黑小麦麦麸戊聚糖的提取、纯化与组成分析

对黑小麦麦麸戊聚糖进行提取、纯化及组成分析。分别以H2O、Ba(OH)2和Na(OH)2为提取介质,提取水溶性和水不溶性戊聚糖;采用(NH4)2SO4分级沉淀、乙醇分级沉淀、凝胶过滤柱层析等方法纯化戊聚糖粗提物,分析其得率和组成。结果表明:水提组分(WEP)主要由葡萄糖(Glc)、阿拉伯糖(Ara)和木糖(Xyl)组成,是β-葡聚糖(79%)和戊聚糖(21%)的混合物。NaOH碱提组分(AEP-Na)中Ara和Xyl含量相对较高,以戊聚糖为主要组成(71%),还含有29%的β-葡聚糖。Ba(OH)2碱提组分(AEP-Ba)主要由阿拉伯糖(Ara)和木糖(Xyl)组成,含有较纯的戊聚糖(96%)。WEP经35%饱和(NH4)2SO4溶液沉淀后,戊聚糖含量由纯化前的21%提高到35%。AEP-Na经DEAE-Sepharose CL-6B柱层析,分级组分AEP-Na1的单糖组成的物质的量比,即n(Ara)∶n(Xyl)∶n(Glc)=0.7∶1∶1.2,其中戊聚糖的n(Ara)/n(Xyl)=0.7。AEP-Ba经不同浓度乙醇沉淀分级组分的戊聚糖主要由Ara和Xyl组成。其n(Ara)/n(Xyl)在0.38~1.02之间,且Ara的取代度随着乙醇浓度的增加而增大。     

小麦麸皮戊聚糖的润肠通便效果研究

对小麦麸皮不同组分的润肠通便效果进行研究,发现小麦麸皮碱溶戊聚糖组分(AEP)具有较好的润肠通便效果,而水溶戊聚糖组分(WSP)和剩余麸皮残渣(AEP-R)的润肠通便效果较差.这说明小麦麸皮中起润肠通便作用的是其中的戊聚糖组分,并且戊聚糖的润肠通便效果与其溶解性有关,溶解性较差的组分具有较好的润肠通便效果,水溶性较好的组分润肠通便效果较差.     

小麦麸皮水溶性戊聚糖的分离及分级纯化

以水为溶剂从小麦麸皮中制备水溶性戊聚糖,采用乙醇分级沉淀、离子交换色谱以及凝胶过滤色谱对所得到的水溶性戊聚糖进行纯化分级,得到两个组成不同的组分P WSPI1 S和P WSPII1 S.单糖组成分析表明:P WSPI1 S组分由阿拉伯糖和木糖组成,P WSPII1 S由阿拉伯糖、半乳糖组成,并含有较多的蛋白质,是一种糖蛋白复合物组分.     

菠萝皮戊聚糖的超声波辅助提取及理化性质研究

采用超声波强化碱液提取分离了菠萝皮中戊聚糖成分,通过DEAE-Cellulose(OH-)柱层析进行纯化,初步分析了菠萝皮戊聚糖的理化性质。结果表明:菠萝皮戊聚糖超声波提取的最佳条件为:超声功率160W,超声时间90min,NaOH浓度2%,碱提温度25℃,凝胶柱层析得到两种纯化戊聚糖。凝胶渗透色谱GPC分析表明,菠萝皮戊聚糖-2是两种物质的混合物,重均分子量分别是166889Da和11837Da;紫外分析表明,菠萝皮戊聚糖-2不含蛋白质和核酸类物质;红外分析表明,其具有典型的多糖吸收图谱。     

双螺杆挤压工艺对大麦面粉中水溶性戊聚糖含量的影响

本文探讨了双螺杆挤压机在不同的工艺条件下对两种大麦CDCCandle(以含蜡质淀粉为主)和Phoenix(以含普通淀粉为主)面粉中的水溶性戊聚糖(WSP)含量的影响,以及不同温度(30、45、65和85℃)段下WSP含量的变化。经挤压处理后面粉中的WSP明显高于没有经挤压处理的面粉,在CDCCandle大麦面粉中WSP的含量随着挤压的温度和湿度增大而增加,但在Phoenix面粉中WSP的含量随着挤压的温度的上升而有降低的趋势。经分析表明戊聚糖的水溶性越小,其阿拉伯糖与木糖(A/X)之比值越小。在未经挤压处理的面粉中,CDCCandle大麦面粉中所含的膳食纤维、β-葡聚糖和戊聚糖的含量均高于Phoenix大麦面粉。     

