4种花生粕蛋白的理化性质及功能特性研究

以花生粕为原料,采用分级提取工艺提取花生清蛋白、球蛋白、醇溶蛋白和谷蛋白,研究4种花生粕蛋白的理化性质和功能特性。扫描电镜观察,4种花生粕蛋白的形态结构各不相同。SDS-PAGE法测定分子量表明,清蛋白含有4种亚基,相对分子量分别为70kDa、40kDa、30kDa、25kDa和15kDa;醇溶蛋白含有2种亚基,分子量分别为25kDa和15kDa;球蛋白含有5种亚基,分子量分别为40kDa、38kDa、30kDa、25kDa和15kDa;谷蛋白含有4种亚基,分子量分别为40kDa、30kDa、25kDa和15kDa。花生清蛋白、醇溶蛋白、球蛋白、谷蛋白的等电点分别为pH3.6、pH5.2、pH4.6、pH5.0。功能性质研究表明,球蛋白的持水性最好,为1.52mL/g,其次为谷蛋白1.10mL/g,清蛋白和醇溶蛋白的持水性较低分别为0.49mL/g、0.14mL/g;清蛋白的持油量相对较高为8.21mL/g,其次为球蛋白为7.16mL/g,谷蛋白和醇溶蛋白的持油量相对较低,分别为3.82mL/g和5.49mL/g;清蛋白的乳化性和乳化稳定性相对较高,乳化能力EC值和乳化稳定性ES值分别为71.4% 和83.33%,谷蛋白次之,EC和ES值分别为66.7% 和82.86%,醇溶蛋白和球蛋白相对较低,EC值分别为64.0% 和62.2%,ES值分别为82.35% 和76.67%。综上,花生粕清蛋白的持油性、乳化性和乳化稳定性相对较好。     

4种花生粕蛋白的理化性质及功能特性研究

以花生粕为原料,采用分级提取工艺提取花生清蛋白、球蛋白、醇溶蛋白和谷蛋白,研究4种花生粕蛋白的理化性质和功能特性。扫描电镜观察,4种花生粕蛋白的形态结构各不相同。SDS-PAGE法测定分子质量表明,清蛋白含有4种亚基,分子质量为70、40、30、25和15 ku;醇溶蛋白含有2种亚基,分子质量分别为25和1 5 ku;球蛋白含有5种亚基,相对分子质量分别为40、38、30、25和15 ku;谷蛋白含有4种亚基,相对分子质量分别为40、30、25和15 ku。花生清蛋白、醇溶蛋白、球蛋白、谷蛋白的等电点分别为pH 3.6、pH 5.2、pH 4.6、pH 5.0。功能性质研究表明,球蛋白的持水性最好,为1.52 mL/g,其次为谷蛋白1.10 mL/g,清蛋白和醇溶蛋白的持水性较低分别为0.49、0.14 mL/g;清蛋白的持油量相对较高为8.21mL/g,其次为球蛋白为7.16 mL/g,谷蛋白和醇溶蛋白的持油量相对较低,分别为3.82 mL/g和5.49 mL/g;清蛋白的乳化性和乳化稳定性相对较高,乳化能力(EC)值和乳化稳定性(ES)值分别为7 1.4%和83.33%,谷蛋白次之,EC和ES值分别为66.7%和82.86%,醇溶蛋白和球蛋白相对较低,EC值分别为64.0%和62.2%,ES值分别为82.35%和76.67%。综上,花生粕清蛋白的持油性、乳化性和乳化稳定性相对较好。     

