野木瓜多糖中糖醛酸含量测定

采用硫酸-咔唑比色法对野木瓜多糖中的糖醛酸含量进行测定,在波长523nm处测定吸光度,实验表明标准半乳糖醛酸浓度在1.67～16.67μg/mL之间呈良好的线性关系,该法简便易行,准确性高,重现性好。探讨了测定过程的影响因素,并通过此法测得野木瓜多糖中糖醛酸平均含量为25.24%。     

广东淮山多糖DFPA-Ⅰ组分的分析及理化性质研究

从广东淮山分离纯化得到均一性的多糖DFPA-Ⅰ,经定性化学反应和光谱鉴定表明DFPA-Ⅰ不含蛋白质、核酸、酚类物质,但含有糖醛酸,为非淀粉类酸性均一性多糖,其重均分子量为64500。DFPA-Ⅰ完全酸水解后纸层析及气相色谱分析(结合糖醛酸含量测定)确定其糖基组成及其摩尔比为甘露糖∶葡萄糖∶半乳糖(Gal)∶半乳糖醛酸=2.18∶1∶3.39∶1.82。     

刺参多糖中糖醛酸、氨基糖和中性单糖的同步测定方法研究

建立柱前1-苯基-3-甲基-5-吡唑啉酮(PMP)衍生高效液相色谱法(HPLC)测定刺参多糖中糖醛酸、氨基糖和中性单糖的方法。刺参多糖用2mol/L三氟乙酸水解、PMP衍生化后,用反相HPLC检测,实现了糖醛酸,氨基糖和中性单糖的良好分离和测定。测定结果表明,刺参多糖含有甘露糖、半乳糖、岩藻糖、氨基葡萄糖、氨基半乳糖和葡萄糖醛酸6种单糖。该方法简便快捷,灵敏度高,重现性良好。     

库尔勒香梨酸性多糖PSAP-1的分离纯化及其糖醛酸含量测定

摘 要：目的 分离纯化库尔勒香梨酸性多糖(Pyrus sinkiangensis Yu. acidic polysaccharide, PSAP-1),检测红外吸收并对其所含糖醛酸进行含量测定。方法 经DEAE-650M、HW-55F及Sephacryl S-300色谱柱进行分离纯化PSAP-1, 通过蒽酮-硫酸法测定多糖含量, 红外光谱法确定其化学键或官能团信息, 采用间羟基联苯法测定PSAP-1中糖醛酸的含量。结果 葡萄糖对照品和PSAP-1的吸光度在0.04~0.12 mg/mL质量浓度范围内线性关系良好, PSAP-1含量为61.51%, 精密度、稳定性、重复性和加样回收率的相对标准偏差(relative standard deviation, RSD)分别为0.2%、1.3%、1.7%、1.4%,均小于2.0%; 红外图谱显示, PSAP-1中有糖醛酸的特征吸收峰。确定D-半乳糖醛酸和PSAP-1的吸光度在0.035~0.055 mg/mL质量浓度范围内线性关系良好, 糖醛酸的含量为62.78%, 精密度、稳定性、重复性和加样回收率的RSD分别为0.14%、0.31%、1.0%、1.1%,均小2.0%。结论 本研究从新疆库尔勒香梨中得到多糖含量高、富含糖醛酸的酸性均一多糖组分PSAP-1, 所确定的PSAP-1多糖含量和糖醛酸含量测定方法准确可靠, 为库尔勒香梨的深层研究提供了基础依据。     