液体悬浮培养发状念珠藻胞外多糖的提取、纯化及性质研究

采用超滤浓缩与乙醇沉淀法提取液体悬浮培养的发状念珠藻胞外多糖,经离子交换和凝胶柱层析纯化后得到2个组分.对组分Ⅱ(NFPS2)进行理化性质研究并用高效液相色谱法测定其表观分子量.结果表明,发状念珠藻多糖组分Ⅱ是非硫酸化多糖,含有较长的侧链和分支,不含核酸和蛋白质,分子量为2.79×105.     

加工工艺对黑小麦麸皮戊聚糖组成与理化性质的影响

以黑小麦麸皮为研究对象,采用挤压、微波-挤压加工工艺处理黑小麦麸皮,分别提取水溶性和水不溶性戊聚糖,并采用离子色谱、高效液相色谱和流变仪分析不同加工工艺条件下戊聚糖组成与理化性质的变化.结果表明:黑小麦麸皮经挤压、微波-挤压加工工艺处理后,水溶性戊聚糖得率增大,水不溶性戊聚糖得率减小,总戊聚糖得率由5.76％分别增加到6.43％和11.32％;不同戊聚糖组分的单糖组成主要由阿拉伯糖、木糖和葡萄糖以及微量半乳糖组成;挤压、微波-挤压处理后葡萄糖含量增加,水溶性戊聚糖的分支度逐步降低,水不溶性戊聚糖分支度逐步升高;各戊聚糖组分的相对分子质量和黏度随加工工艺处理均有所下降,结合态阿魏酸含量明显增加.研究结果表明,采用挤压、微波-挤压加工工艺处理黑小麦麸皮,有助于提高戊聚糖得率,增加水溶性戊聚糖的含量,可以进一步改善戊聚糖的理化性质.     

沙棘果水溶性多糖的分离纯化、组分分析及抗氧化活性的研究

用热水提取沙棘果多糖，乙醇沉淀，并用正交实验确定最佳条件，Sevage法去蛋白，酸性乙醇分级沉淀，分出A、B、C及D四个组分，其中C用DEAE柱层析进一步纯化出C1和C2两个级分，Sephadex G-75及聚丙烯酰胺凝胶电泳证明C1为单一组分，C2为两种多糖混合组分，经薄层层析分析，C1中含葡萄糖。C2的主要级分中含木糖和一未知组分。抗氧化实验表明沙棘多糖具有抗氧化活性，且抗氧化作用随浓度增加而加大。     

黑小麦麦麸多糖的制备与分析

分别以水和饱和Ba(OH)2溶液为提取介质,采用高压辅助水提取、Ba(OH)2碱提取和碱后水提取等方法制备黑小麦麦麸中的水溶性和水不溶性多糖,并采用气相色谱(GC)、高效液相色谱(HPLC)和红外光谱(IR)分析黑小麦麦麸多糖组分的理化性质。结果表明:高压辅助水提组分(WEPH)主要由葡萄糖(G lc)、阿拉伯糖(Ara)和木糖(Xyl)组成,是β-葡聚糖和戊聚糖的混合物;Ba(OH)2碱提组分(AEPH)主要由Ara和Xyl组成,物质的量比为Ara:Xyl=1:1.66,表明含有较纯的戊聚糖,其Ara/Xyl比值为0.60;碱后水提组分(AEPH-H2O)的85%由葡萄糖(G lc)和半乳糖(Man)组成,主要为β-葡聚糖和阿拉伯半乳聚糖,以及少量戊聚糖。富含戊聚糖的AEPH组分相对分子质量最高,为3.81×105,而以β-葡聚糖为主的WEPH和AEPH-H2O组分的相对分子质量较低,其中单一峰组分AEPH-H2O为2.40×105。     

