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Subject: Food and Nutrition × Author: KAU × End date: 2014 × Start date: 2014 × Type: Thesis ×
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    ThesisItemOpen Access
    Standardisation of wax coating in cassava (manihot esculenta crantz) tubers and quality evaluation
    (Department of Home Science, College of Horticulture, Vellanikkara, 2014) Nishidha, Haridas; KAU; Suman, K T
    The present study entitled “Standardisation of wax coating in cassava (Manihot esculenta Crantz) tubers and quality evaluation” was undertaken to standardise the percentage of wax coating to be applied on cassava tubers and to evaluate various physico-chemical and nutritional attributes of wax coated cassava tubers. Three varieties of cassava, M-4, Sreevijaya and Vellayani Hraswa were selected for the study. The standardisation of wax coating was done by using different concentrations of three waxes namely paraffin wax, bee wax and semperfresh on these varieties. The wax formulation at one per cent level which prolonged the days of storage under ambient conditions was selected for the study. The tubers coated with one per cent wax formulations were stored after packing in ventilated paper cartons under ambient conditions till it showed the signs of deterioration. The shelf life qualities such as respiration rate and physiological loss in weight and physical qualities like appearance, colour and extent of vascular streaking were determined at two days interval. The chemical, nutritional and organoleptic qualities were evaluated initially and after two weeks of storage. The respiration of the cassava tubers were determined by the rate of O2 consumption and CO2 liberation. Significant variation was noticed in the respiration rate of unwaxed and wax coated cassava tubers. The respiration rate lower than control was observed only in semperfresh coated tubers throughout the storage period. The physiological loss in weight was minimum in unwaxed tubers followed by semperfresh treated ones except in variety Sreevijaya. In paraffin and bee wax coated tubers the development of vascular streaking and discolouration was at a faster rate than in semperfresh coated and unwaxed tubers. Paraffin and bee wax coated tubers of Sreevijaya and bee wax coated tubers of M-4 showed symptoms of deterioration during second week of storage itself. Changes in chemical and nutritional constituents were observed during storage of waxed cassava tubers. In tubers treated with semperfresh, the rate of moisture loss was comparatively lower during storage. A reduction in protein content was noticed during storage of waxed as well as unwaxed tubers. The fat and fibre content of all the treatments increased during storage. Among wax coated tubers, semperfresh coated tubers showed minimum loss in total carbohydrate content during storage. A significant reduction in starch content during storage was noticed in waxed as well as unwaxed tubers resulting an increase in the total and reducing sugar content of all the treatments. The physico-chemical characters of the tubers were found to be better retained in semperfresh tubers than in control. β-carotene content was noticed only in variety Sreevijaya which decreased significantly during storage. A slight increase in calcium content of waxed and unwaxed tubers was observed during storage. Nearly 18 percent reduction in hydrogen cyanide content was noticed in waxed and unwaxed tubers of the three varieties. The mean scores for different quality attributes of waxed as well as unwaxed cassava tubers of M-4, Sreevijaya and Vellayani Hraswa decreased during two weeks of storage. Compared to control, the mean scores for overall acceptability were lower in wax coated cassava tubers. Among wax coated tubers, semperfresh tubers had better mean scores for different quality parameters. The cost of wax application was found to be maximum for semperfresh, followed by paraffin and bee wax. From this study, it is clear that all types of waxes are not ideal for application in cassava tubers. Among the three types of waxes tried, semperfresh was found to be the most ideal one for application on cassava tubers. But the extended shelf life by application of semperfresh was found to be almost similar to the shelf life of unwaxed tubers. So it can be concluded that harvesting cassava tubers without any mechanical damage and bruises itself is ideal to extend the shelf life.
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    ThesisItemOpen Access
    Development and quality evaluation of nutribars
    (Department of Home Science, College of Horticulture, Vellanikkara, 2014) Shahla, Karuthedath; KAU; Suman, K T
    The present study entitled “Development and quality evaluation of nutribars” was aimed to develop nutribars with cereal flakes, dehydrated fruits, nuts and functional ingredients and to evaluate the physical, chemical, nutritional, organoleptic and shelf life qualities of the developed nutribars. Nutribars were standardised in 24 different combinations based on jaggery honey mix and glucose syrup in which cereal flakes formed the main ingredient. To find out the most appropriate combination for the preparation of nutribars, the treatments were evaluated for various organoleptic qualities. Nutribars prepared using glucose syrup had comparatively better mean scores for different quality attributes than nutribars prepared with jaggery honey mix. Based on the organoleptic scores, six treatments namely T3 (corn flakes in jaggery honey), T6 (rice flakes and corn flakes in jaggery honey mix), T8 (wheat flakes and corn flakes in jaggery honey mix), T12 (wheat flakes in glucose syrup), T16 (rice flakes and corn flakes in glucose syrup) and T20 (corn flakes and oat flakes in glucose syrup) were selected for further studies. The selected nutribars were prepared and packed in polyethylene and laminated aluminium pouches under vacuum. After packaging, the products were stored under ambient conditions for a period of six months and evaluated for various quality parameters during storage. The hardness of the product was evaluated initially. The chemical, nutritional and microbiological qualities of the products were evaluated initially, after third and sixth month of storage. The organoleptic qualities and peroxide value of the products were assessed initially and at monthly intervals for a period of six months. The moisture content of nutribars increased gradually with advancement in days of storage. The increase in moisture content of nutribars packed in laminated aluminium pouches was lower than the nutribars packed in polyethylene pouches. An increase in total sugar and reducing sugar content was observed in the nutribars stored in both packages during storage. The jaggery honey mix based nutribars had comparatively higher total and reducing sugar content than glucose syrup based ones. The protein, fat, fibre, starch, thiamine, calcium, iron, sodium, potassium and zinc content of nutribars decreased during six months of storage. The mean score for overall acceptability of nutribars decreased during storage. The nutribars had mean score above 7.0 in laminated aluminium pouches and in polyethylene pouches at the end of storage. Nutribars packed in laminated aluminium pouches retained its original qualities than polyethylene packed samples up to fourth month of storage. Later much difference in mean scores for the overall acceptability were not noticed with respect to packages. Based on organoleptic qualities, the nutribars prepared with corn flakes in jaggery honey mix (T3) was the most acceptable combination followed by T12 prepared with wheat flakes and T16 prepared with rice flakes and corn flakes in glucose syrup. The nutribars were evaluated initially, after third and sixth month for bacteria, yeast and mold for a period of six months. The bacteria, yeast and mold were not detected initially. An increase in bacterial and yeast count was noticed after third and of storage in all the products. Compared to nutribars packed in polyethylene pouches, microbial count was lower in nutribars packed in laminated aluminium pouches.