Enzyme-assisted extraction of Momordica balsamina L. fruit phenolics: process optimized by response surface methodology

Abstract

The present research work appraises the effect of different enzyme formulations (zympex-014, kemzyme dry-plus and natuzyme) under optimized set of experimental conditions such as time (30–90 min), temperature (25–75 °C), pH (6–9) and solid/enzyme ratio (0.5–6.5%) following central composite design (CCD) on extraction of phenolic bioactives from Momordica balsamina fruit (balsam apple). Out of enzyme complexes employed in this study, zympex-014 offered maximum extraction yield (42.6 g/100 g) at optimized conditions including time (60 min), temperature (50 °C), pH (7.5) and enzyme concentration (6.5%) using CCD. Artificial neural network (ANN) was trained computationally based on the experimental data to predict the optimum BAF extract yield for zympex-014. Significant morphological changes in the cell wall of balsam apple fruit (BAF) were elucidated by scanning electron microscopy (SEM) before (control) and after enzymatic treatment. Relatively a superior antioxidant activity was exhibited by extracts from enzyme-treated BAF relative to the control. GC/MS profiling authenticated the presence of ferulic acid (2.30), quercitin (1.48), benzoic acid (0.41) and gallic acid (0.26 μg/mL) as major potent phenolic bioactives in zympex-014 -assisted BAF extract. While p-coumaric (0.05), m-coumaric acid (0.03) and sinapic acid (0.01 μg/mL) were found in lesser amount. The results of the present study indicated that the devised RSM-based optimized enzyme-assisted extraction, using zympex-014 among others, had significant positive effect on liberation of bound phenolics and thereby enhancing antioxidant potential of BAF extracts.