Extraction of colorant from black rice bran and appication in yogurt

Abstract

This study investigates the coloring potential and antioxidant activity of anthocyanin extracted from black rice bran in yogurt. To achive this, anthocyanin was extracted using ethanol and water and the extract was added into yogurt at different concentrations – 0 mg/100g, 150 mg/100g, and 300 g/100 g. The yogurt samples were stored at 40C for a period of time up to 14 days. The sample at 0 day of storage were measured for proximate content, pH, viable cell count and color. The concentration of the anthocyanin extract reversely correlated to the viable cell count in yogurt, but insignificantly affected pH values. The TPC and TAC in yogurt were correlated to the extract concentration and these values decreased after incubation. The radical scavenging capacity of the yogurt increased with the extract addition and decreased by storage time. In addition, the increase of anthocyanin concentration in yogurt raised the radical scavenging capacity of yogurt from 6.22% to 68.57% at 0 day of storage. However, after long storage time of 14 days, the radical scavenging capapcity at highest concentration of anthocyanin -300 mg/100g droped to 47.31%. At 150mg/100g, the anthocyanin imparted light violet color while at 300mg/100, a dark magenta was imparted to yogurt. Sensory evaluation of yogurt samples with and without anthocyanin extract inclusion after 7 days of storage revealed that addition of anthocynin into yogurt has no effect to the acceptability of the products and the sample ‘s acceptance is satisfactory. Keyword: Anthocyanin, antioxidant activity, black rice bran, phenolic content, yogurt.