Influence Of Soy Lecithin On Physicochemical Property Of Imitation Breast Milk Powder Emulsion And Evaluation Of Its In Vitro Digestion And Microencapsulation

For infants,breast milk is the most comprehensive food with the best nutrition and digestion and absorption.However,due to the influence of objective factors such as social pressure,lifestyle and personal health and other objective factors,so that some infants can not get enough breast milk,so the imitation of breast milk to prepare infant milk powder is necessary.The main component of MFGM(Milk fat globule membrane,MFGM)is phospholipids.Breast milk phospholipids play a vital role in biological processes such as intracellular and intercellular signaling,protein glycosylation,and cytoskeletal rearrangement.It has been demonstrated that has potential benefits for infant health to use the bovine milk phospholipid instead of MFGM to add infant formula.But the bovine milk phospholipid extraction is costly and expensive.Given the strong interest in the biological activity of MFGM compounds,and the potential effects of MFGM on digestion,lipid absorption and metabolic fate,while SL phospholipids Comprehensive,a wide range of sources,so this article uses SL(Soy lecithin,SL)to simulate MFGM.The main ingredients of breast milk were used as raw materials to study the influence of added different concentration of SL on the physical and chemical stability and spray drying of artificial breast milk powder emulsion,and studied its effect on fat and protein digestion of imitation breast milk powder emulsion with simulated digestion system in vitro.(1)Firstly,infant milk powder fat was prepared by the ratio of palm oil:coconut oil:soybean oil:lard = 0.28:0.15:0.12:0.25.The results showed that the fatty acid types and concentrations of mixed fat were within the range of breast milk,which could be used as the fat for milk powder emulsion.The imitation breast milk powder emulsion was prepared in this chapter contains 1.55% protein(whey protein:casein = 6:4),3.5% fat(physically mixed to prepare baby milk fat)and 7% carbohydrate(maltodextrin).The effects of different concentrations of SL(0%,1%,3%,5%,7%,9%,w/w,oil)on the physicochemical stability of the imitation breast milk powder emulsion were studied.The results show that the addition of SL effectively improves the physicochemical stability of the imitation breast milk powder emulsion when SL concentration is 5%(w/w,oil).The emulsion presents the best stability,that is,the average particle size is the smallest,the particle size distribution is single-peak distribution,the molecular repulsion is the largest,the antioxidant capacity is the strongest;when SL concentration is at medium or low level(1%,3%,w/w,oil)and high level(7%?9%,w/w,oil),the emulsion is more likely to cause flocculation during storage.It is proved that SL concentration affects its interaction with protein,and the interaction between SL and protein at appropriate concentration is conducive to the formation of emulsion with physical storage stability and strong oxidation resistance.(2)To perform a simulated digestion system for infants in vitro to study the effects of different SL contents on the digestion of fat and protein in emulsified breast milk powder.According to the physical and chemical properties in the digestion process,the 5%(w/w,oil)emulsion has less flocculation during the digestion process,which is beneficial to increase the effective contact area between digestive enzymes and fats and proteins.It is proved that at this concentration,the interface membrane formed by the interaction between SL and proteins is dense and stable,and can effectively prevent oil droplets from flocculating.Blank emulsion and 0%,1%,3%,7%(w/w,oil)emulsion flocculation in the process of digestion are more serious,is due to the formation of emulsion interface film is thinner,more loose,easy to be destroyed and cause oil droplet aggregation;according to the digestibility and release types of fat and protein,the addition of SL had a significant effect on the digestibility of gastrointestinal fat of all samples,which was related to the stability of emulsion,but had no effect on the hydrolysis and release of fatty acids.The trend of protein digestibility of all samples was consistent with the stability of the emulsion,but the difference was not as significant as that of fat digestion,because the protein was better water-soluble and easy to be exposed to digestive enzymes.(3)The microcapsules were prepared by spray drying method,and the physicochemical properties were determined: the water content and solubility of all microcapsule samples were within the standard range,and the difference was not significant.Scanning electron microscopy showed that only 5%(w/w,oil)of the microcapsules were not broken or cracked,which proved that SL and microcapsules could effectively imbed the oil at sub-concentration,and the results were consistent with the encapsulation rate.TG and DSC data show that the microcapsules in the thermal decomposition temperature is above 190 ?,which proves that microcapsule has good thermal stability.Phase transition temperature is above 70 ?,which proves that the sample microcapsules have good stability at room temperature.