Non-starch polysaccharides from sunflower (Helianthus annuus) meal and palm kernel (Elaeis guineenis) meal—preparation of cell wall material and extraction of polysaccharide fractions

Two different chemical methods, sequential extraction with alkali and sodium chlorite and treatment with 4-methylmorpholine N-oxide (MMNO), were applied to the extraction of non-starch polysaccharides (NSP) from the enzymically deproteinated, water-insoluble cell wall materials of sunflower (Helianthus annuus L) meal and palm kernel (Elaeis guineensis Jacq) meal. The NSP content accounted for 550 g kg^?1 (sunflower meal) and 750 g kg^?1 (palm kernel meal) of the cell wall materials. Neither of the treatments alone was capable of solubilising more than about half of the original NSP. Combined treatment using alkali/chlorite followed by MMNO completely dissolved cell wall material from palm kernel meal, whereas a small residue (40 g kg^?1 of original NSP) was left in sunflower meal. Loss of NSP occurred with both methods (total NSP recovery ranging from 88% for alkali/chlorite extraction of sunflower to 64% for MMNO extraction of palm kernel). Due to differences in solubility revealed upon acidification and/or dialysis, extracts became subdivided into precipitates and soulble fractions. The sugar composition of the resulting fractions enabled a tentative identification of teh major non-starch polysaccharides; sunflower meal was found to contain cellulose, (acidic) xylans, polyuronide-containing fractions and xyloglucan; palm kernel meal was found to contain mannans, cellulose and xylans, with the major part of the mannans originating from the endosperm and the xylans being almost exclusively located in the endocarp.     

Characterisation of Chilean hazelnut (Gevuina avellana) tissues: light microscopy and cell wall polysaccharides

By applying several differential staining techniques and light microscopy, the structure and composition of Chilean hazelnut (Gevuina avellana) seeds were analysed. The structure of the G avellana seed is very simple, with a thin, heavily lignified seed coat and two voluminous cotyledons. The embryo food reserves are uniformly distributed over the cotyledon cells. The cell wall polysaccharides were recovered from the alcohol‐insoluble residue by mild treatment with warm chlorite solution and sequential extraction with alkali solutions of increasing concentration. FT‐IR spectra in the 1200–850 cm^?1 region were used together with chemometric techniques to distinguish the hemicellulosic and pectic polysaccharides in the extracts. The most abundant extracts were fractionated by graded precipitation in ethanol. A xyloglucan was identified by ¹H and ¹³C NMR as the major hemicellulosic polysaccharide, with a sugar composition of 4Glc:3.5Xyl:1Gal:0.5Fuc. The hazelnut cell walls are composed of equivalent amounts of pectic polysaccharides, xyloglucans and cellulose. © 2003 Society of Chemical Industry     

New potato fibre for improvement of texture and colour of wheat bread

The aim of this project was to compare the functional properties of five fibre fractions by baking of wheat bread by substitution 0, 4, 8 and 12 w/w% of wheat flour using dry potato pulp (Fibre 1), a commercial potato fibre (Fibre 2), two fibre prepared from potato pulp by enzymatic hydrolysis (Fibre 3 and 4), and one solubilised fibre (Fibre 5). The effect of chemical composition of fibre on texture, colour, specific weight and volume of wheat bread was studied using objective methods for measurement of texture characteristics, colour (L, a, b) and sensory analysis. Dry potato pulp, Potex (Fibre 2) and two enzymatically prepared fibre powders (Fibre 3 and 4) with a high concentration of lignin and insoluble non-starch polysaccharides (INCP) had a detrimental effect on bread quality by substitution of more than 8% of the wheat flour by fibre. The detrimental effect was mainly due to increased hardness, deformation energy, modulus and gumminess. Multiple linear regression analysis with forward selection was used for determination of the relationship between quality characteristics and of soluble non-starch polysaccharides (SNSP), insoluble non-starch polysaccharides (INCP), cellulose and lignin. The enzymatic solubilised fibre (Fibre 5) with a high concentration of soluble fibre and a low concentration of cellulose and lignin could be used for substitution of at least 12% wheat flour for baking of bread with an attractive colour, delicious texture and flavour.     

