The polysaccharide composition of yellow passion fruit rind cell wall: chemical and macromolecular features of extracted pectins and hemicellulosic polysaccharides

BACKGROUND: Yellow passion fruit (Passiflora edulis var. flavicarpa Degener) is one of the main sources of juice production in tropical regions, the extraction of which generates large amounts of rind and seeds as by‐products. In a view to valorize rinds as a possible fiber source, the whole polysaccharide composition is first investigated. RESULTS: Cell wall material, from rinds, consists of ～80% (w/w) non‐starchy polysaccharides, of which 42% is cellulose, 25% pectic substances and 12% hemicelluloses. Fractional extraction of non‐starchy polysaccharides from cell wall material showed that the degree of methyl esterification, intrinsic viscosity and weight‐average molecular mass of extracted pectins range widely from 5 to 40, from 170 to 580 mL g^?1 and from 58 000 to 105 000 g mol^?1, respectively. Likewise, the intrinsic viscosity and weight‐average molecular mass of extracted hemicellulosic polysaccharides range from 40 to 55 mL g^?1 and from 21 000 to 48 000 g mol^?1, respectively. Chromatographic fractionation of hemicellulosic fractions and glycosyl linkage analysis substantiate the presence of ～90% (w/w) of xyloglucans and 10% (w/w) of glucomannans of the whole fraction. CONCLUSION: The cell wall material, obtained from yellow passion fruit rinds, contains high amounts of non‐starchy polysaccharides. Cellulose appears to be the predominant polysaccharide, thus denoting a potential insoluble fiber source. Copyright © 2008 Society of Chemical Industry     

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.     

Role of pectic polysaccharides in structural integrity of apple cell wall material

Texture modulating properties of aqueous dispersions of apple cell wall material differed from those of tomato or kiwifruit, particularly under high shear. It was previously hypothesized that this may be due to the fact that the apple cell wall showed less in vivo solubilization of pectic polysaccharides during ripening compared to tomato or kiwifruit. However, in vitro solubilization of the pectic polysaccharide content of apple CWM by endo-polygalacturonase and/or extraction with 0.05 M sodium carbonate, did not affect the loss in wall integrity shown by tomato or kiwifruit CWMs under shear. In addition, the pectin-depleted residue after Na₂CO₃ extraction possessed better water retaining and viscosity generating properties than the original cell wall material. Following treatment of apple CWM with cellulase, the viscosity of suspensions decreased, emphasising the role that the cellulose–hemicellulose network plays in the water-retaining capacity of the cell wall. Residue from CWM after cellulase treatment consisted of ∼85% pectic polysaccharides. Surprisingly, the integrity of these “cellulose-free” walls was maintained after shear. It is concluded that differences in structural properties of the CWMs of apple compared to kiwifruit or tomato are not simply related to pectin solubilization but to a fundamental difference in the architecture of the apple cell wall.     

Cocoa bean carbohydrates: roasting-induced changes and polymer interactions

Roasting induced change to carbohydrates and cell wall polysaccharides was investigated in three varieties of cocoa beans. The concentrations of glucose and fructose decreased after roasting but levels of the non-reducing sugars, sucrose, raffinose, stachyose and verbascose, were not markedly affected. Approximately 10% of the arabinose content of the polysaccharides was degraded but, overall, the pectic and hemicellulosic polymers remained intact after roasting. The degree of esterification and acetylation of the pectic polysaccharides were unaffected by roasting. Roasting did promote an interaction between polysaccharides, proteins, polyphenolics and Maillard products. This led to the formation of insoluble complexes which co-purified with, and augmented, the levels of cell wall material isolated from roasted compared to unroasted beans. The implications of the results are discussed in relation to the role that “Klason lignin” plays in the formation of these chemical amalgams during roasting.     

