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Singh P.L.,Central Institute of Agricultural Engineering
Applied Energy | Year: 2011

The thin layer silk cocoon drying was studied in a forced convection type solar dyer. The drying chamber was provided with several trays on which the cocoons loaded in thin layer. The hot air generated in the solar air heater was forced into drying chamber to avoid the direct exposure of sunlight and UV radiation on cocoons. The drying air temperature varied from 50 to 75. °C. The cocoon was dried from the initial moisture content of about 60-12% (wb). The drying data was fitted to thin layer drying models. Drying behaviour of the silk cocoon was best fitted with the Wang and Singh drying model. Good agreement was obtained between predicted and experimental values. Quality of the cocoons dried in the solar dryer was at par with the cocoons dried in the conventional electrical oven dryer in term of the silk yield and strength of the silk. Saving of electrical energy was about 0.75 kWh/kg cocoons dried. Economic analysis indicated that the NPV of the solar dryer was higher and more stable (against escalation rate of electricity) as compare to the same for electrical oven dryer. Due to simplicity in design and construction and significant saving of operational electrical energy, solar cocoon dryer seems to be a viable option. © 2010 Elsevier Ltd.

Tripathi M.K.,Central Institute of Agricultural Engineering | Giri S.K.,Central Institute of Agricultural Engineering
Journal of Functional Foods | Year: 2014

Probiotic foods are reported to provide several health benefits, as they help in maintaining a good balance and composition of intestinal flora, and increase the resistance against invasion of pathogens. The demand of probiotic functional foods is growing rapidly due to increased awareness of consumers about the impact of food on health. Development of foods with adequate doses of probiotics at the time of consumption is a challenge, because several factors during processing and storage affect the viability of probiotic organisms. The presence of probiotics in food products may also adversely affect their quality and sensory properties. Several attempts have been made during the last few decades to improve the viability of probiotics in different food products during their production until the time of consumption. Major emphasis has been given to protect the microorganisms with the help of encapsulation technique, by addition of different protectants, and by alteration of processing and storage conditions. This contribution provides an overview of probiotic foods, factors responsible for survival of probiotics, and advance technologies used to stabilize their viability during processing and storage. © 2014 Elsevier Ltd.

Gangil S.,Central Institute of Agricultural Engineering
Bioresource Technology | Year: 2014

Dominant thermogravimetric signatures related to lignin were observed in cashew shell as compared to these signatures in cashew shell cake. The phenomenon of weakening of lignin from cashew shell to cashew shell cake was explained on the basis of changes in the activation energies. The pertinent temperature regimes responsible for the release of different constituents of both the bio-materials were identified and compared. The activation energies of cashew shell and cashew shell cake were compared using Kissinger-Akahira-Sunose method. Thermogravimetric profiling of cashew shell and cashew shell cake indicated that these were different kinds of bio-materials. © 2013 Elsevier Ltd.

Gangil S.,Central Institute of Agricultural Engineering
Renewable Energy | Year: 2015

The paper proves that briquettes of lignocellulosic crop residues have higher activation energy levels of intrinsic biopolymers as compared to these energy levels in wood, especially in context with the hemicellulosic and cellulosic segment. Binderless briquettes made of residues from pigeon pea and soybean crops were analyzed in comparison with wood. Thermal decompositions of these biofuels were experimented by thermogravimetry under pyrolysis environment and the transitions of the thermogravimetric signals were explained. Popular isoconversional kinetics method, namely integral Ozawa-Flynn-Wall was used to evaluate and compare the activation energies. Kinetics analyzed that wood was thermally weaker than the briquettes. © 2014 Elsevier Ltd.

Thermogravimetric signals of hemicellulose and lignin were found to subside due to the binderless briquetting of soybean crop residue. Minor but distinct thermogravimetric signals of secondary charring reactions were observed in raw crop residue and its briquetted biofuel. The bio-component related kinetics was evaluated using the Kissinger method. Activation energy level of intrinsic cellulosic biopolymer was found higher in briquette than that level in crop residue. The activation energy profile with respect to conversion fraction for raw residue and its briquette was analyzed by the Kissinger eAkahiraeSunose method. The activation energy profile of briquette was superior to raw residue of soybean crop showing the better thermal stability in briquetted biofuel, highlighting the benefits of briquetting process. In addition to the physico-chemical transformations occurred in lignin, the hemicellulose and cellulose related transitions were also expected to play positive role for briquetting. © 2015 Elsevier Ltd.

