The french fries were fried in linseed oil at 170 ℃and 200 ℃, and the trans isomerization and the distribution of trans isomer of α-linolenic acid in frying oil and french fries at different frying temperatures were compared,and the correlation between content of trans isomers of α-linolenic acid and physicochemical indexes (acid value, peroxide value, p-anisidine value, total polor substance content) was explored.The results showed that frying significantly increased the content of trans isomers of α-linolenic acid in linseed oil (p<0.05), the increase trend at 200 ℃ was more obvious, and temperature was the main influencing factor. The content of trans isomers of α-linolenic acid in the oil extracted from french fries was significantly less than that of frying oil, and the difference at 170 ℃ was mare significant than that at 200 ℃.The trans isomers of α-linolenic acid in fring oil was significantly positively correlated with the acid value and total polar components content, and the correlation with the former was stronger.Therefore, the formation of trans isomers of α-linolenic acid in fried linseed oil was related to the deterioration of oil quality, especially to the hydrolysis reaction. |