Quality characterization, variety discrimination and correlations amongst twelve landraces of black rice of Assam and Manipur, India

Abstract

Twelve aromatic black-pigmented rice landraces collected from different districts of Assam and Manipur were analyzed for physicochemical, nutritional, and cooking properties along with phytochemical and starch characteristics. Chakhao black rice varieties are well known from Manipur, but it is not the case for Assam black rice landraces and is largely unknown. In the current study, different characterization parameters were combined, correlated, and analyzed by performing Pearson correlation, unweighted pair group method with arithmetic mean (UPGMA) based clustering and principal component analysis (PCA) for selection of better performing landraces based on loading factors of all component’s v/s principal components. Results showed that Darrang (DR) black rice landrace contained the highest amount of protein (12.62%), whereas the fat content was almost similar in all the landraces. Cooking time of all landraces ranged from 21 to 27 min. EI and TH (Chakhao poreiton) recorded maximum levels of anthocyanin content (171.05 and 171.97 mg C3G/100 g) followed by Golaghat (GG; 168.37). Physically, the kernels varied significantly in size and shape. Highest levels of total phenolic were observed in WI (Chakhao amubi- 175.08 mg GAE /100 g). The amylose content of all the landraces was in the range of waxy and low. The resistant starch ranged from 4.72% to 21.17% in raw rice and 3.28–15.38% in gelatinized rice. Elemental distribution was found to be higher in aleurone layer of all landraces than that of endosperm. The statistical analysis highlighted that Assam landraces, especially the ones from upper Assam are equally competent as Manipur black rice for the desired quality.