Pressurised hot water extraction of phenolic compounds with a focus on eriocitrin and hesperidin from lemon peel

In this study, the extraction of bioactive compounds from lemon peel, a by-product of the food industry, was investigated using pressurised hot water extraction (PHWE) at different extraction temperatures (40-200 degrees C) and times (5-30 min) under 10.34 MPa pressure. The selectivity of the PHWE process on eriocitrin and hesperidin extraction was also tested. The highest total phenolic content (TPC) (59.57 mg gallic acid equivalents g(-1)), total flavonoid content (TFC) (8.22 mg catechin equivalents g(-1)) and antioxidant capacity by DPPH (42.59 mg Trolox equivalents (TE) g(-1)) were obtained at 160 degrees C for 30 min. The maximum eriocitrin (30.41 mg g(-1)) and hesperidin (25.90 mg g(-1)) contents were achieved at 160 degrees C for 5 min with a 5-hydroxymethyl furfural content of 0.07 mg g(-1). PHWE provided better results for individual compounds and antioxidant capacities than conventional extraction. The results indicated the potentiality of PHWE in the selective extraction of eriocitrin and hesperidin from lemon peel by controlling the extraction temperature and time.