【摘要】：In recent years,the source of plant protein has become a research hotspot,and rice bran is a valuable resource with super high nutritional value.However,due to the existence of excessive disulfide bonds in rice bran protein,it is difficult to completely separate and extract it,resulting in rice bran protein.The development of functional properties is limited.In this study,the rice bran protein was fractionated and extracted by physical method,and the structural and functional properties of the different protein components were studiedThe rice bran protein was extracted by the method of alkali-soluble acid precipitation using defatted rice bran as raw material,and the extracted rice bran protein was fractionally extracted by sucrose density gradient centrifugation.First,the effective sucrose concentration gradient was established by pre-experiment in the range of 10%to 50%.On the basis of establishing the sucrose concentration gradient,the experiment uses the protein extraction rate as an index,the SDS-PAGE gel electrophoresis analysis chart as a reference,and the ultracentrifuge as the core equipment to determine the sucrose density gradient method to fractionate the rice bran protein fraction.Good process parameters,sucrose solution concentration(50%,40%,30%,20%,10%),centrifugal force(15000g/min,20000g/min,25000g/min.30,000g/min,35000g/min),rice bran The concentration of protein solution(10mg/mL,20mg/mL,30mg/mL,40mg/mL,50mg/mL)was used as the experimental condition.The optimal classification conditions after optimization were:centrifugation speed 25000g/min,centrifugation time 30min,rice bran protein The concentration of the sample solution was 30 mg/mL,and the basal rice bran protein component Ⅰ,rice bran protein component Ⅱ,rice bran protein component Ⅲ,rice bran protein group were separated under the conditions of sucrose concentration of 50%,40%,30%,and 20%.respectively.Divided into Ⅳ.The extraction rates of the four protein components were 21.6%,24.4%,17.2%,and 12.5%,respectivelyThe functional properties of four different rice bran protein fractions were studied by using four kinds of rice bran protein components by solubility,water holding capacity,oil holding property,foaming and foam stability,emulsifying property and emulsion stability.The results showed that the functional properties of the four rice bran protein components were different.The functional properties of the protein depended on the nature of the surface groups of the protein and also closely related to the protein structure.Four different components of rice bran protein were studied by Fourier transform infrared spectroscopy,DSC thermal denaturation,scanning electron microscopy,sodium dodecyl sulfate-polyacrylamide gel electrophoresis,amino acid analysis and surface hydrophobicity.Changes in the structure of the rice bran protein component.The results showed that there were differences in the secondary structure of the four rice bran protein fractions,with RBPⅠ and RBPⅡ peaking the most.The denaturation temperatures of the four rice bran protein fractions were:68.42℃,83.51℃,89.79℃,and 68.33℃.Scanning electron microscopy revealed that the surface of the four rice bran protein components was rough and porous,which affected the oil retention of the protein.SDS-PAGE gel electrophoresis showed that the molecular weight range of the four rice bran protein components ranged from 74.0KDa to 97.4KDa,41.0KDa to 53KDa,29.0KDa to 30.0KDa,and 13.0KDa to 21KDa.
【圖文】：

邐—？｜收集沉淀ｈ￣？ｌ水洗邋Ｉ￣透析邐冷凍丨？燥ｉ￣米糠蛋白組分ｆ逡逑圖２－１四種米糠蛋白組分分級(jí)工藝流程逡逑四種米糠蛋白組分分級(jí)工藝流程如圖２－１，具體試驗(yàn)操作如下：逡逑將一定量脫脂米糠，按照料液比１：８的比例加入蒸餾水，并用ｌｍｄ／ＬＮａＯＨ逡逑溶液調(diào)節(jié)ｐＨ至９，室溫下攪拌２ｈ，在４０００ｒ／ｍｉｎ條件下離心２０ｍｉｎ，，，收集上清逡逑液，用ｌｍｏｌ／ＬＨＣＬ溶液將上清液ｐＨ至４．５，在４０００ｒ／ｍｉｎ條件下離心２０ｍｉｎ，逡逑收集沉淀，調(diào)至ｐＨ為７，冷凍干燥得米糠蛋白。配制５０％濃度的蔗糖溶液，４°Ｃ逡逑下靜置過夜，然后取一定量米糠蛋白加入蒸餾水配制成一定濃度的蛋白溶液，取逡逑１０ｍＬ５０％蔗糖溶液裝入５０ｍＬ離心管中，用移液槍吸�。欤恚堂卓返鞍兹芤貉仉x逡逑心管壁小心打入蔗糖溶液上方，使用超速離心機(jī)在４°Ｃ和一定轉(zhuǎn)速下離心一段時(shí)逡逑間。將離心得到的沉淀經(jīng)過水洗

邐？邋；．？＞．－邐／邐，逡逑＝—邋■逡逑圖３－２蔗糖溶液濃度對(duì)米糠蛋白組分Ｉ分子量分布的影響逡逑Ｆｉｇｕｒｅ邋３－２邋Ｅｆｆｅｃｔ邋ｏｆ邋ｓｕｃｒｏｓｅ邋ｓｏｌｕｔｉｏｎ邋ｃｏｎｃｅｎｔｒａｔｉｏｎ邋ｏｎ邋ｍｏｌｅｃｕ
【學(xué)位授予單位】：沈陽(yáng)師范大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2019
【分類號(hào)】：TS201.21

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