| Egg white is an important source of high-quality animal proteins with the advantages of high protein,zero fat and similar amino acid pattern to human body.Due to the difficulty of storage and transportation,egg white is generally spray-dried into egg white powder(EWP).EWP has the advantages of long shelf-life,low transportation cost and easy mixing with other base materials.However,spray drying will lead to the decline of the rehydration performance of EWP,which limits its wide application in the food industry.In this paper,spray-dried egg white powder(S-EWP)as the main research object,the cause of the decrease in rehydration properties of S-EWP and the corresponding solutions were explored,and the modified S-EWP was applied to fermented egg white beverage.The main research contents and results are as follows:First of all,the effect of spray drying on the physicochemical properties and rehydration performance of EWP was explored.It was found that the average particle size/surface hydro-phobicity of S-EWP was smaller/larger than that of the control group.This may be the potential reason for the decreasing dispersibility and increasing rehydration time of S-EWP.In addition,EWP presented a spherical structure with smooth surface after spray drying,which was not conductive to the wetting and dispersion of the particle.Secondly,the effect of combined enzyme-heat treatment on the rehydration performance of S-EWP was studied,the effect of heating temperature and the ratio of neutral protease on the rehydration performance of EWP was studied.The results showed appropriate heating treat-ment could obviously improve D20 and D60 and reduce the rehydration time of S-EWP by increasing the particle size,whereas enzymatic hydrolysis was beneficial to the release of highly electronegative peptides,thus increasing the stability of S-EWP in water.The optimal condi-tions for preparing the S-EWP with high rehydration performance was obtained:the tempera-ture was 75°C and the addition of enzyme was 0.03%(the enzyme activity was 60 U/g).In this condition,D20,D60 and coefficient of stability of S-EWP were increased by 20.81%,61.61%and 8.06%,respectively.Besides,the rehydration time was reduced by 61.49%.Then,the modified S-EWP with the best rehydration performance was rehydrated and ap-plied to the production of fermented egg white beverage.With unmodified S-EWP as control group,the effects of the ratio of sucrose and inoculation amount of lactic acid bacteria on fer-mented egg white beverage were explored.It was found that the rehydration solution of modi-fied S-EWP was more conducive to the fermentation of lactic acid bacteria,which was related to the degradation of ovotransferrin.The fermentation of lactic acid bacteria could reduce the stability of the system by reducing the p H,surface charge and increasing the particle size of protein aggregation.Based on the results of sensory evaluation and rapid gas phase electronic nose analysis,it was found that moderate fermentation could improve the flavor of egg white beverage and make it have typical yogurt flavor.The highest sensory score was obtained with6%of sucrose and 5×10~8 CFU/g of lactic acid bacteria inoculation.However,the fermented egg white beverage was prone to settle and needed to be further improved.Finally,the effect of the adding sequence and ratio of guar gum(GG)and xanthan gum(XG)on the quality of fermented egg white beverage system was studied.By comparing the addition of GG and XG before and after fermentation,it was found that the acceptability of egg white beverage prepared by adding polysaccharides after fermentation was higher.At the same ratio,XG had stronger thickening and stabilizing effects than GG in egg white beverage.In addition,since the presence of beany smell in GG,0.5%XG was selected as the stabilizer and thickener of fermented egg white beverage system. |
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