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2016 - 201912020 - 20212
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Subject: Agricultural Engineering × Author: KAU × Start date: 2016 × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Development and evaluation of process protocol for vacuum fried carrot chips (Daucus Carota L)
    (Department of Processing and Food Engineering, KCAET, Tavanur, 2021) Babu, P; KAU; Rajesh, G K
    Carrots are highly nutritious vegetable, which can be consumed in raw and processed form throughout the world. Carrot plays a vital role in the development and protection of human body. Carrot contains vitamins viz., B1(Thiamine), B2(Riboflavin), B6(Niacin) and B12 (Cobalamin) besides rich in source of βcarotene and dietary fibre which are helpful to prevent cancer and other dreadful diseases occur in human body. In Kerala state, carrot production is very limited, but its consumption is more. The postharvest losses of carrot were estimated as 18- 20%. The development of value-added products from carrot was an idealistic solution to reduce the postharvest losses by adopting new processing technologies. At present, due to consumer’s awareness, there is a lot of demand for healthy and tasty snack products with less oil content which provide good health. In this context, investigation on processing technologies focus on producing high quality fried products with less oil content and good textural property. The technology of vacuum frying is a best option for the production of novel snacks which fulfil the consumers demand and meet nutritious requirements. Vacuum frying is a novel technology, in which the food is heated under lower temperature and pressure(<6kPa). Vacuum frying lowers the water activity, oil content, retains the color and preserve nutrients in the fried product. The batch type vacuum frying system consists of two chambers viz., frying chamber (3kg capacity) and oil storage chamber (30-35L capacity). The refined palm oil was used for vacuum frying and de-oiling was done at 1000 rpm for 10 min. After every batch of vacuum frying, the oil was collected for quality analysis. Prior to the research, the physico-chemical properties of raw carrot (Ooty-1) was determined. The pre-treatments viz., blanching, blanching cum drying, blanching cum freezing, freezing and gum coating were optimized based on the quality of vacuum fried carrot chips. The freezing pre-treatment obtained the best results among other pre-treatments in terms of less oil content (14.48 %), water activity (0.214), moisture content (2.67%), hardness (1.282 N) and red color retention of a* value (22.85). The standardization of process parameters were done using RSM (CCRD) based on the quality characteristics of VF-carrot chips. The process parameters seected in this study were frying temperature (100,110 and 1200C), frying pressure (11,13 and 15 kPa) and frying time (16,18 and 20 min). The optimum operating conditions of vacuum frying viz., frying temperature, vacuum pressure and frying time were found to be 100°C, 11 kPa and 16 min respectively. At optimum operating conditions of 100°C, 11 kPa and 16 min, the quality parameters were oil content (11.31%), bulk density(0.873 g/cm3 ), true density(1.714 g/cm3 ), moisture content(3.28%), water activity (0.384), hardness (1.31 N),thickness expansion (60.42%), L*(43.48), a*( 14.36) b*(28.12) and energy content(1021 KJ/100g). Packaging and storage studies were conducted for the treatments which had high sensory score. The laminated aluminium flexible pouch with N2 gas filling was found to be the best packaging technique to enhance the shelf life of VF carrot chips to a storage period of 4 months. The oil quality parameters viz., total polar compounds (TPC), viscosity, peroxide, free fatty acids (FFA) etc were within the allowable limits even after 40 batches of vacuum frying. The total production cost of 1kg of vacuum fried carrot chips was found to be Rs. 355/-.
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    ThesisItemOpen Access
    Investigations on high rate anaerobic bioreactor for energy production from rubber latex processing effluent
    (Department of Farm Machinery and Power Engineering, Kelappaji College of Agricultural Engineering and Technology,Tavanur, 2020) Megha, A S; KAU; Shaji James, P
    Agro-processing industries often contribute significantly in pollution due to discharge of untreated effluents. By anaerobic digestion of these organic effluents, methane rich gas can be produced which is suitable to generate electricity and process heat. But conventional biogas plants are slow in operation with long hydraulic retention times of 35 to 40 days which necessitates large digester volumes. So, anaerobic digestion of high volume agro-processing effluents is feasible only through high rate bioreactors which can reduce hydraulic retention time to few hours. Rubber latex processing effluent (RLPE) is a dilute waste water for which high rate anaerobic treatment can be an affordable technology. Hence, an investigation was taken up to study the performance of Up-flow Anaerobic Hybrid Bioreactor for energy conversion of rubber latex processing effluent (RLPE). Physico-chemical characteristics of RLPE samples were tested and found that RLPE was a dilute waste water with pH in the acidic range. BOD: COD ratio of 0.44 obtained in this study showed good biodegradability of RLPE. A batch anaerobic digestion study was conducted as a preliminary experiment to investigate the biomethanation characteristics of RLPE. The experiment consisted of four treatments having different composition of RLPE with inoculums replicated thrice. This study could prove that RLPE could be subjected to biomethanation and cow dung slurry can be used as inoculum. Even at a lower inoculum: substrate ratio of 1:2, the system could be started up yielding substantial amount of biogas coupled with good TS reduction. Performance of field scale Up-flow Anaerobic Hybrid Bioreactors (UAHBR) was assessed by operating them at different HRTs of 10, 7, 5, 3 and 2 day. During the study an interruption of 2 months in operation occurred due to shut down of the processing unit due to Covid 19. After interruption of 2 months reactor recovered within one month and it proved that hybrid bioreactor could be restarted easily after a shutdown for few months. Reactor was stable in operation during 10, 7, 5, 3 and 2 day HRTs and exhibited good process efficiency with better pollutant reduction and biogas production. Performance was seen deteriorated beyond 5 day HRT. The bioreactors were operated successively at reduced loading rates corresponding to the longer HRTs after reaching the shortest HRT of 2 day. It was observed that there was no considerable difference in daily biogas production with the earlier values obtained during the progressive decrease in HRT. This revealed that the bioreactors would have achieved the maximum possible microbial population already and there was no further improvement in performance on further passage of time. The performance parameters obtained in the investigations with field scale reactors were used for evolving guidelines to design a full scale anaerobic bioreactor. The UAHBR performance was quite satisfactory at 5 day HRT with respect to pollutant reduction as well as energy production. Hence as criteria, full scale plant was proposed to be operated at 5 day and the corresponding reactor volume was 27 m 3 with 7.2 m 3 gas holder volume. The biogas expected to be produced from the full scale plant can be used in a biogas fired rubber sheet dryer which can save about 500 kg of fire wood per day currently used for drying rubber sheets.
