The in vitro scavenging ability of anthocyanin extracts from roselle calyces against reactive nitrogen species and their potential use for nitrite reduction in meat

Abstract

The in vitro scavenging ability of roselle anthocyanin extract (RAE) against reactive nitrogen species (RNS) was compared to anthocyanin extracted from black carrots and red grapes. These anthocyanin samples exhibited concentration and pH dependence on nitrite scavenging activity, with the activity decreasing as pH was increased over the range of 3.0 to 9.0. Concentration dependent activity was also observed for the nitric oxide scavenging and inhibition of peroxynitrite induced oxidation of Evans blue dyes. The potency of RNS scavenging activity for the anthocyanins tested was in the order of grapes > roselle > black carrots. The RAE was then evaluated for its capacity in nitrite reduction in Vienna pork sausage and traditional Thai fermented pork, called Nham. The residual nitrite in Vienna pork sausage treated with 0.3% RAE at 125 or 250 mg/kg reduced nitrite to 65 and 168 mg/kg respectively, after being stored at 4±1 0C for 24 days. The residual nitrite in all Nham samples rapidly decreased around 90% of the initial nitrite level after 3 days of fermentation at 30±1 0C. Overall results show that RAE was a good source of strong reactive nitrogen species scavengers and can potentially be used as a natural nitrite reduction agent in meat products.