荞麦粉主要组分对抗性淀粉形成的影响

以荞麦粉为原料,对其主要组分分别进行单一物质分离和层级分离,利用分离组分后的样品制备荞麦抗性淀粉,分析并探讨了荞麦粉中脂类、清蛋白、球蛋白、醇溶蛋白、谷蛋白和残渣蛋白等组分对抗性淀粉形成的影响.研究结果表明,荞麦粉中脂类或醇溶蛋白的存在会抑制抗性淀粉的生成,使抗性淀粉得率降低;清蛋白、球蛋白或谷蛋白对抗性淀粉的生成均具有促进作用,能显著提高抗性淀粉得率;脱脂后,醇溶蛋白和谷蛋白对抗性淀粉得率的影响效果更明显.     

燕麦面团流变学及加工特性研究

以燕麦粉为原料,以中强筋小麦粉为对照,研究燕麦粉与小麦粉不同配比混合粉的面团流变学特性和食品加工特性.结果认为,与小麦粉相比,燕麦蛋白质组分中清蛋白、醇溶蛋白含量较低,球蛋白含量高,谷蛋白含量稍低.燕麦粉峰值、最大、最终黏度均小于对照小麦粉.加入燕麦粉后,面团形成时间延长,稳定时间降低.用淀粉代替燕麦粉,同样添加量下面包及馒头比容、总评分降低,面条吸水率、总评分降低,失落率升高.当面粉取代量大于5%时,对混粉食品制作品质有显著影响.加入10%、25%、10%燕麦粉制作面条、馒头和面包是较为理想的配比.     

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。     

酶法提取苦荞麦蛋白的理化性质和加工性质

以苦荞麦为原料,采用酶法提取制备苦荞麦粗蛋白,并进一步对粗蛋白进行分离得到4 种蛋白组分,然后对粗蛋白和各蛋白组分的理化性质和加工性质进行研究。结果显示：5 种蛋白的等电点依次是：粗蛋白pH4.6、清蛋白pH4.4、球蛋白pH5.1、醇溶蛋白pH4.5、谷蛋白pH5.2;变性温度依次是：粗蛋白95.5℃、清蛋白100.0℃、球蛋白94.3℃、醇溶蛋白53.4℃、谷蛋白84.0℃;苦荞中各种蛋白质的分子质量都较低,缺乏高分子质量蛋白质组分,容易消化吸收,且氨基酸组成合理,种类齐全,富含赖氨酸。本研究获得的苦荞麦粗蛋白和得率最大的谷蛋白组分,能够在类似火腿肠的体系测试中呈现良好的功能性质。     

燕麦蛋白组分分离提取及其SDS-PAGE电泳分析

通过单因素实验对燕麦蛋白组分的分离提取工艺进行了优化,并通过SDS-PAGE电泳对燕麦蛋白组分进行亚基分析。结果表明:燕麦清蛋白提取的最佳温度为40℃,球蛋白提取最佳盐浓度为7%,醇溶蛋白提取的最佳乙醇浓度为75%,谷蛋白提取的最佳碱浓度为0.05 mol/L,蛋白质提取率为83.1%。SDS-PAGE实验结果显示:燕麦清蛋白在10~100 kD范围内均有分布,燕麦球蛋白由2个亚基组成,分子量分别在97.4~100 kD和43~66.2 kD范围内,燕麦醇溶蛋白亚基大部分集中在18.39~40.72kD之间,燕麦谷蛋白部分亚基分布在20.67~26.66kD与43.29~50.80 kD之间。     

平欧榛子蛋白及其组分的氨基酸组成分析及营养评价

研究以平欧榛子脱脂粉为原料,参照Osborne蛋白分级法,提取制备平欧榛子的清蛋白、球蛋白、醇溶蛋白及谷蛋白,采用碱溶酸沉法制备榛子分离蛋白,利用全自动氨基酸分析仪对平欧榛子蛋白组分进行测定,根据氨基酸分析结果计算平欧榛子蛋白及其组分的营养价值指标.结果 表明分离蛋白和四种蛋白组分均含有18种氨基酸,且谷氨酸含量最高,...     