生物技术法处理对花生粕饲用品质影响的研究

花生粕存在黄曲霉毒素B_1(AFB_1)易超标、非淀粉多糖含量高和蛋白质品质不佳等缺陷,利用微生物(枯草芽孢杆菌、酿酒酵母、乳酸片球菌)发酵结合复合酶制剂处理花生粕,可以综合改善其饲用品质。研究表明:处理后花生粕中AFB_1的去除率为94.6%,非淀粉多糖含量由30%降低至10.5%,蛋白质含量由47.8%提高至61.5%,大分子蛋白明显降解为小分子蛋白,小肽含量由5.36%提高至25.21%,必需氨基酸总量提高了19.67%,乳酸含量由0.7%提高至2.8%。经过生物技术法处理,花生粕的饲用品质得到了明显改善。     

超声水提花生粕多糖工艺的研究

采用响应面法对超声波辅助水提法提取花生粕多糖的工艺进行了研究。探讨了超声功率、提取时间、提取温度、液料比4个因素对花生粕多糖得率的影响。试验结果表明,最佳的工艺条件为超声功率70 W,提取时间24 min,提取温度71℃,液料比29∶1,在此条件下花生粕多糖得率为1.80%。     

Determination of non-starch polysaccharides in cereal grains with near-infared reflectance spectroscopy

Cereal grains contain variable amounts of non-starch polysaccharides, such as arabinoxylans and (1-->3),(1-->4)-beta-glucans (beta-glucans), which are associated with their cell walls. The type and composition of these polysaccharides is of increasing interest in both human and animal nutrition. Reference analysis for these polysaccharides requires the use both enzymic and monosaccharide methods. To evaluate fully the non-starch polysaccharides present in grains, some analysts further distinguish between the soluble and insoluble fractions of these components. Near-infrared reflectance (NIR) spectroscopy provides fast, inexpensive analysis. It is, however, a comparative technique that relies on multivariate calibration of sample spectra and accurate reference analysis. It has the potential to be exploited as a rapid analytical method for nutritionally important polysaccharides. The calibration statistics for arabinoxylans and beta-glucans obtained in this study suggest that NIR can be used in plant breeding, nutritional and product studies to obtain simple and rapid estimates of non-starch polysaccharides. The occurrence of wheats with high cell wall contents together with barleys with high beta-glucan contents is well known. However, to date, this genetic variation has not been extensively exploited for the production of grains for use as human food ingredients.     

Chemical composition,digestibility and protein quality of 12 sunflower (Helianthus annuus L) cultivars

Twelve sunflower (Helianthus annuus L) cultivars grown in Spain were analysed and tested in experiments with rats. The dehulled seeds contained an average of 32.2 MJ kg⁻¹ dry matter (DM) gross energy, 653 g kg⁻¹ DM fat, 60 g kg⁻¹ DM total non-starch polysaccharides (NSP) and 6 g kg⁻¹ DM Klason lignin. The sunflower seed hulls contained 20.2 MJ kg⁻¹ DM gross energy, 53 g kg⁻¹ DM fat, 562 g kg⁻¹ DM total NSPs and 239 g kg⁻¹ DM Klason lignin. The sunflower samples were dehulled and partially defatted (to ∼17% fat) and included in diets for rats. The dehulled, partially defatted samples contained on average 74.6 g nitrogen kg⁻¹ DM and 1.409 mg g⁻¹ phenolic compounds (chlorogenic acid + caffeic acid + derivative 1 + derivative 2) varying from 0.677 to 2.847 mg g⁻¹. Groups of five growing rats were fed diets (9.38% crude protein) containing one of the sunflower cultivars as the only source of protein. Apparent ileal and faecal digestibilities were determined by using an indigestible marker (Cr₂O₃) and faecal digestibility based on total faecal collections. Apparent ileal, caecal and faecal digestibilities of organic matter were 81.2–91.5% (P = 0.05), 95.8–97.1% (P = 0.005) and 94.7–95.3% (P = 0.94) respectively. The apparent faecal digestibilities of DM, energy and protein (N × 6.25) were 93.2–93.8%, 93.5–94.3% and 81.6–84.3% respectively with no differences among cultivars. Biological value (BV) ranged between 63.8 and 73.2% (P = 0.0001) and net protein utilisation (NPU) between 59.9 and 69.5% (P = 0.0001). BV and NPU were positively correlated with lysine and threonine contents, but no correlation with the analysed phenolic compounds was detected. © 1999 Society of Chemical Industry     

