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ThesisItem Open 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.ThesisItem Open Access Development of environment friendly thermoelectric mobile refrigeration system for summer fruits and vegetables(Punjab Agricultural University, Ludhiana, 2020) Pandurang, Chavan Prasad; Sidhu, Gagandeep KaurA 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.ThesisItem Open Access Optimization Of Microwave Assisted Multilayer Drying Of Bittergourd For Capacity Enhancement And Energy Conservation(Punjab Agricultural University, Ludhiana, 2019) Ramandeep Kaur; Satish KumarStudies were carried out on optimization of microwave assisted multilayer drying of bittergourd (Momordica charantia). The drying of bittergourd was carried out by three different methods: Multilayer drying at 5 levels of loading densities (31-60 kg/m2) and air velocities, 2.6-5.41 m/s; Multilayer-cum-microwave drying at 3 power levels (300-600 W) and exposure time (8-24s) with pause time 30s; Multilayer-cum-customized microwave drying at 3 power level (300-600W), exposure time (8-24s) and air velocity (3-9 m/s) with pause time 20s. The drying parameters included moisture content, drying rate, temperature and relative humidity of outgoing air, product temperature, heat utilization factor and specific energy consumption. Quality attributes included rehydration ratio, shrinkage ratio, ascorbic acid, texture (hardness), colour, protein and overall acceptability. Multilayer drying of bittergourd with an initial moisture content of 91% wb was carried out at 60°C in mechanical drier (SATAKE) till it reached 7.05% db. Optimized result of multilayer drying was used for multilayer-cum-microwave drying; product was partially dried at optimized condition up-to 27% wb followed by microwave drying to 7.05% db. The drying time to reach equilibrium moisture content were found to be between 210 – 480, 190 – 213 and 185 -188 min for multilayer, multilayer-cum-microwave and multilayer-cum-customized microwave drying, respectively. The decline in drying rate increased with increase in air velocities, power level and exposure time whereas opposite trend was observed for loading densities. Maximum drying rate (15.25% db/min) was observed for multilayer-cum-customized microwave. Relative humidity of outgoing air and heat utilization factor decreased with drying time but opposite trend was observed for temperature of outgoing air and product. Page model showed the highest adequacy of fit for multilayer drying; Logarithmic model for multilayer-cum-microwave drying and Midli et al model for multilayer-cum-customized microwave drying. The effective moisture diffusivity (Deff) increased with increase in air velocity, power level, exposure time and decreased with increase in loading density. The highest Deff of 1.33×10-05m2/s was observed for multilayer-cum-customized microwave drying, which was 70% higher than multilayer drying. The optimum operating conditions for multilayer drying, multilayer-cum-microwave drying and customized microwave drying were 55.0 kg/m2& 5.0 m/s, 450W & 24s and 450W, 24s & 3.75 m/s, respectively. It was concluded that multilayer drying and multilayer-cum-customized drying resulted in capacity enhancement by 3.3 & 4.84 time more in compare to single layer drying. Alternatively it will resulted in saving drying time by 70 & 79.3% in respective methods. Overall multilayer-cum-customized microwave drying was found to be best method.ThesisItem Open Access Design, development and performance evaluation of LHAassisted hybrid solar dryer for onion (Allium Cepa L.)(Punjab Agricultural University, Ludhiana, 2018) Attkan, Arun Kumar; Alam, M.S.The study was conducted to design, develop and evaluate LHA-assisted hybrid solar drying system. The 3D-CAD model of the hybrid dryer was designed and prepared in NX-8 CAD drawing software on the basis of design calculations. Experiments were conducted to test the developed low humidity air (LHA) system for its regeneration capacity using silica gel for regeneration temperature (60-100ºC), air velocity (3-5 m/s) and loading weight (1-3 kg) using three factors, three levels Box-Behnken design. The optimized regeneration process parameters obtained were 100°C regeneration temperature, 4.77 m/s air velocity and 1.73 kg loading weight resulting in 0.255 kg/hr of regeneration rate, 160 minutes regeneration time, 0.83 kWh power consumed by blower and 0.75 kWh power consumed by heater. In order to evaluate the developed dryer, drying experiments were conducted on onion slices by varying the drying air temperatures (50, 60 and 70°C), KMS pre-treatment (0.1, 0.3 and 0.5%) and loading weight (10, 20 and 30 kg). RSM was employed for optimizing the drying process parameters of onion slices for the developed hybrid solar dryer and found the optimized drying process parameters were 64.98°C drying air temperature, 10 kg loading weight and 0.5% KMS pre-treatment resulting in maximum pyruvate content, rehydration ratio, color L-value, overall acceptability and minimum drying time, color change and power consumed by blower and heater. Mathematical model was developed by writing the heat and mass balance equations for developed dryer. Eight thin layer drying