玉米芯功能性低聚糖分级纯化及抗氧化活性研究

探究玉米芯功能性低聚糖分级纯化前后不同组分的组成、理化性质和抗氧化活性。以玉米芯为原料,采用活性炭柱层析法对玉米芯功能性低聚糖进行分级纯化,对纯化前后组分的聚合度、相对分子质量、阿魏酸基团以及红外光谱特性进行分析,并对酶解低聚糖粗提物(EH)及其纯化组分的自由基清除能力和抑制脂质过氧化能力进行比较分析。结果表明：活性炭水洗脱低聚糖组分(WO)、醇洗脱低聚糖组分(EO)均主要由木糖和阿拉伯糖组成,其中WO含有结合态阿魏酸,为阿魏酰阿拉伯低聚木糖;EO不含结合态阿魏酸,为阿拉伯低聚木糖。EH及其纯化组分WO、EO均具有一定的清除自由基(DPPH·、·OH、ABTS⁺·)能力和抑制脂质过氧化能力,且随浓度的增加而增加,WO抗氧化活性最强,EH次之,EO抗氧化活性较弱。     

黑小麦不溶性膳食纤维酶解产物组成分析及其对全谷物挤压膨化产品品质的影响

目的:对以黑小麦不溶性膳食纤维为原料所制备的木聚糖酶酶解产物(BWXH)的组成及应用特性进行系统分析,并研究其对全谷物挤压膨化产品品质的影响。方法:通过木聚糖酶对黑小麦不溶性膳食纤维进行酶解,得到BWXH,采用双波长法对BWXH中阿魏酰低聚糖含量(FOs)进行测定,并结合离子色谱、傅里叶变换红外光谱等技术对BWXH的单糖组成、低聚糖组成和红外光谱特征等理化特性指标进行了分析;模拟高温高压,对BWXH的稳定性进行检测;并将BWXH添加到全谷物挤压膨化产品中,其对挤压膨化产品的膨化率、感官评分及产品冲泡特性的影响进行分析。结果:BWXH中的FOs含量为0.104 mmol/g,阿魏酰基团含量为0.717 mg/g。通过离子色谱分析,FOs以DP2、DP3和DP4为主,主要单糖组成为阿拉伯糖、木糖和葡萄糖,其摩尔比为1.70:4.25:1.00,分支度(A/X)为0.40。高温高压(121 ℃,0.15 MPa)处理下能够进一步促进BWXH中高聚合度膳食纤维向低聚合度FOs的转变,使FOs含量增加。挤压膨化实验表明,适量(7%)添加BWXH可对谷物挤压膨化产品品质提升具有较好的改善作用。结论:BWXH作为一种低聚糖,可以应用于全谷物挤压膨化产品中,为黑小麦不溶性膳食纤维功能性食品配料的开发提供了一定理论依据。     

酶法制备黑小麦麸皮阿魏酰低聚木糖的工艺优化

研究黑小麦麸皮阿魏酰低聚木糖(FOs)的酶法制备工艺。用木聚糖酶酶解水不溶性膳食纤维制备FOs,通过HPLC分析方法,并结合双波长法和薄层层析法对FOs的含量和组成进行分析。在加酶量、反应时间、p H、温度4个单因素实验基础上,采用四因素三水平的中心旋转设计,以FOs浓度为响应值,使用响应面分析法对FOs的制备工艺进行优化,得到最佳工艺参数为:加酶量15.5 mg/L,酶解时间22 h,温度46℃,p H4.8,在此条件下,FOs的浓度为0.4913 mmol/L。薄层层析和HPLC分析结果表明,酶解液中的低聚糖含有结合态阿魏酸,是阿魏酰低聚木糖。     

