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Performance evaluation of double layered polyethylene greenhouse solar dryer for drying of selected horticultural produce
(Punjab Agricultural University, Ludhiana, 2017) Pinki; Mahesh Kumar
The 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.
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Design, development and performance evaluation of solar assisted mechanical tray dryer for chillies
(Punjab Agricultural University, Ludhiana, 2017) Arora, Sakshi; Mittal, T.C.
The present study was conducted with an objective to design and develop a solar assisted mechanical tray dryer to dry red chillies that uses solar energy during sunshine hours and backup energy during non-sunshine hours to dry the product continuously. The developed dryer consists of 20 tube (1800 mm long)- evacuated tube type solar collector, 4 U-type finned electrical heaters (1kW) and an AC motor (1HP) and blower assembly to provide the required air flow rate. The performance evaluation of designed dryer was done for drying red chilli (CH-27) and compared with sun drying, improved sun drying and mechanical drying. Chillies were given physical pretreatment i.e. chopping; drying kinetics of whole and chopped chillies were studied at 2.5, 5 and 7.5 kg/m2 loading density by sun drying, improved sun drying and mechanical drying technique. The quality parameters included colour, ascorbic acid, capsaicin and colouring matter. Solar assisted mechanical dryer took the minimum time i.e. 54.5 hours to dry whole chillies at 7.5kg/m2 loading density followed by mechanical drying (62 hours), sun drying and improved sun drying both of which took nearly 15 days; accompanied by the lowest final moisture content for both whole (5.20 ± 3.47%) and chopped samples (3.97 ± 1.13%). The quality of the product dried using the developed dryer was found comparable to mechanical drying. 33.69 ± 1.36% saving in energy consumption was observed when solar + electrical mode of designed dryer was used as compared to only electrical heater mode.
Open Access
Engineering characterization of kinnow and tomato for grading using image processing
(Punjab Agricultural University, Ludhiana, 2017) Sandhya; Mahesh Kumar
The present study was undertaken for characterization of kinnow and tomato based on engineering parameters using digital image processing. The images of kinnow and tomato of different grades were acquired using a digital camera. An algorithm using MATLAB was developed to quantify and process these digital images. The geometric parameters such as axial dimensions, mass, volume, density, sphericity, aspect ratio and ellipsoid ratio were recorded. The size of kinnow varied between 62.50-87.41 mm while tomato had size varying from 30.00-77.62 mm. Results of image analysis showed variation of major axis length from 1597.21 pixels to 1987.1 pixels for kinnow. The bulk density was found to be maximum (0.40 g/cc) for kinnow having size 72-74mm whereas it was highest (0.26 g/cc) for tomato of size 57-66mm. The sphericity varied in the range of 0.92-0.94 for kinnow while tomatoes of variety Punjab Chhuhara were found to be oblong. The results obtained by digital image analysis were compared and verified with the experimental observation recorded by vernier caliper. The volume computed from the images of longitudinal view and lateral view of kinnow and tomato of all the grades showed good correlation with the true volume measured by water displacement method. The Bland-Altman approach was used to plot the agreement between the values measured by both the methods and differences between two methods were normally distributed and were estimated to lie between M - 1.96SD and M + 1.96SD, known as 95% limits of agreement. The paired samples t-test results showed that parameters determined with image processing method was not significantly (P>0.05) different from the same parameters measured with vernier caliper. A linear relationship between mass of the kinnow and tomato and the projected area, volume and axial dimensions was also developed for prediction of mass using image processing.
Open Access
Ultrasound assisted aqueous enzymatic extraction of maize (Zea Mays L.) germ oil
(Punjab Agricultural University, Ludhiana, 2017) Datt, Samridh; Sidhu, Gagandeep Kaur
In the present study ultrasound assisted aqueous enzymatic extraction of maize germ was carried out. A three-variable, three-level response surface methodology using Box–Behnken design (BBD) was applied for optimizing the extraction condition in order to obtain the high oil recovery from the maize germ. The three independent variables set were extraction temperature (40-60°C), ultrasonic pre-treatment time (40-60) min, and water to seed ratio (4:1-6:1w/w) at the three levels. A total of seventeen experiments were designed. By considering all the responses simultaneously for optimization, it was found that the optimum conditions for extraction of maize germ using UAAE method was found as incubation temperature of 40°C, time 60 min and water to seed ratio of 4.86:1 respectively. The maximum oil recovery under these was found as 86.20%. The optimized samples had a saponification value of 189.27 (mg KOH/g), acid value 3.15 (mg KOH/g), FFA 1.58 (mg KOH/g), peroxide value of 5.01 (millieq), density 883.55 (kg/m3), color change 20.08, refractive index of 1.50 respectively and total extraction time was 7.5 h and it was taken as the basis for the comparison with solvent extraction method. It was found that oil recovery from solvent extraction was nearly same as that of UAAE but the quality parameters of the UAAE extracted oil was better than that of solvent extracted oil. The oil extracted by the optimized parameters of UAAE oil and the oil extracted by the solvent extraction method were subjected to storage in the glass and HDPE bottles in dark and light under ambient conditions. There was considerable change in the quality parameters in the solvent extracted oil and UAAE oil was quite stable even after the 90 days of storage. The extraction method was also subjected to economic analysis, it was clear that an initial investment of `2479360, the project gives profit of `370685 and payback period of 0.30 years and can provide employment to 2-3 persons.
