控制热氧化冷榨芝麻油的脂肪酸组成及挥发性成分分析

Analysis of Fatty Acid Composition and Volatile Components in Cold-pressed Sesame Oil after Controlled Thermal Oxidation

本文采用气相色谱(GC)和固相微萃取-气相色谱-质谱联用(SPME-GC-MS)方法分析了控制热氧化前后冷榨芝麻油的脂肪酸组成和挥发性成分的变化情况。通过相对气味活度值(ROAV)评价各风味物质对芝麻油整体香气的贡献,并结合聚类分析确定控制热氧化后冷榨芝麻油中的关键风味物质。结果显示,样品中的脂肪酸主要有7种,包括3种饱和脂肪酸和4种不饱和脂肪酸,热氧化后冷榨芝麻油中的亚油酸及总不饱和脂肪酸的含量显著降低;柠檬烯和罗勒烯等烃类是冷榨芝麻油中的主要挥发性成分,其含量占风味物质总量的74.6%;热氧化后样品中的挥发性成分增加了10种,总峰面积是冷榨芝麻油风味物质总峰面积的2.68倍,3-甲基丁醛、癸醛、(E,E)-2,4-壬二烯醛、(E,E)-2,4-癸二烯醛等醛类含量高达67.9%,是热氧化样品的主要挥发性成分,其中亚油酸的氧化产物(E,E)-2,4-癸二烯醛是热氧化冷榨芝麻油中最重要的风味物质。

Gas chromatography （GC） and solid-phase microextraction gas chromatography-mass spectrometry （SPME-GC-MS） were used to analyze changes in the fatty acid composition and volatile components of cold-pressed sesame oil before and after controlled thermal oxidation. The contributions of volatile flavor compounds to the overall flavor of sesame oil were evaluated by the relative odor activity value （ROAV）, and the cluster analysis （CA） method was employed to identify the key flavor compounds in cold-pressed sesame oil after controlled thermal oxidation. Seven fatty acids were identified in sesame oil, including three saturated fatty acids and four unsaturated fatty acids, and a significant decrease in the content of linoleic acid and total unsaturated fatty acids was observed in the cold-pressed sesame oil after thermal oxidation. Limonene and （Z）-3,7-dimethyl-1,3,6-octatriene were the major volatile flavor compounds in cold-pressed sesame oil, and their content accounted for 74.6% of the total amount of volatile compounds. After thermal oxidation, there were ten additional volatile components found in the oxidized sesame oil, and the total peak area of the flavor compounds in the oxidized cold-pressed sesame oil was 2.68-fold that of cold-pressed sesame oil. Among them, the content of 3-methylbutanal, decanal, （E,E）-2,4-nonadienal, and （E,E）-2,4-decadienal accounted for 67.9% of the total volatile components and were thus predominant. Furthermore, （E,E）-2,4-decadienal, a product formed by the oxidation of linoleic acid, was the most important flavor compound in cold-pressed sesame oil after thermal oxidation.