| In this experiment,heat denatured whey protein concentrate(HD-WPC)and high methoxy pectin(HM-P)as the research object,the phase separation behavior of HD-WPC and HM-P mixed systems with different quality ratios was first mainly described.Then,using the above-mentioned phase separation products in combination with oil-in-water(O/W)emulsions to prepare hydrogel,the effects of different quality ratios of HD-WPC and HM-P on the stability of hydrogel were investigated.Finally,the effects of different concentrations of sodium chloride(Na Cl),calcium chloride(Ca Cl2),and transglutaminase(TGase)on the stability of hydrogel were studied.This provides a theoretical basis for the application of hydrogels in products and optimization of processing techniques.The specific research contents and conclusions showed as follows:(1)The phase separation behavior of the whole mixture of HD-WPC and HM-P at different quality ratios(1: 1,2: 1,3: 1,4: 1,5: 1,w/w)was mainly investigated in this paper.The results showed that the upper phase of the complexes was polysaccharide-rich phase.The lower phase of the complexes was protein-rich phase.In addition,the upper phase was continuous phase,the lower phase was dispersed phase,which built a theoretical foundation for the subsequent application in hydrogels.(2)The effects of different quality ratios of HD-WPC and HM-P on the stability of hydrogel prepared by combining with phase separation products prepared by different quality proportions of HD-WPC and HM-P and O/W emulsions were investigated.The results showed that hydrogels had better stability compared with 1% O/W emulsions.When the quality ratios of HD-WPC/HM-P increased,the partical size decreased significantly,but the value of ?-potential value and apparent viscosity significantly increased(P < 0.05);Meanwhile,the quality ratios of HD-WPC/HM-P increased,Conjugated diene(CD)and Thiobarbituric acid reactive substances(TBARS)were first decreased and then increased,and the lowest was 3:1 of the quality ratios of HD-WPC/HM-P(P < 0.05).The trend of protein oxidation of hydrogel were similar to that of hydrogel with lipid oxidation.The above results indicated that with the quality ratios of HD-WPC/HM-P increased,the stability of the hydrogel gradually first increased and decreased,when the quality proportions of HD-WPC/HM-P was 3:1,the hydrogel had the best stability.(3)The above-prepared hydrogel was used as a foundation,the effects of Na Cl concentrations(0~500 m M)and Ca Cl2 concentrations(0~8 m M)on the stability of hydrogel were investigated.The results showed that the addition of Na Cl effected the physical stability of hydrogel.Meanwhile,with the Na Cl concentration increased,the stability of oxidation were increased.Howener,hydrogels with high-concentration Na Cl(400~500 m M)have higher CD and TBARS values compared with non-added Na Cl hyrogel.The above results indicated that with the concentration of Na Cl increased,the stability of the hydrogel gradually first increased and decreased.Higher concentrations of Na Cl(400~500 m M)were harmful to the stability of the hydrogel.The effects of different Ca Cl2 concentrations on the stability of hydrogel were similar to that of hydrogel added with Na Cl.The difference was that the concentrations of Ca Cl2 promoted the stability of the hydrogel.Hydrogel with a Ca Cl2 concentration of 4 m M showed the best stability.(4)The effects of TGase concentrations(0~20 U/g protein)on the stability of hydrogel were investigated.The results showed that with the TGase concentration increased,the stability of physical and oxidation were increased and then decreased,and the hydrogel had the best stability when the TGase concentration was 10 U/g protein.The above results indicated that the addition of TGase promoted the stability of the hydrogel.With the increase of TGase concentration,the stability of the hydrogel increased first and then decreased.Hydrogel with a TGase concentration of 10 U/g protein showed the best stability. |
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