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Optimization of greenhouse drying process for white button mushroom (Agaricus bisporus)
(Punjab Agricultural University, Ludhiana, 2016) Sidhu, Jashandeep Singh; Amarjit Singh
The present study entitled “Studies on optimization of greenhouse drying process for white button mushroom (Agaricus bisporous)” was carried out in the Department of Processing and Food Engineering, Punjab Agricultural University. Mushrooms were pretreated with citric acid and samples without treatment were kept as control. The treated and untreated mushroom samples were dried in greenhouse and open sun during the month of October, 2015.On the basis of microclimate parameters, a mathematical thermal model “BITGREEN” for greenhouse was developed to optimize the drying conditions. The developed model was working satisfactorily to predict the microclimate inside the greenhouse. The drying parameters studied were moisture content, moisture ratio, drying rate, drying air temperatures, solar intensity and relative humidity. The quality parameters included rehydration ratio, shrinkage ratio, colour, texture (hardness), bulk density, protein content and overall acceptability. Moisture content of dehydrated mushrooms reduced from 88-90 (% wb) to 6.5 (% wb) for greenhouse drying (28-46°C) in 48 hours and 8.2 (% wb) for open sun drying (25-32°C) in 72 hours. The Lewis model showed best adequacy of fit for drying of mushrooms. The dried mushrooms were packed in two packaging materials viz. LDPE and PP and stored under refrigerated and ambient conditions for three months. The quality attributes of stored product like colour, texture, rehydration ratio, shrinkage ratio, water gain and overall acceptability were evaluated at 15 days interval. The greenhouse dried mushrooms packed in polypropylene (PP) and stored under refrigerated conditions were found to be highly acceptable upto 75 days of storage. Benefit-Cost ratio of 1.36:1 for subsidized greenhouse revealed that it is profitable to dry mushrooms in greenhouse.
Open Access
Development of Oil Extraction Method from Kinnow Peel
(Punjab Agricultural University, Ludhiana, 2016) Sharma, Pallavi; Tarsem Chand
The study was conducted to develop an oil extraction method from kinnow peel on the basis of shredding of flavedo layer. Mechanical and Solar drying of peel was performed and drying kinetics and physico-chemical characteristics were evaluated. Oil was extracted from fresh peel either by using physical or hydrodistillation method alone or in combination whereas only hydrodistillation method was used in case of dried peel. Qualitative and quantitative analysis of the oil was done. It was observed that oil yield in physical method was 0.179% with a shredding efficiency and extraction time of 88.94% and 25 minutes respectively. The initial and final moisture content of kinnow peel was 316-354.80% and 7.06-7.4% respectively. Luminous intensity and yellowness of peel decreased significantly (p<0.05) in both mechanical and solar drying. Colour difference (∆E) of kinnow peel ranged from 15.33-18.36. Oil retention capacity, total phenols, flavanols, total antioxidant capacity and swelling index decreased significantly (p<0.05) on drying whereas water retention capacity and solubility increased. Highest oil yield was obtained from hydrodistillation from mechanically dried powder. Colour values of varied significantly (p<0.05) with respect to oil extraction method. Physically extracted oil showed highest redness (a) value and whereas highest yellowness (b) was shown by hydrodistilled oil from fresh peel. Saponification value, acid value, specific gravity, refractive index of oil ranged from 181.73-186.90 mg KOH/ g oil, 3.46-5.023 mg KOH / g oil, 0.803-0.856 and1.352-1.486 respectively.
