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1.
Sago pith non-starch polysaccharides were fractionated into cold water solubles (2.6%), hot water solubles (0.8%), dimethylsulfoxide solubles (0.8%), 5% NaOH soluble hemicelluloses (1.2%), 24% KOH–2% H3BO3 soluble hemicelluloses (0.6%), and cellulose (5.3%). Lignin was measured by 5% NaOH extraction (0.6%) and sodium chlorite oxidation (4.2%). Glucose and rhamnose were the major sugars in cold and hot water soluble non-starch polysaccharides. The neutral sugars in dimethylsulfoxide (DMSO) soluble non-starch polysaccharides were found to be enriched in rhamnose, xylose, glucose, and arabinose. Extraction of sago pith with aqueous 5% NaOH produced hemicelluloses, which were enriched in xylose and, to a lesser extent, glucose, arabinose, galactose, and rhamnose-containing polysaccharides, together with 7.4% uronic acids and 3.9% lignin. Further extraction of the delignified pith residue with aqueous 24% KOH and 2% H3BO3 removed the residual hemicellulosic fraction, which was enriched in glucose and xylose-containing polysaccharides, together with 5.8% uronic acids and 1.1% associated residual lignin. Six phenolic acids and aldehydes were detected in the mixtures of alkaline nitrobenzene oxidation of 5% NaOH soluble lignin and associated lignin in hemicelluloses and cellulose fractions. The lignin fraction contained a high proportion of non-condensed syringyl units and small amounts of non-condensed guaiacyl units as well as fewer non-condensed p-hydroxyphenyl units.  相似文献   

2.
The composition of sunflower (Helianthus annuus) seed heads was investigated. High amounts of lignin (12%) were found while glycosides comprised a minor component of the plant material. Lipids were isolated and a total sterol content of 1.05% was found. A protein content of 12.5% was also found. Acid hydrolysis of the plant material showed the presence of combined galacturonic acid (8%), galactose (3.4%), glucose (1.7%), arabinose (0.63%), xylose (0.7%) and rhamnose (21%). The factors influencing the extraction of pectin (11.85%) were studied.  相似文献   

3.
Four varieties of common bean were examined, but there were no significant differences among them. Crude protein content (46.7% and 49.0%) was the main constituent in embryonic axes. The average values of ash, crude fiber and ether extract were 4.2%, 3.7% and 3.0% respectively. Starch was approximately three times more abundant (7.5%) than cellulose (2.7%). Hemicellulose B values were lower (5.5%) than hemicellulose A (9.2%). The mean value of the pectic substances in embryonic axes was 12.3%. The free ethanol-soluble sugars ranged from 2.9% to 4.9%. Verbascose, stachyose, raffinose, sucrose, and galactose were identified and quantified in embryonic axes. Seed coat flour contained cellulose (30.6%), ether extract (0.4%), ash (2.8%), and protein (5.4%). Free ribose, mannose, arabinose, and galactose were present in seed coats in amounts ranging from 0.009% to 0.031%.  相似文献   

4.
屠幼英 《茶叶》2001,27(2):22-24
用高压液相色谱法(HPLC)测定绿茶饮料中茶叶游离多糖和复合多糖的构成和含量。结果显示，茶多糖总量约为绿茶饮料固形物的3．5％，游离多糖和复合多糖分别为1．9％和1．6％；其中包含了6种糖类：鼠李糖、木糖、阿拉伯糖、葡萄糖、半乳糖和甘露糖；而半乳糖和阿拉伯糖在游离多糖和复合多糖中均占80％以上。  相似文献   