酶法制备黑小麦麸皮阿魏酰低聚木糖的工艺优化

研究黑小麦麸皮阿魏酰低聚木糖(FOs)的酶法制备工艺。用木聚糖酶酶解水不溶性膳食纤维制备FOs,通过HPLC分析方法,并结合双波长法和薄层层析法对FOs的含量和组成进行分析。在加酶量、反应时间、p H、温度4个单因素实验基础上,采用四因素三水平的中心旋转设计,以FOs浓度为响应值,使用响应面分析法对FOs的制备工艺进行优化,得到最佳工艺参数为:加酶量15.5 mg/L,酶解时间22 h,温度46℃,p H4.8,在此条件下,FOs的浓度为0.4913 mmol/L。薄层层析和HPLC分析结果表明,酶解液中的低聚糖含有结合态阿魏酸,是阿魏酰低聚木糖。      

分离技术对直链麦芽低聚糖组分含量的影响

为了提高酶解产物中具有特定聚合度的直链麦芽低聚糖组分的含量,分别探究了膜分离、活性炭吸附、葡聚糖凝胶柱层析和不同离子交换树脂等分离技术对直链麦芽低聚糖组分含量的影响。结果显示,膜分离、活性炭吸附、葡聚糖凝胶柱层析、钠型/钙型离子交换树脂层析等技术均不适合直链麦芽低聚糖组分的连续化分离操作;相比而言,钾型离子交换树脂层析分离的效果较好,相比于初始酶解液,分离产物中目标组分G3～G6和G5+G6的比例分别提高了39.53%和8.13%,回收率分别达到78.11%和63.89%。在此基础上,以钾型离子交换树脂为固定相吸附剂,利用模拟移动床可进一步提高终产物中G3～G6和G5+G6的比例和回收率。     

酶法制备麸皮中低聚木糖的研究

木聚糖酶酶解小麦麸皮中的木聚糖制备低聚木糖,试验确定了最佳的酶解工艺条件,即酶添加量为800 IU/g,麸皮用量为12%,酶解温度为55℃,酶解时间为4h,总糖得率为61.02%,DP值为3.01,低聚木糖的得率为28.67%。     

小麦麸皮阿魏酰低聚糖的分离与结构分析

利用色谱技术对小麦麸皮中阿魏酰低聚糖（FOs）进行了分离与结构分析研究。结果表明,FOs由酯化的阿魏酸、阿拉伯糖和木糖所组成。紫外光谱分析表明,FOs的MOPS缓冲液在325nm处有最大吸收值,证明了阿魏酸的存在。红外光谱分析表明,FOs在990cm-1处有一低强度的肩峰,表明阿拉伯糖基的存在,并且与吡喃型木糖O-3位相连;在1731cm-1处有酯键的特征吸收峰。电喷雾电离质谱分析表明,分子质量为722和854的两种化合物是FOs的主要成分。      

小麦麸皮阿魏酰低聚糖的分离与结构分析

利用色谱技术对小麦麸皮中阿魏酰低聚糖(FOs)进行了分离与结构分析研究.结果表明,FOs由酯化的阿魏酸、阿拉伯糖和木糖所组成.紫外光谱分析表明,FOs的MOPS缓冲液在325nm处有最大吸收值.证明了阿魏酸的存在.红外光谱分析表明,FOs在990cm-1处有一低强度的肩峰.表明阿拉伯糖基的存在,并且与吡喃型木糖O-3位相连;在1731cm-1处有酯键的特征吸收峰.电喷雾电离质谱分析表明,分子质量为722和854的两种化合物是FOs的主要成分.     

Bacillus subtilis木聚糖酶的纯化及其对小麦麸皮的作用

采用活性聚丙烯酰胺凝胶电泳和均质提取法相结合,从枯草芽孢杆菌(Bacillus subtilis)固体培养基发酵产物中分离得到了两种木聚糖酶. 薄层色谱和高压液相色谱分析结果进一步表明它们具有内切木聚糖酶的活力,分别定义为xyl Ⅰ和 xyl Ⅱ.两种酶具有相同的最适反应温度(50℃)和最适pH值(7.0).另外,还研究了内切木聚糖酶 xyl Ⅱ对小麦麸皮不溶性膳食纤维的作用.纸色谱分析结果表明,酶解产物中含有阿魏酰低聚糖.     