非洲山毛豆蛋白质组成及其功能特性研究

以山毛豆种子为原料,研究其蛋白质组成及其功能特性。结果表明,脱脂山毛豆粉的总蛋白质量分数为47.11%,其中清蛋白、球蛋白、醇溶蛋白和谷蛋白的质量分数分别为64.04%、8.83%、11.06%和14.50%,另有1.57%的难溶复合蛋白。清蛋白和谷蛋白在pH4和球蛋白和醇溶蛋白在pH5溶解性、起泡性、乳化性均差,而泡沫稳定性和乳化稳定性较好。各蛋白组分的持水持油性均较好。在pH5或pH4的条件下,清蛋白和球蛋白的溶解性、起泡性和乳化性较好,其余蛋白组分相对较差。与大豆蛋白相比,山毛豆主要蛋白清蛋白有较好的溶解度、持水持油性、起泡性、泡沫稳定性、乳化性及乳化稳定性。     

米渣谷蛋白的纯化及功能性质研究

按照Osborne蛋白分级提取渣蛋白,分别得到了清蛋白、球蛋白、醇溶蛋白和谷蛋白,然后采用α-淀粉酶对谷蛋白进行纯化,提纯的谷蛋白纯度可达到90%以上,进而研究食品体系中pH、盐离子和多糖等因素对米渣谷蛋白溶解性、乳化性和乳化稳定性的影响。pH在远离等电点时,有利于谷蛋白的溶解,并提高了乳化性和乳化稳定性;在0.5%NaCl溶液中,谷蛋白的溶解性和乳化性最大,而NaCl浓度为1.0%时,乳化稳定性最低;卡拉胶的添加能显著提高谷蛋白的溶解性、乳化性和乳化稳定性,但过量的卡拉胶会破坏谷蛋白的乳化稳定性。     

莲子中不同蛋白的结构及理化特性对比分析

该研究分别制备了莲子分离蛋白与莲子分级蛋白（清蛋白、球蛋白、醇溶蛋白、谷蛋白）,并对比研究了不同莲子蛋白的溶解性、乳化性、分子特性等结构变化。研究结果表明,莲子中蛋白质约占干基总量的16.14%,4种分级蛋白所占比例依次约为55:6:0.1:25。对比5种不同莲子蛋白,清蛋白溶解性最高,Zeta电位最低值为-21.3 mV,粒径最小值为75.47 μm,分离蛋白乳化性最好,五种不同蛋白的等电点均在4.9附近。光谱研究表明,醇溶蛋白和谷蛋白荧光更强,清蛋白和球蛋白α-螺旋含量更低,醇溶蛋白和谷蛋白β-转角含量更高。光谱研究表明,分离蛋白、清蛋白（球蛋白）的波长蓝移,清蛋白和球蛋白的α-螺旋含量更低,且α-螺旋、β-折叠、β-转角含量也发生不同变化。这些研究结果也表明清蛋白和球蛋白分子柔性相对更高,与其溶解性、乳化性、疏水性密切相关。通过实验有助于揭示莲子分离蛋白和分级蛋白理化特性与分子结构间的构效关系,并为深入研究莲子蛋白的功能特性提供理论依据。     

麦麸中四种蛋白的Osborne法提取分离及性能研究

麦麸蛋白是植物蛋白的一种,通过研究麦麸蛋白的组成及性质以应用于食品工业。用Osborne法分离提取出清蛋白、球蛋白、醇溶蛋白和谷蛋白4种蛋白,考马斯亮蓝法测定等电点。实验表明:清蛋白、球蛋白、醇溶蛋白和谷蛋白的相对含量分别是48.06%、25.12%、18.70%,8.12%;等电点依次为4.0、5.0、5.8、5.2。电镜表观发现,清蛋白和球蛋白分子均连接紧密,清蛋白表面细致多层,局部有孔;球蛋白表面疏松,表面孔较少。醇溶蛋白和谷蛋白分子连接松散,醇溶蛋白呈不规则的球状,谷蛋白表面平滑,分子团多。功能性质测定结果表明:四种蛋白中球蛋白的持水性和持油性最大,分别为5.00g/g和2.40g/g;醇溶蛋白的起泡性、起泡稳定性和乳化力最强,分别为376%、71%和75%。因此,球蛋白适宜作为添加剂应用在肉制品中,醇溶蛋白适宜作为添加剂应用在奶制品和蛋糕等食品配方中。     

