Study On The Mechanism Of Enzymatic Demulsification In The Process Of Extracting Peanut Oil By Aqueous Enzymatic Method

The aqueous enzymatic method is a new technology for extracting vegetable oil and protein.Compared with the pressing method and the solvent extraction method,the water enzymatic method is not only environmentally friendly,low energy consumption,mild operating conditions,high extraction rate,but also can retain the nutrients in the raw materials to the greatest extent,improve the nutritional value of vegetable oil and protein,and has a very wide range Application prospects.The traditional aqueous enzymatic method mainly uses protease to extract peanut oil and protein.Although protease has a good oil extraction effect,protease will hydrolyze plant protein,destroy its functional properties,and reduce the utilization value of protein resources.At the same time,a large amount of emulsion will be produced during the extraction process of aqueous enzymatic method,and it is difficult to demulsify,which greatly limits the industrial application of the aqueous enzymatic method.In this study,peanut protein and oil bodies were extracted with cell wall degrading enzymes to obtain peanut proteins that were not enzymatically hydrolyzed by proteases;then the composition and stability of peanut oil body emulsions were demulsified,and the factors affecting its stability were explored;finally,a compound enzyme method was used Demulsification oil body emulsion,find the best oil body emulsion demulsification process,and explore its demulsification mechanism.First,comparing the extraction effects of different crushing methods on peanut oil bodies and protein,it is found that conventional dry crushing has the best extraction effect on peanut oil bodies and protein,and the peanut oil bodies obtained by conventional dry crushing have the largest particle size and the worst stability.After mechanically pulverizing peanut cells,different cell wall degrading enzymes were used to extract peanut oil bodies and proteins.It was found that cellulase and pectinase had the best extraction effect when the cellulase and pectinase were compounded at a ratio of 1:1;scanning electron microscopy and cell wall composition analysis showed that the compound polysaccharidase had an effect on peanuts.The cell wall damage is the most severe,which can significantly degrade the cellulose,hemicellulose,pectin and other substances in the peanut cell wall components;optimize the enzymatic hydrolysis process of the compound polysaccharide enzyme:enzymatic hydrolysis temperature: 50?;material-liquid ratio: 1:4;enzyme Concentration:1000 U/g;enzymatic hydrolysis time: 1.5 h,the highest extraction rate of peanut oil body and protein is 94.35% and 83.52%.Secondly,two-dimensional electrophoresis and mass spectrometry were used to analyze the composition of the interface proteins in the oil body emulsion,and the phospholipid composition in the oil body emulsion was analyzed by the phosphorus spectrum nuclear magnetic resonance technique.The results show that the endogenous protein in peanut oil body emulsion is mainly composed of oil body protein,oil body calcin,and oil body sterol protein.Large molecular weight exogenous proteins mainly include peanut conglycinin and lipoxygenase;phospholipids;Mainly PC,PS,PE,PI,PA,etc.The highest content is PC.At the same time,the effects of temperature and p H on the stability of oil body emulsion were studied.The analysis of rheometer and laser particle size analyzer showed that high temperature treatment can significantly reduce the emulsification activity and viscosity of oil body emulsion,making oil droplets more likely to aggregate;When p H 5 is close to the isoelectric point of peanut oil body,the interfacial proteins aggregate,the particle size of oil body increases,and the stability of oil body emulsion decreases,which is conducive to subsequent demulsification research.Finally,the demulsification effect of different demulsification methods on oil body emulsions was studied,and it was found that the combination of papain and phospholipase demulsification was the best.Through response surface and single factor optimization experiments,the optimum process parameters of demulsification by complex enzyme were:The ratio is 3.2:1,the enzymolysis temperature is 50.0?,and the enzyme concentration is1800 U/g.Under these conditions,the demulsification rate of peanut oil body emulsion is98.26%.By studying the effects of different enzymes on the composition of the oil body interface membrane and the properties of the emulsion,the enzymatic demulsification mechanism of the oil body emulsion is speculated: during the enzymatic demulsification of peanut oil body emulsion,phospholipase A1 makes the phospholipid molecular layer in the interface membrane lose With the original amphipathic nature,the structure of the interface protein becomes loose and can no longer be stably embedded in the phospholipid molecular layer,and the strength of the interface membrane decreases.Papain degrades the endogenous protein and exogenous protein of the oil body emulsion,making it soluble in the water phase,and the interface film of the oil body emulsion is completely destroyed.The oil droplets lose the electrostatic repulsion and steric hindrance provided by the interface film,and gradually gather and fuse,and the oil body emulsion breaks.