小麦麸皮低聚糖生产中预处理条件研究

该文研究耐高温α–淀粉酶添加量、酶解时间对小麦麸皮去淀粉效果的影响;并研究酸种类、蒸煮温度对木聚糖溶出量的影响。结果表明:耐高温α–淀粉酶添加量0.2%,酶解时间15 min时,小麦麸皮去淀粉效果最好;酸性条件蒸煮的最优工艺:去淀粉麸皮按料液比1∶6,加入0.012mol/L盐酸溶液,120℃蒸煮30 min。HPLC分析结果显示:得到的小麦麸皮低聚糖中,低聚木糖占到52.5%;单糖组分为阿拉伯糖、木糖和葡萄糖,其含量之比1∶3∶0.75。     

黑小麦麸皮酚酸物质的定性分析与阿魏酸含量测定

对黑小麦麸皮中的主要酚酸物质进行制备和定性分析,并测定阿魏酸含量。采用乙醇和氢氧化钠溶液处理黑小麦麸皮,提取样品中的游离态酚酸(free phenolic acids,FPA)和结合态酚酸(conjugated phenolic acids,CPA)。通过液质联用(LC/MS)和紫外光谱(UV)等方法对提取的酚酸物质进行定性分析。紫外光谱显示,游离态和结合态酚酸具有与阿魏酸相似的分子结构。LC/MS检测结果显示,游离态和结合态酚酸的相对分子质量分别为224和194。由此判断黑小麦麸皮中的游离态酚酸FPA主要为芥子酸,结合态酚酸CPA主要为阿魏酸。采用高效液相色谱(HPLC)对黑小麦麸皮中的结合态阿魏酸含量进行测定。结果表明,紫粒黑小麦麸皮的阿魏酸含量为2.07 mg/g,与蓝粒黑小麦麸皮的阿魏酸含量(2.12 mg/g)相近,其含量高于当地种植的普通小麦麸皮的阿魏酸含量(1.17 mg/g)。     

Isolation and chemical characterisation of water-extractable arabinoxylans from wheat and rye during breadmaking

Water-extractable arabinoxylans from wheat and rye flour, dough and bread were isolated and characterised by the determination of the carbohydrate composition and the ferulic acid and diferulic acid contents. For both wheat and rye, the yield of water-extractable arabinoxylans decreased during the breadmaking process, indicating that some of the water-extractable arabinoxylans had become water-insoluble, possibly by the formation of ferulic acid–protein cross-links. The determination of ferulic acid and diferulic acids showed a low degree of dimerisation (less than 1%), which did not increase during the breadmaking process. Separation of the water-extractable arabinoxylans by size-exclusion chromatography showed that the molecular mass distribution of the arabinoxylans changed during breadmaking for both wheat and rye. Dual detection by measurement of the refractive index and the UV absorbance at 310 nm enabled screening for ferulic acid in the molecular mass fractions. Water-extractable arabinoxylans from wheat contained a medium molecular mass fraction which was not UV-active. The determination of ferulic acid in this fraction showed that it was free of ferulic acid.     

Some new results from isolation and fractionation of low molecular weight wheat proteins]

The alcohol-soluble wheat gluten fraction (gliadine) and the petroleum-ether-soluble wheat protein fraction (purothionine) were isolated and analysed. The gliadine fraction was itself fractionated by gel chromatography (Sephadex G-100). The partial hydrolysis of sub-fractions (molecular weight 20000-30000) yielded (after separation by gel and ion-exchange chromatography) several peptide fractions. The amino-acid composition and the N- and C-terminal groups of the gliadine fractions were determined. Characteristic differences were stated between various fractions. By means of gel chromatography, purothionine was separated into 4-6 fractions. The study of the amino-acid composition and of the N-terminal groups of the fractions revealed differences in both properties.     

