Characteristic lipids and their potential functions generated during the aging process of yak ghee

Yak ghee is an important food source for Tibetan herdsmen; however, the lipid composition, functional lipids changed and best consumption period during the aging process of yak ghee have not been determined. In this study, we identified a total of 386 lipids in Zhongdian yak ghee during aging, including glycerolipids (292 species), glycerophospholipids (47 species), sphingolipids (24 species), and fatty acyls (23 species). The lipids in yak ghee dynamically changed during aging, with the final product containing several polyunsaturated fatty acids (including linolenic acid, docosahexaenoic acid, and eicosapentaenoic acid), indicating its high nutritional value. Lipid fingerprints of yak ghee during aging revealed that triglyceride (16:0/16:0/20:5) and triglyceride (18:1/18:3/21:0) etc. were the characteristic lipids in aged yak ghee. The characteristic lipids in yak ghee were mainly enriched in the biosynthesis of unsaturated fatty acids, glycerolipid metabolism, and ether lipid metabolism pathways. This study provides insight into the lipid changes of yak ghee during aging, which offers a theoretical basis for the development of high-value yak ghee products.