Water-extractable Arabinoxylan Research Articles

Recycling of wheat gluten wastewater: Recovery of arabinoxylan and application of its film in cherry and strawberry preservation

This study investigated the effect of an edible water-extractable arabinoxylan (WEAX) coating on the postharvest preservation of strawberries and cherries. The WEAX film was prepared using carboxymethyl chitosan (CMCS) film as a control, with thorough characterization of its film properties. Subsequently, strawberry and cherry fruits were submerged in a solution containing edible film-forming materials and left to be stored at room temperature, followed by the analysis of their physicochemical parameters to assess their preservation efficacy. The results show that the WEAX film exhibited enhanced flexibility, superior water vapor permeability, thermal stability, and surface morphology. Furthermore, the implementation of WEAX film effectively mitigated weight loss, decay, color degradation, softening process, ascorbic acid decline, anthocyanin accumulation, and an increase in malondialdehyde content in fruits. Thus, the incorporation of WEAX coating demonstrates its capability in prolonging the shelf life of fruits post-harvest, underscoring its potential in fruit preservation practices.

Pulsed Electric Field Treatment of Oat and Barley Flour: Influence on Enzymes, Non-starch Polysaccharides, Dough Rheological Properties, and Application in Flat Bread

AbstractThis study examined the effects of pulsed electric field (PEF) treatment on enzymes, non-starch polysaccharides, and bread-making potential of oat and barley flour. Enzyme activity, microstructure, β-glucan extractability, molecular weight (Mw) and structure of non-starch polysaccharides, dough rheology, and flat bread properties were determined. An exponential decay model explained better the residual activity of oat β-glucanase across electric field intensity than barley β-glucanase. PEF treatment of flour at 12 kV/cm for 162 ms significantly reduced β-glucanase activity (40.2–76.5%) while increasing the concentration of total β-glucans (33.5%) and water-extractable arabinoxylans (36–41%). Mw of linear β-d-glucans decreased (9%) while Mw of branched arabinoxylans increased (6–33%). Scanning electron microscopy showed changes in microstructure of barley proteins. Blending wheat flour (70%) with oat or barley flour (30% weight) after PEF treatment enhanced gluten aggregation energy (29–19%) and breakdown viscosity (18–43%) of dough, as well as increased β-glucan content (21–32%) but reduced specific volume (11–24%). The findings of this study provide a comprehensive insight into the PEF’s potential for retarding enzymatic reactions and preserving integrity of cereal non-starch polysaccharides.

Effects of pearling on proximate composition, dough rheology, bread-making quality and health-promoting components of elite wheat cultivars

Though the health benefits of whole wheat products have been widely recognized, their less desirable processing qualities limited consumers’ acceptance. Thus, it is imperative to develop processing techniques for balanced nutritional and processing qualities. In this study, we investigated impacts of two grain pearling (debranning) levels on proximate composition, dough rheological properties, food-making quality, arabinoxylans (AXs), alkylresorcinols (ARs) and phenolic acids composition of two elite bread wheat cultivars. Pearled flour (PF) of Zhongmai 175 retained very good dough extensibility (190.7–195.5 mm), while PF of Zhongmai 578 retained medium-to-strong gluten strength and acceptable bread-making quality. Compared to whole wheat flour, PF preserved major portion of the health-promoting components in wheat grains, i.e., 71.4–94.0 % for water-extractable AXs, 68.1–86.3 % for total AXs, 71.4–92.7 % for alkylresorcinols, 85.5–98.9 % for soluble ferulic acid and 67.3–83.3 % for insoluble-bound ferulic acid. Further investigation is needed to understand the effects of different kernel sizes and debranning rates on nutritional profiles of pearled grains. Taken together, our results suggested that grain pearling can be used to produce wheat products with balanced nutritional and processing quality for improved human health.