紫苏分离蛋白及主要蛋白组分功能性质研究

以脱脂紫苏粉为原料,分别采用碱溶酸沉法和Osborne法制备分离蛋白(PPI)、清蛋白(PAP)、球蛋白(PGP)和谷蛋白(PLP),并对比分析4种蛋白的功能性质。结果表明:PPI、PAP、PGP和PLP蛋白质量分数分别为86.1%、60.1%、82.9%和74.7%,每种蛋白必须氨基酸含量均可以满足FAO/WTO推荐的成人标准。PGP暴露巯基含量最高为27.3μmol/g,PLP二硫键含量最高为20.38μmol/g;SDS-PAGE结果显示分离蛋白中包含了另3种蛋白的所有条带,主要亚基分子质量为10.5、20.1、32.7和40.6 ku;4种蛋白溶解曲线近似为U形,除PGP在pH 5.0以外,其他3种蛋白均在pH 4.0时溶解性最低,所有蛋白在pH 12.0溶解性均最高。起泡性在等电点附近较小,乳化性和乳化稳定性均随pH变化不明显;PAP的持水和持油性相对最大分别为3.81、3.93 mL/g。     

小麦胚蛋白分级提取及功能性研究

以小麦胚为原料,首先采用正己烷低温脱脂,然后利用碱法提取麦胚蛋白（WheatGerm Protein,WGP）,采用Osborne法对麦胚蛋白进行分级,得到麦胚清蛋白、球蛋白、醇溶蛋白和谷蛋白4种组分,分别占总蛋白的32.5%、15.6%、4.2%和12.6%。在此基础上,对麦胚蛋白、麦胚清蛋白、麦胚球蛋白和麦胚谷蛋白的功能性进行定量分析比较。结果表明,4种蛋白中,麦胚蛋白的吸水性最佳,为3.03g/g;麦胚清蛋白的溶解性、起泡性、乳化性和乳化稳定性最好,分别为71.2%、84.8%、63.6%和62.8%;麦胚谷蛋白的吸油性最强,为2.79g/g。     

樟树籽仁蛋白的物理性质及安全性的研究

开发樟树籽仁蛋白作为一种新型植物蛋白资源。以石油醚低温脱脂的樟树籽仁为原料,采用Osborne法对樟树籽仁蛋白进行分级,得到清蛋白、球蛋白、醇溶蛋白和谷蛋白4种组分。为了较全面系统地了解樟树籽蛋白进行理化性质及动物毒性的测定。结果表明,樟树清蛋白、球蛋白、醇溶蛋白和谷蛋白分别占总蛋白的25.64%,23.51%,2.32%和18.39%;等电点分别为3.1,3.5,3.3和4.5;变性温度分别为45.35℃,46.15℃,43.53℃和52.56℃;清蛋白、球蛋白和谷蛋白的必需氨基酸含量丰富,醇溶蛋白含量较低;清蛋白和谷蛋白表面较规则,球蛋白和醇溶蛋白表面发亮;清蛋白、球蛋白和谷蛋白的二级结构主要为β-折叠,醇溶蛋白主要为无规卷曲。MTT和ELISA测定结果表明,在推荐膳食浓度(1.2 g/kg)下不会对BALB/c小鼠肝细胞和脾细胞引起凋亡及免疫炎症的反应,说明在动物水平上樟树籽仁蛋白是安全无毒的。试验对樟树籽仁分离蛋白的研究,为樟树籽仁蛋白质资源的开发利用奠定基础,也为其他植物蛋白质的研究提供理论依据。     

