Effects Of Ultra-high Pressure On The Processing Characteristics Of Corn Protein Meal And Its Application In Mixing Powder

Corn gluten meal is the main by-product of corn starch produced by wet process,which is rich in protein.In order to improve the utilization rate of corn,this subject takes corn as raw material to study the effect of ultra-high pressure treatment on the functional characteristics and structure of corn protein meal.The corn protein meal after ultra-high pressure treatment is used in the development of new high protein blending powder,and its shelf life is tested.The research results are as follows:(1)Through single factor test and response surface analysis,it is determined that the optimum conditions for extracting corn protein by alkali soluble acid precipitation method are as follows: solid-liquid ratio 1:10,extraction p H 12,extraction temperature37 ℃,extraction time 1.5 h,and the protein extraction rate is 65.30%.(2)Compared with the control group,the corn protein meal was kept under high pressure for 200 min under pressure of 15 MPa,and the water holding capacity increased to 4.50 m L/g.The pressure was maintained at 5 min at 400 MPa pressure,and the emulsion stability increased to 47%.The pressure of 10 min was increased to 68.88% at400 MPa pressure,and the oil holding capacity of 15 min was increased to 68.88% m L/g,and the foaming property and foam stability increased to 68.88% and 68.88%respectively.(3)Ultra high pressure treatment changes the structure of corn protein meal:Microstructure and particle size.The results show that under the pressure of 200 ～ 400 MPa,the disulfide bonds in the protein structure break and rearrange,form aggregates and increase the particle size;When the pressure increased to 600 MPa,the protein aggregates gradually dissociated and the particle size decreased with the extension of pressure holding time;Infrared spectrum analysis showed that the functional groups and structure of protein changed.(4)Taking the centrifugal precipitation rate as the inspection index,the formula and preparation method of the prepared powder are determined through single factor test:ultra high pressure corn yellow powder protein 10 g,xylitol 1 g,compound thickener 0.1g,dispersant 0.1 g,the ratio of compound Thickener(xanthan gum and sodium alginate)is 4:6,and the ratio of compound thickener to dispersant is 5:5.At this time,the centrifugal precipitation rate of the prepared powder is the lowest;The mixing temperature is 80 ℃,the flushing volume is 50 ml,and the dispersion and stability are the best.(5)The antioxidant performance of the mixing powder was improved: the clearance rates of ABTS ·,DPPH ·,and · Oh were increased by 3.59%,22.34% and 12.20%respectively.(6)Determination of shelf life of blended powder: during storage,the brightness(L*)of blended powder decreases,(b *)increases,and the moisture content and activity continue to decrease;Microbial test results showed that the total number of colonies exceeded the national standard when the prepared powder was stored at 4 ℃ for 120 days.Therefore,the prepared powder can be stored for 105 days at 4 ℃.