OPTIMIZATION OF EXTRACTION OF POLYPHENOLS FROM CHESTNUT WASTE PRETREATED BY OHMIC HEATING USING BOX-BEHNKEN DESIGN

Abstract

Chestnut processing produces a large amount of waste peels, which contain considerable polyphenols. The aim of this research was to optimize the extraction method for phenolic compounds from industrial chestnut peel pretreated by ohmic heating (OH) by using response surface methodology (RSM). Box-Behnken design (BBD) was used to investigate the effects of three independent variables; namely, extraction time, solid to solvent (S/S) ratio, and temperature, on total phenolic content (TPC) and antioxidant capacity (AC). All independent variables influenced the TPC and AC of the peel extracts. The optimum extraction conditions found were 22.02 min, 1/39.70 (w/v), and 60 °C for extraction time, S/S ratio, and extraction temperature, respectively, resulting in the highest TPC of 34.83 mg GAE/g dry matter (DM) and AC of 35621.38 mmol ascorbic acid equivalent (AEAC)/100 g DM by DPPH. This study showed that water was highly successful for the extraction of polyphenols from the pretreated chestnut peel.