PG Thesis

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    Development of cocoa drier
    (Department of Agricultural Engineering, College of Horticulture, Vellanikkara, 1985) Abdassalam, M; John Thomas, K
    An investigation for the development of an electrically heated, multistage, agitation type cocoa drier, suitable for the Kerala conditions for drying of cocoa beans without impairing the quality, was conducted in the Agricultural Engineering Department of the College of Horticulture under the Kerala Agricultural University. The mini box fermentation method developed in Kerala Agricultural University was selected for fermentation of the beans. The fermented cocoa beans were dried in the sun. The process of sun drying continued upto seven days. The pH of dried beans was 5.2, which was very close to the pH range, 5.3 to 5.5 for good quality beans as per international standards. Hence, the quality of the beans was considered satisfactory. A bulb heated drier developed earlier in K.A.U. was tested* The capacity of the drier tested was 30 kg of fermented beans. The bean could be dried to the desired moisture content in 38 hours. The moisture content of the dried beans was about eight per cent. From the result it was found that for drying one kg of fermented beans approximately 0.760 K.W.H. of electrical energy was required. pH of the dried beans was 5.00. The bulb heated drier was modified and fitted with a 500 watts electric coil heater was also tested. Beans were dried to the desired moisture content in 34 hours. Moisture content of the dried beans was about eight per cent. The result showed that approximately 0.57 K.W.H. of electrical energy was required for drying one kg of fermented beans. The quality of the dried bean was satisfactory because pH of the dried beans was 5.0.The cost of drying per kg of fermented beans was Re.0.47. A modified C.P.C.R.I. model drier of capacity 60 kg of fermented beans was fabricated, tested and economics worked out. For attaining the required moisture content of about eight per cent, the time taken was 64 hours. The result revealed that approximately 0.533 K.W.H. of electrical energy and an amount of Re. 0.36, was required for drying one kg of fermented beans. pH of the dried bean was 5.1 and hence quality of the dried bean was also satisfactory. The modified C.P.C.R.I. model drier fitted with an half h.p. electric motor and a blower was also tested.Beans were dried to the desired moisture content in 42 hours. The result showed that for drying one kg of fermented beans approximately 0.610 K.W.H. of electrical energy was required. Cost of drying per kg of fermented bean was Re. 0.56, Quality of the dried bean was satisfactory since pH was 5.2. An agitation type electrically heated multistage drier of 90 kg capacity was designed, fabricated, tested and its economics was worked out. Tests were carried out with two quantities of cocoa (i.e. 90 kg, and 60 kg), 3 3 different quantity of air (i.e. 0.4 m /second, 0.2 m / second) and varying temperatures (i.e. 56°C, 47°C and 42°C). Air temperature and humidity at various sections of the drier were noted. Also the weight loss of the bean at every hour of drying was noted by using an infrared moisture meter, and the final pH of the dried bean by using a pH meter. From the experiment, using various quantities of beans, with different temperature and air flow, it was found that for drying 90 kg of cocoa beans a temperature of 47°C and air flow rate of 0,4 m3/sec was optimum, for this type of drier. The energy consumed/kg of bean was appromimately 0.69 K.W.H. The pH of the dried beans was found to be 5.3 and hence the quality of the dried bean was satisfactory. Cost of drying per kg of fermented bean was Re. 0.45. One of the objectives of this project was to evolve suitable design of an equipment for drying large quantities of cocoa beans. With this in view an agitation type multistage drier of 2000 kg capacity of fermented beans was designed. Prom the cost analysis it was seen that the cost of drying one kg of bean was only Re. 0.22. The cost of the drier was about Rs.23,000/-. The advantage of agitation type multistage drier are as follows. As the beans were moving in the drier better uniformity in drying was achieved and they were not exposed to high temperature continuously which helped in maintaining the quality of the beans. The drying time was reduced considerably. Energy consumption was less and cost of drying was only 50 per cent compared to other driers. Due to stage by stage drying the loss of heat is reduced and hence the thermal efficiency is high.
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    Development of small scale equipment for extraction of Cocoa butter and production of cocoa powder
    (Department of Agricultural Engineering, College of Horticulture, Vellanikkara, 1982) Ganeshan, V; George, T P
    The primary objective of this project was to evolve a viable technology and equipment system for small scale processing of cocoa beans. The study mainly concentrated on the development of an extraction unit for the separation of butter from cocoa mass. Various equipment required for small scale processing of cocoa beans were either identified or designed.
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    Studies on drying of fish using a BARC - type solar dryer.
    (Department of Processing Technology,College of Fisheries, Panangad, 2011) Vimaladevi, S; Sajan George
    A study was conducted with the aim of evaluating the drying efficiency of a newly designed solar dryer (modified BARC type) in comparison with conventional sun drying. The materials used for drying were beheaded prawn (Metapenaeus dobsoni) and salted fish (Cynoglossus macrostomus). Rate of drying was found to be influenced by the atmospheric temperature and humidity, either using dryer (test or by sun drying (control). In the case of prawn, the drying period was 7h by dryer compared to control which took about 10h whereas in the case of fish it was only 7h compared to control which took about 9h. Various parameters such as moisture content, water activity, TPC, TFC, TVBN content and PV, during drying were monitored. The quality variations in prawn or fish were significantly lower when dried using the solar dryer compared to direct sun drying. Sensory evaluation based on colour, odour, texture and taste, also proved that the solar dried samples were of superior quality compared to control. Sorption isotherm for test and control did not vary much in shape for both prawn and fish. This indicates that the effect of the type of drying on the bound water of the products. For conducting storage studies the dried prawn and dry salted fish, both test and control, were packed in low permeable polypropylene- polyamide bags and stored at room temperature for about 80 days. Quality parameters, viz., moisture content and water activity, TPC, TFC, TVBN content, PV and sensory evaluation based on colour, odour, taste and texture were evaluated during storage. Both test and control samples remained acceptable throughout the storage period. However, the quality of prawn or fish dried in solar dryer was found to be superior compared to their respective sun dried control samples. The additional cost was only Rs 2.40/ kg for dried prawn and Rs 2.00/ kg for dry salted fish. The equipment is recommended for small scale production of dried products.