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20202
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Subject: Processing and Food Engineering × End date: 2020 × Start date: 2020 × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    Shelf life enhancement of sprout inherent bulb crops using irradiation
    (Punjab Agricultural University, Ludhiana, 2020) Sharma, Pallavi; Sharma, S. R.
    The present study was undertaken to study the effect of different irradiation doses on storage life of bulbs and minimally processed onion and garlic. Onion and garlic bulbs were irradiated within dose range of 0-0.2 kGy and stored under ambient conditions (Temp 25-35°C and RH 45-75%) whereas minimally processed onion and garlic i.e. onion rings and garlic cloves were irradiated within dose range of 0-2.5 kGy, packaged in polypropylene (PP), perforated polypropylene and vacuum packages and stored under ambient (Temp 25-35°C and RH 60-70%) and refrigerated (Temp 4-5°C and RH 70%) storage conditions. Physical and chemical quality parameters i.e. physiological loss in weight (PLW), rotting, sprouting, total soluble solids, firmness, ascorbic acid, pyruvic acid for onion, allicin content for garlic, microbial load and overall acceptability of both bulbs and minimally processed crops were determined and assessed for their keeping quality. Dose of 0.12 kGy was found to be the best in maintaining the marketable quality of onion bulbs for 3 months and garlic bulbs for 4 months with no sprouting and minimum PLW and rotting percentage under ambient storage conditions. Onion rings packaged in perforated polypropylene packages and irradiated with 1.5 kGy had shelf life of 20 days whereas garlic cloves packaged in polypropylene packages and irradiated at 1.5 kGy had shelf life of 77 days under refrigerated storage conditions. A computer program using C sharp language (C #) based on above quality parameters was also developed to access marketability of bulbs as well as minimally processed onion and garlic.
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    ThesisItemOpen Access
    Development of environment friendly thermoelectric mobile refrigeration system for summer fruits and vegetables
    (Punjab Agricultural University, Ludhiana, 2020) Pandurang, Chavan Prasad; Sidhu, Gagandeep Kaur
    A mobile thermoelectric refrigeration system of 100 liter storage capacity and cold temperature attainment capacity of 15±2°C for storage of summer fruits and vegetables was designed. Developed system consisted of assembly of four peltier modules, liquid cooled evaporator, air cooled heat sink, DC fan, water as a coolant, etc. and have a capacity to removed 360W of refrigeration load. The system was powered using electric battery and operated at no load and with loading of fruit and vegetables. The results indicated that developed thermoelectric refrigeration system operated without loading reduces temperature inside the cooling chamber from 36.2°C to 15.4°C in 210 minutes, whereas, from 38.70°C to 15.10°C in 360 minutes when operated with load. The coefficient of performance (COP) of system was found to be 0.85. The storage study indicated that PLW of bitter gourd, okra, mango and papaya was significantly reduced (p<0.0001) to 11.51%, 10.99%, 12.29% and 19.17% respectively, compared to those stored at ambient storage condition. An overall colour change for crop was significantly reduced to 14.04, 11.46, 16.41 and 23.68 for bitter gourd, okra, mango and papaya respectively. The results of physiological quality of stored crop also indicated that no significant difference (p<0.0001) exist between thermoelectric refrigeration and vapour compression refrigeration system. The shelf life of crop was increased up to 7, 8, 10 and 12 days for bitter gourd, okra, mango and papaya respectively. So, thermoelectric refrigeration, being an eco-friendly and sustainable technology, useful for generating carbon credits along with cold chain management of perishable crops.