MICROWAVE-ASSISTED ALKALINE EXTRACTION OF WHEAT GERM PROTEIN AND ITS FUNCTIONAL PROPERTIES

Wheat germ contains abundant wheat germ protein,which has equilibrium amino acids proportion.Microwave-assisted alkali extraction method was used to extract wheat germ protein from wheat germ in the present study.The effect of microwave pretreatment time,liquid to solid ratio,alkali pH,extraction time and temperature on the extraction rate of wheat germ protein was investigated.The extraction process was optimized by using orthogonal experimental design method.The results showed that the optimum microwave-assisted alkali extraction conditions for wheat germ protein were as follows:microwave time 3 min,liquid to solid ratio 25:1,pH 13 and 50℃,under which the wheat germ protein extraction rate was above 90%.Furthermore,after microwave treatment,the solubility,water holding capacity,oil holding capacity,emulsifying activity and foaming ability of wheat germ protein increased by 13.71%,27.61%,43.26%,24.41% and 19.08%,respectively,while the emulsion stability and foam stability decreased by 9.02% and 16.54% respectively.It was concluded that proper microwave pretreatment could increase the extraction rate and improve the functional properties of wheat germ protein.