5.
A (glucurono)arabinoxylan extract obtained from water-unextractable cell wall material of industrial wheat bran was fractionated by means of anion-exchange chromatography and graded ethanol precipitation. Methylation analysis and enzymic degradability of various fractions were used to elucidate their structures. Approximately one third of the extracted (glucurono)arabinoxylan was very lowly substituted (Ara/Xyl≈0·2). Substitution occurred predominantly by arabinose at theO-3 position of xylose residues. Enzymic degradation showed a random distribution of the substituents, which are probably interrupted by stretches of 6 or more contiguous unsubstituted xylose residues. More than half the extracted (glucurono)arabinoxylan was highly substituted (Ara/Xyl≥1). The complexity of the structure was shown by poor enzymic degradability and the presence of considerable amounts of branched arabinose and terminal xylose. Substitution of xylose occurred not only throughO-3 mono-,O-2 andO-3 disubstitution by terminal arabinose andO-2 monosubstitution by (4-O-methyl)glucuronic acid, but also through dimeric arabinose, xylose and possibly galactose containing branches as well as through 2,3-linked arabinose. The remainder of the extracted (glucurono)arabinoxylan (15%) was either intermediately substituted (Ara/Xyl≈0·5) or very highly substituted (Ara-Xyl≈1·2) and associated with protein and lignin.  相似文献   

6.
Summary Texture of boiled potato tubers (cv. Beate) was studied over several months of storage at either 4 or 8 °C, in relation to dry matter content, non-starch polysaccharides (NSP), methyl groups, glucose, starch and amylose. The dry matter content decreased significantly during storage at 4 °C, but increased at 8 °C due to evaporation. The insoluble NSP contained rhamnose, galactose, arabinose, xylose, mannose, fucose and glucose; the first three sugars decreased significantly after the first 7 weeks of storage. Fracturability and percent compression before break increased during storage at 8 °C, particularly percent compression after 15 weeks. The change in fracturability could partly be explained (R2=43.4%) by the content of the NSP and the increase in percent compression by dry matter (R2=91.8%). Changes in texture during storage at 4 °C, however, were not striking, and could not be explained by changes in the potato components that were analysed.  相似文献   

7.
The homologus 20 kD prolamin from kodo millet and other minor millets viz. barnyard, little and foxtail millets, were purified using preparative gel electrophoresis and reversed phase high performance liquid chromatography (RP-HPLC). The amino acid composition of the purified 20 kD prolamin protein from different minor millets revealed higher content of glutamic acid, alanine, leucine and serine and lower quantity of lysine and methionine. They contain 55 to 58 percent of non-polar amino acids which make them more hydrophobic than other protein fractions. The total number of amino acid residues per polypeptide chain ranged from 152 to 155 based on theoretical calculation. Peptide mapping of the 20 kD prolamin hydrolyzed with trypsin gave fewer cleavage products than expected. The antigenic relationships among these minor millets and cereals viz. wheat, maize, rice, sorghum, finger millet and pearl millet were studied using the antibody raised against the 20 kD prolamin. Cross reactivity was seen in all the minor millets at the 20 kD region. But in barnyard and little millets lower molecular weight polypeptides also cross reacted with the antibody. Immunoblotting studies revealed that the prolamins from other cereals and millets are related to the 20 kD prolamin of kodo millet. Rice was the only common cereal that did not cross react immunologically with the antibody raised against 20 kD prolamin of kodo millet.  相似文献   

8.
Pectin was found in the fruits ofDovyalis caffra W. (3.7%). Acid hydrolysis of the isolated pectin material afforded galacturonic acid (63%), galactose (26.8%), arabinose (2.13%), xylose (1.42%), and rhamnose (0.3%). With sugar and acid, pectin gave a gel of 100-grade. The fruits were shown to contain 15 combined amino acids. Glutamic acid, aspartic acid, and leucine comprised 28.25, 13.56, and 10.60% of the total amino acid content, respectively.  相似文献   

