Sunflower oil is known as “healthy edible oil”, rich in linoleic acid, vitamin E, sterols, squalene and other bioactive substances, and it has a variety of physiological functions such as anti-inflammatory, anti-aging, anti-cholesterol, and antioxidant. Sunflower seed meal is a by-product of the production of sunflower seed oil, containing various high value-added components such as protein, chlorogenic acid and carbohydrate, so that it has great application potential in the food field. In this review, we elaborate on recent significant progress in the sunflower seed processing industry, focusing on the new technologies and methods used for sunflower seed pretreatment, oil extraction, and comprehensive utilization of meal, in order to provide a reference for the quality improvement of sunflower oil and the high-value development of sunflower meal.

In this study, rapeseed seeds were subjected to steam explosion pretreatment (0.4–1.4 MPa) and then coldpressed into oil. The microstructures of the untreated and treated seeds were characterized by transmission electron microscopy (TEM), and the quality of rapeseed oil was comprehensively evaluated by measuring fatty acid profiles, functional components, and antioxidant capacity. The results showed that after treatment, the seeds’ cell structure became incomplete, accompanied by oil accumulation and protein denaturation. As the explosion pressure increased, the moisture content gradually declined from 42.17% to 92.24%, and the oil yield initially increased and then decreased, and the contents of oleic acid, linoleic acid, and α-linolenic acid significantly changed. The energy generated during steam explosion pretreatment could effectively destroy active substance complexes, resulting in the release of more free polyphenols, so that the average content of total phenols in the treatment group was increased by 9.56 folds on average when compared with the control group. Especially, the content of 2,6-dimethoxy-4-vinylphenol reached a maximum value of 2157.95 mg/kg. Phenolic compounds could chelate metal ions, consequently enhancing antioxidant activity of the oil. Specifically, the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity and ferric ion reducing antioxidant power (FRAP) were increased on average by 13.12 and 12.62 folds, respectively. Meanwhile, the contents of tocopherols and phytosterols increased first due to the dissolution of lipid concomitants, and then decreased due to thermal degradation. Multiple antioxidant components could work together to prolong the induction period of the oxidation of the treated oil up to 22.92 h. In summary, steam explosion pretreatment effectively improved the nutritional and antioxidant properties of rapeseed oil.