酶—碱法高效提取小麦麸皮生产戊聚糖工艺的研究

采用水提法和酶—碱法提取小麦麸皮戊聚糖,通过单因素实验、正交分析的方法确定了水溶性戊聚糖(WSP)最佳提取工艺为反应温度62℃,反应时间为1.5h,酶浓度为0.55%,pH为4.2,水溶性戊聚糖提取率为15.3%。通过验证实验得到反应温度为60℃,反应时间1.5h,酶浓度为0.50%,pH为4.5。水溶性戊聚糖提取率达到15.6%。酶—碱法提取碱溶性戊聚糖(WIP)最佳工艺条件为料液比1∶20、温度为55℃,作用时间为1.5h,碱浓度为20%。在此条件下戊聚糖提取率17.4%。通过验证实验得到料液比为料液比为1∶18,温度为50℃,作用时间为1.5h,碱浓度为20%。碱溶性戊聚糖提取率为17.7%。实验制得样品中总戊聚糖含量为59.25g/100g,其中可溶性戊聚糖为含量为45.1g/100g。     

138个小麦品种(系)戊聚糖含量的研究

为了了解小麦品种戊聚糖含量及其变化情况,选用138个小麦品种(系)作为试验材料,分析其籽粒总戊聚糖、水溶性戊聚糖和非水溶性戊聚糖含量。结果表明,总戊聚糖、水溶性和非水溶性戊聚糖质量分数的平均值分别为7.62%、1.08%和6.54%,变幅分别为5.76%~9.69%、0.62%~1.73%和4.69%~8.78%,标准差和变异系数分别为0.89、0.21、0.87和11.66%、18.98%、13.30%。总戊聚糖与水溶性戊聚糖含量呈显著正相关,总戊聚糖与非水溶性戊聚糖含量呈极显著正相关。采用最长距离法对参试的138个小麦品种籽粒的总戊聚糖、水溶性以及非水溶性戊聚糖含量进行聚类分析,结果聚为四类。同时,在本试验中,来源于豫、鲁及北方地区品种(系)的戊聚糖平均含量高于来源于苏、皖及长江流域地区品种(系),国外品种(系)的戊聚糖平均含量低于国内品种(系)。     

Influence of Pentosanase and Oxidases on Water-extractable Pentosans during a Straight Breadmaking Process

ABSTRACT: Effects of flour type and enzymes on total pentosans (TP) and water‐soluble pentosans (WSP) and composition of isolated water‐extractable pentosans (WEP) during a straight breadmaking process were investigated. Two wheat flours (F1, F2) and 3 enzymes (pentosanase, glucose‐oxidase (GOX) and lacasse (LAC)), and their combinations were used. The presence of pentosanase increased the WSP content while oxidases produced a decrease. Extractability of pentosans was greater for dough than for bread but the latter had higher purity. Major sugars were xylose (Xyl) and arabinose (Ara) with a xylose/arabinose ratio between 1.00 and 1.56. Molecular weight profiles (MWP) of WEP comprised 5 fractions with the same distribution for the 2 flours but different relative proportions.     

Small strain viscoelastic behaviour of wheat gluten – pentosan mixtures

Gluten and water-soluble pentosans were extracted from defatted flours of two different wheat cultivars, having different grain hardness and baking quality. The rheological behaviour of the hydrated gluten samples and the effect of arabinoxylan-rich fractions of water-soluble pentosans (WSP) on their viscoelastic properties were studied in shear by dynamic measurements. The hydrated gluten samples showed the typical viscoelastic behaviour of a transient network, approaching the plateau zone at low frequencies. The WSP had only a small impact on this behaviour, causing a reinforcement of the network, as shown by the increase of storage modulus (G), but also an increase in dissipative processes caused by a higher degree of structural rearrangements within the network, as shown by the higher frequency dependence of G and the higher value of the loss angle tangent. By interchanging the gluten and the WSP fractions of the two wheat varieties, it was shown that the observed effect was also dependent on the source from which the WSP originated. The glutens in the presence of WSP were also less sensitive to the thermal treatment than the glutens alone, as shown by the lower magnitude of variation of G with temperature.     

