Combination of ultrasound-assisted aqueous enzymatic extraction and cooking pretreatment for date seed oil recovery

Date seed oil is a good source of natural antioxidants due to the presence of phenols, tocopherols, and sterols. The present research is the first study on the extraction of date seed oil by combining the ultrasound-assisted aqueous enzymatic extraction method and the cooking pretreatment. In this study, the effects of two independent variables namely the sample to solvent ratio (at six levels of 1: 2, 1: 3, 1: 4, 1: 6, 1: 8 and 1:10) and the cooking time (at four levels of 0, 20, 40 and 60) were investigated on dependent variables namely the extraction yield, total phenolic compound, peroxide value, and acid value of date seed oil. The results indicated that optimum conditions for extraction of date seed oil were sample to solvent ratio of 1: 2 and the cooking time of 40 min. Furthermore, the Scanning Electron Microscopy images of date seed powder after selective treatments indicated the destruction and fragmentation of residual pulp structures by increasing the cooking time. In general, results of the present study indicated that it was important to select the appropriate sample to solvent ratio and implement the pretreatment of cooking to extract oil with high yield and quality. Combination of the ultrasound-assisted aqueous enzymatic extraction method and the cooking pretreatment can be proposed as a new extraction method in the oil industry. This new extraction method can improve the oil extraction efficiency and the quality of extracted oil.