Effect of different pretreatment techniques on quality characteristics, chemical composition, antioxidant capacity and flavor of cold-pressed rapeseed oil
Lu Jiang, Weiguo Wu, Shuhui Wu, Junling Wu, Yu Zhang, Luyan Liao
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.