Evaluation of bioactive compounds extracted from Hayward kiwifruit pomace by subcritical water extraction

The utilisation of fruit by-products from industrial waste is one of the important global trend to address sustainability in food production. This study was conducted to evaluate the advantage of subcritical water extraction (SWE) for recovery of phenolic compounds from kiwifruit pomace as a functional ingredient. The extraction process was designed by altering the extraction conditions including temperature (170-225 degrees C) and time (10-180 min) at a constant pressure (50 bar). The presence of phenolic compounds and their antioxidant activities, as well as the Maillard reaction products (MRPs) were evaluated in this study. Extraction under 200 degrees C and 90 min were found to give the best phenolic compounds recovery (60.53 mg CaE/g DW) with regard to lower formation of adverse compounds. The most abundant phenolic compounds in the extracts were identified as (+)-catechin, chlorogenic acid, p-coumaric acid, Protocatechuic acid and caffeic acid. The formation of MRPs during SWE has revealed the potential formation of antioxidants from natural phenolic compounds and possible association with antioxidant activity. The study is also indicated that subcritical water is a more advantageous technique for extracting certain phenolic compounds than conventional solvent extraction. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.