The present study aims to evaluate the effect of polishing on the quality attributes of the indigenous rice varieties of Assam namely Aghuni bora and Kajoli chakua. In the study procured paddy varieties were processed using standard protocols into unpolished, 5% polished and 10% polished forms. Standard analytical procedures were followed to evaluate the physical, chemical and sensory quality of the rice samples. Cooking characteristics of the rice varieties were also evaluated in terms of their water uptake ratio, grain elongation ratio and cooking time. Data obtained were analysed statistically to determine significant differences (p<0.05). The findings revealed a progressive reduction in kernel dimensions and mass. The Thousand kernel weight decreased from 19.62 to 15.64 g in Aghuni bora and from 20.68 to 15.22 g in Kajoli chakua. The Bulk density of the samples increased from 0.63 to 1.29 g ml-1 in Aghuni bora and from 0.71 to 1.36 g ml-1 in Kajoli chakua across polishing. The lightness value showed an increasing trend from 65.99 to 72.78 in Aghuni bora and from 65.40 to 69.81 in Kajoli chakua, while a* and b* values decreased, indicating a loss of natural pigmentation. An improvement in cooking quality in terms of water uptake ratio and a decrease in cooking time was evident from 16.00 to 10.12 min in Aghuni bora and from 17.33 to 9.80 min in Kajoli chakua. A significant reduction in protein, fat, crude fibre, ash and mineral contents with increased polishing were also observed. The study concludes that with milling up to 5.00%, an optimal balance could be achieved between nutritional retention, cooking efficiency, sensory acceptability and reduced processing losses.
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Cooking quality, Degree of milling, Indigenous rice varieties, Physico-chemical properties, Sensory quality
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