Change in phenolic compound content, reductive capacity and ACE inhibitory activity in noni juice during traditional fermentation

Abstract

Morinda citrifolia L., also known as noni, has a long history of traditional use in the Hawaiian and Taihitian islands as cure-all medicine. Recently, commercial noni juice products have been imported from different countries and delivered directly to consumers with claims of multiple health benefits, including anti-cancer and immuno-stimulating activities. In this study, phenolic compounds content, free radical and superoxide anion radical scavenging activities were determined in two noni juices with different extent of maturity from traditional fermentation process. Ripe noni fruits gave higher juice yield with a lighter color. In general, juice from ripe fruits contained higher total quantities of phenolic compounds, condensed tannins, flavonoids and scopoletin, and thus exhibiting better scavenging capacity for free radical, superoxide anion radicals and H2O2 and higher ACE inhibitory activity. Fermentation processing gave better juice recovery, whereas prolonged fermentation time reduced the reductive phytochemical content and some related bioactivities.