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20202
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Subject: Processing and Food Engineering × End date: 2020 × Start date: 2020 × Thesis Type: M.Tech. ×
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    ThesisItemOpen Access
    Development and optimization of pectin-based smart coating for fresh guava (Psidium guajava L.)
    (Punjab Agricultural University, Ludhiana, 2020) Japsimran Kaur; Preetinder Kaur
    Present 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.
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    ThesisItemOpen Access
    Optimization of process parameters for mechanized preparation of maize flour based flatbread
    (Punjab Agricultural University, Ludhiana, 2020) Kathuria, Prerna; Sidhu, Gagandeep Kaur
    The 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.