催熟与微波预处理对菜籽油品质的影响

Effects of chemical ripening and microwave pretreatment on quality of rapeseed oil

应用催熟与微波技术对油菜籽进行预处理,测定不同条件下低温压榨菜籽油的质量指标,旨在从生产和加工角度探讨两者对菜籽油品质的影响。结果表明:催熟使菜籽油酸价和过氧化值降低,对脂肪酸含量有影响,VE和植物甾醇含量降低,总酚含量略有增加;微波使菜籽油的酸价和过氧化值升高,而对其脂肪酸组成无显著影响(P>0. 05);微波提高了未催熟和催熟油菜籽低温压榨菜籽油中V_E、植物甾醇、总酚、canolol的含量;催熟油菜籽所得菜籽油的各项抗氧化指标均高于未催熟油菜籽,且两者经微波预处理后,DPPH自由基清除能力、铁离子还原能力(FRAP值)、氧化诱导期(IP)显著升高,分别为未微波处理的14. 6~15. 2倍、13. 0~16. 3倍、1. 3~1. 8倍,表现出较高的抗氧化活性和氧化稳定性。由此可见,合理催熟在一定程度上提高了菜籽油品质,而微波预处理在改善油脂品质方面效果更为突出。

Rapeseed was pretreated with ripening and microwave,and the quality indexes of low-temperature pressed rapeseed oils were determined to explore the effects of the two pretreatment methods on the quality of rapeseed oil from the perspective of production and processing. The results showed that ripening led acid value,peroxide value,V_E and phytosterol contents of rapeseed oil to decrease and total phenol content to increase slightly. Ripening had a certain effect on fatty acid content. Microwave treatment caused the acid value and peroxide value to increase,but had no significant effect on fatty acid composition (P > 0. 05). In addition,microwave increased the contents of V_E,phytosterol,total phenol and canolol in rapeseed oil from no ripening and ripening rapeseed. Compared with rapeseed oil from no ripening rapeseed,the antioxidant capacity of rapeseed oil from ripening rapeseed was higher,and the DPPH free radical scavenging capacity, iron ion reduction ability and oxidation induction period of the two rapeseed oils significantly increased after microwave treatment,which were 14. 6-15. 2 times,13. 0-16. 3 times,1. 3-1. 8 times of the rapeseed oil from rapeseed without microwave treatment,showing high antioxidant activity and oxidative stability. Thus reasonable ripening improved the quality of rapeseed oil to a certain extent,and simultaneously microwave pretreatment could continue to expand such advantages.