An Attempt to Identify the Low Molecular Feruloylated Oligosaccharides in Beer

Ferulic acid (4‐hydroxy‐3‐methoxycinnamic acid), predominantly in ester form in arabinoxylan chains, is the main phenolic acid present in barley and malt. Only about 1% of the total ferulic acid in barley is present in the free form. A number of previous works concerned the contents of free and esterified ferulic acid in a broad range of popular beers, but there is little information about the possible composition of feruloylated oligosaccharides in beers. The aim of this preliminary work was to purify the feruloylated oligosaccharides from lager beers (by the means of preparative chromatography) followed by composition elucidation using TLC, HPLC with RI or UV detection and ¹H‐NMR. Indeed, the qualitative analyses of isolated fractions from beer revealed that the fractions contained ferulic acid in the ester form (as proven after mild alkaline hydrolysis). It was also shown that molecular masses of oligosaccharides present in the purified beer fractions were similar to the masses of arabinose and xylooligosaccharides in the range of xylose to xylohexaose. Although a number of purified beer samples contained oligosaccharides of higher molecular masses, these were not further characterized. Taking under consideration the presented results, it can be concluded that beer can be a good source of feruloylated oligosaccharides, significant in the context of human health benefits.     

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.     

发酵麦麸阿魏酰低聚糖的纯化工艺及其心脏保护作用研究

以发酵麦麸阿魏酰低聚糖( Feruloylated oligosaccharides, FOs)粗提液为原料,研究Amberlite XAD-2 大孔吸附树脂结合Sephadex LH-20 葡聚糖凝胶对发酵麦麸FOs的纯化工艺和效果,同时考察分离纯化后发酵麦麸 FOs对斑马鱼心脏损伤的保护作用。结果表明：Amberlite XAD-2 大孔吸附树脂分离发酵麦麸FOs的最佳吸附条件为：上样液浓度4.0 mg /mL,上样液pH 4.0,上样体积40 mL,在此条件下吸附率可达83.76%;最佳的解吸条件为：乙醇浓度50%、洗脱体积15 mL,在此条件下解吸率可达94.80%。Sephadex LH-20 葡聚糖凝胶进一步纯化发酵麦麸FOs的最佳条件为：洗脱剂乙醇浓度25%,上样量1.25 mL,洗脱流速 0.3 mL/min,在此条件下,分离出的组分最多;紫外光谱分析表明纯化发酵麦麸 FOs中有阿魏酸的存在;纯化后发酵麦麸 FOs含量由粗提液的（1107.796 ± 52.18）nmol/g提高到（2217.38 ± 25.36 ）nmol/g,提高了2倍,纯化效果较佳;此外,经分离纯化后发酵麦麸FOs能有效缓解特非那定诱导的斑马鱼心率和降低斑马鱼心脏SV-BA间距,表明分离纯化后发酵麦麸 FOs具有良好的心脏保护作用。     

Association of non-starch polysaccharides and ferulic acid in grain amaranth (Amaranthus caudatus L.) dietary fiber

The association of ferulic acid, an alkali-extractable phenolic acid in amaranth (Amaranthus caudatus L., Amaranthaceae) insoluble fiber (trans-ferulic acid: 620 microg.g-1, cis-ferulic acid: 203 microg.g-1), and non-starch polysaccharides was investigated. Enzymatic hydrolysis of insoluble amaranth fiber released several feruloylated oligosaccharides that were separated using Sephadex LH-20-chromatography and reversed phase-high performance liquid chromatography (RP-HPLC). Three compounds were unambiguously identified: O-(6-O-trans-feruloyl-beta-D-galactopyranosyl)-(1-->4)-D-galactopyranose, O-(2-O-trans-feruloyl-alpha-L-arabinofuranosyl)-(1-->5)-L-arabinofuranose, and O-alpha-L-arabinofuranosyl-(1-->3)-O-(2-O-trans-feruloyl-alpha-L-arabinofuranosyl)-(1-->5)-L-arabinofuranose. These feruloylated oligosaccharides show that ferulic acid is predominantly bound to pectic arabinans and galactans in amaranth insoluble fiber. 5-O-trans-Feruloyl-L-arabinofuranose was the only compound isolated in pure form from an acid hydrolyzate. This compound may have its origin from pectic arabinans but also from arabinoxylans.