Effect of Cooking and Pre-Cooking on Cell-Wall Chemistry in Relation to Firmness of Carrot Tissues

The aim of this work was to investigate heat-induced changes in cell wall polysaccharides of carrot in relation to texture. Discs of fresh carrot (Daucus carota cv Amstrong) tissue were subjected to cooking (100°C, 20 min), with or without a pre-cooking treatment (50°C, 30 min). Alcohol-insoluble residues were prepared from the tissues and were extracted sequentially with water, NaCl, CDTA, Na₂CO₃ and 0·5 M KOH to leave a residue. These were analysed for their carbohydrate compositions, their degree of methyl esterification and the molecular size of selected soluble polysaccharides. Cooking caused tissues to soften. This involved cell separation, an increase in water- and salt-soluble, high-molecular-weight pectic polysaccharides and a concomitant decrease in the pectic polymers in all wall extracts and the residue. Pre-cooking prior to cooking enhanced cell–cell adhesion and reduced the extent of softening. This was accompanied by a general reduction in the degree of methylesterification of cell-wall pectic polymers, and a decrease in the cooking-induced modification to all pectic fractions. The firming effect of pre-cooking could be reversed by extracting the precooked+cooked tissue with CDTA, a chelating agent. The role of Ca²⁺ cross-linked polymers and pre-cooking in the enhancement of firmness are discussed. © 1997 SCI.     

Effect of dry‐salt processing on the textural properties and cell wall polysaccharides of cv. Thasos black olives

BACKGROUND: Thasos is an olive variety cultivated mainly in Greece used to produce ‘naturally black dry‐salted olives’. This process consists in placing the olives in disposed layers with coarse sodium chloride. The loss of water and other solutes gradually debitters and wrinkles the fruits. In this study, the effect of dry‐salt processing on the texture and cell wall polysaccharide composition was investigated. RESULTS: This type of processing affected primarily the mechanical properties of the olive flesh. In processed olives, this tissue was approximately 4.5 times stronger and also more deformable up to failure and stiffer than that from the raw olives. The dry‐salt processing had its strongest effect on pectic polysaccharides. This included the increment of solubilization of arabinose‐rich polymers in aqueous solutions, and thus their partial loss to the soak medium during dry‐salting. Contrarily, galacturonic acid‐rich polymers were further retained in the processed olives, probably by their stabilization within the cell walls by reduction of the electrostatic repulsion between the acidic groups of these polysaccharides due to sodium ions. CONCLUSION: The texture improvement of olive flesh by dry‐salt processing seems to be correlated with the reorganization of the galacturonic acid‐rich pectic polysaccharides into the cell wall of the fruit. Copyright © 2008 Society of Chemical Industry     

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.     

Evaluation of ethanol fermentation parameters for bioethanol production from sugar beet pulp and juice

The aim of this study was to investigate the efficient utilization of sugar beet pulp, as well as raw, concentrated raw and thick sugar beet juice, for bioethanol production. Different fermentation conditions were examined. The influence of raw material pre‐treatment (pasteurization or sterilization), type of batch culture process (stationary or shaken) as well as the type of Saccharomyces cerevisiae yeast preparation on the yields of the process were studied. Moreover, the fermentation process effectiveness was examined in connection with the quality of the obtained distillates. Sterilization, stationary batch culture and Safdistil C‐70 yeast preparation were identified as the most profitable factors for sugar beet pulp fermentation, providing a high fermentation efficiency and ethanol yield (87.7% of theoretical ethanol yield). Concentrated raw beet juice resulted in a value of 94.2% of theoretical yield, and thick juice a 92.6% yield. The results suggest that bioethanol production from sugar beet pulp and sugar beet juice has promise as an alternative fuel. The raw spirits obtained from the sugar beet juice were characterized as having the lowest quantity of volatile by‐products. Copyright © 2014 The Institute of Brewing & Distilling     

De‐esterification pattern of Valencia orange pectinmethylesterases and characterization of modified pectins

BACKGROUND: Pectinmethylesterase (PME, E.C. 1.1.11) isozymes from Valencia orange preparations with different specific activities were used to de‐esterify citrus and sugar beet pectins. Enzymatic modification offers the opportunity to create pectins of tailored functionality and gelling ability. RESULTS: Based on nuclear magnetic resonance spectra, catalysis by all PME extracts produced block‐wise de‐esterification patterns in both citrus and sugar beet pectins. PME activity resulted in increased numbers of contiguous de‐esterified groups and decreased numbers of contiguous esterified groups. De‐esterification by PMEs increased the elastic property (G′) of citrus and sugar beet pectins in the presence of calcium from 10 to 571 and from 0.05 to 201 Pa, respectively. CONCLUSIONS: The results demonstrate the predilection of citrus PMEs toward block wise de‐esterification of pectins and the relationship between calcium binding ability and de‐esterification degree and patterning. Within a narrow range of de‐esterification (37–48%) and with a narrow distribution of contiguous groups, PME modification did not markedly change gelling ability. At lower or higher de‐esterification values, a 2‐fold increase or 50‐fold decrease, respectively in G′ values was observed. Copyright © 2008 Society of Chemical Industry     

