Study On The Preparation Of Milk Fat Globule Proteins And Mechanism Of Creamy Membrane Reconstitution

Fat Globule Membrane(MFGM)Protein is not only rich in nutritive value,but also has anti-inflammatory and anti-cancer effects,promotes neurological development in infants and young children,and can also act as an emulsifying agent to maintain the stability of the oil and water system.Therefore,it is very suitable for addition to high-fat infants formula.Two kinds of membrane protein products were prepared and compared with the protein components of commercially available membrane protein products,and the stability differences of different membrane proteins with fat globule membranes were re-established;two high-fat liquid milk systems were prepared,and the effect of membrane protein products on lipid stability in high-fat liquid milk was studied,the mechanism of membrane proteins involved in the reconstitution of fat globule membrane was also studied.SDS-PAGE combined with liquid chromatography-mass spectrometry(LC-MS/MS)was'used to analyze the MFGM protein components in the membrane protein samples obtained from the cream after different centrifugal speeds and whipping times.The protein components in the commercial MFGM protein product were compared.difference.In order to determine the preparation process of the membrane protein-rich protein product,the cream is cooled to 10?.and whipped with an egg beater until the ice water in the washing cream is transparent.The collected buttermilk is centrifuged at 5000 g for 20 min,and collected,freeze-dried the supernatant solution;when determining the preparation of a protein product that is rich in specific membrane protein components,collect the buttermilk that is whipped within 2 min after the cream is sent to serve as a raw material for enriching Butyrophilin(BTN)protein.The buttermilk was used when whipped for 2 min and 8 min as the raw material for Tissue glycoprotein periodic acid Schiff 6/7(PAS6/7)enrichment.the MFGM-10 product had 268 specific proteins,which was significantly higher than other membrane protein products.Among them,the contents of xanthine oxidoreductase(XDH/XO)protein and BTN protein were relatively higher in MFGM-10 products;the content of tissue glycoprotein periodic acid SchiffF ?(PASIV)was highest in 7500 MFGM products;the contents of lipid droplet binding protein(ADPH)and PAS6/7 were the highest in self-made MFGM protein samples.Through sensory evaluation,compared with the reconstited commercially available infant formula powder,the fat stability of infant formula was analyzed by kinetic instability(TSI value),ratio of absorbance before and after centrifugation,and particle size index.An infant formula with good taste and fat stability was finished.The homogenization parameter is preheated at 50 ? and pressure at 25 MPa.At the same time,a correlation equation between shelf life and temperature is fitted:TSI=0.0183T+0.473.The shelf life at 4? is approximately 53 days.The TSI value and the absorbance ratio before and after centrifugation were used as the fat stability indicators of the high-fat liquid milk system of the added MFGM protein products,and the total content of the MFGM proteins in the liquid milk system and the relative content of the main membrane protein determined by SDS-PAGE were analyzed.Mechanism of action of membrane proteins in the reconstitution of the fat globule membrane in a high-fat liquid milk system was also studied.The results showed that the most important membrane proteins that affect fat stability in high-fat milk are XO and BTN.XO plays an important role in the regeneration of fat globules.The role of ADPH and PASIV membrane proteins must rely on XO to participate in the reconstitution of the fat globule membrane.In the reconstitution of the fat globules,casein and whey proteins are also involved,further enhancing the stability of high-fat liquid milk,and the tissue glycoprotein is PAS6/7.As the medium in which P-lactoglobulin and a-lactalbumin are bound to the fat globules,in the liquid milk system containing vegetable oils,PAS6/7 can exert stronger emulsification than XO and BTN to maintain the stability of infant formula milk.