Characterization and multivariate analysis of decortication-induced changes in pearl millet

Decortication is an important unit operation in millet processing that removes the hard cellulosic outer covering and bran that have adhered to the surface of the grain. Due to the unevenness in the distribution of the nutrients in millet grain, the decortication process significantly affects the biochemical and nutritional qualities. Hence an investigation was carried out to study the effects of decortication on the milling, nutritional, and functional aspects of pearl millet. The experiment was carried out using full factorial design with grain moisture content (8,10 and 12 %) and polishing time (60, 80, and 100 s) as independent variables. The degree of polish, endosperm yield and percent broken valued varied from 10.72 % to 19.56 %, 83.47-90.29 %, 2.76-5.78 %, respectively. Increased polishing time had a considerable positive impact on the degree of polishing and the proportion of broken grains, but a negative impact on endosperm yield. Antinutrients like tannins and phytates showed a declining trend along with the increase in polishing time. The findings of correlation analysis and Principal Component Analysis showed a strong association between crude fiber, proteins, phytates, tannins, and oil absorption capacity. Hierarchical Cluster Analysis effectively clustered the treatments into different clusters based on their similarities.