绿豆中四种蛋白质的分级提取与功能性质研究

采用Osborne方法分级分离了绿豆中的蛋白质,得到四种蛋白组分:清蛋白、球蛋白、醇溶蛋白和谷蛋白,并对其进行功能性质评价。对比评价结果表明:溶解度大小为:清蛋白>球蛋白>谷蛋白>醇溶蛋白;四种蛋白组分中,谷蛋白持水与持油能力较好,清蛋白起泡性较好,醇溶蛋白颜色最好、感官接受度较高,四种蛋白组分在碱性条件下均有较好的乳化性,且均在270~280nm处产生最大吸收峰。     

苦荞蛋白质的低消化性研究Ⅰ——热处理、还原二硫键及添加芦丁对其体外消化率的影响

采用Osborne分级分离的方法从苦荞粉中制备得到清蛋白、球蛋白、醇溶蛋白和谷蛋白。体外消化率测定结果表明,四种蛋白组分的消化率均低于对照-小麦胚分离蛋白和大豆分离蛋白,并且四种组分的体外消化率也存在不同程度的差别:清蛋白最高,谷蛋白最低。热处理可以明显提高苦荞粉四种蛋白组分的体外消化率。添加芦丁不但没有降低四种蛋白组分的体外消化率,反而均有一定程度的提高。二硫键的破坏,除醇溶蛋白得以提高之外,对于其它三种组分只是提高了初始水解速度,最终体外消化率没有明显提高。体外消化实验后,四种蛋白组分所剩的残渣蛋白SDS-PAGE分析结果表明:这些残渣蛋白的谱带存在相似之处:在20kDa处有一条很窄的谱带,在14～10kDa处的谱带较宽。     

Walnuts (Juglans regia L): proximate composition,protein solubility,protein amino acid composition and protein in vitro digestibility

Walnuts contained 16.66% protein and 66.90% lipids on a dry weight basis. Non‐protein nitrogen values ranged from 6.24 to 8.45% of the total nitrogen when the trichloroacetic acid concentration was varied within the range 0.25–1.0 M . Albumin, globulin, prolamin and glutelin respectively accounted for 6.81, 17.57, 5.33 and 70.11% of the total walnut proteins. Walnut proteins were minimally soluble at pH 4.0. The majority of total walnut protein polypeptides had estimated molecular weights in the range 12 000–67 000. The Stokes radius of the major protein in walnuts (glutelin fraction) was 66.44 ± 1.39 Å. Lysine was the first limiting essential amino acid in total walnut proteins as well as in the globulin and glutelin fractions. Leucine and methionine plus cysteine were the second limiting essential amino acids respectively for the prolamin and albumin fractions. Hydrophobic and acidic amino acids dominated the amino acid composition in all protein fractions. Native and heat‐denatured walnut glutelins were easily hydrolysed by trypsin, chymotrypsin and pepsin in vitro. © 2000 Society of Chemical Industry     

Japanese barnyard millet (Echinochloa frumentacea): Protein content,quality and SDS–PAGE of protein fractions

Total protein from five varieties of Japanese barnyard millet (Echinochloa frumentacea,) was separated into albumin/globulin, prolamin and glutelin fractions. The protein fractions were examined by sodium dodecylsulphate polyacrylamide gel electrophoresis. Total protein of the varieties ranged from 110·5 to 139·3 mg g^?1 of which 11·3–17·2% was albumin/globulins, 6·8–9·3% prolamins, 7·5–11·6% prolamin–like, 5·9–9·1% glutelin-like and 39·3–54·4% true glutelins. Amino acid analyses of the total protein showed that the varieties had essentially the same ammo acid composition. With the exception of lysine the amino acid levels adequately matched the provisional FAO scoring pattern. The amino acid composition of the protein fractions was also very similar. Electrophoretic analysis showed that the albumin/globulin fraction contained three or four components; the prolamin and glutelin fractions each had five components. The glutelin fraction had higher molecular weight components than the other two fractions.     

