Effect of different pretreatment techniques on quality characteristics, chemical composition, antioxidant capacity and flavor of cold-pressed rapeseed oil

Abstract

This study investigated the effects of different pretreatment techniques (microwave heating, infrared heating, oven heating and enzymatic methods) on the quality of cold-pressed rapeseed oil (CPRO) with commercially available first-grade pressed rapeseed oil (CFO) as a control. The results showed that CPRO is more nutritionally valuable than CFO while meeting the quality standard without refining. Microwave heating pretreatment's cold-pressed rapeseed oil (MHO) exhibited a higher oil yield (70.83 ± 0.40 %), a higher trace active ingredient content (tocopherol 53.79 ± 0.19 mg/100g, phytosterol 726.98 ± 4.14 mg/100g, and polyphenol 87.09 ± 0.08 mg GAE/100g), and a stronger antioxidant capacity. Correlation analysis and multiple linear regression analysis indicated that antioxidant capacity was mainly related to the content of α-tocopherol and polyphenols. Microwave heating promoted the degradation of the Maillard reaction and glucosinolates, significantly improving the flavor of CPRO. Therefore, microwave heating is a promising pretreatment technology for the production of high-quality CPRO.