Thumbnail Image

Thesis

Browse

20133
Reset filters
Subject: Processing and Food Engineering × End date: 2013 × Start date: 2013 ×
Reset filters

Search Results

Now showing 1 - 3 of 3
  • Thumbnail Image
    ThesisItemRestricted
    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
  • Thumbnail Image
    ThesisItemOpen Access
    PROCESS OPTIMIZATION FOR EXPRESSION OF OIL FROM DEHULLED SUNFLOWER (Helianthus annuus L.) SEEDS
    (PAU Ludhiana, 2013) Arul Selvam T; Tarsem Chand
    Mechanical expression of oil from dehulled sunflower seed is highly desirable as it provides, at low cost, non-contaminated, nutritionally rich press cakes which can be processed into nutritious edible foods. Unfortunately, mechanical oil extraction process suffers from certain drawbacks. The dehulled sunflower seeds obstruct forward movement inside the expeller barrel due to the absence of hull portion and less friction. The main focus of the present study was to maximize the oil recovery and obtain nutritionally rich press cakes from dehulled sunflower seeds using mechanical oil expression. Physical and mechanical properties were studied under four different moisture content ranged from 6-18 % (d.b.). The results showed that the geometric mean diameter, surface area, volume, sphericity and aspect ratio, thousand seed/kernel weight, true density, porosity, the angle of repose, static coefficient of friction and rupture energy were found to be increasing linearly for seed and kernel. Whereas bulk density, initial cracking force and mean rupture force decreased linearly with the increase of moisture content for both seed and kernel under study. Pre treatments in the form of steaming and addition of bio-based friction materials such as rice bran and wheat bran at different levels were employed. Central composite rotatable design was used to generate a set of experiment at different pretreatment levels during oil expression. A statistical model predicted the maximum oil yield efficiency, maximum protein, minimum fibre, minimum residual oil, minimum chlorogenic acid, minimum free fatty acid and minimum peroxide value of dehulled sunflower oil and press cakes at these optimized variable conditions for rice bran incorporation: steaming time of 10 min, steaming pressure of 0.5 kg cm-2 and rice bran incorporation of 13.88g 100g-1 of dehulled sunflower seed. For wheat bran incorporation it was at steaming time of 15 min, steaming pressure of 1.00 kg cm-2 and wheat bran incorporation of 15g 100g-1 of dehulled sunflower seed. Using these variables results are validated under experimental condition in three independent replicates. Rice bran incorporated oil expression gave best results with high desirability value.
  • Thumbnail Image
    ThesisItemRestricted
    STUDY ON ESSENTIAL OIL EXTRACTION OF SWEET BASIL (Ocimum basilicum)
    (PAU, 2013) Karanvir Singh
    The present study was undertaken to find the kinetics of sweet basil oil extraction using steam and hydro distillation techniques, to access the quality of extracted oil and to optimize the process parameters for oil extraction. Sweet basil was procured from farms of Fieldfresh Foods Pvt. Ltd., VPO Ladhowal, Distt Ludhiana. The oil was extracted from fresh sweet basil leaves, shade dried sweet basil leaves and sun dried sweet basil leaves with moisture content 85.29%, 17.33% and 12.75% respectively. For extraction of oil from sweet Basil leaves at different moisture contents hydro distillation and steam distillation methods took 3-6 and 0.75- 1 hrs respectively. In case of hydro distillation method there is no oil recovery for each sample during first one hour and it started during second hour whereas in case of steam distillation method oil recovery started within 15 minutes. Maximum yield of 0.27% at 17.33% moisture content and minimum oil yield of 0.23% at 12.75% moisture content was observed in hydro distillation whereas in steam distillation method maximum yield of 0.62% at 85.29% moisture content and minimum yield of 0.16% at 12.75% moisture content was observed. The oil obtained from distillation methods was light yellowish to pale yellowish in color with very little greenish ting. Saponification value, acid value, specific gravity and refractive index were found to be 8.00, 1.90, 0.92 and 1.460 respectively. Sweet basil oil recovered was found to be insoluble in water. Steam distillation method was found to be the best method for oil extraction with maximum oil recovery and minimum time of extraction.