Study Of Modification Egg-white Protein And Its Foaming Properties

The objective of this study was to investigate the factors which had the important effects on the foaming properties of egg-white protein. The results showed that the foaming properties of egg-white protein were enhanced by enzyme modification and physical modification including heat denaturation and foam stabilizing agent such as polysaccharides. Consequently, a new approach for the application of egg-white protein in food industry was developed.1,The effect of environmental factors and technological condition on the foaming properties of egg-white protein were studied. According to the experiments, the general factors influencing the foaming properties were considered and the optimum conditions were found: the foaming properties of egg-white protein were improved by moderate addition of NaCl,but high concentration of NaCl solutions above 0.5%(w/v) were found to depress foaming; the foam capacity was highest at pH2 and pH10,while it was least in the is electric region; the concentration of lipids above 0.5%(w/v) were found to intensely depress foaming. A series of additives was tried out in order to further improve foam stability, and the best results were obtained by the addition of xanthan gum with the concentration of 0.175%(w/v).Under these conditions the temperature and mixing time were kept on 60℃and 20min,respectively,which seemed to yield the best foams incapacity. Finally the foaming properties reached the peak with the whipping time of 4min.2,In terms of the effect of environment factors on the foaming properties of egg-white protein, physical modification by addition of xanthan were used to improve the foaming properties. The conditions for foam generation were optimized using response surface methodology, and the optimum processing conditions were found to be:5.6% (egg-white protein concentration), 0.29% (xanthan concentration), 45℃(temperature), 22 min(heating time),3.3min(whipping time).At this condition, foarming capacity can reach 113%.3,Neutral protease was used to hydrolysis egg-white protein. We studied the influence of solid/liquid ratio, enzyme concentration, pH, temperature and time to the foaming properties of product. The orthogonal experiments showed that the optimum condition are: solid/liquid ratio 1:10,enzyme concentration 0.4% ,pH 6.5 ,temperature 40℃,reaction time 3h.At this condition, the solubility can reach 65.15%, foarming capacity and foam stability can reach 70%,and 45%.