OPTIMIZATION OF POLYPHENOL EXTRACTION FROM CHESTNUT WASTE PRETREATED BY OHMIC HEATING USING BOXBEHNKEN DESIGN

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, extraction time, solid to solvent (S/S) ratio, and temperature on total phenolic content (TPC) and antioxidant capacity (AC) of water extracts. All independent variables influenced the TPC and AC of the peel extracts. The optimum extraction conditions found were 22.02 min, S/S ratio of 1/39.70 (w/v), and 60 degrees C, resulting in the highest TPC of 34.83 mg gallic acid equivalent (GAE)/g dry matter (DM) and AC of 35.62 mol ascorbic acid equivalent (AAE)/100 g DM by DPPH. This study showed that water was almost effective for the extraction of polyphenols from the pretreated chestnut peel.