Effect Of Three Kinds Of Polysaccharides On Gelling Properties Of Whey Protein

Whey protein(WPC)and three kinds of polysaccharide: hydroxypropyl methyl cellulose(HPMC),carboxymethyl chitosan(CMC)and inulin(IN)were taken as raw materials for the proporation of gel,by heat treatment,mainly interacte effect on the protein gel texture properties,microstructure,thermal stability and rheological properties.Firstly,the effects of the concentration of added whey protein,the type of added polysaccharides and the concentration on the effect of whey protein gel were investigated by single factor experiment.The texture characteristics of whey protein-polysaccharide gel were evaluated by measuring the color difference,texture property and water holding capacity of the gel.In the concentration range(12-16%,w/v),the gel strength,rupture strength,viscosity and water holding capacity of whey protein gel increased with the whey protein concentration.The color difference of WPC-CMC gel is obviously different from WPC-HPMC and WPC-IN gels.WPC-HPMC gel was formed by adding 1%(w/v)HPMC into whey protein of fixed concentration(12%,w/v),and WPCCMC gel formed by adding 5%(w/v)CMC had the high water holding capacity and viscosity.Secondly,the microstructure of whey protein-polysaccharide gel was observed by laser confocal microscopy and field emission electron scanning electron microscopy.The thermodynamic properties of whey protein-polysaccharide gel were studied by differential scanning calorimetry(DSC).The DSC showed that the WPC-CMC gel structure formed after the addition of CMC was significantly different from the microstructure of other samples,WPC-CMC gel presented sponge-like structure,while whey protein gel,WPC-HPMC gel and WPC-IN gel presented foamy structure.The results of DSC showed that with the increase of the content of polysaccharide,the temperature of the endothermic transition peak of whey protein-polysaccharide gel decreased.Compared with whey 9kprotein gel,WPC-CMC gel formed by adding 5%(w/v)CMC has the lowest endothermic transition peak temperature.Finally,rheological properties of whey protein-polysaccharide gel were studied by rheological study.The results showed that the WPC-IN solution had the same linear viscoelastic zone as the whey protein solution.WPC-HPMC and WPC-CMC solutions behave as pseudoplastic fluids,and the linear viscoelastic range was significantly widened.The results of temperature scanning showed that the WPC-CMC gel with 5%(w/v)CMC was the most viscoelastic,and the WPC-CMC gel with 1%(w/v)IN was the least viscoelastic.The results showed that the addition of HPMC could improve the gel strength of whey protein gel and reduce the viscosity of whey protein gel.The whey protein gel formed by adding CMC has high viscosity but poor gel strength.The addition of inulin can improve the water holding capacity of whey protein gel.The addition of inulin can improve the water holding capacity of whey protein gel.This study provides a theoretical and practical reference for the preparation and performance study of whey protein-polysaccharide gel,which will provides a research basis for the application of whey protein-polysaccharide gel in food.