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ThesisItem Embargo Development of process protocol for the production of powder from stevia (stevia rebaudiana)(Punjab Agricultural University, 2023) Kalsi, Baldev Singh; SandhyaStevia rebaudiana leaves, renowned for their natural sweetness, have gained prominence as a healthier alternative to artificial sweeteners. The present research explores various aspects of Stevia leaf processing such as drying, extraction, and grinding, with a vision of optimizing both quality and efficiency. The fresh stevia leaves were dried using different methods: sun drying, convective drying (30-80°C), microwave drying (180 to 900 W) and multistage/hybrid drying: convective pre drying at 50 °C until reaching moisture content of 0.18 g/g, 0.43 g/g and 1.50 on dry basis (db) and then microwave finishing drying at power levels of 360, 540, and 720 W. The Artificial Neural Network (ANN) exhibited a reasonably good fit across all drying conditions to predict drying kinetics, surpassing the maximum R2 range and minimum χ2 and RMSE from the mathematical model. The multistage drying done at 1.50g/g-540W achieved the lowest total color difference (ΔE) value i.e 1.97 compared to other methods, indicating minimal color alteration. Furthermore, ascorbic acid content showed maximum retention after multistage drying at conditions of 1.50g/g-540W (23.50 mg/100g), followed by 1.50g/g-720W (23.04 mg/100g). Further, the total phenolic content also showed excellent results, with multistage drying at 1.50g/g-720W yielding the highest value (58.88 mg GAE/g), followed by 1.50g/g-540W (58.26 mg GAE/g). Additionally, very high antioxidant activity (78.67 %) was retained at the multistage drying at 1.50g/g-540W. The multistage drying at 1.50g/g-540W was selected as best drying as it not only significantly reduced drying time but also preserved the quality and bioactive compounds of Stevia leaves. A lab scale ohmic heating setup was also developed for extracting stevioside and bioactive compounds from dried leaves. The optimization of the ohmic heating assisted-extraction was executed using response surface methodology with temperatures (40-70°C), time (5-15 min) and solvent/ leaf powder ratio (10:1-30:1 ml/g) as independent parameters. The optimized conditions observed were 51.02˚C for 10.297 minutes using Solvent/leaf powder ratio of 30:1 ml/g for maximum stevioside, total phenolic content and antioxidant activity with overall desirability of 0.91. The innovative ohmic heating extraction method proved highly efficient, achieving an approximately 50% higher extraction efficiency for natural compounds from Stevia leaves compared to conventional thermal extraction. Besides enhancing the yield of valuable components, the novel approach also reduces processing time. After considering both visual decolorization and the impact on important quality parameters, the extract decolorized with 1g of activated carbon per 100 ml of stevia extract was deemed the most optimal choice. To combat the hygroscopic nature of Stevia extract powder, inulin (10% w/v) was introduced as an encapsulating agent before the spray drying process. The resulting spray-dried powder displayed favorable characteristics, ensuring improved stability. Moreover, successful crystal formation of stevia powder was achieved using Erythritol. The developed process demonstrated economic viability. In conclusion, this comprehensive study resulted in a process protocol for development of powder from stevia leaves keeping in view consumer preferences.ThesisItem Embargo Development of protocol for postharvest quality management of stored mung bean using microwave and ozone(Punjab Agricultural University, 2023) Kulwinder Kaur; Satish KumarThe study aimed to optimize process parameters for ozone gas and microwave energy pre-treatment to maximize the mortality of C. maculatus (also known as pulse beetle) while minimizing the adverse effects on grain quality. Response surface methodology (RSM) was used, employing a Box-Behnken design (3x3) for ozone gas treatment and a full factorial design (2x3) for intermittent microwave heating. The optimized conditions for ozone gas treatment were moisture content: 11.28 %, ozone concentration: 939.98 ppm and exposure time: 2 h. For intermittent microwave heating, the optimal conditions were moisture content: 11.60 %, microwave power level: 435 W at a constant exposure time: 48 s, bed thickness: 4.5 cm, and air velocity: 3 m/s. These optimized conditions resulted in maximum mortality of all stages of C. maculates along with improved grain quality parameters. A grain recirculatory type ozone gas-based fumigation system was designed using Solid Works CAD software. The system showed a saturation time of 21.77 min, a saturated concentration of 1836.96 µg/L, an estimated half-life period of ozone as 10.35 min, and specific energy consumption of 524.62 kJ/kg. The proximate and mineral analysis of mung bean treated in the developed system showed a significant (p<0.05) decrease in protein, fat, and mineral content compared to the untreated samples but it varied non-significantly (p>0.05) vis-à-vis microwave treatment. Fourier Transform Infrared Spectroscope and Scanning Electron Microscope micrographs further confirmed molecular and structural modification in treated mung bean leading to reduced cooking time and enhanced functional, thermal, and pasting properties. The relationship between equilibrium moisture content and water activity predicted storage conditions as safe moisture content at aw 0.6: 11.80- 12.64 %, db and 7.87-13.43 %, db for ozone and microwave-treated mung bean respectively. The storage behavior of treated samples was studied over a 12-months using different packaging materials at retail and bulk levels. Variation in moisture content, headspace CO2 gas, and cumulative weight loss remained within safe limits while phytic acid content, total flavonoid content and antioxidant activity decreased with an increase in storage period with slight variation under high barrier films. Germination percentage was much higher