小麦醇溶蛋白沸石分离工艺优化及其组分分析

目的：探究谷朊粉中醇溶蛋白的提取分离方法。方法：以醇溶蛋白凝沉率为评价指标,优化谷朊粉醇溶蛋白的静置凝沉工艺。进一步以优化后的静置凝沉工艺制备的醇溶蛋白为原料,研究碱液处理沸石分离醇溶蛋白组分工艺,重点考察碱液质量分数（20%,50%,80%）、加热时间（30,60,120 min）以及加热温度（30,50,70,90 ℃）对沸石分离醇溶蛋白组分的影响。结果：谷朊粉中醇溶蛋白提取率为24%,4,10,20,30 ℃下静置凝沉40 h后,醇溶蛋白凝沉率分别为16.6%,20.6%,24.0%,18.9%。显微图像表明,开始凝沉时醇溶蛋白中大小球状蛋白均出现（α-、β-、γ-醇溶蛋白）,凝沉10 h后,在4,10 ℃下出现虫状醇溶蛋白（ω-醇溶蛋白）,凝沉20 h后,虫状醇溶蛋白聚集体大量出现。沸石处理温度为50 ℃、KOH质量分数为20%、处理时间为120 min时醇溶蛋白分离量最大,分离量为10.336 g/kg沸石。同组空白试验所分离出的醇溶蛋白为4.730 g/kg沸石,分离最大量相较于空白试验分离量多出5.606 g/kg沸石。根据紫外最大波长分析,醇溶蛋白及其组分的最大紫外吸收波长均在288.4 nm附近。柱层析第1组分主要成分是低分子量醇溶谷蛋白,第2组分主要成分是高低分子醇溶谷蛋白和α-、β-、γ-、ω-醇溶蛋白,第3组分主要成分为低分子量醇溶谷蛋白。结论：温度对醇溶蛋白凝沉速率影响很大,沸石改性可提高所分离醇溶蛋白量,且分离量与KOH溶液质量分数及改性时间密切相关。     

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。     

超声波作用对小麦抗性淀粉形成影响

以小麦淀粉为原料,通过超声波结合酶法制备抗性淀粉,研究超声波作用对抗性淀粉形成影响。结果表明,超声波对抗性淀粉形成最佳工艺条件为:淀粉乳浓度15%、超声波功率225 W、超声波温度50℃、作用时间50 min;在此条件下,小麦RS3得率为8.379%,比未经超声波作用得率2.91%提高约2.88倍。     

绿豆抗性淀粉制备技术研究

以普通绿豆淀粉为原料,研究了热处理温度、时间、pH、水 分舍量、冷冻冷藏时间及干燥温度对抗性淀粉得率的影 响。结果表明,在抗性淀粉制备过程中的pH对测定结果 无显著影响,冷冻处理可以提高抗性淀粉的得率,低温干 燥有利于抗性的形成。绿豆抗性淀粉的最佳制备条件为 淀粉水分含量80％,热处理温度150℃,处理时间60min, -20℃冷冻24h并于60℃干燥。     

Changes in prolamin and high resistant starch composition during the production process of Boza, a traditional cereal-based beverage

The aim of this work was to analyze changes occurring in cereal protein and starch composition throughout the production process of Boza for its potential exploitation as functional beverage. A sharp decrease in the extractability of albumins, globulins, glutenins and prolamins was found in the processed samples after the cooking step. This phenomenon was confirmed analyzing the extracted cereal proteins on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, which also revealed an apparent decrease in the number of wheat albumin/globulin, glutenin and prolamin bands in the gruel samples in comparison with that shown by the related flours. The application of an improved extraction procedure and reverse-phase high-performance liquid chromatography analysis confirmed that the prolamin content in Boza decreased markedly in comparison with that of the flour samples. Under the experimental conditions applied, the resistant starch content of Boza resulted significantly higher than that of flours; thus, this beverage can be regarded as a “high fiber” food in accordance with the recent European regulations. This is the first report that throws light on changes occurring in protein and starch components throughout the production process of Boza and provides direct evidence on the low prolamin and high resistant starch contents of this traditional cereal-based beverage.     

Characterization of protein fractions from chickpea (Cicer arietinum L.) and oat (Avena sativa L.) seeds using proteomic techniques

Albumin, globulin and glutelin fractions were prepared from chickpea and oat seeds using sequential extractions. Molecular characteristics of individual protein fractions were investigated using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) in combination with proteomic techniques. SDS-PAGE results revealed that chickpea albumin and globulin fractions (C-Ab and C-Gb) showed protein bands with molecular weights (MWs) related to subunits of legumin (11S globulin) and pea vicilin (7S globulin); oat protein fractions (O-Ab, O-Gb and O-Gt) showed most protein bands with MWs related to subunits of oat 12S globulin (avenalin). With proteomic analysis, eighteen tryptic peptides from chickpea globulin fraction showed sequence homology that corresponded to chickpea legumin α- and β-subunit (NCBI accession number: gi|6273402; theoretical mass 56,216 Da) while sixteen tryptic peptides from chickpea albumin fraction (C-Ab) were identified as chickpea provicilin precursor (NCBI accession number: gi|82173888; theoretical mass 51,390 Da); fifteen tryptic peptides from oat protein fractions were identified with origin from oat 12S seed storage globulin 1 (NCBI accession number: gi|134918; theoretical mass 58,508 Da). The identified tryptic peptide, ALIVPQNFAIAAK, was commonly found in chickpea glutelin fraction (C-Gt), rice glutelin fraction (R-Gt), and oat albumin, globulin and glutelin fractions (O-Ab, O-Gb and O-Gt).     