黄瓜多糖的体外抗氧化活性

目的：测定黄瓜中总糖含量,分离制备黄瓜多糖并测定其糖醛酸含量、单糖组成以及评价其体外抗氧化活性。方法：采用苯酚-硫酸法测定黄瓜提取物中的总糖含量;用硫酸-咔唑法测定黄瓜多糖中的糖醛酸含量;采用1-苯基-3-甲基-5-吡唑啉酮(PMP)柱前衍生化高效液相色谱(HPLC)分析单糖组成;并在体外抗氧化评价体系研究黄瓜多糖对DPPH自由基、超氧阴离子自由基(O2－ ·)和羟自由基( ·OH)的清除活性以及总还原力(TRP)。结果表明：黄瓜多糖的总糖含量为63.5%,糖醛酸含量为10.6%。HPLC分析表明：黄瓜多糖由D-甘露糖、L-鼠李糖、D-葡萄糖醛酸、D-半乳糖醛酸、D-葡萄糖、D-木糖、D-半乳糖、L-阿拉伯糖等8种单糖组成,物质的量比为4.08:2.78:1.00:5.82:6.07:2.78:8.48:6.58。黄瓜多糖有明显的抗氧化活性,在质量浓度为20mg/mL时,对DPPH自由基、O2－ ·、 ·OH的清除率分别为92.31%、83.57% 和77.59%,并发现其有明显的还原能力。结论：黄瓜多糖是一种典型的杂多糖,具有较强的抗氧化活性。     

海地瓜多糖中蛋白含量测定方法比较

比较4种常用的蛋白定量方法来测定海参多糖中蛋白含量,建立海参多糖中蛋白含量的测定方法。氨基酸组成折算出海地瓜多糖中蛋白含量为(5.06±0.31)%,将此结果作为其他测定方法比较的标准。采用4种常用的蛋白定量方法:Folin-酚法、BCA法、考马斯亮蓝法、荧光光度法进行测定,对测定结果进行比较分析。Folin-酚法、BCA法、荧光光度法测定多糖中蛋白含量分别为(4.92±0.20)%、(6.29±0.51)%、(3.88±0.25)%。考马斯亮蓝在反应中不显色,此法检测不出多糖中蛋白。经比较分析,Folin-酚法精确度高,重现性好,测定时间短,操作简便,对仪器要求低,可以准确简便地测定海地瓜多糖中蛋白含量。     

阿里红多糖中糖醛酸的含量测定

采用间羟基联苯法对阿里红多糖中的半乳糖醛酸进行含量测定,在波长520nm处测定吸光度,实验表明标准半乳糖醛酸浓度在0.01～0.05mg/mL之间呈良好的线性关系,该法简便易行,准确性高,重现性好。探讨了测定过程的影响因素,并通过此法测定阿里红多糖中的半乳糖醛酸平均含量为17.07%。     

热带雨林博罗霍果多糖的单糖组成分析

研究了博罗霍果多糖的不同提取条件和对其含量及单糖的组成进行测定。方法1的提取条件为样品经乙醇溶液除去单糖和寡糖,脱脂、水提醇沉法提取多糖,用苯酚-硫酸法测定多糖含量,酸水解后用HPLC-ELSD法测定多糖组成。方法2的提取条件为样品经冷冻干燥,乙醇溶液除去单糖和寡糖后,用苯酚-硫酸法测定多糖含量,酸水解后用气相色谱衍生法测定多糖组成。方法1提取得多糖含量为6.2%,其单糖组成为半乳糖、阿拉伯糖、鼠李糖。方法2提取得多糖含量为11.2%,其单糖组成为半乳糖、阿拉伯糖、甘露糖和葡萄糖,糖醛酸含量为0.24%。博罗霍多糖是以中性糖为主且含少量糖醛酸的杂多糖。     

海藻和海藻酸钠中糖醛酸含量的测定

利用阴离子交换树脂对酸水解后的海藻酸钠进行分离,得到D-甘露糖醛酸(M)和L-古洛糖醛酸(G),经过高效液相色谱、电喷质谱及核磁共振确定其纯度和结构.利用自制的M和G作为标准品绘制标准曲线,用外标法计算得到海藻酸钠样品中M含量为63.06%,G含量为11.48%;海藻样品中M含量为21.65%,G含量为4.67%.该实验为海藻胶及海藻寡糖中的D-甘露糖醛酸和L-古洛糖醛酸含量的测定奠定了一定的基础.     