Steam explosion technology as a tool to alter the physicochemical properties of intermediate wheatgrass (Thinopyrum intermedium) bran

Products containing the perennial grain intermediate wheatgrass (IWG) have recently entered the market, but little is known about the effect of processing operations on its constituents. This study investigated the effect of steam explosion (SE) conditions, i.e., temperature (130, 150 or 170 °C) and residence time (5 or 10 min), spanning severity factors from 1.6 to 3.1, on physicochemical properties of IWG bran. Even the lowest temperature and shortest time combination (130 °C, 5 min), was sufficient to inactivate peroxidase, generally regarded as the most heat-stable enzyme in grains. Contents of free phenolic acids as well as water-extractable arabinoxylans significantly increased while phytic acid was reduced after SE. However, starch damage, free fatty acids as well as browning (all negatively affecting quality) increased with treatment severity. Thus, SE is a promising technology to reduce enzymatic activity, enhance phenolic and soluble fiber contents in IWG bran, but severity factors >2.5 may negatively affect quality.

Effects of whole wheat flour on frozen dough and steamed bread during freeze-thaw cycles

The research on Chinese steamed bread (CSB) with whole wheat flour (WWF) is limited and has not been discussed during freeze-thaw. This study investigated the effects of WWF addition on the dough and CSB quality during freeze-thaw cycles. The results of low-field nuclear magnetic resonance (LF-NMR) and dynamic rheological properties demonstrated that the WWF reduced the adverse changes of freeze-thaw treatment on the dough. Characteristics, texture, and cross section analysis of CSB showed that WWF (20%) could relatively maximize stability. To study the mechanism, arabinoxylan (AX) and water-extractable arabinoxylan (WEAX) from WWF were added to dough. Consistent with WWF, it was found that they could improve freeze-thaw tolerance of frozen dough and CSB. Meanwhile, WEAX (1.12%) could better increase quality and freeze-thaw tolerance of CSB. The results presented in the study indicate that the anti-freeze-thaw effects of WWF could be attributed to AX and WEAX.

Studies on the degradation pattern of wheat malt endo-1,4-β-xylanase on wheat-derived arabinoxylans.

Wheat malt endo-1,4-β-xylanase is a key enzyme for arabinoxylan degradation, but its wheat-derived arabinoxylan degradation pattern is unclear. Water-extractable arabinoxylan (WEAX) of 300-750 kDa and 30-100 kDa were the two components with the highest degradation efficiency of wheat malt endo-1,4-β-xylanase, followed by > 1000 kDa WEAX, but 100-300 kDa WEAX showed the lowest degradation efficiency. The main enzymatic products were the 5-30 kDa WEAX, which accounted for 57.57%, 68.15%, and 52.28% of WAXH, WAXM, and WAXL products, respectively. The enzymatic efficiency of wheat malt endo-1,4-β-xylanase was relatively high, and the continuity of enzymatic efficiency was good, especially since the enzymatic reaction was the most intense in 1-3 h. WEAX of > 300 kDa was highly significant and positively correlated with viscosity. In comparison, WEAX of < 30 kDa was highly significant and negatively correlated with viscosity. As the enzymatic degradation proceeded, there were fewer and fewer macromolecular components but more and more small molecule components, and the system viscosity became smaller and smaller. In this study, it was found that wheat malt endo-1,4-β-xylanase degraded preferentially 300-750 kDa and 30-100 kDa WEAX, not in the order of substrate size in a sequential enzymatic degradation. Wheat malt endo-1,4-β-xylanase was most efficient within 3 h, primarily generating < 30 kDa WEAX ultimately. The main products were highly significantly negatively correlated with the system viscosity, so that the system viscosity gradually decreased as the enzymatic hydrolysis proceeded. © 2024 Society of Chemical Industry.

