亚麻籽油在煎炸过程中的品质变化

本文研究了常规煎炸条件下，经过不同煎炸时间的亚麻籽油营养成分、理化指标及有害物质含量，并通过主成分分析对其煎炸性能进行了综合评价。结果表明:未经煎炸的亚麻籽油不饱和度达81.77%，其α-亚麻酸的含量为47.50%，是一种富含多不饱和脂肪酸、高营养价值的食用油。亚麻籽油在170 ℃连续煎炸60 h（5 d）过程中，亚麻籽油的色泽、酸价、过氧化值、折光指数、羰基价、极性组分、生育酚含量、脂肪酸组成均有显著（P<0.05） 变化，煎炸全程没有产生苯并（α）芘；5种主要脂肪酸（α-亚麻酸、油酸、亚油酸、棕榈酸、硬脂酸）含量均呈下降趋势，C17:0以下的五种饱和脂肪酸（辛酸、癸酸、月桂酸、肉豆蔻酸、棕榈酸）含量均呈逐渐升高的趋势，其余脂肪酸呈下降趋势。通过煎炸性能分析，煎炸35 h后的亚麻籽油的酸价超过国家限量，其他项目均在国家限量范围以内，经综合评估30 h基本到达亚麻籽的煎炸使用极限，在30 h的煎炸时间内是一种健康良好的煎炸用油。

Quality Change of Flaxseed Oil during Frying Process

The nutritional composition, physicochemical indexes and harmful substance contents of flaxseed oil during frying process under conventional frying condition were studied in this paper, and its frying performance was comprehensively analyzed by principal component analysis. The results showed that the unsaturation of flaxseed oil without frying was 81.77%. The content of α-linolenic acid was 47.50%, which was a kind of high nutritional value edible oil. During the 60 h (5 d)170 ℃ continuous frying, the color, acid value, peroxide value, refractive index, carbonyl value, polar components, tocopherol content and fatty acid composition of flaxseed oil changed significantly (P<0.05) , and there was no Benzo (α) pyrene produced in the whole frying process. The content of five main fatty acids (α-linolenic acid, oleic acid, linoleic acid, palmitic acid and stearic acid) all showed downward trend, and the content of five saturated fatty acids which were below C17:0 (octanoic acid, capric acid, lauric acid, myristic acid and palmitic acid) increased gradually with frying time extended, the content of other fatty acids decreased. The analysis of frying performance showed that the acid value of flaxseed oil after 35 h frying had exceeded the national limit, and other indexes were within the national limits. Frying for 30 h had basically reached the frying limit of flaxseed oil. It would not be recommended to use flaxseed oil for frying beyond the limit, it would be a healthy frying oil within 30 h.