9.
A uronic acid — containing polysaccharide was isolated from the green marine algal speciesUlva lactuca by extraction with water, dilute hydrochloric acid solution, and ammonium oxalate solution. The latter agent was the best for extracting the highest amount of the polysaccharide material which contained glucuronic acid (11.4%), glucose (3.64%), arabinose (5.01%), xylose (4.55%), and rhamnose (27.33%). Partial acid hydrolysis studies and attempted fractionation on DEAE-cellulose pointed out that the polymeric carbohydrate material ofUlva lactuca may be a heteropolysaccharide. This polysaccharide appeared to contain, besides its main backbone, sequences involving glucose, arabinose and xylose.
Zusammenfassung Aus dem Thallus der marinen GrünalgeUlva lactuca L. wurde durch Extraktion mit Wasser, verdünnter Salzsäure und Ammoniumoxalat-Lösung eine Polysaccharid-haltige Uronsäure isoliert. Als bestes Extraktionsmittel erwies sich dabei die Ammoniumoxalat-Lösung, da damit die höchsten Ausbeuten erzielt werden konnten. Das Polysaccharid-haltige Material enthielt Glucuronsäure (11,4%), Glucose (3,64%), Arabinose (5,01%), Xylose (4,55%) und Rhamnose (27,33%).Untersuchungen über partielle Säurehydrolyse und Fraktionierung auf DEA-Cellulose ergaben, daß das polymere Kohlehydratmaterial derUlva lactuca L. ein Heteropolysaccharid sein kann. Dieses Polysaccharid enthält wahrscheinlich neben seinem Hauptbestandteil weitere Verbindungen mit Glucose, Arabinose und Xylose.
Résumé Un uronique acide — contenant polysaccharide a été isolé d'un vert genre d'algue marinUlva lactuca par extraction avec l'eau, dilue une solution de hydrochlorique acide, et une solution d'ammonium oxalate. La dernière action a été la meilleur pour son extraction de la plus grande quantité du polysaccharide materiel qui contient glucuronique acide (11.4%), glucose (3.64%), arabinose (5.01%), xylose (4.55%), et rhamnose (27.33%). Les études concernant le partial hydrolysis acide et la fractionation essayée sur DEAE-cellulose marquent que le material du carbohydrate polymeriqued'Ulva lactuca peut être un heteropolysaccharide. Ce polysaccharide apparait qu'il contient à côté de son propre material, des successions contenant résidus de glucose, arabinose et xylose.
  相似文献   

10.
The fatty acid, carbohydrate and amino acid composition of dried pistachio kernels was determined. On a dry weight basis they contained about 55% oil. The unsaturated fatty acids oleic and linoleic constituted about 80% of this oil. Carbohydrate analysis of a hydrolysed sample showed the predominant sugar to be glucose followed by galactose and mannose with traces of fucose, arabinose and xylose. The total amino acid content was about 25% by weight. Nine essential amino acids were present with only cystine in a limiting amount and with a high level of lysine.  相似文献   

11.
An investigation of the composition of two varieties ofLupinus termis seeds showed the presence of proteins, free amino acids, lipids, lignin, polysaccharides and mannitol. The polysaccharide materials (27.47 – 34.33%) consisted of starch, combined galacturonic acid, galactose, arabinose, xylose and rhamnose. Combined galactose and rhamnose comprised the major components of polysaccharide materials. Protein's constituted 46.11 – 50.57% ofL. termis seeds. The amino acid composition of the seeds as well as those of the proteins isolated with different agents were determined. The amino acid patterns of free and combined amino acids varied according to the extracting agent.  相似文献   

12.
采用GC法分析苦丁茶中可溶性单糖的研究   总被引：2，自引：0，他引：2  
通过恒温水浸泡,干燥后利用二甲基亚砜(DMSO)作溶剂,六甲基二硅胺烷(TMDS)和三甲基氯硅烷(TMCS)作硅烷化试剂,将单糖衍生化为三甲基硅醚衍生物,以肌醇为内标物,用SE-30毛细管色谱柱,测定了苦丁茶中单糖的组成及含量。同时对比了二甲基酰胺及吡啶的溶解能力和N,O-双三甲基硅烷基乙酰基(BSA)的衍生化效果。方法的相对标准偏差小于8.0%,测得的苦丁茶中单糖含量分别为:葡萄糖0.355%,果糖0.440%,半乳糖4.000%,核糖0.035%,木糖0.150%,阿拉伯糖0.006%。  相似文献   

