Identification And Release Behavior Of Wheat Germ Protein With Mass Spectrometry

Wheat germ protein(WGP)is one kind of protein products which is extracted by alkalisolution and acid-isolation from the defatted wheat meal.At present,WGP has broad application prospects in foodstuff and other chemical fields.However,there are several problems existed in the traditional extraction process,such as high water content,low extraction rate,pretty of whey waste water,low resource utilization and low additional value of product.This research was conducted to develop a new method of alkali-solution and acidisolation to extract WGP from wheat meal,and investigate the impact of extraction conditions on the release behavior of different kinds of proteins in wheat meal based on the identification of protein species by mass spectrometry(MS).The obtained products from pilot scale experiment of wheat germ could be applied in production.The protein yield and protein content of the obtained products could be further increased by adjustion of extraction temperature,solution pH value and extraction duration.The main conclusions were as follows:1.Based on the identification of protein components by HPLC-MS,wheat germ protein extract was separated and collected by HPLC.Then the extract was further identified by trypsin digestion technology combined with HPLC-MS.The result indicated that different protein in the column shows different retention time.A total of more than 30 kinds of proteins were identified in this experiment,17 of which were high abundance protein.2.On the basis of protein components identification technology,the dissolution process of every protein in wheat meal was detected,and the release rate and release quantity of which were also compared.The results showed that the release rate of low molecular weight proteins was higher than that of high molecular weight protein,and the release rate of proteins in dynamic extraction process was higher than that in static extraction process.In addition,Chromosome 3B protein with a retention time of 18.78 min in dynamic extraction process had the quickest release rate,and the release of which reached 90% by extracting twice.3.Based on the research of wheat germ protein enzyme solution,wheat germ peptides prepared by hydrolyzing and defatting wheat germ protein under different conditions were investigated.The studied condition included solid-to-liquid ratio,extraction temperature and pH value of the solution.The comparison of process curve of papain,subtilisin and compound protease hydrolyzing and defatting wheat germ protein showed that compound protease had the best hydrolysis result.The optimum reaction conditions of compound protease were asfollows: substrate concentration 11.11%,pH 7,temperature 45 ?,enzyme-substrate ratio1:200,reaction time45 min.Under this condition,the highest hydrolysis efficiency of wheat germ protein was 87%.In addition,the preparation method of wheat germ protein can also be applied to enterprise production with a high protein content by using the pilot reactor,tube type centrifuge,spray dryer,freezer dryer and other equipment.This study applied the technology of alkali-solution and acid-isolation in the extraction of wheat germ protein,investigated the effect of different extraction conditions on the yield of protein and release rate,and optimized the isolation and identification of wheat germ protein,which had great reference value to establish a new extraction process of wheat germ protein.