Cooperative Emulsification Mechanism And Application Of Coconut Protein And Sodium Alginate

Hainan,located at the southernmost tip of China,is the only tropical province in China and has jurisdiction over 2/3 of the country's maritime land.Coconut production accounts for more than 90%of the country,and algae resources should not be underestimated.Coconut protein is not fully utilized as a by-product of coconut oil processing,and the recovery of protein increases the added value of the overall economy of the process.This experiment used coconut milk as raw material to extract coconut milk isolate protein(CMIP),systematically study the emulsification performance and emulsification mechanism of CMIP as a natural emulsifier,and synergistically prepare it with sodium alginate(SA)Emulsion,explore the influence of SA molecular weight and M/G ratio(Mannuronic to Guluronic acid ratio)on its rheological behavior and emulsification performance,and examine its feasibility for the transportation of biologically active ingredients.The specific results are as follows:(1)Using CMIP as an emulsifier to prepare emulsions,analysis showed that the protein solubility of CMIP,EAI and its Zeta-potential and creaming index were significantly affected by the p H and CMIP concentration of the emulsion.At the same time,it was observed that the stability effect of the CMIP emulsion sample was poor,and stable and clear delamination appeared after short-term storage.However,no fat precipitation was observed during long-term storage.The results showed that sufficient CMIP can be quickly adsorbed on the surface of oil droplets,which can better inhibit the aggregation of droplets.(2)Analyze and study the influence of p H and SA concentration on the stability of CMIP emulsion.When the p H value was higher than 6,the protein solubility increased to6359?g/m L,the EAI is 20.814 m²/g,the Zeta-potential was higher than-50 m V,the milk droplets were uniformly dispersed,and the particle size was around 1.7?m.When the p H was higher than 5.At this time,the stability of CMIP-SA emulsion was significantly higher than that of CMIP emulsion.With the increase of SA concentration,the CI value of CMIP-SA emulsion increased from 19.5%to 48%and then decreased to 0 at 0.5 wt%SA.SA adsorbed onto the surface of CMIP-coated oil droplets,increasing the Zeta-potential and interface thickness of the droplets.The three-dimensional network structure formed by SA restricts the droplets from floating and the emulsion stability is significantly increased.A stable emulsion was obtained at p H 6,2%CMIP,0.6%SA,and 5%MCT.(3)Explore the influence of ionic strength(0?300 m M Na Cl,0?5 m M Ca Cl₂),temperature(-80,-20,4,30,70,90?)on the stability of CMIP-SA emulsion.The results show that the addition of Na⁺has no significant changes in the emulsion potential,particle size and other indicators,but the emulsion is unstable due to electrostatic shielding.The action of Ca²⁺and-COO^-promotes the increase of the Zeta-potential,particle size and viscosity of the emulsion.The concentration of 1-3 m M promotes the stability of the emulsion,and the gelation of the emulsion becomes unstable when it is 4-5 m M.Freeze-thaw(-80?,-20?)and high temperature(90?)lead to changes in the interface structure and the emulsion becomes unstable.(4)Acid modification prepared sodium alginate(SAs)with different molecular weight and M/G ratio.The results of infrared spectroscopy(FTIR)showed that the chemical bonds within SA molecules did not change significantly,only the glycosidic bonds were broken.The rheological analysis results showed that the SA solution was a pseudoplastic liquid,and the apparent viscosity of the acid-modified SA solution decreases rapidly as the molecular weight decreases.As the molecular weight decreases,the interfacial tension of the SA-Ms stabilized emulsion increases significantly,the absolute value of the Zeta-potential of the SA-Ms solution and its emulsion decreases significantly,and the TSI increases,indicating that the molecular weight played an important role in the emulsifying ability of SA.In addition,SAs with high M/G form finer droplets.(5)Build different interfacial membrane emulsions contain?-carotene to study the effects of CMIP,SAs concentration,SA molecular weight and other conditions on milk droplets during gastrointestinal simulated digestion.The results showed that the gelation of SAs can significantly reduce the damage of gastric juice to the emulsion,and compared with SA,the structure of SA-Ms-coated milk droplets remains intact.In summary,CMIP is an effective material developed as an emulsifier for food-grade Pickering emulsions.The synergy of SA and CMIP significantly improves the stability of CMIP emulsions and is suitable for emulsions delivered as active substances.