Changes in gross chemical composition with emphasis on lipid and protein fractions during germination of fenugreek seeds

Germination of fenugreek seeds for 3 and 5 days increased moisture, crude protein, crude fibre, non-protein nitrogen and ash contents, but total lipids and carbohydrates were decreased. Marked increases of Na and P, as well as Mg and Zn were observed. Triacylglycerols decreased continuously and this was accompanied by an increase in free fatty acids, monoglycerides, sterolesters and polar lipids. Albumin was the major protein fraction followed by globulin, glutelin and prolamin. Germination increased glutelin and non-protein nitrogen; the other fractions were decreased. The protein in vitro digestibility was improved after germination. PAGE showed a marked dissociation of albumin and globulin fractions after germination.     

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     

蛋白组分对籼米粉糊化特性的影响机理探讨

通过逐一去除蛋白组分的方法研究了蛋白组分对籼米粉糊化特性的影响,并分析了影响这些变化的蛋白结构基础。RVA和DSC分析结果表明,不同组分的蛋白在去除之后,峰值粘度、热糊粘度和最终粘度均有不同程度的升高,崩解值、回生值及糊化温度均有不同程度的降低。SDS-PAGE和显微结构分析表明,各组分对糊化特性的影响机理应有差异:谷蛋白通过与纤维素类物质的紧密结合,在糊化过程中阻碍淀粉粒的溶胀;醇溶蛋白可能是通过蛋白体自身的溶胀与淀粉相互作用而影响;清、球蛋白通过活性蛋白对籼米成分的水解或合成等改变而影响;淀粉粒结合蛋白则可能对籼米的基础糊化特性影响较大。与分离重组法比较,逐一去除蛋白组分的方法因为蛋白组分之间的相互作用影响较大,对糊化特性的影响与分离重组法略有差异。     

小米蛋白的分子组成及结构特性

利用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳、扫描电子显微镜、差示扫描量热法以及傅里叶红外光谱（Fourier transform infrared spectrometer,FTIR）对小米中4 种蛋白组分进行结构特性分析。研究表明,醇溶蛋白是由低分子质量亚基（11～25 kDa）构成,而清蛋白、球蛋白和谷蛋白亚基分布较广（11～180 kDa）,其中清蛋白所含亚基数目最多,醇溶蛋白、清蛋白以及球蛋白分子之间连接紧密,以聚集状态存在,而谷蛋白分子连接松散,表面光滑。球蛋白在71.33 ℃条件下发生变性;醇溶蛋白的变性温度最高,达到110.67 ℃。FTIR研究表明,醇溶蛋白、谷蛋白和球蛋白的二级结构主要由β-折叠构成,其含量分别为37.72%、43.39%、42.23%;β-转角以及β-反平行折叠结构含量最丰富的是醇溶蛋白,分别为16.64%和12.73%。4 种蛋白组分结构含量差异显著（P＜0.05）。     

山药淀粉与燕麦β-葡聚糖共混体系理化及消化性能研究

为研究燕麦β-葡聚糖对山药淀粉的影响,采用快速粘度分析仪制备山药淀粉与燕麦β-葡聚糖共混体系,测定了共混体系的糊化性质、热特性、流变性和消化性能等。糊化特性分析表明,燕麦β-葡聚糖能够降低山药淀粉的黏度、回生值,抑制山药淀粉的短期回生。热特性结果表明,燕麦β-葡聚糖的加入使共混体系的糊化焓ΔH显著降低（P<0.05）,最低值为7.34 J/g。红外谱图分析表明,山药淀粉与燕麦β-葡聚糖之间未发生共价结合,主要通过氢键作用。质构特性分析表明,燕麦β-葡聚糖的添加使共混体系凝胶结构变弱。静态流变学特性分析表明,燕麦β-葡聚糖的加入使共混体系的表观黏度降低;动态流变学特性分析表明,燕麦β-葡聚糖可显著降低山药淀粉的黏弹性。X射线衍射结果表明,凝胶作用改变了晶体类型,且相对结晶度从38.40%降至16.30%。此外,燕麦β-葡聚糖的加入,降低了共混体系的消化性,提高了抗性淀粉含量,最高值为49.24%。本研究可为开发燕麦β-葡聚糖/淀粉基食品提供理论依据。     

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.