Effects Of Heat Treatment On The Physicochemical Properties And In Vitro Digestion Characteristics Of Camel Milk

Camel milk has high health and nutritional value,so it is loved by more and more consumers and has broad market prospects.Currently,commercially available camel milk products are generally heated and homogenized.These operations have significantly changed the natural structure and composition of proteins and lipids in camel milk.Therefore,in this thesis,the raw camel milk was homogenized and heat-treated,the physical and chemical properties of camel milk protein were measured,and an in vitro gastrointestinal digestion model of infants was constructed to study the changes of protein and fat during the digestion process of heat-treated camel milk.Provide theoretical basis and guidance for the future development of camel milk functional food for infants,the elderly or other people with special nutritional needs.The main results of this paper are as follows:(1)The effect heat treatment on the physichemical properties of camel milk.The results showed that heat treatment had a significant effect on the emulsification activity(EAI)and emulsification stability(ES)of camel milk(P<0.05).The overall trend of EAI and ES showed an inverse relationship.The EAI of UHT homogenized camel milk reached a maximum of 9.43m²/g.ES reached the minimum value of 16.93%.The foamability(FC)and foaming stability(FS)were significantly affected by the heat processing method(P<0.05).The FC of UP homogenized camel milk reached the maximum value of 56.25%,and the FS value was 22.37%.Compared with raw camel milk,the four thermal processing methods have a significant impact on the solubility of camel milk(P<0.05),and the solubility of UHT homogenized camel milk reached the maximum value of 21.60%;the thermal processing method has an effect on water holding capacity(WHC)and oil holding capacity(OHC)has a significant impact(P<0.05),UP homogenized camel milk has the highest WHC,which is 126.63%;HTST homogenized camel milk has the highest OHC,which is 400.08%(2)The effect of heat treatment on the in vitro lipid digestion of camel milk simulated infants.The results showed that during the entire digestion process,compared with raw camel milk,the zeta potential,particle size and distribution,and microstructure of heat-treated camel milk were significantly different(P<0.05).The rate of intestinal fat release:homogenized camel milk>raw camel milk>HTST homogenized camel milk>UHT homogenized camel milk.The content of free fatty acid(FFA)in raw camel milk and heat-treated camel milk did not change significantly at each digestion stage(P>0.05).Gastrointestinal release of FFA is mainly C16:0 and C18:1n9c,followed by C14:0 and C18:0.Among them,raw camel milk and HTST homogenized camel milk released the most FFAs of C16:0,and UHT homogenized camel milk FFA released the most C16:0 and C18:1n9c.(3)The effect of heat treatment on the protein digestion of camel milk simulated infants in vitro.With the whole digestion process,the free amino acid gradually decreased(P<0.05),but the free amino acid content of raw camel milk and heat-treated camel milk did not change(P>0.05).Peptide identification after gastrointestinal digestion.The top ten peptides in different camel milk have high similarity.Most camel milk peptides are derived from casein(>50%),mainly including?-casein and?s₁-casein.Protein,?s₂-casein and xanthine dehydrogenase,etc.A total of 754 peptides overlap,accounting for 53%of the total peptides.Among them,HTST homogenized camel milk peptide is the most,with 1166 peptide sequences.A total of 47 bioactive peptides are predicted,with the most bioactive peptides from?-casein.UHT homogenized camel milk has up to 33 bioactive peptides.