Selection of elderberry (Sambucus nigra L.) genotypes best suited for the preparation of elderflower extracts rich in flavonoids and phenolic acids

The importance of raw material and extraction parameters for obtaining a high content of flavonoids and phenolic acids in elderflower extracts was investigated. Nine phenolic acids (3-O-, 4-O-, and 5-O-caffeoylquinic acid, 3-O- and 5-O-p-coumaroylquinic acid, 1,5-di-O-, 3,4-di-O-, 3,5-di-O- and 4,5-di-O-caffeoylquinic acid) and six flavonol glycosides (quercetin-3-O-rutinoside, quercetin-3-O-glucoside, kaempferol-3-O-rutinoside, isorhamnetin-3-O-rutinoside, isorhamnetin-3-O-glucoside, and quercetin-3-O-6″-acetylglucoside) were identified and quantified in elderflowers and/or extracts thereof by liquid chromatography-mass spectrometry (LC-MS) and high-performance liquid chromatography-diode array detection (HPLC-DAD), respectively. The yield of elderflower extracts depended significantly on processing conditions and raw material properties and the maximum yield of elderflower extract was obtained by extraction for a maximum of 10 days at 4 °C using an extraction liquid consisting of a maximum of 20 w/w % sugars and 5% citric acid. The effects of the extraction liquid composition and raw material on the concentration of phenolic acids and flavonol glycosides in elderflower extracts were determined by factor analysis. Several elderberry genotypes were found to be useful for processing of elderflower extracts with a relative high concentration of phenolic acids and flavonol glycosides.     

Impact of methyl 5-O-(E)-feruloyl-α-L-arabinofuranoside on in-vitro degradation of cellulose and xylan

Abstract : The potential for inhibition of ruminal cell wall degradation by soluble phenolic acid-carbohydrate complexes was assessed using a synthetic molecule, methyl 5-O-(E)-feruloyl-α-L -arabinofuranoside (FA-Ara). In-vitro 24 and 72 h degradabilities of glucose from microcrystalline cellulose, and neutral sugars and uronic acids of oat spelts xylan were determined. Treatments included 0 (Control), 15, 150, 1500, and 4500 μmol liter^?1 of methyl α-L -arabinofuranoside (Me-Ara), FA-Ara, or ferulic acid (FA). Additions of 1500 and 4500 μmol liter^?1 Me-Ara; 15 and 150 μmol liter^?1 FA-Ara; as well as 4500 μmol liter^?1 FA significantly (P < 0·05) decreased 24 h cellulose degradation. Arabinose degradation from xylan after 24 h was decreased (P < 0·05) by 1500 and 4500 μmol liter^?1 concentrations of Me-Ara and FA-Ara. No inhibitory effects of added compounds on 72 h glucose, xylose, or arabinose degradability were observed. Very little FA-Ara remained intact after 24 h. Following 72 h, no added FA-Ara was detectable, suggesting extensive degradation by microbial feruloyl esterases. Extent of polysaccharide degradation, in vitro, was not limited by a soluble phenolic acid-carbohydrate compound, which accurately models a known cell wall complex.     