13.
Nutrient composition and protein quality of minor millets   总被引：1，自引：0，他引：1  
Nutrient composition of five minor millets produced and consumed in dry land regions and tribal areas of Andhra Pradesh, India, was evaluated. The millets analysed were Italian millet (Setaria Italica), French millet (Panicum miliaceum), Barnyard millet (Echinachloa colona), Kodo millet (Paspalum scrobiculatum) and little millet (Panicum miliare). The nutrients analysed were proximate principles, amino acids, fibre components, calcium, Phosphorus and Iron. Protein and energy were evaluated by true digestability (TD), biological value (BV), net protein utilization (NPU) and digestible energy (DE) in rats. The protein content was higher and lysine content lower, when compared to major millets. Dehusked millets had lower total dietary fibre (TDF) and tannin. The TD of protein ranged between 95.0 to 99.3, whereas the BV was between 48.3 and 56.5. All the millets were poor sources of calcium, phosphorus and iron, with the exception of french millet.  相似文献   

14.
菠萝皮果胶的分离纯化及组成分析   总被引：2，自引：0，他引：2  
以热带水果菠萝皮为原料,采用漂烫灭酶、酸法提取和醇沉工艺提取果胶,对提取果胶的分离纯化和组成进行研究.结果表明:菠萝皮果胶经离子交换层析后分离纯化出1个中性组分,命名为PRP-N,2个酸性组分,命名为PRP-1、PRP-2.比对PRP-1、PRP-2的组成和结构发现,PRP-1的半乳糖醛酸含量较低,中性糖含量较高,单糖成分主要为鼠李糖、半乳糖和阿拉伯糖,以鼠李糖半乳糖醛酸Ⅰ型(RG-Ⅰ)结构为主,侧链主要成分为阿拉伯糖和半乳糖,通过4-O-Rha连接到主链上;PRP-2的半乳糖醛酸含量高,中性糖含量低,以半乳糖醛酸型(HG)和鼠李糖半乳糖醛酸Ⅱ型(RG-Ⅱ)结构为主,含有少量RG-Ⅰ型果胶分子结构.PRP-1比PRP-2的流体力学体积小,且聚合度分布更集中.  相似文献   

15.
Summary Potato tuber bulkiness was studied in an attempt to elucidate the role of the cell wall (CW) in the tissue texture. The volume of the tissue homogenate was measured before and after enzymatic degradation of insoluble pectic substances (PS) and cellulose. Enzymatic removal of PS resulted in disappearance of the middle lamella ultrastructure, leading to a slight volumetric reduction at most, and both were retained the inner CW and the starch grains in the lumen. Enzymatic degradation of cellulose resulted in the loss of the CW ultrastructure and of the homogenate bulkiness; starch and protoplasmic residues precipitated separately. Among the neutral sugars, starch-glucose was the predominant one (ca. 15% of the fresh weight), and the others were cellulose-glucose, rhamnose, arabinose, xylose, mannose and galactose. The microfibrillar lattice of the cellulose glucan provided the tissue bulkiness and texture. Other factors such as pectin and starch may affect texture through interactions with the microfibrillar lattice of cellulose. Contribution from the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel. No. 1518-E, 1985 series.  相似文献   

16.
An extraction method based on the use of dilute alkaline solutions of hydrogen peroxide removing the lignin present in lignocellulosic materials (Gould, J. M. Biotechnology and Bioengineering 26 (1984) 46–52), was studied for the extraction of non-starch polysaccharides (NSP) from wheat bran. The influence of extraction temperature and time, hydrogen peroxide (H2O2) concentration and percentage of bran in the alkaline hydrogen peroxide solution on the extraction yields of non-cellulosic glucose, arabinose and xylose residues were investigated. Extraction for 4 h at 60 °C with an alkaline (pH 11.5) H2O2-solution (2·0%) and 2·0% wheat bran in the extractant yielded an alkaline extract containing 77% of the wheat bran total arabinose content, 65% of the total xylose content and 86% of the total non-cellulosic glucose content.  相似文献   

