Asian Research Thesis Index

Abstract

Rice bran, one of the main by-products of rice milling industry, has been recognized as an excellent source of edible oil, protein, dietary fiber and allied micronutrients. In Pakistan, it is under-utilized and generally used in poultry feed and fuel purposes. It contains about 15-20% edible oil, which could efficiently be used for bridging the oil deficiency in the country. Current research was conducted to utilize indigenous rice bran (RB) for oil extraction as well as preparation of value-added products. Rice bran samples, stabilized by extrusion cooking, microwave heating and parboiling; were analyzed for lipase activity during 60 days storage. On the basis of analysis, microwave (MW) stabilization was found to be the most effective stabilization technique in controlling lipase activity. After stabilization, oil was extracted from bran samples and evaluated for physical & chemical characteristics, fatty acid profile and antioxidant potential. In current study, microwave stabilized rice bran (MW-RB) was preferred on the basis of better stability (FFA, POV and TBA no.), color of oil and high antioxidant potential. MW stabilized fullfat rice bran (FFRB); its defatted portion (DFRB) and extracted oil (RBO) were used for efficacy studies and preparation of value added products. The diets prepared from selected treatments alongwith control were fed to four groups of SD-rats for 45 days and evaluated for physical and hematological parameters. The rats fed on RBO diet had the highest feed intake (19.21g/rat/day); water intake (37.81mL/day) and gain in body weight (7.24g per rat/week). Mean squares for organs weight, renal and liver functioning tests exhibited non-significant differences with respect to diets and study periods in different groups of rats. Animals fed on RBO, FFRB and DFRB resulted significant reduction in serum cholesterol, LDL and triglycerides. It was concluded that experimental diets imparted no adverse effects on the animal growth and improved serum profile of SD-rats; showing suitability of RB and RBO for product development. In the 2 nd phase of research, RBO was supplemented in cookies by replacing normal shortening. It was concluded that rice bran oil can successfully be used for preparation of cookies upto 40-60%. Moreover, FFRB and DFRB were mixed separately with commercial straight grade flour in different proportions and analyzed for chemical composition and rheological behavior to find out the most appropriate compositions showing suitability for preparation of cookies and leavened bread. Later, cookies and leavened breads were prepared from selected FFRB and DFRB supplemented flours. On the basis of physicochemical and sensory assay, it was concluded that cookies can be supplemented 10-20% and leavened pan bread upto 15% with either type of rice bran without affecting nutritional and sensory quality attributes. From the present investigation, it is concluded that rice bran has a potential to be used for oil extraction and preparation of value added products. This will not only be helpful to fulfill the country’s edible oil requirement but also to cope with the protein deficiency in the communities at risk through bran supplemented value added products.

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