| In order to improve the comprehensive utilization of yak fat, the deodorization of yak fat was carried out with fresh yak fat as raw material by using yeast glucan, active dry yeast, β-cyclodextrin and tea polyphenol, respectively. The fishy odor value of yak oil prepared from yak fat was used as the evaluation index, and the deodorization conditions for the four deodorization methods were optimized by single factor experiment. Headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) was used to analyze the composition and content of volatile flavor substances of yak oil produced from yak fat before and after deodorization, the relative odor activity value (ROAV) was used to analyze the possible fishy odor substances, and the sensory properties of yak oil before and after deodorization were compared. The results showed that the optimal conditions for the four deodorization methods were yeast glucan mass fraction of 1.2%, material-liquid ratio of 1∶ 4, and soaking time of 2 h for yeast glucan deodorization; active dry yeast mass fraction of 1.1%, material-liquid ratio of 1∶ 4, soaking time of 40 min for active dry yeast deodorization;β-cyclodextrin mass fraction of 0.6%, material-liquid ratio of 1∶ 4, soaking time of 40 min for β-cyclodextrin deodorization; tea polyphenol mass fraction of 0.35%, material-liquid ratio of 1∶ 3, soaking time of 50 min for tea polyphenol deodorization. There were 63, 61, 68 and 65 volatile flavor substances in yak oil deodorized with yeast glucan, active dry yeast, β-cyclodextrin, and tea polyphenol, respectively, in which the contents of possible fishy odor substances were reduced compared with undeodorized yak fat. The fishy odor substances of yak fat could be (E)-2-octenal, 1-octen-3-ol, n-hexanoic acid, heptanoic acid, caprylic acid, oleic acid and so on. The yeast glucan treatment had the best deodorization effect on yak fat, as determined by the combination of volatile substance analysis and sensory evaluation. In conclusion, yeast glucan, β-cyclodextrin, active dry yeast, and tea polyphenol solution soaking treatment can reduce the content of fishy odor substances in yak fat, and among them, the deodorization effect of yeast glucan is the best. |
