Microwave-assisted aqueous enzymatic extraction of oil from Isatis indigotica seeds and its evaluation of physicochemical properties, fatty acid compositions and antioxidant activities

Abstract

A novel and green microwave-assisted aqueous enzymatic extraction (MAAEE) of oil from Isatis indigotica seeds was investigated in the present study. Enzyme cocktail (cellulase/proteinase/pectinase=1/1/1, w/w/w) was found to be the most effective in releasing the oil. Under the optimal conditions as enzyme concentration 1.82% (w/w), temperature 43°C, time 83min and irradiation power 375W, the highest oil recovery of 59.27% was obtained using the emerging technique. As compared to conventional Soxhlet extraction-derived oil (SEO), MAAEE-derived oil (MAAEEO) revealed the similar physicochemical properties but exhibited better oxidation stability. In addition, MAAEEO had higher contents of valuable polyunsaturated fatty acids, tocopherols and phenolics as against SEO, and it exhibited considerable antioxidant activities with IC50 values 9.58 and 15.03mg/mL, according to DPPH radical scavenging assay and β-carotene/linoleic acid bleaching test, respectively. Scanning electron micrographs illustrated the severely structural disruptions of sample cell walls and membranes by MAAEE.