Gangil S.,Central Institute of Agricultural Engineering
Cellulose | Year: 2014

Distinct splitting of the cellulosic polymer signal was seen in thermogravimetric analysis of cashew shell (CS). The splitting was more pronounced in CS as compared to cashew shell cake. The splitting of cellulosic polymer peaks was ascribed to cellulosic depolymerization occurring in two phases during thermal degradation of CS. Three protective tissue configurations of CS was considered responsible for this phenomenon. Kinetics were compared by using two model free isoconversional methods, namely the Friedman and Ozawa-Flynn-Wall. © 2014 Springer Science+Business Media Dordrecht.

Gangil S.,Central Institute of Agricultural Engineering
Environmental Engineering Science | Year: 2014

Thermogravimetric degradation of two kinds of char obtained from two different types of systems, confined and unconfined, was studied. In a confined system, charring was accomplished in a closed chamber in which vapors produced during the charring process were captured within the system and were forced to condense on the char being produced. In the unconfined charring system, a passage was available for the escape of gaseous substances evolved during the charring process; the presence of condensed volatiles in produced char was low. Using thermogravimetric analysis, differences between chars produced in these two systems were studied and it was proved that the char from the unconfined system showed a superior profile of apparent activation energy as compared with the char from the confined system due to higher presence of condensed vapors of volatiles in the char produced in confined conditions. A first-order derivative of thermogram of the char generated in the unconfined system showed a broad peak, at higher temperature segments, ascribed to the thermal decomposition of heavier volatiles and lignin. Activation energies for both types of char were determined and compared using the Coats-Redfern method. Char obtained from the unconfined system had higher thermal stability. This article recommends that for generation of more thermally stable char, unconfined charring chambers should be preferred. A new direct and simple method was used in this article to define the accelerating or retarding nature of thermal decomposition process using segmental analysis of conversion fraction. © 2014 Mary Ann Liebert, Inc.

Murugkar D.A.,Central Institute of Agricultural Engineering
Journal of Food Science and Technology | Year: 2014

The effect of sprouting of soybean and preparing soymilk and tofu on the yield, nutritional quality, anti-nutritional profile, colour attributes, organoleptic quality and texture profile (tofu) of four commonly used varieties of India were studied to assess the feasibility of using sprouting as a non-chemical, non-thermal tool to improve quality of soy products. Soymilk was prepared from sprouted and unsprouted seeds with process parameters of 121 °C for 25 min. Coagulation of soymilk was done with 3% CaSO4 at 80 °C. Products from sprouted varieties showed an increase in protein (fb) of 7% in milk and 13% in tofu across varieties; a reduction in fat (fb) of 24% in milk and 12% in tofu; in trypsin inhibitor (db) of 73% in milk and 81% in tofu; in phytic acid (db) of 59% in milk and 56% in tofu across varieties. Tofu from sprouted seeds had higher protein and whiteness index but tofu strength was around 43% lesser than its unsprouted counterpart. Taste acceptability showed an increase of 10% and 6.3%; flavour of 23.2% and 11.6% and overall acceptability of 9.9% and 4.4% in milk and in tofu respectively from sprouted varieties. The improvements in composition and quality parameters was seen in all the varieties tested showing that sprouting could be beneficial for product development across varieties. The time and temperature used for production of soymilk was conventional (121 °C for 25 min). Evaluation of time and/temperature reductions could be tried out to reduce the heat requirement and intensity, which could result in better nutritional and functional quality products © 2011 Association of Food Scientists & Technologists (India).

Gangil S.,Central Institute of Agricultural Engineering
Energy and Fuels | Year: 2014

The consolidation of different polymeric bioconstituents was clearly observed in briquetted biofuel produced from pigeon pea crop residues. Critical thermogravimetric diagnosis showed that the scattering of tail end segments of thermograms taken at different heating rates was remarkably low in briquetted biofuel as compared to the scattering in raw material. The consolidation of polymeric cellulose and lignin was discussed and explained. Kinetics was evaluated using isoconversional integral Ozawa-Flynn-Wall method. The activation energy profile of briquetted biofuel dominated over the raw pigeon pea stalks showing higher thermal stability, which was evidence, positive toward the consolidation of intrinsic biopolymers due to briquetting process. © 2014 American Chemical Society.

Transitions of thermogravimetric signals beneficial for formation of the binder-less briquetted biofuel of pigeon pea crop residues were investigated. Thermal hardening or softening of the different components of bio-material in briquetted biofuel was explained in terms of transitions of thermogravimetric signals and activation energy levels. The activation energy profiles with respect to conversion fraction for raw residue and its briquette was studied by Kissinger-Akahira-Sunose method. The activation energy profile of briquette showed dominancy over raw residues of pigeon pea crop highlighting the overall hardening in briquetted biofuel. © 2014 Elsevier Ltd. All rights reserved.

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