Water-extracted polysaccharides of selected cereals and influence of temperature on the extractability of polysaccharides in sorghum

Non-cellulosic and non-starchy (I₂-KI negative) glucose-rich polysaccharides from wheat, ragi, rice and sorghum were extracted with water at ambient temperature (25°C). Ethanolic fractional precipitation of the polysaccharides yielded a number of fractions containing varying proportions of hexoses (0.7–98%) and pentoses (1–56%). Polysaccharides from sorghum were also extracted at 4, 55°C and at boiling water temperature. Prior amylolysis of the sorghum flour followed by extraction at boiling water temperature was found to give a better yield of non-starch glucose-rich polysaccharides.     

A preliminary study of monosaccharide composition and α‐glucosidase inhibitory effect of polysaccharides from pumpkin (Cucurbita moschata) fruit

In this work, crude polysaccharide extracts were extracted from pumpkin (Cucurbita moschata) fruit by hot water. After removal of proteins and purification, polysaccharides of pumpkin fruit (PP1‐1) were subjected to structural identification. Gas chromatography analysis indicated that PP1‐1 comprised of galactose (86.4%), and glucose (13.6%). The molecular weight of PP1‐1 was measured to be 0.87 × 10⁴ Da by gel permeation chromatography. The inhibitory kinetic evaluation showed that it was non‐competitive inhibition of PP1‐1 on the α‐glucosidase‐catalysed hydrolysis of PNPG. The Michaelis–Menten constant (K_m) was 0.106 m , and the inhibitory constants (K_i), 0.435 mg.     

Cell wall polysaccharides implied in green olive behaviour during the pitting process

Olive fruits processed as “Spanish green olives” were sorted into two batches depending on their pitting behaviour: those that broke under punch pressure, and those that were pitted without damage. Cell wall polysaccharides from both batches were isolated. The main changes were lower amounts of carbonate-soluble and 24 % KOH-soluble polysaccharides and a higher proportion of 4% KOH-soluble polysaccharides in broken olives. The carbonate-soluble fraction from broken olives was poorer in homogalacturonans, polysaccharides that could help in increasing texture. The 24% KOH-soluble fraction from the same olive batch was poorer in xylans and xyloglucans, the former being present in a higher proportion in the 4% KOH-soluble fraction and the last in cellulose residue. The new xylans of the 4% KOH-soluble fraction were of high (around 250 kDa) and low (6–40 kDa) molecular weights. Carbonate-soluble and 24% KOH-soluble fractions are very important in maintaining cell wall structure, which is responsible for vegetable product firmness. Received: 28 September 1999     

Effect of non-starch polysaccharides on the in vitro digestibility and rheological properties of rice starch gel

The starch digestibility and rheological properties of gels were evaluated in the presence of three non-starch polysaccharides (agar, xanthan gum and konjac glucomannan) with rice starch. Each polysaccharide was added to 30% (w/w) rice starch suspension at defined concentrations and starch gels were prepared. The extent of starch gel digestibility was determined by an in vitro method and rheological properties by a dynamic oscillatory test and a compression test. The added polysaccharides suppressed starch hydrolysis in the gels compared with the control, and a concentration dependency of this suppressive effect was observed. Adding agar and xanthan gum increased the storage shear modulus (G′) of starch gels, while adding konjac glucomannan decreased G′ values. The results indicate that the suppressive effect of non-starch polysaccharides on starch digestibility appears to be not only due to the rigidity of the gel, but also the interaction between starch and non-starch polysaccharides.     