A Rheological Study of Wheat Starch-Water-soluble Pentosan Mixtures Under Hydrothermal Gelling Conditions

ABSTRACT: Heterogeneous water-soluble pentosans (WSP) were extracted from 2 different wheat flours. The dynamic rheological behavior of starch-WSP mixtures was investigated to elucidate the effect of WSP on starch gelatinization and quenching the starch gels. In general, WSP had a detrimental effect on starch gelation. The decrease of water availability due to WSP may explain the observed higher onset temperature for starch gelatinization. However, the observed changes in rheological behavior during cooling and aging, and the more pronounced effects observed at excess water, suggest dependence on the WSP source and that WSP may have a more specific interacting effect with the amylose and/or amylopectin which prevents reorganization of both macromolecules within the starch network. Keywords: wheat starch, water-soluble pentosans, dynamic rheological properties, gelatinization     

海带岩藻多糖的分离与部分性质研究

研究了海带岩藻多糖的提取、影响因子及其纯化 ,岩藻多糖的分离最适条件为 :温度80℃ ,浸提时间 10h。经浓缩后 ,再用终 φ(乙醇 ) =60 %醇析获得粗品。岩藻粗糖经DEAE 纤维素的纯化后得FuⅠ、FuⅡ、FuⅢ、FuⅣ 4个组分 ,其硫酸根质量分数依次为 7 2 % ,1 95 % ,2 6 0 %和 17 2 %。同时对其红外光谱性质作了研究。     

柳蒿芽多糖的分离纯化及结构初步分析

柳蒿芽干品经热水浸提,所得多糖分别经脱蛋白、脱色、乙醇沉淀、DEAE 纤维素和SephadexG-100 凝胶层析柱分离纯化,得到3 种多糖组分(PSWP-1 ﹑ PSWP-2 和PSWP-3),经过高效液相色谱分析表明：PSWP-1 相对分子质量为1.1513 × 105D,水解单糖由鼠李糖和葡萄糖组成,摩尔比为1.000:1.703;PSWP-2 相对分子质量为1.2491 × 105D,水解单糖由葡萄糖组成;PSWP-3 相对分子质量为1.1663 × 105D,水解单糖由鼠李糖和葡萄糖组成,摩尔比为1.000:2.189。红外光谱分析表明,3 种多糖组分均为一种β- 型糖苷键相连的吡喃多糖。     

Characterization of hemicelluloses of sugar beet roots grown in Morocco

Hemicelluloses, extracted by means of concentrated alkali (1 m , followed by 4 m sodium hydroxide) from alcohol-insoluble, pectin-free residue of Moroccan sugar beet samples, obtained by using 1 m NaOH were collected twice in 1996 (Early and Late samples). The hemicellulose extracts were precipitated by aqueous ethanol at 50 and 75%, giving three fractions P50, P75 and S (supernatant), each aqueous ethanol fraction represented approximately one-third of the initial material. The supernatants were mostly arabinose (271–339 m g⁻¹ and 115–164 mg g⁻¹, for the 1 m and the 4 m extracts, respectively). Proteins were present in the supernatants and P75 fractions. Glucuronic acid and diferulic acid were present in some samples. Fractionation of P50 and P75 on DEAE Sepharose gave initial fractions containing fucose, xylose and glucose (xyloglucans). The fractions from P75 were rich in mannose and glucose (glucomannans). Those fractions that were retained were rich in xylose and arabinose but also glucose (up to 40–45 mol%) in the case of the Late season samples. The material that could only be eluted from the DEAE column by 0.5 m sodium hydroxide was mostly composed of xylose (74–80 mol%). Methylation analysis of these fractions showed the characteristic structure of xylans.     

猪肚菇子实体多糖的分离纯化及抗氧化活性测定

目的：研究多猪肚菇子实体多糖的抗氧化活性。方法：用热水浸提新鲜猪肚菇子实体,乙醇沉淀多糖,Sevag 法去除多糖中的蛋白,DEAE-52 纤维素柱层析、Sephadex S-200 凝胶柱层析进一步纯化,然后进行抗氧化活性测定。结果：DEAE 柱层析纯化后得到两种多糖组分A 和B,Sephadex S-200 凝胶柱层析证实A 为单一组分,组分A 的抗氧化活性测定结果显示其具有抗氧化活性,且抗氧化活性随其质量浓度的升高而升高。结论：分离纯化后的猪肚菇多糖具有抗氧化活性,且活性呈现剂量效应,随质量浓度升高而升高。