in jaggery chocolate increased initially as compared to the control (initial moisture content of fresh jaggery was 7.44%), and then decreased with increasing the duration of storage in all treatments. While a gradual fall in moisture content was observed in storage period days with all storage conditions. The maximum decreased of moisture content % was found in unwrapped jaggery chocolate with stored in incubator for period of zero to 60 days. While minimum decreased of moisture content % was observed in jaggery chocolate wrapped in aluminium foil and stored in refrigerator. Hence results showed that jaggery chocolate stored in incubator with unwrapped conditions had less moisture content compared to other conditions. Optical Density The optical density of the freshly prepared jaggery chocolate control was 0.12 (Table 2). The optical density of jaggery chocolate unwrapped stored in incubator was found static from zero to 60 days. However Jaggery chocolate stored in refrigerator, incubator and ambient temperature with packaging material aluminium foil and butter paper was increased in zero to 60 days. The maximum value of optical density (0.54) of jaggery chocolate was observed in unwrapped with ambient condition after 60 days. While minimum change in optical density was observed when jaggery chocolate was stored in incubator with wrapped in aluminium foil (0.22), stored in ambient condition with wrapped in aluminium foil (0.25) and stored in incubator Table 1 Moisture content (%) of jaggery chocolate at different storage conditions % Moisture content (days) Ambient Refrigerator Incubator Table 2 Optical density of jaggery chocolate at different storage conditions Optical density (days) Ambient Refrigerator Incubator

4 Sugar Tech (Apr-June 2011) 13(2): with unwrapped (0.24). However in other condition a remarkable increase in the optical density during storage. It is evident that browning in terms of optical density increased gradually with the progress of storage period in all cases but the results were less pronounced in the jaggery chocolate stored in the incubator. Effect of Storage Period on Hardness The hardness of the fresh jaggery chocolate control was 7.21 kgf. When jaggery chocolates were stored without any packaging material, the hardness was found to be increased from 0 to 60 days compared to control under all storage conditions, viz., ambient (7.43 kgf), refrigerator (7.69 kgf) and incubator (9.75 kgf). While, jaggery chocolate, wrapped in aluminum foil and stored in all conditions, was found to be gradually decreased (Table 3). Sensory Evaluation Colour The sensory score for colour of chocolate samples stored under different storage conditions showed on average colour score ranging from 6.87 to 7.37 for the chocolates stored in incubator during the entire period of storage (Table 4). For chocolates, stored in refrigerator, the score was in the range of Under ambient conditions, stored chocolates scored in range of As the storage period increased, the colour was observed to be dark. The chocolates kept in incubator, showed a decrease in the colour intensity whereas those stored in the refrigerator, showed a fairly significant increase in the colour during the storage period. Appearance The average appearance score for jaggery chocolates kept in incubator ranged from 6.62 to 7.5 during storage of 60 days (Table 5). While the chocolates stored in refrigerator, had scored ranging from 7.12 to In case of jaggery chocolates stored in ambient conditions the score was in the range The chocolates stored in the incubator had the least average score while those in the refrigerator had the maximum average score for appearance. Taste The average taste score ranged from to 7.25 for jaggery chocolates stored in incubator during the entire period of storage (Table 6). The jaggery chocolate stored in refrigerated conditions scored from 6.5 to Jaggery chocolate stored in ambient conditions, showed the score Texture The average texture score ranged from 6 to 7.2 for the chocolates stored in the incubator (Table 7). The score of Table 3 Hardness of jaggery chocolate at different storage conditions Hardness (kgf) Ambient Refrigerator Incubator Table 4 Colour of jaggery chocolate at different storage conditions Colour Ambient Refrigerator Incubator

5 154 Sugar Tech (Apr-June 2011) 13(2): Table 5 Appearance of jaggery chocolate at different storage conditions Appearance Ambient Refrigerator Incubator Table 6 Taste of jaggery chocolate at different storage conditions Taste Ambient Refrigerator Incubator Table 7 Texture of jaggery chocolate at different storage conditions Texture Ambient Refrigerator Incubator Table 8 Flavour of jaggery chocolate at different storage conditions Flavour Ambient Refrigerator Incubator chocolate sample stored in refrigerator ranged from 7 to 8 and those stored in ambient condition was 6.5 to 7.5. The texture was quite acceptable to the panel. Flavour The average flavour score of jaggery chocolate stored in incubator ranged from 6 to 7 (Table 8). For the chocolate samples stored in the refrigerator, score ranged from 7.12 to 7.75 and stored under ambient condition, the variation was observed to vary from 6.5 to Overall acceptability Jaggery chocolate stored in incubator had average overall acceptability score ranged from 6.5 to 7.25 (Table 9). Whereas for the chocolate samples, stored in the refrigerator the range was from 7.25 to 8.5 and for the chocolate

6 Sugar Tech (Apr-June 2011) 13(2): Table 9 Overall acceptability of jaggery chocolate at different storage conditions Overall acceptability Ambient Refrigerator Incubator samples kept in ambient condition the score range was from 6.75 to The chocolate stored at low temperatures was much more acceptable than one stored under ambient conditions Conclusion The storage studies on jaggery chocolate conducted in the Department of Post Harvest Process & Food Engineering revealed that jaggery chocolate could be stored for a period of 2 months without any major changes in its quality. Quality attributes can be maintained, if the chocolates, wrapped in aluminium foil are stored in refrigerator (8 10 C). Sensory attributes, like colour, appearance, taste, texture, flavour and overall acceptability scored good for the samples of chocolates wrapped in aluminum foil and stored in refrigerator. References Anonymous Guide for sensory evaluation of foods. IS 6273: Part-II, New Delhi. Anonymous Method for sampling and analysis of sugar confectionary. IS Directorate general of Health Sciences. Ministry of Health and family welfare. Government of India, New Delhi. Anonymous Determination of density and moisture content. IS 1734, part-i, New Delhi. Anonymous India s sugar consumption. Times of India. Accessed 10 July Gopalan, C., B.V. Rama Shastri, and S.C. Balasubramanian Nutritive value of Indian foods. Hyderabad: National Institute of Nutrition, ICMR. Kedari S. Ramesh Selection of level of ingredients in jaggery chocolate using response surface methodology. M.Tech. Thesis, GBPUA&T., Pantnagar. Kadam S. Appasaheb Process optimization of liquid jaggery based chocolate. M.Tech. Thesis, submitted to department of Post harvest process and Food Engineering, Pantnagar. Pandey, Adya Prasad Indian Sugar Industry a strong industrial base for rural India, BHU.