Effect of commercial enzymatic preparation with pectolytic activities on conventional extraction and ultrasound-assisted extraction of oil from grape seed (Vitis vinifera L.)


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Conventional solvent extraction (CE) and ultrasound-assisted extraction (UAE) in hexane for oil from untreated and enzyme-treated grape seeds were investigated and compared. Among the output power tested (50, 100 and 150 W) in UAE on untreated seeds, UAE at 150 W for 30 min with liquid-to-solid ratio 8:1 (v/w) gave oil extraction yield comparable to CE (ca. 14% w/w) for 6 h with liquid-to-solid ratio 12:1 (v/w). CE and UAE at 150 W did not influence the fatty acid profiles of oil. CE oil was found to be the most oxidised. The enzymatic treatments (2, 4 and 6 g per 100 g seeds of Rapidase® Expression) prior to CE enhanced by 2.5% of the oil yield. Enzymatic treatments higher than 2 g per 100 g seeds increased relative value of some fatty acids both in CE and UAE. Enzymatic pretreatment from 2 to 4 g per 100 g seeds significantly improved some physicochemical parameters of oil quality when extracted by CE, but not by UAE.