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Theses

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2013 - 20162
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Subject: Agricultural Processing and Food Engineering × Type: Thesis × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Optimization of process parameters for cryogenic grinding of dried ginger
    (Department of Food and Agricultural Process Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 2016) Bhavya, Francis; KAU; Santhi Mary, Mathew
    The processing of spices requires additional care because they are sensitive to atmospheric parameters like temperature and light. The exposure to temperature during any of the processing stage may lead to their quality deterioration in terms of colour, volatile oil, volatile oil constituents, oleoresin content etc. The grinding of spices at cryogenic temperatures helps in retaining the heat sensitive components in the spices. This study envisages on the cryogenic grinding of dried ginger in order to optimize the grinding conditions, considering the important quality characteristics and compared the cryoground powder with the conventionally ground ginger. The physical properties which affect the grinding process directly or indirectly were also determined. The experiments on cryogenic grinding have been carried out for different feed rates and grinding temperature and the best combination was determined in terms of product quality as well as grinding characteristics. The optimized feed rate and temperature were 35 kg/h and -130±5°C. The lower temperature in the grinding zone solidifies the moisture and oil components in the raw material and makes it brittle, which facilitates the grinding easy and faster thus leads to less energy consumption. The extreme cold condition prevents the volatile oil loss and lead to their higher retention. The comparison of cryoground powder with the powder obtained by conventional method has shown that cryogenic grinding prevented the essential oil and oleoresin loss of ginger considerably and retained its constituents. The colour of cryoground ginger powder was superior and the particle size was finer. The time of grinding and specific energy consumption was found lower in cryogenic grinding. The packaging studies on ginger powder showed that laminated aluminum foil is suitable for long term storage.
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    ThesisItemOpen Access
    Post harvest evaluation of bitter gourd as influenced by growing condition, harvest maturity, prepacking and storage
    (Department of Processing Technology, College of Agricutlure,Vellayani, 2013) Gajanan Baburao, Phuke; KAU; Geethalekshmi, P R
    The present investigation on “Postharvest evaluation of bitter gourd as influenced by growing condition, harvest maturity, prepackaging and storage” was carried out at the Department of Processing Technology, College of Agriculture, Vellayani during 2011-2013, with the objective to determine the stage of harvest maturity and its influence on postharvest life along with prepackaging and storage condition for organically and conventionally grown bitter gourd (var. Preethi) and to develop a postharvest package for extended shelf life with minimum nutritional loss. The experiment was conducted in three continuous phases such as determination of harvest maturity, precooling treatments, prepackaging and storage. Growth and development studies conducted for determining harvest maturity revealed that fruit length, width, weight and flesh thickness increased periodically till 15 days of flowering and percentage of increase was negligible 15 days after flower opening. But conventional fruits recorded higher values for all these physical characters at all the stages of maturity. Considering the development of both external and internal fruit characters, 14 and 15 days after flower opening were selected as optimum harvest maturity for further postharvest studies. Hydrocooling of harvested fruits with 150 ppm sodium hypochlorite was found as the best sanitizing treatment for maintaining the postharvest quality and increased shelf life for both harvest maturities (14 and 15 days) and growing conditions (organic and conventional). Prepackaging and storage trials revealed that prepackaging treatments, growing conditions and storage temperature had significant influence on shelf life and nutritional qualities of fruits. Fruits with 14 days maturity, grown organically, prepackaged in micro ventilated polyethylene and stored under refrigerated condition had resulted in lowest PLW. Nutritional parameters of fruits viz, protein, acidity, fibre, calcium, magnesium, iron and ascorbic acid were analysed before storage and at the end of shelf life. Before storage, none of the factors except growing conditions had significantly influenced the nutritional parameters. Fruits grown conventionally had higher protein and organic fruits exhibited high fibre, Ca, Mg, Fe and ascorbic acid content. Storage studies revealed that refrigerated storage after prepackaging in micro ventilated PE had lower nutritional and physiological changes during storage. From the study it can be concluded that bitter gourd (var. Preethi) fruits can be harvested at 14 days maturity for export and long distance market and 15 days for domestic market grown under both organic and conventional system in order to reduce the postharvest losses. Harvested fruits precooled with water containing 150 ppm sodium hypochlorite, prepackaged in micro ventilated polyethylene and stored under refrigerated condition was effective for extending the shelf life with minimum nutritional loss.