Cell wall compositions of raw and cooked corms of taro (Colocasia esculenta)

The monosaccharide compositions of parenchyma cell walls of raw and cooked corms of taro, Colocasia esculenta cv Tausala Pink, were determined. The cell wall constituents were sequentially extracted using CDTA, Na₂CO₃, 1 M KOH, 4 M KOH and water to leave a final residue (α‐cellulose). The monosaccharide compositions of the cell walls and cell wall fractions from the raw and cooked corms were consistent with the presence in these cell walls of large amounts of cellulose and pectic polysaccharides. The monosaccharide composition of the cell walls of the raw corms resembled the monosaccharide compositions of primary cell walls of other non‐commelinoid monocotyledons and dicotyledons. Cooking of the corms resulted in alteration of the cell walls, with solubilisation of pectic polysaccharides occurring earlier in the sequential fractionation and possibly changes in the extractability of xyloglucans and/or xylans. © 2000 Society of Chemical Industry     

Gamma-Radiation Affects Cell Wall Composition of Strawberries

Tissue softening limits the use of gamma irradiation for controlling postharvest microbial development on some produce. The carbohydrate composition of the cell wall of the strawberry (Fragaria ananassa Duch. cv. Chandler) fruit and of cell wall fractions was compared in untreated controls and in fruit irradiated at 4 kGy, a dose causing tissue softening. Cell wall polysaccharides were partially degraded, particularly cellulose and pectic substances. However, neutral sugars from the pectic and hemicellulose fractions were not affected by irradiation, in contrast with cell wall degradation during ripening.     

Structure of pectic polysaccharides isolated from onion Allium cepa L. using a simulated gastric medium and their effect on intestinal absorption

The polysaccharide fraction extracted with simulated gastric juice from onion bulbs contained a mixture of galactan with short-length sugar chains, pectic polysaccharides and evident content of proteinaceous material. Galacturonan and rhamnogalacturonan were the main constituents of the linear regions of the sugar chains of the pectic polysaccharides. The ramified regions included rhamnogalacturonan-I. NMR data revealed that the side chains of the ramified region contained mainly 1,4-linked β-d-galactopyranose residues and lesser content of 1,3-linked β-d-galactopyranose and 1,5-linked α-l-arabinofuranose residues. Furthermore, the proteinaceous material was determined to be partly linked to the sugar chains.     

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     

Non-starch polysaccharides from sunflower (Helianthus annuus) meal and palm-kernel (Elaeis guineensis) meal—investigation of the structure of major polysaccharides

For the identification and characterisation of major non-starch polysaccharides from sunflower (Helianthus annuus L) meal and palm-kernel (Elaeis guineensis Jacq) meal, extracts obtained by sequential alkaline extraction and delignification of the corresponding cell wall materials were subfractionated by graded ethanol precipitation and size-exclusion and adsorption chromatography. Determination of the sugar and glycosidic linkage composition of extracts and subfractions and intact cell wall materials allowed the identification and quantification of a variety of polysaccharides. In sunflower meal, cellulose (42% of total non-starch polysaccharides), pectic polysaccharides (24%), (4-O-methyl)-glucuronoxylans with 8-11% uronic acid substitution (24%), (gluco)mannans (5%) and fucoxyloglucans (4.5%) were encountered. Major polysaccharides in palm-kernel meal were linear mannans with very low galactose substitution (78% of total non-starch polysaccharides), followed by cellulose (12%) and small amounts of (4-O-methyl)-glucuronoxylans and arabinoxylans (3% each).     

超滤分级甜菜中果胶的理化性质及乳化特性研究

利用超滤技术将甜菜果胶分为相对分子质量不同的4个级分,并采用高效液相色谱(HPLC)、傅里叶变化红外光谱(FT-IR)和气相色谱(GC)等技术研究了不同级分果胶分子的结构组成及其乳化特性。结果表明:甜菜果胶中截留相对分子量(MWCO)大于100,000的含量最大,达到64.86%;果胶相对分子量与其性质直接相关,随着相对分子量的增大,果胶中半乳糖醛酸、阿魏酸和酯化度均增大,单糖种类增多,而单糖的含量却减少,其分布亦有差异;相对分子量不同的果胶乳化性有很大不同,其中分子量为4.64×104Da组分的果胶乳化活性和乳化稳定最好。     

