Digestive Characteristics And Intestinal Probiotics Of Milk Fat Globules

Milk fat globules(MFGs)are the main source of dietary energy for infants and a key carrier of breast milk functional factors.When breastfeeding is restricted,bovine and caprine milk is often used as a breastmilk substitute to meet the infant’s dietary.The difference between alternative milk fat and breast milk is due to the lactation mechanism of the species on the one hand,and the milk processing procedure that the breast milk substitute must go through on the other hand.These reasons will lead to changes in MFG composition and structure,which in turn drive the separation of MFG nutritional value and functional properties.This study explored the differences in MFG availability caused by different milks and different processing techniques from the perspective of MFG’s microstructure,compositional changes,lipolytic behavior and functional exercise.The lipolysis kinetic models of bovine and caprine MFG are similar.Bovine MFG tends to produce short-chain saturated fatty acids and has the highest lipolysis degree during gastric digestion.Bovine MFG increased the abundance of Oscillospira,due to the lack of cell-cell junction proteins and mucin,the regulation of gut microecology by bovine MFG was not readily apparent.The lipolysis rate of caprine MFG is prominent in infants’ digestion,which is due to the weak phospholipid-glycoprotein barrier.Caprine MFG directly promoted the colonization of probiotics and the emergence of the biomarker Allobaculum.Mucin 1 in caprine MFG was primarily responsible for inducing probiotic adhesion.Human MFG has the most completed digestibility after gastrointestinal digestion.Phospholipid barrier,exogenous lipase,and lipolysis-regulating proteins are the advantages of human MFG.Human MFG enhance the efficacy of probiotics by inhibiting pathogen function.Akkermansia and Bifidobacterium were identified as the dominant microbiota by human MFG.Mucin and complement inhibitory protein were found in human MFG to inhibit different pathogens.Pasteurized MFG tends to form protein aggregates to prevent lipolysis.However,the aggregate is rich in neutrophil degranulation products,which are effective in killing pathogens.Homogenized MFG has the lowest hydrolysis rate due to the reconstituted antilipase barrier and exposed apolipoprotein.Simultaneously,the reconstituted barrier can compensate for the lack of the complement cascade.Spray-dried MFG had the highest hydrolysis rate attributable to the disrupted MFG barrier and the released of lipoprotein lipase and endothelial lipase.The immunomodulatory properties of spray-dried MFG proteins are mainly mediated by the toll-like receptor signaling pathway.The research lays the foundation for the selection and processing of breast milk substitutes and the improvement of infant formula.