微波消解-离子色谱法测定枸杞多糖的含量及组成

目的 建立微波消解-离子色谱法测定枸杞多糖含量及组成的方法。方法 分别考察了三氟乙酸浓度、微波消解温度及微波消解时间对枸杞多糖消解效率的影响,优化了离子色谱法检测枸杞多糖的色谱条件,并对所建立的方法进行方法学评价。结果 枸杞多糖最佳消解条件为温度120℃、时间20 min、三氟乙酸浓度3 mol/L;经方法学评价, 9种单糖和2种糖醛酸均具有良好的线性关系,相关系数均大于0.98;精密度相对标准偏差小于3.00%,检出限和定量限良好。通过对枸杞中单糖组成的分析,表明在枸杞中葡萄糖、木糖、半乳糖、甘露糖、阿拉伯糖、鼠李糖、果糖、岩藻糖、核糖、半乳糖醛酸、葡萄糖醛酸是组成枸杞多糖的主要成分。结论 微波辅助消解方法可以大大缩减枸杞多糖的消解时间,可用于快速检测枸杞多糖的含量。     

An explorative study on the cell wall polysaccharides in the pulp and peel of dragon fruits (Hylocereus spp.)

The pectic and hemicellulosic cell wall polysaccharides from the pulp and the peel of white-flesh and red-flesh dragon fruits (Hylocereus spp.) were isolated and compared in terms of degree of methoxylation (DM), solubility properties (relative content of uronic acids and neutral sugars in different fractions), neutral sugar composition, molar mass distribution, and affinity toward some specific anti-pectin antibodies. Hereto, the alcohol-insoluble residues were extracted and sequentially fractionated using hot water, a chelating agent, sodium carbonate, and potassium hydroxide solutions to obtain different pectin fractions and a hemicellulose fraction. Chemical analyses were used to characterize these polysaccharide fractions. The results show that cell wall polysaccharides of the pulp and especially of the peel from white-flesh and red-flesh dragon fruits contain significant amounts of pectic substances that are lowly methyl-esterified. The cell wall polysaccharides of the peel as well as those of the pulp contain high amounts (38–47 %) of loosely bound (water-soluble) pectic substances. In the water-soluble fraction (WSF) of the peel samples, uronic acids are the predominant monomers. On the contrary, rhamnogalacturonan-I type neutral sugars, and especially arabinose and galactose, contribute equally, as compared to uronic acid, to the WSF of the pulp samples. Despite the low average DM value of pulp and peel pectin, pectic substances in both samples showed affinity for antibodies with different specificities indicating that a wide range of epitopes, including long blocks of unesterified galacturonic acids (GalA) residues as well as (short) blocks of esterified GalA residues, is present. No large differences between the pectic substances among the different dragon fruit varieties were observed.     

Validation of a Combined Enzymatic and HPLC Method for Screening of Pectins in Fruits of Japanese Quince (Chaenomeles japonica)

A combined enzymatic and HPLC method was validated for analysis of galacturonic acid (GalA) in (1) alcohol-insoluble solids (AIS), and in (2) pectins, extracted from fruits of Japanese quince (Chaenomeles japonica), by comparison with a standard colorimetric method (using metahydroxydiphenyl) for analysis of uronic acids (UA). For analysis of AIS, the results of the colorimetric and the enzymatic/HPLC methods were identical (UA and GalA in average 20 g/100 g AIS dry weight). For analysis of pectins, the colorimetric method resulted in consistently higher estimates (UA in average 63 g/100 g pectins dry weight) compared to the enzymatic/HPLC method (GalA in average 57 g/100 g pectins dry weight). The enzymatic/HPLC method also proved to be useful as a simple and efficient screening method, since a very high Pearson correlation (R=0.93) was obtained between GalA estimates of the homogenized fruit sample and the AIS content of acid-extracted pectins.     

