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Development of process protocol for the production of powder from stevia (stevia rebaudiana)
(Punjab Agricultural University, 2023) Kalsi, Baldev Singh; Sandhya
Stevia 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.
Embargo
Development of protocol for postharvest quality management of stored mung bean using microwave and ozone
(Punjab Agricultural University, 2023) Kulwinder Kaur; Satish Kumar
The 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.
Embargo
Development of process protocol for packaging and storage of groundnut kernels
(Punjab Agricultural University, Ludhiana, 2022) Gurjeet Kaur; Sidhu, Gagandeep Kaur
The 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.
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.
Restricted
Engineering characterization of selected cereal grain and legume crops for physical quality determination using machine vision technology
(Punjab Agricultural University, Ludhiana, 2021) Sharma, Rohit; Mahesh Kumar
A study was undertaken for the determining relevant engineering properties for physical quality estimation of selected wheat and green gram refractions using machine vision technology. The most common wheat varieties PBW 725 and Unnat PBW 343 and green gram varieties SML 832 and SML 668 were considered for the present study. The kernels were grouped into four categories such as sound grains, damaged grains, shriveled grains and broken grains for wheat. The type of grains for green gram include sound grains, shriveled grains, discolored grains and broken grains. For image acquisition, Digital images of one hundred kernels of each selected refraction of wheat and green gram were acquired using the flatbed scanner model CanoScan 5600F with CCD 6-line color with white fluorescent light source. The computer programming language Python version 3.7 and OpenCV image processing library were used for analysis of the images. A total of 30 features related to size and shape (14 features), color (10 features) and texture (6 features) of the selected kernels. For each category of refractions, red (R), green (G), and blue (B) color densities were extracted. Algorithms have been developed for analysis of images of refraction. A linear relationship was obtained between actual and predicted lengths and widths of selected refractions. The experimental results for length of refractions were found non-significant in comparison to predicted value at 95% confidence interval with R2 in the range of 0.81–0.94. The comparison results for width for all refractions are found statistically non-significant at 95% confidence interval and R2 was in the range of 0.73–0.92 for wheat refractions of both selected varieties. The paired samples t-test results showed that all parameters determined with image processing method was not significantly (P>0.05) different from the same parameters measured with vernier caliper. Another linear relationship was found between individual kernel weight and projected area with R2 in the range of 0.51 to 0.92 and between the volume of refractions derived from measured dimensions and calculated from image with R2 in the range of 0.75 to 0.93 for both wheat varieties. Correlation behavior between different parameters were observed using pearson correlation matrix. It was observed that in all wheat and green gram refractions, the individual kernel weight was found correlated significantly with projected area, perimeter, major diameter, feret diameter arithmetic mean diameter, geometric mean diameter, surface area and volume of kernels.
Open Access
Mathematical modeling of osmo assisted freeze drying process for strawberries (Fragaria vesca)
(Punjab Agricultural University, Ludhiana, 2021) Sidhu, Jashandeep Singh; Gupta, . S.K.
The study entitled “Mathematical modeling of osmo assisted freeze drying process for strawberries (Fragaria vesca)” was undertaken to characterize the effect of process parameters; osmotic solution concentration (40-80 °Brix), solution to fruit ratio (4-8 STFR) and freeze drying temperature (-20 to -40°C) on drying kinetics and quality attributes. The treatments with -20°C freeze drying temperature required more time for drying as compared to -30 & -40°C (2to 4 hours) to reduce the moisture content from 87.2% wb to 4.2±0.1 % wb. The input parameters for osmo-freeze drying process for strawberry halves were optimized by „Multiple Response Optimization‟ technique with optimum operating conditions recorded as freeze drying time temperature: -40°C, osmotic solution concentration: 79.43° Brix and solution to fruit ratio (STFR): 6.61. Corresponding to these values, the value of responses was rehydration ratio: 7.150, shrinkage ratio: 0.627, colour change: 6.661, bulk density: 502.19 kg/m3, % vitamin-c retained: 71.846%, texture (hardness): 8.1871Kg-f, and overall acceptability: 83.431%. The best fit of experimental data for osmotic dehydration was observed in Penetration model followed by GEM model. The overall performance of the mathematical model developed in VISUAL BASIC-6.0 for prediction of freeze drying time for osmo-freeze drying was satisfactory (0.122-7.285 % error) and can be used for predicting the freeze drying time for osmo-freeze drying of strawberries. The osmo-freeze and freeze dried products packed in three types of packaging materials viz. high density polyethylene, laminate aluminium pouches & glass jars were kept under refrigerated and ambient storage conditions. Overall, it was concluded that osmo-freeze drying of strawberry halves at optimized conditions of 79.43°B osmotic solution, 6.61 solution to fruit ratio (STFR) and 40°C freeze drying temperature gave better quality product as compared to freeze drying and can be stored for 5 and 3 months in refrigerated and ambient conditions respectively.
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.
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 Kaur
A 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.
Open Access
Optimization Of Microwave Assisted Multilayer Drying Of Bittergourd For Capacity Enhancement And Energy Conservation
(Punjab Agricultural University, Ludhiana, 2019) Ramandeep Kaur; Satish Kumar
Studies 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.

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