models (Newton, Page, Modified Page, Exponential, Asympotic, Two-term exponential Wang and Singh and Logistic) were fitted to mass transfer data and their adequacy of fit was investigated. Page equation accurately describes the drying behavior of onion slices Six EMC models (Modified Exponential, Modified Halsey, Modified Oswin, Modified Chung-Pfost, Guggenheim-Andersonde Boer (GAB) and BET) were fitted to the EMC data to investigate the sorption behavior of onion slices. Modified exponential equation was found superior for explaining the sorption behavior of onion slices with in the selected temperature and relative humidity range. A computer program was written in VISUAL BASIC language to develop the model. The developed computer model showed close agreement between the measured and predicted values and was quite effective in predicting the drying behavior of treated onion slices with average % error of 9.31, 11.43% and 2.93% for moisture content, moisture ratio and product temperature respectively. The cost economics of the developed hybrid solar dryer was evaluated on the basis of benefit cost ratio (Rs. 1.49), breakeven point (101.96 kg) and payback period (0.092 year) of dried onion powder at selling price of Rs. 400/- per unit respectively. Overall, the developed hybrid solar dryer was found quite energy efficient, economically viable and capable in maintaining the quality of dried onion slices.ThesisItem Open Access Development of pectin-based bio nanocomposite films for food packaging(Punjab Agricultural University, Ludhiana, 2018) Nitin Kumar; Preetinder KaurThe present study was carried out to extract pectin from kinnow fruit peels and to assess its potential application in fabrication of pectin-based bio nanocomposite films. Pectin was extracted with nitric and citric acid and the effect of extraction time (30 to 60 min), temperature (60 to 80°C) and pH (1.5 to 2.5) was investigated on various physico-chemical properties of extracted pectin. The values of pectin yield, degree of esterification, intrinsic viscosity and molecular weight were higher in citric acid extraction of pectin as compared to nitric acid extraction. The extracted pectin and magnesium hydroxide nanoparticles were mixed with glycerol to develop bio nanocomposite films. The effect of pH (7 to 10) of the mix and sonication levels (20 to 100%) was significant on various film properties. At optimised levels of pH (9.80) and sonication (98.45%), the corresponding values of thickness, area, moisture absorption, tensile strength, elongation at break, water vapour transmission rate and gas transmission rate were 0.028 mm, 444.95 cm2, 5.51%, 4.44 MPa, 42.95%, 65.11 g m-2day-1 and 19.72 cm3 mm m-2day-1atm-1 respectively. The developed bio nanocomposite films had melting point of 7.38°C and glass transition temperature (-17.4°C). The film completely degraded in soil (25% M.C) 110 days and exhibited antimicrobial properties (inhibition zone = 7.89 mm) against E coli. The developed films were then compared with commonly used polymers (low density polyethylene and polypropylene) by packaging fresh cherry tomatoes (CV ) and storing under ambient (30°C, 61% RH) and low temperature storage conditions (10°C, 90% RH). The type of packaging material and storage conditions affected the physico-chemical parameters of the packaged produce viz. PLW, firmness, lycopene content, TSS and titratable acidity. The total cost of pectin-based bio nanocomposite films was estimated as Rs. 1075 per kg.ThesisItem Open Access Drying Of Red Chillies (Capsicum Annum L.)And Its Subsequent Effect On Storage(Punjab Agricultural University; Ludhiana, 2005) Tarsem Chand; Jarnail SinghThesisItem Open Access Design and evaluation of modified atmosphere packaging for litchi (Litchi chinensis Sonn.)(PAU, 2014) Virk, Ramandeep KaurThe study on design and evaluation of modified atmosphere packaging for litchi was undertaken to select the suitable polymeric film for extending the shelf-life of litchi based on respiration rate of litchi and permeability of commercially available films at different temperatures. The litchi fruits of cv. Culcuttia were packed in LDPE (100 gauge) without perforations, 12, 14 and 16 perforations. The fruits were stored under room temperature (40±3°C and 40-65% RH) and low temperature (2±1°C and 93-95% RH). Control fruits were also kept at both storage conditions. The analysis was carried out to estimate the quality and shelf-life of stored litchi. It was found that LDPE (100 gauge) with 14 perforations of 0.5mm was the best film for extending the shelf-life of litchi. To enhance the effect of MAP on litchi, various postharvest treatments viz. Sulphur fumigation, acid treatments (0.25 and 0.5% salicylic acid, 2 and 4% citric acid and 2 and 4% hydrochloric acid) alone and in combination with sulphur fumigation were given to litchi fruits. Among the postharvest treatments, the fruits treated with SO2+HCl (2 and 4%)+perforated LDPE and SO2+ 4%CA+ perforated LDPE were able to retain the overall quality of fruits for maximum storage duration of 28 days.ThesisItem Restricted Studies On Drying Behaviour Of Red Chillies (Capsicum Annum) In Solar Dryers(Punjab Agricultural University; Ludhiana, 2005) Mehta, Sanjeev; Amarjit Singh