Morphological study, nutritional value and phytochemical estimation of four indigenous rice (Oryza sativa L.) varieties of Assam, India

India is a major producer and consumer of rice. Assam is one of the top rice-producing states of the country and is situated in the indo-Burma hotspot, it is gifted with exceptionally rich rice diversity. These indigenous rice varieties have unique properties and are cultivated by the local farmers and are only used for the preparation of traditional cousins. In the present study, four indigenous rice varieties namely Kumol saaul, Kola Bora, Kola kunkuni Joha and Khamti Lahi have been selected for nutritional profiling and bioactive compounds screening. The biochemical estimation of the nutrients was carried out following the guidelines of the Association of Analytical Chemists International. For phytochemical screening, the methanolic extract of the rice samples was prepared and qualitative as well quantitative tests were performed following standard protocols. The carbohydrate content was higher in Kumol saaul (48.3±0.34) and khamti Lahi (38.64±0.4) and therefore may be used to prepare breakfast for the farmers while working in the paddy field and to prepare traditional cousin Tupula vat respectively. The protein content was highest in Kola bora (8.9±0.02) which are used for the preparation of traditional food. Crude lipid, Crude fiber, vitamin and Mineral content also showed significant differences in the four rice varieties. The total anthocyanin content and antioxidant activity were found more in Kola Bora (328.26±0.87, 81.45±2.29) and Kola Kunkuni Joha (11.90±0.89, 67.34±1.23). Thus, the study clearly showed that these indigenous rice varieties are not only traditionally important but also a good source of nutrients and bioactive compounds. It is expected that, in-depth knowledge of nutrients and other bioactive compounds in the rice varieties may be beneficial for their promotion in global the market as well as germplasm conservation.