Recycling of wheat gluten wastewater: separation, characterisation, and solution rheology of arabinoxylans

SummaryA significant volume of gluten production wastewater, containing arabinoxylan, is generated during wheat processing, presenting an underutilised resource. In this study, water‐extractable arabinoxylan (WEAX) was obtained from this wastewater through water extraction and alcohol precipitation, followed by purification, and its chemical and rheological properties were subsequently investigated. The analysis revealed a mean molecular weight of 4.57 × 104 Da for WEAX, with arabinose (38.08%) and xylose (43.77%) as the predominant monosaccharides. Notably, the sample exhibited characteristic structural properties of arabinoxylan, as confirmed by FT‐IR spectra. Scanning electron microscopy further revealed a heterogeneous solid morphology, comprising filamentous flake and spherical structures. Moreover, WEAX demonstrated favourable thermal stability and revealed shear‐thinning behaviour, as well as weak gelation, as evidenced by thermogravimetry, differential scanning calorimetry, and rheological analysis. This study not only presents a novel approach for the resource treatment of wheat gluten production wastewater but also contributes new insights into the characterisation of arabinoxylan.

Fermentation of Lactobacillus fermentum NB02 with feruloyl esterase production increases the phenolic compounds content and antioxidant properties of oat bran

In this study, strains producing feruloyl esterase were screened by Oxford Cup clear zones method and by evaluating the ability to decompose hydroxycinnamoyl esters. The strain was identified by 16S rDNA molecular biology. The contents of dietary fiber, reducing sugar, water-extractable arabinoxylans, phytic acid, total phenolics, total flavonoid, phenolic compounds composition, microstructure and antioxidant activity in bran before and after fermentation were studied. Eight strains producing feruloyl esterase were screened, among which strain P1 had the strongest ability to decompose hydroxycinnamoyl esters. The strain was identified and named L. fermentum NB02. Compared with unfermented bran, fermented bran exhibited higher contents of soluble dietary fiber, reducing sugar, water-extractable arabinoxylans, total phenolics, total flavonoid, and lower insoluble dietary fiber and phytic acid content. The dense surface structure of bran was destroyed, forming a porous structure. The release of phenolic compounds increased significantly. L. fermentum NB02 fermentation improved the antioxidant capacity of bran.

Advancing Quantification of Water-Extractable Arabinoxylan in Beer: A High-Throughput Approach.

Water-extractable arabinoxylan (WEAX) may cause major problems during clarification processes in a brewery owing to its ability to form gel networks. However, high WEAX contents can also enhance the nutritional quality of the final product as they play an important role in the human diet. Therefore, precise quantification of WEAX is required. Current methods are very time- and resource-consuming as well as limited in the number of samples and in some cases provide low accuracy. Thus, a reproducible high-throughput method for the quantification of WEAX optimized for beer was developed, reaching recovery rates (RRs) of almost 100%. The assay is based on Douglas's colorimetric method. Hydrolysis was conducted using glacial acetic acid to induce the formation of red color complexes resulting from the interaction between pentose degradation products and phloroglucinol. The method was successfully transferred to a multi-mode microplate reader to minimize the loss of color intensity over time and to obtain a high throughput. By using 96-well plates, up to 40% of the previous analysis time could be saved, and a larger number of samples could be analyzed in one batch. The collected data determined xylose as an optimal calibration standard due to high accuracy and reproducibility. The respective AX control standards showed RR within the range of 95-105% without exception. To validate and show the ruggedness of the modified method, WEAX concentration in seven commercial German beers (e.g., lager, pilsner, wheat beer, non-alcoholic beer) was quantified. Interfering hexose sugars that lead to measurement errors when analyzing samples with high amounts of fermentable sugars (e.g., non-alcoholic beer produced by limited fermentation) were eliminated by Saccharomyces diastaticus fermentation. Further investigations were carried out by means of LC-MS in order to obtain additional information about the reddish product in the hydrolyzed samples. In this context, C16H12O6 could be identified as one of numerous condensation products, contributing to the coloring. The collected data showed the impact of diverse factors on the measured AX concentration and helped optimize the experimental procedure for a high sample throughput with precise and highly reproducible results. The proposed quantification method should be primarily used in completely fermented finished beer to emphasize the time aspect. Wort samples and non-alcoholic beer produced by limited fermentation can be also analyzed, but only after fermentation with S. diastaticus.