Effect of heat,rutin and disulfide bond reduction on in vitro pepsin digestibility of Chinese tartary buckwheat protein fractions

Protein fractions (albumin, globulin, prolamin and glutelin) were extracted from defatted tartary buckwheat flour. The in vitro pepsin digestibilities of the four protein fractions were different, and albumin was more susceptible to pepsin hydrolysis. The native structure of the four protein fractions may be destroyed by heat treatment, and the digestibilities were all improved significantly (P < 0.05). Adding rutin to the digestion mixture of the four fractions did not cause a decrease in pepsin digestibility, although it did cause a significant increase in certain instances (P < 0.05). Treatment with β-mercaptoethanol (2-ME) only caused a higher initial proteolysis rate and did not increase the final digestibility distinctly except for prolamin. After pepsin digestion, the remaining proteins of unhydrolyzed albumin, globulin, prolamin and glutelin (untreated) shared some similarities. They also exhibited a minor band at 20,000 Da and a broad band at 10,000–14,000 Da.     

IN VITRO DIGESTIBILITY OF CHINESE TARTARY BUCKWHEAT PROTEIN FRACTIONS: THE MICROSTRUCTURE AND MOLECULAR WEIGHT DISTRIBUTION OF THEIR HYDROLYSATES

Our previous study showed that in vitro pepsin digestibility of Chinese tartary buckwheat protein was relatively low compared to those of other edible seeds. In vitro pepsin digestibilities of four protein fractions of tartary buckwheat, microstructure and molecular weight (MW) distributions of hydrolysates were investigated. In vitro pepsin digestion assay showed that the digestibilities of tartary buckwheat protein fractions were albumin (81.20%), globulin (79.56%), prolamin (66.99%) and glutelin (58.09%). Scanning electron microscopy showed that albumin and globulin fractions were digested by pitting from the outer surface to the inner part and were more digestible, while prolamin and glutelin fractions resisted digestion because only the outer surfaces of their protein bodies were digested and the interior was protected. MW distribution of the hydrolysates from the four protein fractions was determined by high‐performance liquid chromatography. The hydrolysates of albumin mainly consisted of polypeptides with lower MW. The hydrolysates of glutelin had larger polypeptides together with small and medium‐sized peptide fractions.     

Fractionation and characterization of tartary buckwheat flour proteins

Protein fractions (albumin, globulin, prolamin and glutelin) were extracted from defatted tartary buckwheat flour. Albumin was the predominant protein fraction (43.8%) followed by glutelin (14.6%), prolamin (10.5%), and globulin (7.82%). Albumin was relatively rich in histidine, threonine, valine, phenylalanine, isoleucine, leucine and lysine. Globulin had high levels of methionine and lysine. Prolamin was high in histidine, threonine, valine, isoleucine, and leucine. Glutelin was rich in histidine, threonine, valine, isoleucine, and leucine. SDS–PAGE analysis, under non-reductive and reductive conditions, showed that disulfide bonds existed in the four fractions. Non-reduced albumin showed major bands at 64, 57, 41, and 38 kDa, and globulin at 57, 28, 23, 19 and 15 kDa. Reduced albumin and globulin shared two common bands at 41 and 38 kDa. Reduced prolamin showed major bands at 29, 26, 17 and 15 kDa. In vitro pepsin digestibility of the four fractions (from high to low) was: albumin > globulin > prolamin and glutelin.     

苦荞麸皮蛋白的提取分离及清除自由基作用研究

以苦荞二道荞麸为原料,进行复合蛋白提取和蛋白质Osborne分级分离,并对各蛋白组分进行清除自由基能力研究。结果表明,苦荞麸皮中最主要的蛋白组分为清蛋白,占蛋白总量的51.22%;其次为球蛋白和谷蛋白,分别占13.69%和17.07%;最少的为醇溶蛋白,占8.83%。苦荞麸皮复合蛋白及各蛋白组分均有体外清除自由基作用,其中水溶性清蛋白和球蛋白清除自由基能力高于醇溶蛋白和碱溶蛋白,且在低浓度范围内,随蛋白质浓度增加,清除能力呈线性提高,但在高浓度时却无明显量效关系。     

