4. Conclusion
In the present work, AEE process proved to be effective in extracting RBO. Alcalase 2.4L was found to give higher oil yields than Celluclast 1.5L, Hemicellulase, Pectinex Ultra SP-L, Viscozyme L. Comparisons of the physicochemical characteristics of AEEO with those of SEO revealed that different extraction methods had influence on the quality parameters of RBO. Briefly, iodine value, saponification value in the AEEO were found to be higher than SEO. AEEO had lower acid value and peroxide value which was considered to be a high quality oil. The content of wax and phospholipid in AEEO was lower, which could simplify the refining steps. In addition, GC-MS results showed that AEE increased the amounts of unsaturated fatty acids compared with SE. A comparison of the content of bioactive compounds showed that RBO extracted by the AEE was more abundant in vitamin E, sterols, squalene and oryzanol. DSC results indicated that the different methods used for oil extraction caused the variations in the melting and crystallization behaviour of RBO. In comparison to the SEO, AEEO were found to have lower crystallization and melting points. Moreover, SEM results demonstrated that the destruction of cell walls and the decrease of substances in the cell by AEE. These results suggested that AEE offers an efficient, environment friendly and easy procedure of RBO extraction and the oil produced by this emerging method can be used as high-quality edible oil in food industry.