Fibre and short-chain carbohydrate composition in rye varieties, novel industrial milling fractions and breads

AbstractRye is an important raw material of bread due to tradition and its favourable nutritional and technological qualities. Despite the beneficial fibre composition, a special group of short-chain carbohydrates, the so called FODMAPs (fermentable oligo-, di-, monosaccharides and polyols) may cause problems for patients with irritable bowel syndrome. The aim of our work was to investigate the non-starch carbohydrate (dietary fibre compounds, short-chain carbohydrates) composition of rye varieties, and of their novel milling fractions obtained from industrial milling trials and test loaves made from them. Regarding fibre and short chain carbohydrate composition, rye varieties did not show significant differences. In new subfractions, fibre and FODMAP composition were described, among profiles most of them differ from commonly used flours, independently from variety. The yeast fermentation and baking caused a decrease in water-extractable arabinoxylan content, at the same time increased the substitution pattern of water-extractable arabinoxylans. Furthermore, breadmaking process decreased the fructan content, and therefore increased the fructose level, thus modifying the short-chain carbohydrate composition. Based on our knowledge, this research is among the first ones investigating the fibre and short-chain composition of rye from the seeds to the consumable final products.

Effects of Co-Modification by Extrusion and Enzymatic Hydrolysis on Physicochemical Properties of Black Wheat Bran and Its Prebiotic Potential.

Black wheat bran (BWB) is an important source of dietary fiber (DF) and phenolic compounds and has stronger nutritional advantages than ordinary WB. However, the low content of soluble dietary fiber (SDF) negatively influences its physicochemical properties and nutritive functions. To obtain a higher content of SDF in BWB, we evaluated the impact of co-modification by extrusion and enzymes (cellulase, xylanase, high-temperature α-amylase, and acid protease) on water extractable arabinoxylan (WEAX) in BWB. An optimized co-modification method was obtained through single-factor and orthogonal experiments. The prebiotic potential of co-modified BWB was also evaluated using pooled fecal microbiota from young, healthy volunteers. The commonly investigated inulin served as a positive control. After co-modification, WEAX content was dramatically increased from 0.31 g/100 g to 3.03 g/100 g (p < 0.05). The water holding capacity, oil holding capacity, and cholesterol adsorption capacity (pH = 2.0 and pH = 7.0) of BWB were increased by 100%, 71%, 131%, and 133%, respectively (p < 0.05). Scanning electron microscopy demonstrated a looser and more porous microstructure for co-modified BWB granules. Through in vitro anerobic fermentation, co-modified BWB achieved a higher content of Bifidobacterium and Lactobacillus than inulin fermentation. In addition, co-modified BWB induced the highest butyric acid production, indicating high potential as prebiotics. The results may contribute to improving technologies for developing high-fiber-content cereal products.

Effects of cereal grain cell wall composition and structure on starch digestion.

Wheat is an important food crop, and its characteristics vary depending on the region of cultivation; different environments have varying effects on the composition of the grains. We previously reported the effects of environmental factors on wheat grain cell wall composition and structure. The variations in the structure of aleurone cell walls between different wheat samples were examined to determine the effects of aleurone cell walls on grain starch digestion properties. Ten different varieties of wheat grains with different aleurone cell wall structure and composition constituted a simple research system used to investigate their effect on the starch digestion of bread. The aleurone cell wall thickness ranged from 3.05 μm to 4.67 μm, and the arabinose to xylose ratio of water-extractable arabinoxylan was in the range 0.79-0.97. With the increase in arabinoxylans content or cell wall thickness, the total digestibility of starch within the bread decreased; this phenomenon may be related to the changes in the interaction between polysaccharides and starch granules in this process. The results of the present study showed that the wheat cell wall structure has a great impact on starch hydrolysis, indicating that the change in the digestibility of starch in flour and bread may be a result of changes in the cell wall structure leading to different combinations, thus affecting digestibility. The present study showed that the cell wall combines the starch granules during the bread-making process; thus, the diffusion of enzymes through the cell wall was hindered. © 2023 Society of Chemical Industry.

