Study On Extraction, Modification By Ultrasound Assisted Glycosylation And Application Of Wheat Bran Protein

Wheat bran is the main by-product of wheat flour,which is about 5% of the wheat.In China,the wheat bran was mainly used for feed and fermentation industry,rarely used for deep processing and recycjing,so the economic value and the comprehensive utilization rate of it is low.Wheat bran contains relatively rich resources of protein,accounts for about 14% of its content,is a good resource of protein.So the extraction,modification and application of wheat bran protein had important significance.First of all,wheat bran as raw material,wheat bran protein extraction process was studied.Enzyme pretreatment method was used to extract proteins,wheat bran protein extraction rate was used as index,the effects of the ratio of cellulase and pectinase,enzyme dosage,p H,reaction temperature and reaction time on the extraction yield were studied.According to the single factor experiments,the optimum extract process for wheat bran protein was determined through Box-Benhnken central composite design and response surface methodology.The results showed that the cellulase and pectinase ratio 3:1,363 u/g enzyme dosage,p H 5,reaction temperature 54.7 ℃,reaction time 2.4 h,the protein extraction rate was 49.80%.The wheat bran protein as raw material,ultrasonic assisted glycosylation was used to modify it.The preparation conditions of wheat bran protein-glucose graft,and wheat bran protein-soluble starch graft were studied.Effects of wheat bran protein concentration,the ratio of wheat bran protein and glucose or soluble starch,ultrasonic power,ultrasonic temperature, ultrasonic time,on grafting degree,and the solubility had been analysed in single factor experiment.The surface hydrophobicity,emulsify ability and emulsify stability,gel strength and fluorescence intensity were studied.The results were as follows: the wheat bran protein concentration 1%,the ratio of wheat bran protein and glucose was 1:4,ultrasonic power 100 W, ultrasonic temperature 75 ℃,ultrasonic time 100 min,and degree of graft 39.90%,the solubility was 48.20%;the wheat bran protein concentration 1%,the ratio of wheat bran protein and soluble starch was 1:2,ultrasonic power 100 W,ultrasonic temperature 70 ℃,ultrasonic time 120 min, and degree of graft 36.73%,the solubility was 47.39%.The results showed that degree of graft and the solubility of wheat bran protein-glucose graft was better than wheat bran protein-soluble starch graft.Compared with the unmodified protein,the surface hydrophobicity,emulsify ability and gel strength of the modified protein was improved,and the emulsify stability was rarely changed.Fluorescence intensity of wheat bran protein-grafts was increasing,it due to side chains of the modified protein unfold,more leucine was exposed.TheΔH of modified wheat bran protein decreased,and more sensitive to heat treatment.The experiment that put the modified wheat bran protein added to the meatballs was carried out.Single factor experiments were carried out to determine the effects of wheat bran protein added in the meatballs.The results showed that,the effects of wheat bran protein-soluble starch graft on the sensory evaluation standard and the quality and structure of meatballs were better than wheat bran protein-glucose graft.This is because the wheat bran protein-soluble starch graft’s gel strength and water-holding capacity were higher than the wheat bran protein-glucose graft.According to the above process to make meatballs,the meatballs had tissue integrity,and full of elasticity,with wheat bran fragrant air and lustre,had high nutritional value,and the taste is very good.