真空冷冻干燥和超声波预处理对植物油品质特性的影响

Effect of vacuum freeze-drying and ultrasonic pretreatments on quality characteristics of vegetable oils

为探究低温预处理技术对植物油品质的影响,以油菜籽、亚麻籽、花生、葵花籽、芝麻为原料,进行超声波和真空冷冻干燥预处理,采用螺旋榨油机压榨制油,分析植物油感官指标(色泽、气味、黏度、透明度、滋味)、理化指标(酸值、过氧化值、色泽、水分及挥发物)、营养组分(脂肪酸、甘油三酯、总酚、维生素E)及挥发性组分的变化。结果表明:经超声波预处理,植物油的透明度、滋味和气味较好,而真空冷冻干燥预处理植物油的黏度、气味和滋味与未处理组相比变化不明显;经2种方式预处理后,5种植物油的酸值和过氧化值均符合食品安全国家标准,脂肪酸和甘油三酯组成及含量无显著性变化(p>0.05),但挥发性成分有明显变化;经真空冷冻干燥和超声波预处理,除超声波预处理葵花籽油外,植物油中总酚含量分别是未处理组的1.04~1.90倍和1.10~1.55倍,除菜籽油外,植物油中维生素E含量分别比未处理组增加了0.50%~26.56%和1.40%~49.99%。总体而言,超声波和真空冷冻干燥预处理不会造成植物油感官品质、脂肪酸和甘油三酯含量的下降,且能提高微量营养组分的含量,获得综合品质较好的植物油。

In order to investigate the effect of low-temprerature pretreatment technology on the quality of vegetable oils,rapeseed,flaxseed,peanut,sunflower seed and sesame were used as raw materials,they were pretreated with ultrasonic and vacuum freeze-drying,the oil was extracted by screw press,and the changes of sensory indexes(colour,odour,viscosity,transparency,taste),physicochemical indexes(acid value,peroxide value,colour,moisture and volatile compounds),nutritional components(fatty acids,triglycerides,total phenols,vitamin E)and volatile components of vegetable oils were analyzed.The results showed that the transparency,taste and odour of the vegetable oils were better after ultrasonic pretreatment,while the viscosity,odour and taste of the vacuum freeze-drying pretreated vegetable oils did not change significantly compared with those of untreated group.The acid value and peroxide value of the five vegetable oils after the two pretreatments complied with the national standards for food safety,and there were no significant changes in the fatty acid and triglyceride composition and content(p>0.05),but there were significant changes in the volatile compounds.After vacuum freeze-drying and ultrasonic pretreatment,the total phenol content of vegetable oils,except ultrasonic pretreated sunflower seed oil,was 1.04-1.90 times and 1.10-1.55 times that of the untreated group,respectively;and the vitamin E content of vegetable oils,except rapeseed oil,was increased by 0.50%-26.56%and 1.40%-49.99%,respectively,compared with that of the untreated group.In general,ultrasonic and vacuum freeze-drying pretreatment don't cause the decrease of sensory quality,fatty acid and triglyceride content of vegetable oils,and increase the content of micronutrient components to obtain vegetable oil with better comprehensive quality.