Borah, AbhijitBhattacharjee, Tania2020-12-182020-12-182017-07https://krishikosh.egranth.ac.in/handle/1/5810156942Paddy is dehulled to obtain brown rice, which is milled before consumption. Degree of milling (DOM) affects various intrinsic and extrinsic properties of rice. Paddy (one each of glutinous and non- glutinous variety) was abrasively milled to various degree of milling (0-21%). The study was undertaken to model the milling qualities, colour, texture, vitamins and minerals i.e. with reference to milling qualities the head rice yield (HRY) which was found to decrease for non-glutinous rice variety from 66.87% at DOM 0% to 42.24% at DOM 21%. For glutinous variety, it was found to decrease from 71.38% at DOM 0% to 43.6% at DOM 21%. The total yield was also found to be decreasing with increase in DOM i.e. 74.09% at DOM 0% to 64.18% at DOM 21% for non-glutinous variety and for glutinous variety it was found to be 74.087% to 64.18% (DOM 0-21%).With increase of DOM the whiteness of the rice increased with an L* value ranging from59.58% to 67.96% on highest DOM. The colour difference was found to be very high varying from 0-21% DOM. Texture and other Nutritional qualities varied widely among the ranges of different DOM. This research work was concerned with the loss of nutrients during the processing of rice using two varieties. Concentration of minerals was determined by using Atomic Absorption Spectroscopy (AAS). For mineral estimation rice samples were decomposed with concentrated nitric acid and absorbance of each sample and standards was noted. From graphs, concentration of minerals (Ca, Zn, Fe, P, Cu) was determined. With AAS mineral estimation, non glutinous rice was found to be more nutritious from nutritional point of view than glutinous variety. 6% DOM can be considered as overall threshold limit to retain nutritional properties. With increase in DOM, Fe and Cu loss in glutinous rice was less. From the study it can also be inferred that, brown rice is more nutritious as with polishing, nutrition level decreases abruptly. With increased DOM it further decreases and beyond 15%DOM nutritional benefits of rice are almost lost. Thus, it was concluded in the study that degree of milling strongly affects the various quality aspects of milled rice which were successfully modelled during milling operation giving an average estimation that glutinous rice should not be subjected to DOM >6% for better economic return. However, for better market acceptability, non-glutinous rice can be subjected to 9-15% DOM from HRY perspective.EnglishThesis