Non-starch polysaccharides of tomatoes I. Characterizing pectins and hemicelluloses

For analysing the non-starch polysaccharides (NSP) of tomatoes, the alcohol-insoluble solids were fractionated using water, EDTA solution and sodium hydroxide solution, and the sugar and uronic acid components were determined by capillary gas chromatography. Highest yields of monosaccharides were obtained when the pectin and cellulose fractions were treated with methanesulfonic acid prior to methanolysis by diluting with methanol and heating to 100??°C for 2?h. However, treatment with concentrated formic acid followed by methanolic hydrochloric acid was best suited for the hemicellulose fractions. In this way, 81% of total tomato NSP (5.1?g/kg fresh weight) were characterized for their monosaccharide pattern. Free and associated pectins amounted to 28%, xyloglucans and other hemicelluloses to 30% and cellulose to 23%.     

Changes in cell-wall composition and degradability of sorghum during growth and maturation

Samples of sorghum (Sorghum bicolor Moench × Sorghum sudanense Stapf, cv ‘P 988’) were harvested at five growth stages. Quantitative methylation and acetalation–methylation methods were used to examine changes during growth of cell-wall polysaccharides, their association with phenolic compounds and the effects of changes on rumen degradability. Cellulose degradability, as measured by a nylon-bag method, decreased from 82·5% at the youngest stage to 36·5% at the milk-ripe stage, at a greater rate of change than degradability of dry matter. Among the monosaccharides contributing to cell-wall polysaccharides, the degradabilities of arabinose and uronic acid residues were consistently higher than those of xylose and glucose, the main components of structural carbohydrates. Recovery of parent neutral sugars from cell wall polysaccharides, calculated as the sum of partially methylated alditols, was in good agreement with the values obtained by direct estimation of individual sugars as their alditol acetate derivatives. Total non-starch polysaccharide content increased from 31·1% to 45·1% between the first two growth states, with little change evident thereafter. The relative proportion of individual to total sugars remained consistent throughout growth. The values for arabinose, xylose and glucose residues accounted for 4·9%, 27·9% and 63·0% of total neutral sugars, respectively. The pattern of glycosidic linkages detected could be mainly ascribed to the presence of (1–4)-β-D -glucans (cellulose), arabinoxylan, (1–3)(1–4)-β-D -glucans, (1–4)-β-D -galactan, (1–3)(1–6)-β-D -galactan, rhamnogalacturonan and, possibly, xyloglucan. The cellulose content of the five sorghums was, in order of growth, 14·3%, 21·8%. 22·3%, 21·2% and 22·0% of dry matter. The ratio of the mixed-linked g1ucan:cellulose decreased during growth. Arabinoxylan, the predominant hemicellulosic polysaccharide, was estimated to comprise about 33% of total neutral sugars consistently for all sorghum samples. Arabinose, found largely as terminal residues in the cell walls, carried various amounts of alkali-labile substituents, particularly at position 0–5, depending on the growth stage of sorghum. The extent of 0–5 substitution was closely correlated with both the lignin content (total phenolics minus phenolic acids, r = 0·903) and with cellulose degradability (r = 0·915).     

Characterisation of polysaccharides of copra meal

To investigate the polysaccharide composition of copra meal, defatted meal was treated successively by hot water extraction, delignification with sodium chlorite and protein elimination with protease. The deproteinised holocellulose obtained was treated by extraction with 16% NaOH to give an alkaline extract and an alkali insoluble fraction. Acidification of the alkaline extract with glacial acetic acid gave a product termed polysaccharide A and subsequent ethanol precipitation of the acidified liquor gave a product termed polysaccharide B. The hot water extract (HWE) and polysaccharide B were further fractionated by gel permeation chromatography. Sugar composition analyses of the extraction products examined by gas-liquid chromatography indicate that mannan is the major polysaccharide in copra meal and accounts for about 61% of the total polysaccharides in the deproteinised holocellulose. Other polysaccharides present in copra meal are, in descending order, cellulose, arabinoxylogalactan, galactomannan, arabinomannogalactan and galactoglucomannan.     

Effects of simulated digestion in vitro on cell wall polysaccharides from kiwifruit (Actinidia spp.)