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    ThesisItemOpen Access
    Tank mix application of cyhalofop-butyl with selected herbicides for weed control in wet seeded rice
    (College of Horticulture, Vellanikkara, 2016) Atheena, A; KAU; Prameela, P
    Herbicidal weed control is very common in rice cultivation. Application of pre- emergence and post emergence herbicides or two post emergence herbicides as follow up sprays is usually recommended to take care of diverse weed flora in rice. As this increases the cost incurred in spraying, farmers prefer single spray of a mixture of herbicides or a broad spectrum herbicide. Cyhalofop-butyl is a common cost effective post emergence selective herbicide that controls grass weeds, especially the rice associated weed Echinochloa spp. and Leptochloa chinensis. The present study was carried out to study the efficacy and economics of tank mix application of cyhalofop-butyl with selected herbicides (pre emergence, post emergence and early post emergence) and to study the response of weed flora to tank mix application. A field experiment was conducted in Alappad kole lands from September 2015 to January 2016, using the rice variety Uma (MO-16). There were a total of 16 treatments replicated thrice. Almix® [chlorimuron-ethyl (10%) + metsulfuron-methyl (10%)], ethoxysulfuron, carfentrazone-ethyl, pyrazosulfuron-ethyl, pretilachlor, pendimethalin were tank mixed with cyhalofop-butyl and were also applied as follow up sprays, two days after cyhalofop-butyl application. For better comparison, sole application of cyhalofop-butyl, as well as a broad spectrum post emergence herbicide, bispyribac sodium, were also included apart from hand weeded and unweeded controls. Pre emergence herbicides were sprayed at six days after sowing (DAS), and early post emergence herbicide at 10 DAS. All tank mix herbicide applications were done at 18 DAS and follow up post emergence herbicide applications at 20 DAS (i.e., two days after the application of cyhalofop-butyl). Hand weeding was carried out at 20 DAS and 40 DAS. The data on weed spectrum revealed that broad leaf weeds and grasses were dominant and at 30 DAS they constituted 47 per cent and 46 per cent of the population respectively, whereas sedges constituted only 7 per cent. Echinochloa stagnina was the dominant grass and Monochoria vaginalis, the dominant broad leaf weed. Among tank mix applications of herbicides, cyhalofop-butyl + pyrazosulfuron-ethyl recorded the least weed dry matter production while among various sequential application of herbicides, the lowest weed dry matter accumulation was noted in cyhalofop-butyl followed by (f.b.) Almix® and both were statistically comparable. Among various herbicides and herbicide mixtures, both tank mix and sequential applications of carfentrazone-ethyl caused severe phytotoxicity in rice. However, the crop recovered by seven days after spraying and plant growth parameters were not affected with all the treatments registering comparable plant height at all stages. At both 30 DAS and 60 DAS, hand weeded treatment registered the highest tiller count. However, this was on par with bispyribac sodium, pyrazosulfuron-ethyl + cyhalofop-butyl and cyhalofop-butyl f.b. Almix®. Highest and statistically superior grain yield was registered in hand weeded treatment. Application of cyhalofop-butyl + pyrazosulfuron-ethyl and bispyribac sodium were the next best treatments with respect to grain yield and were superior to all other treatments. Except for pyrazosulfuron-ethyl all other herbicides resulted in lower grain yields when tank mixed with cyhalofop-butyl with weed index in the range of 13to 18 per cent and weed control efficiency in the range of 61 to 76 per cent (at 30 DAS). Application of follow up sprays of herbicides for control of broad leaf weeds after cyhalofop-butyl resulted in grain and straw yields comparable to that of single application of bispyribac sodium, which recorded a higher B:C ratio of 2.4. From this study it can be concluded that tank mix application of cyhalofopbutyl with pyrazosulfuron-ethyl at 18 DAS can be recommended for effective control of mixed weed flora in wet seeded rice as this treatment resulted in the highest B:C ratio (2.5) as well as net returns. It is not advisable to go for tank mixing of cyhalofop-butyl with Almix® as it will lead to complete loss of activity of cyhalofopbutyl. Tank mixing of pre emergence herbicides with cyhalofop-butyl was found to be less effective than their sequential application.