Effect of thermal treatment and storage on bioactive compounds, organic acids and antioxidant activity of baobab fruit (Adansonia digitata) pulp from Malawi

Abstract

Bioactive compounds of baobab (Adansonia digitata) pulp from Malawi were investigated. The effect of thermal treatment and storage on selected quality attributes of the juice was also evaluated. Organic compounds were analysed by HPLC; total phenol content (TPC) and total antioxidant activity (FRAP, ABTS and DPPH) were measured by spectrophotometry. Malawi baobab pulp contains high levels of procyanidin B2 (533±22.6mg/100g FW), vitamin C (AA+DHA) (466±2.5mg/100g FW), gallic acid (68.5±12.4mg/100g FW) and (−)-epicatechin (43.0±3.0mg/100g FW) and showed a maximum TPC of 1.89×103±1.61mg GAE/100g FW. The maximum antioxidant activity was 2.81×103±92.8mg TEAC/100g FW for FRAP, 1.52×103±17.1mg TEAC/100g FW for ABTS and 50.9±0.43% DPPH for DPPH. Thermal pasteurisation (72°C, 15s) retained vitamin C which further showed extended half-life under refrigeration temperature (6°C). Procyanidin B2, (−)-epicatechin, TPC and antioxidant activity fluctuated during storage. Antioxidant activity was significantly correlated (p≤0.05) with bioactive compounds and TPC.