亚麻籽油煎炸薯条过程中不同构型反式α-亚麻酸的含量及分布

Content and distribution of trans α-linolenic acid with different configurations in linseed oil during frying French fries

为研究不同煎炸温度下不同构型反式α-亚麻酸(TALA)在煎炸薯条和煎炸油中的分布情况,在170、200℃下进行亚麻籽油煎炸薯条实验,比较不同温度的煎炸过程中不同构型的TALA在煎炸油中的含量变化及TALA在煎炸薯条和煎炸油中含量的比值变化情况。结果表明:两个煎炸温度下煎炸油中均检测到6种构型的TALA,即9t,12c,15c-C18∶3、9c,12t,15c-C18∶3、9c,12c,15t-C18∶3、9c,12t,15t-C18∶3、9t,12t,15c-C18∶3和9t,12c,15t-C18∶3,而三反式构型的9t,12t,15t-C18∶3在整个煎炸过程中并未形成,6种构型的TALA均在200℃煎炸亚麻籽油中含量更多;煎炸亚麻籽油中TALA以单反式构型为主,约占TALA总含量的94%;3种单反式α-亚麻酸含量均随煎炸时间的延长和煎炸温度的升高呈显著增加趋势,3种双反式α-亚麻酸的含量从大到小依次为9t,12c,15t-C18∶3、9c,12t,15t-C18∶3、9t,12t,15c-C18∶3,且煎炸温度和煎炸时间对9t,12c,15t-C18∶3含量影响较大,对另外两种的影响较小;煎炸油中检测到的6种TALA在200℃煎炸薯条中均有检出,而在170℃煎炸薯条中仅检出了5种,未检出9t,12t,15c-C18∶3;薯条中各构型TALA的含量通常低于煎炸油的,170℃煎炸时,大部分TALA在薯条和煎炸油中的含量比值随煎炸时间延长逐渐变小,而200℃煎炸时,大部分TALA含量比值在整个煎炸过程中差异不显著。

In order to study the distribution of trans α-linolenic acid(TALA) with different configurations in French fries and frying oil at different frying temperatures, the French fries were fried with linseed oil at 170℃ and 200℃, the content changes in frying oil and the content ratio change in French fries and in frying oil of TALA with different configurations during frying at different frying temperatures were compared. The results showed that six configurations of TALA were detected at both frying temperatures, including 9t,12c,15c-C18∶3, 9c,12t,15c-C18∶3, 9c,12c,15t-C18∶3, 9c,12t,15t-C18∶3, 9t,12t,15c-C18∶3, and 9t,12c,15t-C18∶3. While, the 9t,12t,15t-C18∶3 was not formed during frying. More TALA was formed in the linseed oil frying at 200℃ than at 170℃. The single trans α-linolenic acid was dominant and accounted for about 94% of the total amount of TALA in frying linseed oil. The content of the three types of single trans α-linolenic acid increased significantly with the increase of the frying time and the frying temperature. The content of the three double trans α-linolenic acid in descending order was 9t, 12c, 15t-C18∶3, 9c, 12t, 15t-C18∶3 and 9t, 12t, 15c-C18∶3. The frying temperature and frying time had a greater influence on the content of 9t, 12c, 15t-C18∶3. However, the effects on the other two double trans-forms were small. The six configurations of TALA detected in frying linseed oil were all detected in the French fries fried at 200℃. However, only five configurations of TALA were detected in the French fries fried at 170℃, and 9t, 12t, 15c-C18∶ 3 was not detected. Most of the content of six configurations of TALA in French fries was lower than that of corresponding frying oil. When frying at 170℃, most of the TALA content ratios in French fries and frying oil decreased gradually with the increase of frying time. When frying at 200℃, most of the TALA content ratios in French fries and frying oil had no significant difference during the entire frying process.