Evaluation of the extraction efficiency for polyphenol extracts from by‐products of green kiwifruit juicing

The health benefits of fruits are attributable in part to their bioactive components such as phenolics and pectic polysaccharides. By‐products derived from kiwifruit processing can be a good source of such bioactive compounds. Extracts were produced using different concentrations of ethanol in water (0%, 30%, 50%, 74% and 96% v/v) from by‐products (skin, residue and pulp) of the green‐fleshed kiwifruit (Actinidia deliciosa‘Hayward’) juicing process. The amounts of phenolic compounds and uronic acid (UA) as well as the phenolic composition in each extract were determined. Results show that different by‐products contained different concentrations of phenolics and pectic polysaccharides. Based on total phenolic contents, 96% v/v ethanol appeared to be the best extraction medium. The 30% or 74% ethanolic dilution was the second best medium for phenolic extraction from skin and pulp/residue, respectively. Water was a good medium for extracting satisfactory quantities of phenolics as well as the highest concentration of pectic polysaccharides. Phenolic profiling by high‐performance liquid chromatography (HPLC) was used to detect individual phenolic compounds in an extract. Results using HPLC showed that alkali pre‐treatment has improved the extraction efficiency of phenolics as a function of alkali concentration, fruit tissue type, extraction media, by‐product preparation method, and class of polyphenols. As a result more efficient methods for both extraction and characterisation of polyphenols could be evaluated.     

Pectin recovery from apple pomace: physico-chemical and functional variation based on methyl-esterification

This study explored the valorisation of apple pomace by extracting pectin with both high and low degrees of esterification (DM). Two types of pectin were extracted with a DM of 43.29% being low methoxyl (LM) pectic polysaccharide and high methoxyl (HM) pectin with a DM of 65.88%. HM pectin was characterised by a WHC and OHC of 1.3 g g⁻¹ and 0.4 g g⁻¹, respectively, compared to 0.32 g g⁻¹ and 0.14 g g⁻¹, respectively, for LM pectic polysaccharide. HM pectin possessed greater purity indicated by 69.18% GalA, whereas LM pectic polysaccharide possessed 41.26% GalA. HM pectin revealed better functionality in terms of high emulsifying activity which was concentration-dependent, and emulsion stability than LM pectic polysaccharide. The solubility of HM pectin was 90.8%, which is preferable for various industrial applications. LM pectic polysaccharide was characterised by a higher % radical-scavenging activity in a concentration-dependent manner. XRD analysis revealed LM pectic polysaccharide to possess higher crystallinity (53%) and SEM analysis revealed its surface to be rough and coarse.     

全自动氨基酸分析仪法测定4种贝类肌肉中谷胱甘肽和游离氨基酸含量

建立一种测定贝类肌肉中谷胱甘肽和游离氨基酸的全自动氨基酸分析仪法,以4种常见贝类为研究对象,采用0.02 mol/L盐酸溶液作为提取剂,体积分数5%磺基水杨酸溶液为蛋白沉淀剂,同时优化了缓冲溶液的组成及洗脱程序,并对该方法的线性范围、检出限、精密度以及回收率进行测定。结果表明:贝类肌肉中的谷胱甘肽和游离氨基酸有着较好的分离效果,线性关系良好,相关系数为0.999 1~0.999 9,检出限(RSN=3)为0.07~0.27μmol/L,加标平均回收率为86.40%~102.42%,日内和日间相对标准偏差分别为0.31%~0.73%和1.14%~2.60%。4种贝类肌肉组织中的游离氨基酸含量比较丰富,总游离氨基酸含量分别为1 396.39、1 016.04、911.15、287.01 mg/100 g,文蛤青蛤缢蛏牡蛎,主要的游离氨基酸为牛磺酸(Tau)、谷氨酸(Glu)、丙氨酸(Ala)、精氨酸(Arg);谷胱甘肽含量分别为103.20、82.53、61.77、33.37 mg/100 g,青蛤文蛤缢蛏牡蛎。该方法适用于贝类肌肉中谷胱甘肽和游离氨基酸含量的测定与分析。     

Molecular Composition of Onion Pectic Acid

ABSTRACT: Pectin was extracted, then pectic acid was purified without autolysis. It contained 93.7% uronic acid and 6.3% neutral sugar. Using exopolygalacturonase, exopolygalacturonate lyase and endopolygalacturonase, the molecular composition of onion pectic acid was determined; the proportion of galacturonic acid residue from the nonreducing end to rhamnogalacturonan (RG) was 9.7%, while that of the reducing end to RG was 46.7%. From RG to RG, the proportion of galacturonic acid residue was 41.0%, and the RG region was 2.6%.     

