Study Of Preparation And Emulsifying Properties Of Potato Protein Hydrolysatesdextran Copolymer

In this experiment,Potato Protein(PP)was taken as the main research object,and alkaline protease hydrolyzed for 0,20,40,60,80 and 120 min.First,the emulsifying property of Potato protein hydrolysates(PPH)was studied by determining the solubility,emulsifying activity,emulsifying stability,surface hydrophobicity,ζ-potential and particle size.Moreover,the antioxidant activity of PPH was evaluated by reduction ability,DPPH free radical scavenging ability and inhibition liposome oxidation ability.Subsequently,the effects of mild maillard reaction on the emulsifying properties of PPH were studied.Three sugars(glucose,maltodextrin and dextran)were used to crosslink with PPH to optimize the maillard reaction conditions.By measuring free amino content,production of schiff base,changes in endogenous fluorescence spectra,emulsification and inhibition liposome oxidation capacity,the emulsifying property of the copolymer generated by the reaction of three sugars with PPH and the effect on the antioxidant capacity of PPH were compared.At the same time,The emulsifying property and the stability of emulsion preparation PPH-Dextran copolymer were further studied by interfacial tension,apparent viscosity,particle size,photoelectric potential and thiobarbital value.This study provides experimental basis and theoretical basis for improving the emulsifying property of protein.The main research results are as follows:(1)Compared with potato protein,the antioxidant capacity and emulsifying capacity of the PPH were significantly improved(P < 0.05).With the increase of hydrolysis time,the reduction capacity,the DPPH free radical scavenging capacity and the inhibition liposome oxidation capacity of PPH showed a gradually increasing trend.However,the emulsifying property,surface hydrophobicity,hydroxylation potential and particle size of PPH showed an upward and then downward trend,and PPH had the best emulsifying property under moderate hydrolysis for 60 min(P < 0.05).(2)PPH hydrolyzed for 60 min and dextran were mildly maillard-reacted.The reaction temperature,reaction time,concentration of reactant and pH conditions were optimized.The reaction conditions were pH 7.0,reaction concentration 10%,reaction time 3 d.Among the three sugars(glucose,maltodextrin and dextran),the copolymer of glucan and PPH had the highest free fatty acid content,the least Schiff base formation,the weakest fluorescence intensity,the best emulsifying activity and emulsifying stability(P < 0.05),and retained the original ability of PPH to inhibit lipid oxidation.However,the emulsifying effect of the copolymer formed by glucose and PPH was poor,and the ability of inhibiting lipid oxidation was slightly reduced.It also showed that the longer the molecular chain of sugar was,the better the emulsifying property of copolymer formed with PPH.(3)The stability of emulsions prepared by PPH and PPH-Dextran as emulsifiers was compared.The results showed that PPH-Dextran copolymer had higher interfacial tension and apparent viscosity than PPH.The emulsion prepared by PPH-Dextran copolymer significantly reduced the particle size,increased the negative charge on the surface of the emulsion droplet(P < 0.05),and significantly improved the emulsifying effect of PPH.In addition,PPH-Dextran copolymer retained the original antioxidant activity of PPH and the emulsion formed had good oxidation stability.