Developing radio frequency pretreatment technology for improving yield and quality of flaxseed oil extractions

Abstract

Flaxseed is considered as a major raw material for producing functional vegetable oil. To promote the extraction process of flaxseed oil, effects of radio frequency (RF) pretreatment at investigated temperatures (70, 90, 110, 130, and 150 °C) on yield, physicochemical property and sensory quality of flaxseed oil were determined. The results showed that the yield of flaxseed oil increased from 31.29 to 38.23% after RF pretreatment at 150 °C (p < 0.05). The total phenolic, lignan, antioxidant capacity, chlorophyll, and carotenoid contents of flaxseed oil increased significantly with the increase of RF pretreatment temperature (p < 0.05). Nonetheless, the higher RF pretreatment temperatures caused a slight increase on oil oxidation indices (free fatty acid, peroxide value, conjugated diene, conjugated trienes, and p-anisidine value). These results provide theoretical guidance for practical applications of RF pretreatment in the production and processing of edible vegetable oil.