Characterisation of Rosa Mosqueta seeds: cell wall polysaccharide composition and light microscopy observations

The utilisation of enzymes for the extraction of vegetable oils from seeds has been a topic of growing interest in recent years. Knowledge of the cell wall polysaccharide composition is important to select the enzyme(s) necessary for the most effective degradation of the cell walls. The purpose of the present work is to characterise the seeds of Rosa Mosqueta (Rosa aff rubiginosa) by light microscopy (where several differential staining methods were applied to analyse the seed structure) and by the isolation of cell wall polysaccharide extracts. The mature seed of Rosa Mosqueta has a very thick and structurally complex seed coat comprising heavily lignified tissue. The embryo has two cell layers of remaining endosperm tissue (indicating that this is an exalbuminous seed), two voluminous cotyledons that contain the oil, and bundles of provascular tissues distributed perpendicularly to the transverse axis of the embryo. The major non‐cellulosic polysaccharides from the non‐lignified tissues are glucuronoxylans and pectic polysaccharides; glucans are also present in small amounts. The major non‐cellulosic polysaccharides from the lignified tissues are glucuronoxylans. Concerning the use of enzymes for oil extraction, microscopy and cell wall polysaccharide analysis showed that the use of pectic enzymes followed by a xylanase or a cellulase should be explored. © 2000 Society of Chemical Industry     

紫薯果胶类多糖的成分分析及稳定性研究

以超声波辅助酶法提取及纯化紫薯果胶类多糖,并对其主要成分及稳定性进行分析.结果表明:所得紫薯果胶类多糖的干燥减量、酸不溶灰分、pH值、总半乳糖醛酸、酯化度、总糖、蛋白质含量分别为4.32％、0.32％、4.22、65.24％、31％、65％、1.02％,符合相关标准.测出所得紫薯果胶类多糖的重均分子量为70745 Da...     

Enzymatic extraction of galactan-rich rhamnogalacturonan I from potato cell wall by-product

Potato cell wall was used as low-value source for the enzymatic extraction of galactan-rich rhamnogalacturonan I (RG I). The effects of selected reaction parameters of endo-polygalacturonase from Aspergillus niger-catalyzed isolation of RG I and their interactions were investigated by response surface methodology. Models were developed to relate independent parameters (cell wall concentration, enzyme amount, reaction time) to responses (yield, neutral sugar content, saccharide molar composition, weak acidic fraction proportion). The most significant parameters that affected extracted polysaccharide yield and its galactose (Gal) and arabinose (Ara) contents were the cell wall concentration and enzyme amount. The interaction between the cell wall concentration and the reaction time was the most determinant for the yield. However, the cell wall concentration and the enzyme amount exhibited significant interaction effect on Gal and Ara contents. Comparison of predicted and experimental values validated the established predicted models, which can be used to identify the conditions for the isolation of RG I-type pectic polysaccharides with selected structural and saccharide composition properties. The monosaccharide composition and the linkage patterns confirmed the isolation of galactan-rich RG I type pectic polysaccharides. The present study is expected to increase the capability to generate RG I targeting specific composition and functional properties.     

Does Information about Sugar Source Influence Consumer Liking of Products Made with Beet and Cane Sugars?

Beet sugar contains an off‐aroma, which was hypothesized to generate expectations on the acceptability of a product made with beet sugar. Thus, the objective of this study was to assess the impact of information about the sugar source (beet vs. cane) on the overall liking of an orange‐flavored beverage. One hundred panelists evaluated an orange‐flavored powdered beverage mix and beverage made with beet and cane sugars using a 5‐phase testing protocol involving a tetrad test and hedonic ratings performed under blind and informed conditions. Tetrad test results indicated that there was a significant difference (P < 0.05) between the beverage mix made with beet sugar and cane sugar; however, no difference was found between the beverage made with beet sugar and cane sugar. Hedonic ratings revealed the significance of information conditions on the panelists evaluation of sugar (F = 24.67, P < 0.001); however, no difference in the liking was identified for the beverage mix or beverage. Average hedonic scores were higher under informed condition compared to blind condition for all products, possibly because labels tend to reduce uncertainty about a product. Results from this study are representative of the responses from the general population and suggest that they are not affected by sugar source information in a beverage product. Based on concerns with the use of beet sugar expressed in the popular press, there may be a subgroup of the population that has a preconceived bias about sugar sources due to their prior experiences and knowledge and, thus, would be influenced by labels indicating the sugar source used in a product.