The Extraction Of Millet Protein By Ultrasonic-assisted Enzymatic Method And The Preparation Of Compound Millet Protein Powder

In the north of China,millet,whose planting area and annual output are all very large,is one of the major food crops.It contains all kinds of nutrients which are complete,rich,and also has high digestibility.There is about 10% of crude protein in millet,which is much higher than the ordinary cereal grain.Besides that,it is a kind of low allergenic protein,and it is suitable for pregnant women and infants.The polypeptide has antioxidant.This experiment,using millet as raw material,extract millet protein by ultrasonic-assisted enzymatic technique and do the response surface method optimization.And thenit studied the functional properties of the millet protein,which was extracted by this method,and prepare the millet beverage withthe nutrients remained after the extraction of millet protein.Finally,preparate composite millet protein power withwhey protein powder,soy protein powder,and the extraction of millet protein powder in reasonable collocation.The main conclusions of this study are as follows:(1)On the basis of single factor experiment,and through the analysis of response surface experimental design,the optimum conditions are: hydrolysis temperature is 44℃,enzyme dosage is 2.5%,ultrasonic power is 420 W,ultrasonic time is 25 min.experiments were repeated 3 times under the above optimal conditions,the extraction rate of millet protein is 74.26±1.2%.(2)A comparative study on Millet protein of some functional properties of extraction of ultrasonic assisted enzymatic and alkali,compared the ultrasonic assisted enzymatic extraction of millet protein with alkali extraction of millet protein,millet protein solubility was increased by 35%,the water holding capacity increased by 11%,the oil holding capacity increased by 33%,the foaming and foaming stability increased by 18% and 24%,the emulsifying activity and emulsion stability were increased by 42% and 30%.(3)After studied the technology of preparing millet beverage with extraction residue of millet protein,the best proportion of preparing millet beverage is: fructose syrup 6%,citric acid 0.15%,milk powder 6%,the addition amount of compound additive is 0.2%.The sensory score is 93,under the optimum conditions.(4)The millet protein powderwas mixed with whey protein and soybean protein powder according to the food and human protein amino acid pattern,and then preparate the compound protein powder.The best ratio of orthogonal optimized compound protein powder is: 30% whey protein powder,20% millet protein powder,30% soybean protein powder.Finally,do amino acid analysis of the best proportion mixture,and the score is 90.