Characterization of red and purple-pericarp rice (Oryza sativa L.) based on physico-chemical and antioxidative properties of grains.

Abstract

In the preset study range of variations in physico-chemical, cooking characteristics and antioxidant properties of six pigmented rice (four purple and two red) cultivars from north east India were evaluated. Significant variation (P<0.05) was detected among the cultivars for all the traits evaluated except for volume expansion ratio (VER). All the genotypes had long slender grain. Hulling and milling % for all the genotypes were more than 74 and 61%, respectively. Head rice recovery (HRR) was more than 50% in Manipuriblack, Kalobhat and Assambiroin. The range of amylose content (AC) varied from 2.19 to 24.87% where as Mornodoiga was found with highest AC. All the genotypes except Manipuriblack elongated more than 9mm after cooking. Most of the genotypes were found with soft gel consistency (GC). Similarly, all the genotypes except Assambiroin had water uptake (WU) value £ 100ml/100g rice. The concentration of total anthocyanin content (TAC), total phenolic content (TPC) and antioxidant activity (ABTS) differed significantly among the genotypes with highest concentration of these parameters were observed for the purple grain (Mamihunger) whereas no significant difference between the colour groups (red and purple) was observed for total flavonoid content (TFC), gammaoryzanol and phytic acid content which envisages that value of these parameters depends on genotypes and not on kernel colour. A high correlation of TAC with TPC and ABTS suggest that the major phytochemicals responsible for the tested antioxidant activities are phenolic acids and anthocyanin.