The influence of Morinda citrifolia fruit maturity level, parts and storage length on total phenols, ascorbic acid, antioxidant activity and ethylene gas emission

Abstract

Different parts of noni plant (Morinda citrifolia) were analyzed for total phenols, total ascorbic acid and antioxidant activity at three different maturities. Results showed higher total phenols content (TPC) in seeds (9.63–12.48) than in pulp (4.47–8.69), and leaves (3.55–6.51 mg GAE/g−1 DW). Ascorbic acid content ranged between 0.21–0.90, 0.23–0.97 and 0.30–0.69 mg g−1 for pulp, skin and leaves respectively. Immature fruits had higher TPC and higher antioxidant activity than mature ripe fruits and leaves. Total ascorbic acid content was highest (P < 0.05) in the seeds (1.31–1.79 mg g−1). Mature ripe fruits should be harvested for high ascorbic acid contents. For functional benefits and medicinal use, mature green fruits are recommended for the best antioxidant potential and phenol content. Longer storage resulted in higher ethylene biosynthesis which correlated inversely to total phenols content (-0.92) and antioxidant activity (-0.92). Further compositional and in vivo analyses of noni plant parts is suggested.