燕麦麸蛋白的组成及功能性质研究

以燕麦麸为原料制备了燕麦麸浓缩蛋白（OBPC）。同时，也按照Osborne蛋白分级提取方法对燕麦麸蛋白进行了精细的分类，分别得到了燕麦麸清蛋白、球蛋白、醇溶蛋白和谷蛋白。球蛋白和谷蛋白是燕麦麸蛋白的主要组分。清蛋白提取液中含有高含量的可溶性碳水化合物，可以通过（NH4）2S04分级沉淀的方法将其纯度由6．5％提高到67．2％。SDS-PAGE的结果表明OBPC及各蛋白组分有不同的分子组成。OBPC及各蛋白组分的功能性质，包括溶解性、持水持油性、乳化活性、泡沫性质也分别进行了测定，以评价燕麦蛋白作为一种潜在的配料在食品中的应用价值。     

Preparation and characterization of high‐quality rice bran proteins

Rice bran contains 120–200 g kg^?1 protein in addition to a large amount of fat, carbohydrate, and phytic acid. Rice bran protein (RBP) fractions were refined by a two‐step preparation to eliminate residual carbohydrate. The first step involved the sequential extraction of defatted rice bran into RBP fractions using their distinct solubility to give 37 g kg^?1 of albumin, 31 g kg^?1 of globulin, 27 g kg^?1 of glutelin, and 2 g kg^?1 of prolamin. In the second step, carried out by dissolving in respective solvent and isoelectric precipitation, the protein content of each fraction increased from 69% to 97% for albumin, from 71% to 90% for globulin, from 74% to 83% for glutelin, and from 18% to 20% for prolamin. The low protein content in the prolamin fraction might be due to its low solubility in the protein assay. Emulsifying stability index and surface hydrophobicity increased in the second‐step preparation of albumin and globulin, but not of glutelin. Emulsifying properties of RBPs were lower than that of a soybean protein isolate. Denaturation temperatures and enthalpy values of denaturation for albumin, globulin, glutelin, and prolamin were 50.1 °C/1.2 J g^?1, 79.0 °C/1.8 J g^?1, 74.5 °C/3.0 J g^?1, and 78.5 °C/8.1 J g^?1, respectively. No significant differences in the denaturation temperatures and enthalpy values of denaturation of RBP fractions were obtained with these two‐step preparations (P < 0.05). Copyright © 2007 Society of Chemical Industry     

Extractability and Chromatographic Characterization of Wheat (Triticum aestivum L.) Bran Protein

About 70% of the protein for human consumption is derived from plants, with cereals as the most important source. Wheat bran protein has a more balanced amino acid profile than that of flour. We here for the first time report the amino acid, size exclusion, and SDS‐PAGE profiles of bran Osborne protein fractions (OPFs). Moreover, we also investigated how OPFs are affected when physical barriers which entrap proteins in bran tissues are removed. Albumin/globulin is the most abundant OPF. It is richer in lysine and asparagine/aspartic acid than other OPF. Most bran albumin/globulin proteins have a molecular weight (MW) lower than 30 k and their chromatographic profiles differ from those of flour. The prolamin has high levels of proline and glutamine/glutamic acid. It is rich in proteins with a MW of 30 to 45 k and about 66 k reflecting contamination with gliadin from endosperm. The glutelin has high levels of glycine, proline, and glutamine/glutamic acid. Its protein is of intermediate and high MW with little protein with MW lower than 30 k. The high (MWs from 80 to 120 k) and low (MW around 45 k) MW glutenin subunits of flour are also present in bran. The glutelin of wheat endosperm is named glutenin. Ball milling releases albumin/globulin and glutelin but not prolamin. Not all glutelin was endosperm glutenin as a substantial part was entrapped in the aleurone cells.