Sugar Tech (Apr-June 2011) 13(2):150–155 DOI 10.1007/s12355-011-0089-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 0.529 and 4.29 kgf to 11.58 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 6–8.5. 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, 263145 U.S. Nagar, Uttarakhand, India e-mail:
[email protected]
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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 B1, vitamin B2, vitamin B5, vitamin B6, vitamin C, vitamin D2, 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.
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To study the effect of various storage conditions on the quality of jaggery chocolate To study the effect of packaging material in textural properties and sensory characteristics of jaggery chocolate
Fresh jaggery
Heating upto110 oC
Materials and Methods Raw Materials
Addition of ingredients Milk powder (150gm) Butter (75gm) Cocoa powder (75gm) Coffee powder (6gm)
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.
Mixing in stirrer machine for 2-3 min
Moulding in dies
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 40–45°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
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
period of 36 h. The moisture content of Jaggery was calculated as Mc ¼
M1 M2 100 M0
where Mc Moisture content of the sample, per cent (wb); Mo Initial weight of the sample taken, g; M1 Weight of the sample before oven drying ? weight of dish with cover, g; M2 Weight of the dish with cover containing dried and desiccated sample, g Optical Density 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).
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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.
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 15–60 days with all storage conditions. The maximum decreased of moisture content 7.44–5.82% was found in unwrapped jaggery chocolate with stored in incubator for period of zero to 60 days. While minimum decreased of moisture content 97.44–7.32% 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
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
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) Storage conditions
Packaging material Aluminium foil
Butter paper
Unwrapped
15
30
45
60
15
30
45
60
15
30
45
60
Ambient
7.93
7.75
7.39
7.20
7.47
7.28
7.12
7.02
7.68
7.48
6.22
6.10
Refrigerator
8.42
8.08
7.49
7.32
8.13
7.82
7.34
7.12
8.26
7.71
7.23
7.20
Incubator
7.71
7.51
6.85
6.50
6.94
7.20
6.63
6.55
6.76
6.84
6.09
5.82
Table 2 Optical density of jaggery chocolate at different storage conditions Optical density (days) Storage conditions
Packaging material Aluminium foil
Butter paper
Unwrapped
15
30
45
60
15
30
45
60
15
30
45
60
Ambient
0.17
0.175
0.222
0.250
0.16
0.208
0.281
0.300
0.18
0.214
0.529
0.540
Refrigerator
0.15
0.231
0.408
0.410
0.15
0.313
0.368
0.380
0.21
0.395
0.507
0.520
Incubator
0.17
0.214
0.207
0.220
0.21
0.178
0.315
0.330
0.12
0.207
0.232
0.240
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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.
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.
Effect of Storage Period on Hardness
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 8.37. In case of jaggery chocolates stored in ambient conditions the score was in the range 6.75–7.25. The chocolates stored in the incubator had the least average score while those in the refrigerator had the maximum average score for appearance.
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).
Appearance
Taste 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 7.37–8.25. Under ambient conditions, stored chocolates scored in range of 7.12–8. As the storage period increased, the colour was observed to be dark. The
The average taste score ranged from 6.375 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 8.37. Jaggery chocolate stored in ambient conditions, showed the score 6.75–7.625. 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) Storage conditions
Packaging material Aluminium foil
Butter paper
15
30
45
60
15
30
Ambient
6.14
6.35
6.09
6.51
5.26
5.92
Refrigerator
6.33
3.65
5.85
2.60
4.95
5.38
Incubator
4.29
6.61
4.64
5.29
7.56
5.54
Unwrapped 45
60
15
8.35
9.85
6.35
5.89
3.75
6.93
10.06
7.66
9.34
30
45
60
6.67
7.89
7.43
5.05
4.34
7.69
11.58
7.09
9.75
45
60
Table 4 Colour of jaggery chocolate at different storage conditions Colour Storage conditions
Packaging material Aluminium foil 15
30
Butter paper 45
60
15
30
Unwrapped 45
60
15
30
Ambient
7.75
8.00
7.25
7.45
7.12
7.63
7.25
7.40
7.50
7.62
7.25
7.30
Refrigerator
7.50
8.25
8.12
8.55
7.62
7.75
7.37
7.40
7.37
8.00
7.87
7.25
Incubator
7.37
7.25
7.00
7.12
7.50
7.37
7.12
7.20
7.00
7.12
6.87
6.85
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Table 5 Appearance of jaggery chocolate at different storage conditions Appearance Storage conditions
Packaging material Aluminium foil
Butter paper
Unwrapped
15
30
45
60
15
30
45
60
15
30
45
60
Ambient
7.00
7.25
7.12
7.10
6.75
7.00
7.00
7.21
7.00
7.25
7.12
7.00
Refrigerator
7.25
7.75
8.37
8.28
7.62
7.75
7.50
7.37
7.12
7.25
7.50
7.25
Incubator
7.25
6.75
6.62
6.75
7.50
7.00
7.12
6.85
7.12
7.12
7.00
7.12
Table 6 Taste of jaggery chocolate at different storage conditions Taste Storage conditions
Packaging material Aluminium foil
Butter paper
Unwrapped
15
30
45
60
15
30
45
60
15
30
45
60
Ambient
7.00
7.62
6.87
6.87
7.12
7.00
7.25
7.25
6.75
7.25
7.12
7.00
Refrigerator
6.50
8.37
8.12
8.00
7.25
7.12
7.5
7.37
7.12
7.5
7.62
7.37
Incubator
7.25
6.37
6.62
6.37
6.75
6.75
6.62
6.25
6.37
7.00
6.62
7.00
Table 7 Texture of jaggery chocolate at different storage conditions Texture Storage conditions
Packaging material Aluminium foil
Butter paper
Unwrapped
15
30
45
60
15
30
45
60
15
30
45
60
Ambient
7.37
7.37
7.12
7.12
6.50
7.50
7.00
7.12
7.00
7.50
7.12
7.00
Refrigerator
7.00
8.00
7.62
7.37
7.12
7.37
7.50
7.25
7.12
7.37
7.25
7.25
Incubator
6.75
6.62
6.37
6.25
6.37
7.25
6.00
6.25
6.12
6.37
6.12
6.00
Table 8 Flavour of jaggery chocolate at different storage conditions Flavour Storage conditions
Packaging material Aluminium foil
Butter paper
Unwrapped
15
30
45
60
15
30
45
60
15
30
45
60
Ambient
6.87
7.62
7.00
7.12
6.75
7.12
7.00
7.12
6.50
7.12
6.87
6.50
Refrigerator
7.25
7.62
7.62
7.50
7.37
7.37
7.25
7.00
7.12
7.12
7.75
7.70
Incubator
6.87
6.37
6.62
6.12
7.00
6.87
6.37
6.25
6.00
6.62
6.25
6.25
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.
to 7.75 and stored under ambient condition, the variation was observed to vary from 6.5 to 7.62. Overall acceptability
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
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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
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Table 9 Overall acceptability of jaggery chocolate at different storage conditions Overall acceptability Storage conditions
Packaging material Aluminium foil
Butter paper
Unwrapped
15
30
45
60
15
30
45
60
15
30
45
60
Ambient
7.12
7.87
7.25
7.12
7.00
7.50
6.87
6.50
6.75
7.25
7.12
7.00
Refrigerator
7.37
8.50
8.25
8.12
7.62
7.87
7.37
7.12
7.25
7.25
7.50
7.25
Incubator
7.25
7.00
6.50
6.12
6.87
7.25
6.75
6.50
6.25
6.25
6.50
6.50
samples kept in ambient condition the score range was from 6.75 to 7.875. 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.
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