Loading...
Thesis
Browse
36 results
Search Results
ThesisItem Open Access Development of a prototype for shelf life enhancement of guava juice using manothermosonication(Punjab Agricultural University, Ludhiana, 2019) Kalsi, Baldev Singh; SandhyaInvestigation was carried out to study the effect of ultrasound in combination with temperature and pressure treatment on the juice of guava (variety: Arka Amulya). For experiments, a pressurizing system was designed in CREO 3.0 software and constructed from the local market of Ludhiana. The juice samples were exposed to manothermosonication at combinations of three temperatures (40, 60 and 800C) and three pressure levels (100, 200, and 300 kPa) for three holding times (2, 6, and 10 min). Response surface methodology (RSM) was applied to optimize the conditions of the manothermosonication of guava juice. The main criteria for constraints optimization were minimum color change, pH, total plate count, total mold/ yeast and maximum ascorbic acid, total soluble solids, titratable acidity and overall acceptability. The juice samples treated under optimized conditions for manothermosonication were packed in two packaging material (glass and PET bottles) and stored at ambient and refrigerated conditions. The juice samples were also treated with ultrasonication and thermosonication for storage and their physicochemical, phytochemical, microbial anyalysis and sensory evaluation was done at regular intervals of 7 days. The optimized conditions for manothermosonication obtained were: Heating temperature= 63.810C, Pressure= 184.16 kPa and holding time = 2 minutes for each process. The highest microbial inactivation and retention of TSS and color (*L-value) along with highest overall acceptability score was observed in manothermosonicated samples. Thus, results showed that guava juice manothermosonicated and packed in glass bottles have better quality and a shelf life of six weeks under refrigerated conditions.ThesisItem Open Access Modification and evaluation of indirect type solar dryer for bitter gourd slices (Momordica charantia L.)(Punjab Agricultural University, Ludhiana, 2019) Borse, Sudarshan Murlidhar; Manpreet SinghThe present study was conducted to modify the drying cabinet of indirect type solar dryer and evaluate its performance for drying of bitter gourd slices. Drying cabinet was modified with skewers on rack arrangement for proper air circulation over the samples and better maneuvering of samples during drying. Modified drying cabinet was evaluated in comparison to existing drying cabinet having trays for bitter gourd slices. The drying experiments were conducted to evaluate the effect of different process parameters viz., pretreatment, loading, drying method on the drying behavior and quality of dried bitter gourd slices. The quality parameters viz., total phenolic content, total flavonoid content, total chlorophyll content, antioxidant capacity, colour (L, a, b, ΔE), ascorbic acid content, shrinkage, rehydration characteristics (rehydration ratio, coefficient of rehydration and percent water in the rehydrated sample) and hardness were studied. The final moisture content of the solar dried bitter gourd slices was in the range 6.84-8.27% wb. The dried product obtained using modified drying cabinet was of better quality as compared to existing drying cabinet of indirect type solar dryer and open sun drying. The average values for total phenolic content, total flavonoid content, total chlorophyll content, ascorbic acid content and antioxidant capacity for best sample dried using modified drying cabinet of indirect type solar dryer were 0.227, 0.032, 0.248, 1.26 mg/g dw and 72.90 % respectively. The dried bitter gourd samples were stored in different packaging materials (LDPE, LAF and vacuum) and the storage quality of dried bitter gourd slices was also studied at regular intervals. The quality attributes of dried bitter gourd slices were affected during storage in different packaging materials. The vacuum sealed pouches for storage of dried bitter gourd slices were found to be best on the basis of quality retention. The quality data obtained for various dried samples was statistically analyzed by using completely randomized design and the quality data obtained during storage experiment was analyzed by factorial completely randomized design using statistical software SAS 9.3. The quality parameters were significantly (p<0.0001) affected by the drying method, pretreatment, loading, packaging material and storage period.ThesisItem Open Access Development of a prototype for shelf life enhancement of guava juice using manothermosonication(Punjab Agricultural University, Ludhiana, 2019) Kalsi, Baldev Singh; SandhyaInvestigation was carried out to study the effect of ultrasound in combination with temperature and pressure treatment on the juice of guava (variety: Arka Amulya). For experiments, a pressurizing system was designed in CREO 3.0 software and constructed from the local market of Ludhiana. The juice samples were exposed to manothermosonication at combinations of three temperatures (40, 60 and 800C) and three pressure levels (100, 200, and 300 kPa) for three holding times (2, 6, and 10 min). Response surface methodology (RSM) was applied to optimize the conditions of the manothermosonication of guava juice. The main criteria for constraints optimization were minimum color change, pH, total plate count, total mold/ yeast