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ThesisItem Open Access Development and optimization of pectin-based smart coating for fresh guava (Psidium guajava L.)(Punjab Agricultural University, Ludhiana, 2020) Japsimran Kaur; Preetinder KaurPresent study was undertaken with an objective to extract and to develop smart pectin-based coating from the guava fruit. Selection of guavas for extraction of pectin was done on the basis of different physio-chemical properties as influenced by harvesting season (rainy, winter) and maturity stages (immature green, mature, over-ripe yellow and infested). To develop pectin-based coating, pectin was extracted from mature green guavas and mixed with different plasticizers (glycerol, sorbitol, polyethylene glycol) with optional anti-microbial agent (Turmeric powder). The effect of different pectin to cellulose ratio (50:50, 60:40; 70:30), plasticizers with or without addition of turmeric for various coating properties was investigated and found to be significant (p<0.05). At best combination of pectin to cellulose ratio (50:50), plasticizer (glycerol) with turmeric, the corresponding values of moisture content, thickness, weight, color, tensile strength, density, viscosity, surface tension, water vapor transmission rate were 0.95%, 0.385 mm, 1.7 g, L:48.11, a:19.41, b:33.13, 4.10 MPa, 6.88 g/cc, 0.23 Pa.s, 26.42 N/m, 61.17 gm-2d-1, respectively. On the other hand, pectin coating without turmeric showed moisture content, thickness, weight, color, tensile strength, density, viscosity, surface tension, water vapor transmission rate as 0.99%, 0.353 mm, 1.4g, L:73.76, a:6.34, b:13.46, 4.20MPa, 6.24 g/cc, 0.25 Pa.s, 26.96 N/m, 63.44 gm-2d-1, respectively. The developed pectin-based coating with and without turmeric had melting point of 134.280C and 138.210C, respectively. The coatings having turmeric exhibited enhanced antimicrobial properties against E. coli, Yersinia, Salmonella, Shigella, Vibro sp .and campylobacteria sp. The shelf-life of guavas coated with developed pectin (50:50; glycerol; with and without turmeric) was assessed under ambient conditions (22OC,78% RH), retail market temperature (15OC, 85% RH) and low temperature conditions (5OC and 80% RH). Results indicated significant enhancement in quality with extended shelf-life of guavas upto 15 days and 12 days under low temperature conditions for coating with and without turmeric, respectively.ThesisItem Open Access Optimization of process parameters for mechanized preparation of maize flour based flatbread(Punjab Agricultural University, Ludhiana, 2020) Kathuria, Prerna; Sidhu, Gagandeep KaurThe present study was done to optimize the process parameters for mechanized preparation of maize flour based flatbreads. The whole maize kernels were procured from the farms of Punjab Agricultural University, Ludhiana. The kernels were cleaned, processed into flour and sieved into fine and very fine flour particles. Maize flour was blended with wheat and gram flour in the blending percentage of 20, 30 and 40. Flour samples were tested for physicochemical properties like moisture content, protein content, crude fat, ash content, crude fiber, carbohydrates, titrable acidity, color, swelling power, water holding capacity and oil holding capacity. The blending percentage of gram flour and wheat flour had a significant effect on protein content, crude fat, crude fiber, carbohydrates, titrable acidity, color value, swelling power, water holding capacity and oil holding capacity. The optimization of process parameters was done using Box-Behnken design using Response Surface Methodology (RSM). The three independent variables set were resting time of dough (0, 10 and 20 min), blending percentage of flour (20, 30 and 40%) and temperature of water to knead the dough (18°, 27° and 36°C). Optimum conditions obtained were 12.45 min resting time, 38.90% blending percentage and 31.47°C water temperature for blending with gram flour and for wheat flour blending, optimum conditions obtained were 20 min resting time, 20% blending percentage and 29.68°C water temperature respectively. Moisture content of flatbread decreases linearly with storage period in both the storage conditions respectively. Browning index increases linearly with storage period but the increase was more prominent in gram flour flatbread. After considering all the parameters, it was found that gram flour blended flatbreads were more acceptable than wheat flour blended.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 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 Restricted Performance evaluation of double layered polyethylene greenhouse solar dryer for drying of selected horticultural produce(Punjab Agricultural University, Ludhiana, 2017) Pinki; Mahesh KumarThe present study was conducted with an objective to evaluate the performance of double layered greenhouse solar dryer for drying of horticultural crops cabbage, spinach, onion and carrot that uses solar energy. Greenhouse solar dryer used was of 10×6 square ft area with polyethylene layering over trays. Exhaust fan was used at speed of 2.08 m/sec for forced convection. The performance evaluation of greenhouse solar dryer was done for drying of cabbage, spinach, onion, carrot and compared with open sun drying, single layer natural convection solar drying, double layer natural convection solar drying, single layer forced convection solar drying, double layer forced convection solar drying. All the four crops cabbage, spinach, onion and carrot were given physical treatment i.e. cutting; drying kinetics of all the crops chosen was studied by open sun drying, single layer natural convection solar drying, double layer natural convection solar drying, single layer forced convection solar drying, double layer forced convection solar drying techniques. The quality parameters included colour, ascorbic acid, polyphenol content, shrinkage ratio, rehydration ratio and overall acceptability. Double layer solar drying under forced convection took the minimum drying time i.e. 480, 275, 585, 385 min for cabbage, spinach, onion, carrot respectively followed by double layer solar drying under natural convection i.e. 785, 495, 665, 885 min for cabbage, spinach, onion, carrot respectively; accompanied by final moisture content 6-7% (db) for all crops. The quality of double layer solar drying under forced convection found comparable with open sun drying.