Cell Wall Composition of Olives

Cell walls of olives (Olea europaea L.), Hojiblanca and Manzanilla, were isolated and fractionated into polysaccharides, and compositions compared. Pectic and hemicellulosic fractions were purified by ion exchange and gel filtration chromatography, and neutral sugar and uronic acid composition determined. Differences occurred between cultivars and seasons: Manzanilla had higher pectic polysaccharides and lower xylans. Hojiblanca showed similar but lesser differences. Arabinans were the main neutral pectic polysaccharides with arabinose > 80%. Homogalacturonans and rhamnogalacturonans were > 50% of the acidic pectic fractions. Degree of esterification and molecular weights were related to extracting solvent. Xyloglucans and galactoglucomannans were neutral hemicelluloses with molecular weights ? 260 kD. Glucuronoarabinoxylans had higher molecular weights (up to 400 kD). Acidic xylans were important in the pulp.     

体外模拟柴达木大肥菇胞内多糖在幼龄肠道的消化特征

该文以柴达木大肥菇胞内多糖(intercellular polysaccharides, IPS)为研究对象,借助3～5岁年龄段人群的肠道菌群构建体外肠道酵解模型,通过液相色谱法、气相色谱法和苯酚-硫酸法测定单糖及醛酸、短链脂肪酸的组分和含量变化以及总糖含量变化等指标探究IPS的体外酵解特征。结果显示,在体外酵解48 h过程中,胞内多糖不断被肠道菌群降解,在酵解12 h时酵解率已达100%;多糖降解产生葡萄糖、甘露糖、葡萄糖醛酸、半乳糖醛酸、阿拉伯糖5种单糖及醛酸,其总量随着酵解时间的延长呈先上升后下降趋势,在酵解6 h时达到含量最高峰,与对照组相比差异显著(P<0.05);单糖及醛酸被微生物群落进一步酵解后产生乙酸、丙酸、正丁酸、异丁酸、异戊酸及正戊酸6种短链脂肪酸,其总量随着酵解时间的延长呈持续上升趋势,与对照组相比差异显著(P<0.05);丰富的短链脂肪酸含量使发酵体系中的pH逐渐下降,最终稳定在3.56±0.01,与对照组相比差异显著(P<0.05)。综上,解析柴达木大肥菇IPS在肠道中的酵解、消化特性,可拓展柴达木大肥菇多糖开发为功能因子的营养健康内核。     

The digestion of monosaccharide residues of the cell walls of oat and vetch hays by rumen contents in vitro

The extent and pattern of digestion of oat hay (Avena sativa L.) and vetch hay (Vicia sativa L.) monosaccharides by rumen contents was studied in vitro. The ratios of matrix polysaccharides to lignin were 1.25:1 and 3.82:1 in the vetch and oat hays, respectively. Glucose, xylose and uronic acids were the main sugars in both plants, comprising about 90% of the total monosaccharides. Glucose, xylose and arabinose were mainly confined to the cell walls (CW), whereas galactose and uronic acids were found in high proportions in the soluble fraction. Vetch had a particularly high uronic acid content (14.4 g 100 g^?1 DM), of which 71% was pectic material. The ratios of CW-glucose to CW-xylose were 2.23:1 and 3.74:1 in the oat CW and vetch CW, respectively. Based on monosaccharide analyses of the CW material, it is suggested that the degree of branching of the matrix polysaccharides is about twice as high in vetch as in oat hay. Total glucose and xylose were more digestible in oat than in vetch hay, whereas most of the minor sugars and the total uronic acids were more digestible in the vetch. Irrespective of species, CW glucose was more digestible than CW xylose. The digestibilities of CW glucose, CW xylose and CW uronic acid were: 61.0, 55.3, 51.5, 34.3 and 62.7, 42.6 for the oat hay and vetch hay, respectively. Following the pattern of digestion, CW arabinose and CW glucose were digested faster than CW xylose and CW uronic acid, irrespective of plant species. The extent of digestion at 12 h of incubation of these sugars was higher in vetch than in oat hay. It is suggeted that the concentration ratio of rapidly to slowly degradable CW sugars, in a given plant, is a major determinant of the rate of CW digestion by rumen microorganisms.