and maximum ascorbic acid, total soluble solids, titratable acidity and overall acceptability. The juice samples treated under optimized conditions for manothermosonication were packed in two packaging material (glass and PET bottles) and stored at ambient and refrigerated conditions. The juice samples were also treated with ultrasonication and thermosonication for storage and their physicochemical, phytochemical, microbial anyalysis and sensory evaluation was done at regular intervals of 7 days. The optimized conditions for manothermosonication obtained were: Heating temperature= 63.810C, Pressure= 184.16 kPa and holding time = 2 minutes for each process. The highest microbial inactivation and retention of TSS and color (*L-value) along with highest overall acceptability score was observed in manothermosonicated samples. Thus, results showed that guava juice manothermosonicated and packed in glass bottles have better quality and a shelf life of six weeks under refrigerated conditions.ThesisItem Open Access Comparative analysis of drying kinetics of Stevia under various drying conditions(Punjab Agricultural University, Ludhiana, 2019) Manveen Kaur; Gupta, Satish KumarA study on the effect of drying method and layer thickness on the drying kinetics of stevia leaves was conducted at varying thickness of 1, 1.5 and 2cm using different methods viz. open sun drying, mechanical tray drying and forced convection solar drying (shade and without shade). Results for all the methods indicated that drying took place in the falling rate period. The drying times observed from various drying methods ranged from 240-540 minutes with lowest drying time being 240 min for mechanically tray dried sample of thickness 1cm and highest drying time being 540 min for sun dried sample of thickness 2cm. The moisture ratio as well as the drying rate decreased with an increase in the drying time for all the drying methods. The Page model for mechanical drying and Logarithmic model for sun and solar drying showed greater adequacy of fit between experimental and predicted data among other models. The stevia samples were analysed before and after drying for their physicochemical parameters viz. moisture content, colour, total sugar and total soluble solids. The least change in quality parameters was found to be in mechanically tray dried sample of thickness 1.5 cm followed by solar without shade dried sample of thickness 2cm. The dried stevia samples were also assessed for their quality parameters at a regular interval of 15 days over the storage period of three months, packaged in LDPE poly pack and LAF pack under ambient and refrigerated conditions. It could be inferred from the storage study that samples in LAF packaging material and under refrigerated conditions performed better.ThesisItem Open Access Design, development and evaluation of ozonation system for shelf life enhancement of minimally processed onion (Allium cepa L.)(Punjab Agricultural University, Ludhiana, 2019) Aslam, Raouf; Alam, M. S.The study was carried out to design and develop an ozonation treatment system for sanitization of horticultural produce with aqueous ozone. The developed ozonation system was evaluated for minimally processed onion (cut slices and whole peeled) based on kinetics of degradation, application methods, homogeneity of dissolution, ozone demand under no-load and full load of produce. The system was conceptually designed using CREO 3.0 software for a maximum design capacity of 15 kg minimally processed onion and the ozonation process parameters were optimized using response surface methodology. Experiments were conducted to optimize the developed system process parameters i.e. ozone concentration (1-5 ppm), exposure time (2-8 min) and pH of water (3-5) for cut sliced as well as whole peeled onion. Optimization was done to maximize microbial log reductions, pyruvate content and overall acceptability. In order to assess the efficacy of ozonation treatment, both the forms of minimally processed onion were sanitized at optimized conditions and were compared with samples exposed to 100 ppm chlorine and water washed (control). The treated samples were packed in cling wrapped HDPE tray packs and were stored under ambient (26.8 to 37.3 oC, 10-57% RH) as well as refrigerated conditions (5±1oC, 90±1% RH) and were monitored for change in quality attributes at regular intervals. The results revealed that the developed system effectively sanitized minimally processed onion without significantly affecting the quality parameters. The degradation kinetics of dissolved ozone was found to follow a first order reaction with a half-life of 18.23 min. Among different methods of ozone application tested, splashing method yielded better log reductions. Among the two types of minimally processed onion used for evaluation of developed system, cut slices were observed to exhibit a higher ozone demand in comparison to whole peeled onion. The optimized sanitizing conditions obtained for cut sliced onion were 5 ppm ozone concentration, 8 min of exposure time and an aqueous pH of 3.01 whereas 4.51 ppm ozone concentration, 8 min of exposure time and an aqueous pH of 3 for whole peeled onion with a desirability of 0.95. The samples stored under refrigerated conditions were observed to have a higher shelf life than samples stored under ambient conditions. Among the samples stored under ambient conditions, aqueous ozone treated samples had a significantly better shelf life (2 days) as compared to chlorine treated (1 day) samples. Whereas, under refrigerated storage conditions, a higher shelf life was observed for minimally processed onion treated with chlorine followed by ozone. The microbial shelf life of minimally processed onion treated with ozone and stored under refrigerated conditions was found out to be 13 days for cut slices and 16 days for whole peeled onion.