| In order to improve the quality of yak ghee, the yak ghee was prepared from the yak milk from Qinghai Tibet plateau, and then was refined by hydration degumming and alkali deacidification. The effects of 50% citric acid addition, degumming temperature and degumming time on degumming rate were investigated by single factor experiment, and the degumming process was optimized by orthogonal experiment. The effects of deacidification temperature, excess alkali quantity, alkali mass fraction and deacidification time on deacidification rate were investigated by single factor experiment, and the deacidification process was optimized by response surface methodology. The fatty acid composition and volatile components of yak ghee were analyzed by GC-MS. The results showed that the optimal degumming process conditions were 50% citric acid addition 0.6%, degumming temperature 60℃ and degumming time 30 min, and the degumming rate could reach 94.12%. The optimal deacidification process conditions were excess alkali quantity 0.4%, alkali mass fraction 10%, deacidification temperature 60℃ and deacidification time 30 min, and the deacidification rate could reach 91.85%. After degumming and deacidification, the content of phospholipid, peroxide value and acid value of yak ghee decreased significantly, the color was yellow and transparent, the content of unsaturated fatty acids increased significantly, the content of volatile components aldehydes and ketones increased significantly, while the content of acid compounds decreased significantly. In conclusion, after degumming and deacidification, the color and flavor of yak ghee improved obviously, and the quality of yak ghee improved. |
