Assessment of Antioxidant Properties of Tamarind Fruit Pulp and its Effect on Storage Stability of African Bread Fruit Seed dhal and Flour

Abstract

This study evaluated the antioxidant activities of tamarind fruit pulp in scavenging 1, 1-diphenyl-2-picryl hydroxyl radical (DPPH) and in suppressing thiobarbituric acid reactive substances (TBARS) formation, as a marker of lipid oxidation, in African breadfruit seed dhal and flour. Water and ethanol extracts of tamarind fruit pulp at different concentrations were used to scavenge DPPH radical. Parboiled (100°C; 15 min) breadfruit seeds were dehulled to seed dhal, oven-dried (50°C; 72 h), and half of the dhal milled into flour. Samples (100 g each) of the seed dhal and flour added and mixed together with aqueous suspensions (0, 1.0, 2.0, 3.0 or 5.0 g per 5 ml water) of tamarind fruit pulp were analysed for TBA values within 4 months of storage at 26 ± 2°C. The water and ethanol extracts scavenged DPPH in a dose-dependent manner. The ethanol extract had IC50 of 38.17 while the water extract had IC50 of 7.32, indicating much higher antioxidant activity of water extract. Tamarind fruit pulp inhibited lipid oxidation in breadfruit seed dhal and flour as evident from the mean thiobarbituric acid (TBA) value which decreased with increasing concentrations of the fruit pulp. Antioxidant activity of the fruit pulp was higher in the flour than in the dhal within 4 months of storage. Both seed dhal and flour treated with tamarind fruit pulp had lower mean TBA values ranging from 2.80 to 4.12 ppm Malonaldehyde as against 4.55 to 4.91 ppm for untreated samples. Tamarind fruit can thus be further studied for possible exploitation as a natural antioxidant for use in food, drug and cosmetic products.