17.
Fucoidans are sulfated heteropolysaccharides found in the cell walls of brown seaweeds (Phaeophyceae) and in some marine invertebrates. Generally, fucoidans are composed of significant amounts of L-fucose and sulfate groups, and lesser amounts of arabinose, galactose, glucose, glucuronic acid, mannose, rhamnose, and xylose. In recent years, fucoidans isolated from brown seaweeds have gained considerable attention owing to their promising bioactive properties such as antioxidant, immunomodulatory, anti-inflammatory, antiobesity, antidiabetic, and anticancer properties. Inflammation is a complex immune response that protects the organs from infection and tissue injury. While controlled inflammatory responses are beneficial to the host, leading to the removal of immunostimulants from the host tissues and restoration of structural and physiological functions in the host tissues, chronic inflammatory responses are often associated with the pathogenesis of tumor development, arthritis, cardiovascular diseases, diabetes, obesity, and neurodegenerative diseases. In this review, the authors mainly discuss the studies since 2016 that have reported anti-inflammatory properties of fucoidans isolated from various brown seaweeds, and their potential as a novel functional material for the treatment of inflammatory diseases.  相似文献   

18.
Three cultivars of pearl millet, CO 6 (good milling and good popping), a traditional variety [(TV) good milling but poor popping] and MBH 157 (poor milling and poor popping) were examined microscopically for their kernel texture and analysed for carbohydrate and protein composition. The endosperm texture of CO 6 and TV were corneous, while that of MBH 157 was floury. The pericarps of CO 6 and TV were thin, single layered with compact aleurone cells, but in contrast, that of MBH 157 was thick and multilayered, with loosely arranged aleurone cells. No significant differences in the physico-chemical characteristics of the isolated starches of the millet varieties were noticed. Starch and non-starch polysaccharide contents of CO 6, MBH 157 and TV varieties were 72·9, 75·3, 65·8% and 6·5, 8·5, 15·7%, respectively. Glucose, arabinose and xylose were the major sugars in the NSP fractions. CO 6 and TV varieties contained higher proportion of pentosans with higher ratios of arabinose/xylose and uronic acid.  相似文献   

19.
Sorghum and millet phenols and antioxidants   总被引：5，自引：2，他引：5  
Sorghum is a good source of phenolic compounds with a variety of genetically dependent types and levels including phenolic acids, flavonoids, and condensed tannins. Most sorghums do not contain condensed tannins, but all contain phenolic acids. Pigmented sorghums contain unique anthocyanins that could be potential food colorants. Some sorghums have a prominent pigmented testa that contains condensed tannins composed of flavan-3-ols with variable length. Flavan-3-ols of up to 8–10 units have been separated and quantitatively analyzed. These tannin sorghums are excellent antioxidants, which slow hydrolysis in foods, produce naturally dark-colored products and increase the dietary fiber levels of food products. Sorghums have high concentration of 3-deoxyanthocyanins (i.e. luteolinidin and apigenidin) that give stable pigments at high pH. Pigmented and tannin sorghum varieties have high antioxidant levels that are comparable to fruits and vegetables. Finger millet has tannins in some varieties that contain a red testa. There are limited data on the phenolic compounds in millets; only phenolic acids and flavones have been identified.  相似文献   

20.
茶多糖的组分及理化性质   总被引：65，自引：6，他引：65  
粗老茶中含有较高能治疗糖尿病的茶多糖成分。用紫外、红外和气相色谱等方法对茶多糖分析结果表明，它是由糖类、蛋白质、果胶和灰分等物质组成；其多糖部分为阿拉伯糖、木糖、岩藻糖、葡萄糖和半乳糖等，各单糖的组成比例为５．５２：２．２１：６．０８：４４．２０：４１．９９。多糖的分子量约１０７０００。茶多糖的热稳定性较差，高温或过酸和偏碱均会使其中的多糖部分降解。它在沸水中溶解性能较好，但不溶于高浓度的有机溶剂。文中还对粗老茶中的降血糖成分、茶多糖组分和分子量上的差异原因，以及茶多糖中灰分含量高的原因进行了讨论。  相似文献   

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