Open Access
Fabrication of ventilated structure for storage of onion
(Punjab Agricultural University, Ludhiana, 2017) Nancydeep Kaur; Mahesh Kumar
Onion is an important crop of the country that is consume throughout the year. Recently due to greater economic return associated with this crop, the farmers in our state have also paid enough attention for the cultivation of this crop. Looking at the physiology of this crop there is a lack of proper storage structure for keeping the bulb for such a long time so the present study was undertaken to develop suitable storage structure. As storage life of the onions is linked with its harvesting at proper stage followed by thorough curing. Properly harvested onion crop at vegetable farm of PAU was field cured. It was also cured in shade as well as in mechanical drier. Using this information a ventilated onion storage structure of capacity 1.25 tonn was fabricated. The results indicated that the highest losses (22.55 %) were recorded when the onion cured at the open field for 5 days, followed by shade curing treatment (18.08 %) for 9 days and the lowest losses were 15.8 % for the artificial curing treatment at the end of storage period. Physical characteristics of onions i.e. average size, angle of repose and bulk density was calculated as 32.75-68.67 mm, 26⁰ and 560 kg/mᶟ respectively. Ventilated storage structure was (size 1.2m х 1.2m х 1.5m) made up of angle iron frame and MS 1 inch square mesh. For ease of loading and unloading the onion, an inclined surface at the base with angle of repose 26 degrees has been provided. Three axial flow fans at the base of ventilated storage structure created variable air flow rate with air velocities of 0.27 m/s, 0.32 m/s, 0.69 m/s, 0.9 m/s and 1.38 m/s. Onions in bulk were filled in the structure and samples of 10 kg of 5 onion bags were kept at different location within the structure and at different air velocities for this study. The variations in vital parameters were compared with commercially cold stored onions in cold stores (0 to -1⁰C). It was observed that PLW, sprouting, TSS, colour difference, moisture content, hardness, ascorbic acid and reducing sugars during 3 months of storage varied significantly at CD 5% level of significance. This study indicates that onions which were stored at air speed 1.38 m/s and cold stored showed minimum loss and maximum retention of chemical properties. But due to high rent of cold stored onions, cold storage is not normally preferable in India.
Open Access
Design and Optimization of Modified Atmosphere Packaging for black carrot (Dacus carota L.)
(Punjab Agricultural University, Ludhiana, 2016) Singla, Mohit; Ashok Kumar
The present study was undertaken to Design and optimization of Modified Atmosphere Packaging (MAP) for black carrot (Dacus carota L.) to obtain the maximum shelf life on the basis of quality attributes and sensory evaluation during the storage study experiment. Respiration and transpiration rates of black carrot at different temperatures viz. 5, 10 and 15°C were determined. The respiration rate was described assuming the mixed model inhibition in the enzyme kinetics model. Arrhenius relationship was used to explain the temperature dependence of respiration rate, respiratory quotient and transpiration rate of fresh black carrot. A theoretical analysis for design of MAP for selection of appropriate packaging film was carried out by matching the data obtained in respiration study with the permeabilities of commercially available packaging films. Black carrot was packed in LDPE and stored under different conditions such as film thickness: 100, 150, 200 gauge; package fill weight = 100, 300, 500g; level of perforations: 0, 2, 4; storage temperature: 5, 10, 15°C. The qualitative analysis of black carrot throughout the storage study was done in terms physiological loss in weight, total colour difference, firmness, total soluble solids, antioxidants, flavonoids and anthocyanins. Sensory evaluation was done on the basis of visual appearance, odour rating and water accumulation. The study also revealed that the low temperature storage better retained the quality and quantity of fresh black carrot during its storage. MAP along with low temperature storage helped in enhancing shelf life of fresh black carrot upto 24 days. The optimized conditions obtained for shelf life extension of black carrot under MAP by using response surface methodology was temperature: 5°C, film thickness: 200 gauge, fill weight: 500 g, perforations: 0.
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OPTIMIZATION OF CONVECTIVE-CUM-MICROWAVE DEHYDRATION OF OYSTER MUSHROOMS (Pleurotus sajor-caju)
(2013) Sakti Bansal
Investigations were carried out to study the effect of drying parameters viz. loading density, air velocity, power level on convective-cum-microwave dehydration of oyster mushroom. Multi layer drying of commercially grown mushroom cv. Pleurotus sajor-caju was carried out at 3 levels of loading densities (26-52 kg/m2) and air velocities, 3-5 m/s and microwave drying was carried out at 3 power levels (270-810 W). The drying parameters studied were drying rate, temperature and relative humidity of outgoing air, product temperature and heat utilization factor. Quality attributes included rehydration ratio, shrinkage ratio, texture (hardness and chewiness), colour and overall acceptability. Multi layer drying of mushroom with an initial moisture content of 91% wb was carried out at 60°C in a mechanical drier till the moisture content reached 27% wb followed by drying in microwave oven to a final moisture content of 6.89% wb. It was observed that drying rate, 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. The decline in drying rate increased with increase in air velocities and power level whereas opposite trend was observed for loading densities. Increase in loading density and air velocity resulted in decrease in heat utilization factor and relative humidity however temperature of outgoing air and product showed the opposite trend. Logarithmic model showed the highest adequacy of fit for multi layer drying and two term exponential model for microwave drying. The effective moisture diffusivity increased with increase in both loading density and air velocity. The increase in loading density resulted in increase in rehydration ratio, shrinkage ratio, colour change but decrease in texture and overall acceptability. The increase in air velocity resulted in increase in rehydration ratio, hardness, colour change overall acceptability but decrease in shrinkage ratio and chewiness. The increase in power level resulted in increase in rehydration ratio, texture, colour change and decrease in shrinkage ratio and overall acceptability. The optimum conditions for convective-cum-microwave drying of mushroom were found to be 38.80 kg/m2 loading density, 3.86 m/s air velocity and 413.6 W power level. Keywords: Oyster mushroom, drying kinetics, quality, optimization

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