Das, PranatiDevi, Laishram Maria2022-02-262022-02-262019-07https://krishikosh.egranth.ac.in/handle/1/5810182932Rice is one of the most widely consumed staple foods, especially in Asia. It accounts for 20 per cent of the world’s dietary energy supply. As a major component of rice, starch plays an important role in human nutrition, and consequently its characterisation in rice variants is of high nutritional importance. To this, the present study estimated the in-vitro starch digestibility (resistant starch (RS), non-resistant starch (NRS) and total starch (TS)), available starch (AS), hydrolysis index (HI) and in-vitro glycemic index (GI) of different processing techniques. Ten red kernel rice varieties of Assam were analyzed for the effect of both raw rice flour and freshly cooked rice in dehusked rice and 6 per cent degree of polishing. Dehusked and polished rice yield were 68.33±0.38 to 75.23±0.19 per cent and 64.14±0.13 to 73.67±0.29 per cent, respectively. Head rice yield (HRY) and broken rice yield (BRY) of the dehusked rice varieties were 54.03±0.34 to 74.34±0.05 per cent and 0.68±0.06 to 14.55±0.32 per cent, respectively. Polishing of rice grains decreased HRY (41.76±0.40 to 68.39±0.09%) but increased BRY (2.05± 0.11 to 22.52±0.41%). The dehusked samples had 17.64±0.11 to 19.17±0.04 g/100 g of RS, 61.19±0.07 to 66.28±0.19 g/100g of NRS and 80.01±0.11 to 85.02±0.20 g/100g of TS. Resistant starch decreased significantly (p≤0.05) on polishing as well as cooking, while NRS and TS increased significantly (p≤0.05) in polishing. However, TS decreased on cooking. Available starch, hydrolysis index and glycemic index of the dehusked rice samples were in the range of 51.80±0.14 to 89.57±0.51 per cent, 3.37±0.02 to 14.67±0.03 per cent and 41.91±0.03 to 50.99±0.11 per cent, respectively. Polishing of the rice samples showed no significant (p≥0.05) change in AS, HI and GI. Cooking significantly reduced AS, whereas HI and GI content increased significantly (p≤0.05) upon cooking. Therefore, polishing and cooking of rice grains had significant effect on the in-vitro starch digestibility and GI. In addition, varieties of Jul and Kaoi Jamfri had comparatively higher RS and lower GI, and thus can be recommended for popularization. Also, further research can be extended for analyzing the effect of degree of polishing and different cooking methods on starch digestibility and GI. Such nutritionally distinguished rice varieties could be used to develop rice based products and supplementary food mixes which have therapeutic values.EnglishThesis