Study On The Preparation And Activity Of Hypocholesterolemic Peptides From Whey Protein

Hyperlipidemia is one of the highest mortality rates in China,and the main method of treatment at this stage is to use targeted drug therapy to reduce the cholesterol content of the blood.There are high cost of treatment and with the large toxic side effects.Whey has high nutritional value,and when the whey protein is hydrolyzed by the corresponding protease,it will produce a number of bioactive peptides.However,there are a large number of experiments to hydrolyze whey protein and to study its hypotensive efficacy,while the study of cholesterol-lowering peptides is more limited.Therefore,this experiment was carried out on the hydrolysis of whey protein by enzymatic method,to study on reducing cholesterol after the hydrolysis of whey protein peptides,which has very important practical significance and theoretical value for the development of new probiotics and functional healthy food.This article through enzymolysis,ultrafiltration and anion exchange resin method to make whey protein concentrate(WPC80)desalination preliminary,through the animal experiment to conduct to the activity,and through the animal experiment to conduct to the validate results.The peptides have significant activity.The main research contents and results are as follows:(1)Optimization of enzymatic hydrolysis conditions of whey protein cholesterol lowering peptides:The inhibition of cholesterol micellar solubility and degree of hydrolysis as the standards,through the single factor experiments,comparing the best enzymes that the former choose to hydrolysis the whey protein for cholesterol lowering peptides,and we choose the compound enzyme of trypsin and neutral protease to hydrolyze the whey protein(WPC80).The inhibition of micellar solubility of cholesterol as the standard,through response surface methodology,the optimal hydrolysis conditions of enzymatic hydrolysis:substrate concentration was 7%,enzyme/substrate was 6%,enzyme dosage ratio of trypsin and neutral protease 4:1,action time of rypsin and neutral protease was 8+2 hours,The maximum inhibition of micellar solubility of cholesterol was 19.81%.According to the above conditions,the inhibition rate is 19.19%,which proves that the model is highly effective.(2)Study on concentration of cholesterol-lowering peptides by ultrafiltration:the optimal process level was determined by the membrane flux of unit time,the temperature is 45 ?,the pressure is 0.20MPa,the concentration of hydrolysis peptide is about 7%.The hydrolysis of peptide solution on the inhibition of cholesterol solubility before and after ultrafiltration rate were measured and make comparison,obtained peptides after ultrafiltration of cholesterol lowering biological activity increased from 19.83%to 29.71%,ultrafiltration is an effective means for the separation and concentration of whey protein peptide cholesterol and enhance its biological activity.(3)Study on purification and desalination of cholesterol-lowering peptides by anion-exchange resin:Based on the single factor experiment,the optimal flow rate of the anion and cation experiment was determined by the peptide desalting rate and the recovery rate:The optimum flow rate of cation exchange resin was 9BV/h;the best anion exchange resin was 11BV/h.According to the above conditions for desalination of active peptide solution,to get the final result is:the desalination rate reached 93.41%,peptide recovery rate was 82.55%,desalination inhibitory peptide rate increased from 29.71%to 47.82%by ultrafiltration.(4)The composition of the cholesterol-lowering peptides:the total content of the peptides can reach to 82.46%,the moisture content is about 4.68%,the ash content is about 0.91%.(5)Experimental study on verification of cholesterol-activated peptides:A group of mice as a blank control,while the other two groups B and C were fed whey protein and prepared whey protein cholesterol-lowering peptides.At the end of the experiment,the content of fat in the blood of three groups of mice were measured.The results showed that:group C of mice with A,B two groups of mice significantly reduced the level of triglycerides in the blood cholesterol,low density lipoprotein and high density lipoprotein and blood(P<0.05).