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 Restricted Optimization of process variables of multilayer mechanical drying of white button mushroom (Agaricus bisporus)(Punjab Agricultural University, Ludhiana, 2019) Wahid, Aseeya; Satish KumarStudies were carried out on optimization of process variable for multilayer mechanical drying of white button mushroom (Agaricus Bisporus). The drying of mushroom was carried out at 3 levels each of temperature (45-650C), air velocities (1.0-5.4 m/s), and loading densities (26-52 kg/m2). Single layer drying with loading density of 10 kg/m2 was kept as control. For optimization of multilayer drying process variables ‘RSM’ 3 - Factor Box–Behnken was used. Samples dried at optimized conditions were packed and stored for 5 months under refrigerated and ambient condition. The drying parameters included moisture content, drying rate, temperature and relative humidity of outgoing air, product temperature, heat utilization factor, coefficient of performance and specific energy consumption. Quality attributes included rehydration ratio, shrinkage ratio, ascorbic acid, texture (hardness), colour, protein and overall acceptability. Mushroom with an initial moisture content of 91.80 ± 0.5 (% wb) was dried in mechanical drier (SATAKE) till it reached final moisture content of 6.35 - 6.10 %db. The decline in drying rate increased with temperatures, air velocities, whereas opposite trend was observed for loading densities. Maximum drying rate (17% db/min) was observed for 650C, 5.4m/s and 26 kg/m2. The average temperature of outgoing air, temperature of product and specific energy consumption was lower than that of single layer drying but opposite trend was observed for relative humidity, heat utilization factor, coefficient of performance. Logarithmic model showed the highest adequacy of fit for both multilayer and single layer drying. The effective moisture diffusivity (Deff) increased with temperature, air velocity and decreased with loading density. The highest Deff of 4.92×10-06 and 5.40×10-06 m2/s was observed for multilayer and single layer drying respectively. It was concluded that Button mushroom dried by multilayer drying at 550C, 5.4 m/sec and 43 kg/m2 will give better quality product compared to single layer drying. Multilayer dried button mushroom packed in laminate can retain quality for 5 and 3 months under refrigerated and ambient condition respectively. Multilayer drying resulted in capacity enhancement by 2.34 times to that of single layer drying, alternatively single layer took 4.30 times more time to that of multilayer drying, to dry the same amount of product.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 and Evaluation of Refraction Based System for Dehydration of Potato(Punjab Agricultural University, Ludhiana, 2018) Zalpouri, Ruchika; Preetinder KaurThe present study was conducted to develop and evaluate a refraction based system for dehydration of potato. Refraction based drying system was developed in Pilot plant, Department of Processing and Food Engineering, Punjab Agricultural University. The potatoes were peeled, cut into quarters, hot water blanched and immersed in 0.2% KMS solution for 15 min. After pretreatment, the potatoes were processed into puree and a known amount of distilled water was added to the puree to achieve desired TSS levels. The potato puree was dried by different drying methods viz. convective tray drying and refraction based drying system. The drying experiments were carried out at different TSS (8, 10 and 12º Brix), different blanching time (3, 4 and 5min) and at varying drying temperature 50, 60 and 70°C in convective tray drying and 70, 80 and 90oC in the refraction based drying system. It was observed that the physical properties of potato flakes were significantly affected by blanching time (p< 0.05). The moisture content ranged from 6.16-1.57% (db) and 7.61-3.46% (db) of potato flakes dried in refraction based drying system and convective tray dryer. Color values varied significantly (p<0.05) with respect to the drying method. Response Surface Methodology was used for optimization of process parameters. For refraction based drying system, the optimum operating conditions for drying temperature, blanching time and TSS were 70.00°C, 5.00 min and 11.54°Brix. At optimum condition, the values of responses were as follows protein content (31.66 mg/g), starch content (144.04 mg/g), reducing sugars (0.75 mg/g) and total sugars (6.25 mg/g) of dried potato flakes. For convective tray drying, optimum operating conditions for drying temperature, blanching time and TSS were 50.00°C, 4.23 min and 12.00°Brix. At optimum condition, the values of responses were as follows protein content (19.40 mg/g), starch content (16.47 mg/g), reducing sugars (0.94 mg/g) and total sugars (6.41 mg/g) of dried potato flakes. After considering all the parameters, it was found that refraction based drying system was more efficient as compared to the convective tray dryer.