Cell wall polysaccharides are resistant to digestion and absorption in the human small intestine and are considered to be delivered to the colon in a chemically unaltered state. In this paper, pulp from green and gold kiwifruit was subjected to in vitro upper-intestinal tract digestion and the chemical and physical changes to cell wall polysaccharides (dietary fibre) were investigated. Yields of insoluble fibre decreased slightly with simulated digestion while soluble fibre yields increased. Constituent sugar and glycosyl linkage analysis of the soluble and insoluble fibre fractions revealed that the chemical composition and structure of the non-starch polysaccharides remained largely unchanged. However, the degree of methylesterification of galacturonic acid residues present in the pectin-rich soluble fibre fractions of both fruit decreased with treatment; size-exclusion chromatography detected changes in the molecular weight profiles of these fractions. These changes may affect the physicochemical properties and fermentability of kiwifruit dietary fibre in the large intestine.     

Effects of sodium hydroxide on cereal straws in relation to the enhanced degradation of structural polysaccharides by rumen microorganisms

The action of sodium hydroxide on the rate and extent of loss of wall polysaccharides from wheat and barley straws incubated in the rumen of the sheep was studied using a nylon bag technique. Cellulose loss reached a maximum in straws treated with 10 g NaOH 100 g^?1 straw. Further increase in amounts of alkali applied resulted in additional solubilisation of straw constituents, particularly xylan, but did not further enhance cellulose degradation. Rates of degradation of isolated straw, cotton and wood celluloses correlated with three of four measures of cellulose crystallinity obtained by X-ray diffraction and infrared analysis. Treatment of cellulose samples with 20 g NaOH 100 g^?1 cellulose did not affect rates of loss or produce detectable changes to cellulose morphology. Loss of acetic acid esters, which accompanied alkali treatment, did not relate to improvements to digestibility. The rate of loss of cellulose from delignified neutral detergent fibre (NDF) was that shown by the isolated straw cellulose, despite the presence of acetylated hemicellulose. Deacetylation of delignified NDF with NaOH or sodium methoxide did not enhance rates of xylose or cellulose loss. In lignified wall material (NDF) the molar ratio acetyl:xylose (approximately 1:3.5) and proportion of the major phenolic acids (p-coumaric and ferulic acids) remained essentially constant throughout the course of degradation in the rumen. It is suggested that loss of phenolic acids, while not directly contributing to digestibility enhancement, may model the susceptibility of ester linkages formed between polysaccharide and polyphenolic material to alkali. The extent of solubilisation of p-coumaric acid produced by NaOH showed a linear relationship with cellulose digestibility. An upper limit of 40% acid detergent lignin and 55% of total phenolics were released by NaOH, the extent of release closely paralleling cellulose digestibility. Phenolic material resistant to alkali remained associated with wall polysaccharides and was not released from nylon bags until over 50% of cellulose (and hemicellulose) had been degraded.     

Identification of selected seaweed polysaccharides (phycocolloids) by vibrational spectroscopy (FTIR-ATR and FT-Raman)

The wide industrial application of phycocolloids (e.g. alginates, agar and carrageenans) is based on their particular properties to form gels in aqueous solution. These seaweed polysaccharides present a chemical structure related with the taxonomic position of the algae: carrageenans are produced by carrageenophytes (red algae belonging mainly to the genera Kappaphycus, Eucheuma, Chondrus, Gigartina and Chondracanthus). Recently, new spectroscopic techniques have provided more accurate identification of the natural composition of the polysaccharides produced by these seaweeds. With the combination of two spectroscopic techniques (FTIR-ATR and FT-Raman) it is possible to identify the principal seaweed colloids in ground seaweed samples as in extracted material. Since the seaweed samples receive the minimum of handling and treatment (e.g. they are simply dried and ground), the composition determined represents, as accurately as possible, the native composition of the phycocolloids.