Abstract: This study analyzed the changes in the physicochemical indexes, fatty acids and volatile compounds of the leaf fat of horses raised in Xinjiang after heating treatment at different temperatures of 100, 120, 140, 160, 180 and 200 ℃. The peroxide value (POV), p-anisidine value (p-AV), acid value (AV) and chromaticity values were measured, and the fatty acid composition and volatile compounds were determined using gas chromatography (GC) and headspace gas chromatography mass spectrometry (HS/GC-MS), respectively, sensory evaluation was performed and relative odor activity (ROAV) values were calculated. Results showed that the AV of horse fat heated at 160 ℃ was 1.62 mg/g, and it sharply increased when the heating temperature exceeded 160 ℃ while the p-AV remained stable. With increasing heating temperature, the POV increased signi?cantly and then decreased, reaching a maximum value of 0.124 g/100 g at 160 ℃. The percentage of polyunsaturated fatty acids in horse fat decreased from 20.87% to 14.54% with increasing temperature, 13.59%–20.06% of which was linoleic acid. In addition, 49, 50, 45, 47, 56 and 51 volatile substances were identified after heating at 100, 120, 140, 160, 180 and 200 ℃, respectively, with the major ones being aldehydes, alcohols, ketones, furans, acids and esters. Totally 11 key flavor compounds were eventually determined by principal component analysis (PCA) combined with ROAV values. Sensory evaluation showed that horse fat heated at different temperatures had significant differences in characteristic flavor properties such as fatty aroma and delicate fragrance (P < 0.05). The results from this study can provide a theoretical basis for the quality control and flavor improvement of horse fat.

Key words: horse fat; volatile compounds; headspace gas chromatography-mass spectrometry; relative odor activity value; principal component analysis