Optimization of Extraction of Phenolic Antioxidants from Tea (camellia Sinensis L.) Fruit Peel Biomass Using Response Surface Methodology

Tea (Camellia sinensis L.) fruit peel, the main byproduct during the manufacture of tea seed oil, was used as raw material for the recovery of phenolic antioxidants. The effect of ethanol concentration, extraction time, and extraction temperature on total phenolic content (TPC) and ferric-reducing antioxidant power (FRAP) of the extracts from tea fruit peel was investigated. The maximum predicted TPC (47.5 mg GAE/g dry peel) was obtained under the optimum recovery conditions (43% ethanol, 60°C, and 33 min) given by using response surface methodology (RSM). A high correlation (R = 0.929, p < 0.01) between TPC and FRAP value was identified by linear regression analysis. Furthermore, gallocatechin (GC) and epigallocatechin (EGC) were found to be the major individual catechins in the extracts from tea fruit peel. Ethanol/aqueous extraction has been presented as an effective method for the recovery of phenolic antioxidants from tea fruit peel.