than the Indian minimum Seed Certification Standards and was above 80 % for all treated samples. Ozone and microwave- treated mungbean grains packed in metalized laminated polymer (MLP) or cast polypropylene (CPP) bags at the retail level exhibited the longest shelf life of more than 12 months with acceptable quality, while LDPE (400-gauge) was found suitable for bulk packaging. Techno-economic analysis showed storage of treated and suitably packed grains has the potential to ensure long-term financial stability with an average payback period of less than one year.ThesisItem Embargo Development of process protocol for packaging and storage of groundnut kernels(Punjab Agricultural University, Ludhiana, 2022) Gurjeet Kaur; Sidhu, Gagandeep KaurThe spring grown groundnuts are prone to quality deterioration owing to high temperature and relative humidity during the harvesting. The present work investigated the impact of treatments and packaging systems on quality of groundnut kernels during storage. Spring varieties J87 and TG37A developed by Punjab Agricultural University were selected for the study. The fresh groundnut pods were dried using solar hybrid dryer at 60°C till the moisture content below 10% was achieved. Sample was decorticated and clean and healthy kernels were selected for the study. The sorption isotherms were developed at 25, 35 and 45°C temperature and water activity (aw) range of 0.110-0.975 in order to predict the suitable storage conditions. The equilibrium moisture content increased with increase in aw and the isotherms of type II were observed. The experimental data was fitted to seven mathematical models and Guggenheim Anderson de Boer and Double Log Polynomial were considered to be best fitted models. The safe storage conditions determined from best fitted models indicated that moisture content of J87 and TG37A varieties should not exceed 7.70 and 9.86 % (db) respectively during storage. The samples were subjected to three treatments viz. dry roasting (166 °C for 7 min), ozonation treatment (6 mg/L for 30 min) and combined ozonation-roasting (ozonation at 6 mg/L for 30 min followed by dry roasting at 166 °C for 7 min). The groundnut kernels were packed in low-density polyethylene (L), aluminum lined LDPE Ziplock bags (S) and aluminum laminate bags under nitrogen flushing (N) and in high barrier 5-layer polymeric laminate (PE/adhesive/EVOH/adhesive/PE) under vacuum packaging techniques. The samples were kept under ambient conditions for 12 months of storage period. Samples were analyzed for different quality parameters viz., moisture content, color characteristics, fracturability, radical scavenging activity, flavonoid content, protein, free fatty acids and aflatoxin content. Results indicated that treatments led to significantly (p<0.05) affect all the quality parameters except the hue angle and free fatty acids of J87 kernels and hue angle and chroma of TG37A kernels. The aflatoxin content after treatments exhibited values that were below the FDA established limit (20 µg/kg) for aflatoxins in groundnut kernels. The moisture content, chroma, total color difference, free fatty acids were found to be increased and hue angle, fracturability and protein content decreased with increase in storage period. FFA of groundnut kernels packaged in different materials were within acceptable limits (< 3%) for ozonated and ozonated-roasted samples. Radical scavenging activity and flavonoid content indicated a declined trend and then inclined as storage period approached 12 months. The maximum variation in quality parameters were observed in LDPE and zip lock bags. Vacuum and nitrogen flushed bags provided stable conditions with minimum alterations in quality of kernels. Microbial evaluation indicated dominance of Fusarium, Penicillium and Aspergillus spp. which was maximum in zip pouches followed by LDPE bags. It can be concluded that dried groundnut kernels with combined ozonation-roasting treatment, vacuum packaged in 5-layer modified polymeric laminate can be stored at ambient storage conditions for 12 months with maximum retention of quality parameters.ThesisItem Open Access Design, Development and Evaluation of Solar Hybrid Essential Oil Extraction System from Turmeric(Punjab Agricultural University, Ludhiana, 2022) Tiwari, Ravindra Kumar; Mittal, T. C.The present study was conducted to design and develop solar hybrid essential oil extraction system at Department of Processing and Food Engineering, PAU, Ludhiana. The conceptual design of the solar hybrid essential oil extraction system was done for essential oil extraction from turmeric. The system was designed in such a way that it will extract oil from a batch of about 10 kg of raw material. The volume of the distillation unit has a capacity of 0.061m3, the steam generation unit has a capacity of 0.057m3 and the condensing unit has a capacity of 40.50%. The smallest grates size (14.50mm) has the highest oil yield as compared to the largest grates size (17.53mm). The extracted essential oil was evaluated qualitatively in terms of refractive index, specific gravity color, saponification value, acid value, and ester values. The range of various chemical properties are specific gravity (0.89-0.93), refractive index (1.52-1.55), saponification value (35.21-38.13mg KOH/g), ester value (3.59-5.56mg KOH/g), acid values (31.61-32.59mg KOH/g) and colour values are L (32.70-38.90), a (-1 to -5.60) and b (10.6-19.40). The benefit-cost ratio was computed as 1.13 and break-even point for solar hybrid essential oil extraction system can be achieved after 1.85 years. The developed solar hybrid essential oil extraction reduces the extraction time (11.50%), energy consumption (11.75%) and can produce good quality essential oil which is free from wax. This environment friendly developed system lower operating and maintenance costs. The further analysis of the total extraction time and less energy consumption may help in designing a suitable solar hybrid essential oil extraction system with proper control of its operating parameters, and optimization of the process.
