Title : Effect of physical processing of commercial de-oiled rice bran, hydrothermal and biotechnological treatments on nutraceutical content and antioxidant activity of rice bran; Physico-chemical and nutritional properties of germ from different types of rice bran
Rice bran is a rich source of nutrients and nutraceuticals, which has bio-functional properties. Deoiled rice bran, a major byproduct of rice bran oil industry, is not yet efficiently utilized for human consumption due to its poor edible quality. Various physical processing methods like sieving, pin milling and air classification were applied to upgrade the quality of bran and also to investigate its effect on particle size distribution, content of ash, protein, total dietary fiber, insoluble fiber, soluble fiber and oryzanol as well as total antioxidant activity in bran fractions. The effect of processing such as steaming, germination and parboiling on nutraceuticals and in vitro bioactive properties of rice bran from three different rice varieties namely Jyothi (pigmented), IR64 and Sona masuri (non-pigmented) were investigated. Within the varieties envisaged, pigmented Jyothi variety contained higher levels of vitamin E, soluble, bound and total polyphenol, flavanoids, free radical scavenging activity and total antioxidant activity. Size separation, pneumatic air classification and saline separation procedures employed to separate germ from different types of rice bran (raw, steamed and parboiled) were collected from rice mills and were analyzed individually for physico-chemical and nutritional properties. The protein, fat, and oryzanol content of steamed and parboiled germ showed an average increase of 5.28, 2.15, and 0.08%, respectively compared to raw rice germ. The free fatty acid content was < 6.2% for pure germ. The thiamine content was highest in raw germ (1.61mg/100g) and least for parboiled germ (0.26mg/100g). Phosphorus content of parboiled germ was least (32.47%) compared to raw germ (72.1%). Rice germ could be utilized for food formulations, like geriatric food, mother food, and specialty foods.