Study on the spatio-temporal variation of arabinoxylan and alkylresorcinol in wheat grains

The purpose of this study was to clarify the spatio-temporal variation of arabinoxylan (AX) and alkylresorcinol (AR) in wheat. The total arabinoxylan (TOT-AX), water-extractable arabinoxylan (WE-AX), and AR contents of wheat from the main wheat producing areas of China were investigated. The effects of the geographical origin, variety, harvest year, their interactions, and irrigation frequency on the content and structure vibrations of AX and AR in wheat grains were studied based on the field experiment combined with one-way and multi-way analysis of variance. The results showed that the TOT-AX, WE-AX, and AR contents of wheat from the main wheat producing areas of China were 27.03–64.16 mg/g, 3.81–9.70 mg/g and 275.6–661.7 µg/g, respectively. Except for the irrigation, other factors had significant effects on the AX and AR contents of wheat, and the variety had the greatest effect. Xiaoyan 22, Xinmai 18, and Hengguan 35 had the highest TOT-AX, WE-AX and AR contents, respectively. The O-H stretching vibration of AX and AR and the skeleton vibrations of the aromatic ring of AR was mainly affected by the variety. This study indicated that Xiaoyan 22, Xinmai 18, and Hengguan 35 can be used for producing foods with high TOT-AX, WE-AX, and AR contents, respectively.

Determining levels of water-extractable and water-unextractable arabinoxylan in commercial Swedish wheat flours by a high-throughput method

A high-throughput method for quantification of water extractable arabinoxylan (WE-AX) and water unextractable arabinoxylan (WU-AX) was adapted for and evaluated on 197 commercial Swedish wheat flours, collected continuously during harvest years 2018 and 2019. In the method, starch was hydrolysed by alpha-amylase and WE-AX was precipitated with 80% ethanol. AX residues were quantified by gas chromatography after acid hydrolysis. The method had a good repeatability (2.1% RSDr for total AX). Spring wheat flour had a higher WE-AX content (0.68%) and lower WU-AX content (1.19%) than winter wheat flour (0.56% and 1.31%). The variation of total AX content was high for winter wheat flour (1.5–2.2%), with no correlation to ash or protein content. Total AX content differed significantly both between harvest years and locations, indicating an impact from environment on AX composition. Overall, the method enabled high-throughput analysis of wheat flour and can be further used to study how endogenous AX impacts baking quality.

The fate of insoluble arabinoxylan and lignin in broilers: Influence of cereal type and dietary enzymes

Insoluble fiber degradation by supplemented enzymes was previously shown to improve fermentation in poultry, and has been further postulated to disrupt the cereal cell wall matrix, thus improving nutrient digestion. Here, we characterized insoluble feed-derived polysaccharides and lignin in digesta from broilers fed wheat-soybean and maize-soybean diets without or with xylanase/glucanase supplementation. Enzyme supplementation in wheat-soybean diet increased the yield of water-extractable arabinoxylan (AX) in the ileum. Still, most AX (> 73 %) remained insoluble across wheat-soybean and maize-soybean diets. Analysis of so-far largely ignored lignin demonstrated that a lignin-rich fiber fraction accumulated in the gizzard, while both insoluble AX and lignin reaching the ileum appeared to be excreted unfermented. More than 20 % of water-insoluble AX was extracted by 1 M NaOH and 11–20 % was sequentially extracted by 4 M NaOH, alongside other hemicelluloses, from ileal digesta and excreta across all diets. These findings showed that enzyme-supplementation did not impact AX extractability by alkali, under the current experimental conditions. It is, therefore, suggested that the degradation of insoluble AX by dietary xylanase in vivo mainly results in arabinoxylo-oligosaccharide release, which is not accompanied by a more loose cell wall architecture.

Effect of steam explosion on nutritional components, physicochemical and rheological properties of brown rice powder.

Brown rice powder is underutilized mainly due to its lower starch digestibility and poor processing performance. The present study investigated the potential of steam explosion on the improvement of nutritional and physicochemical characteristic in brown rice powder and rheological property of paste. Compared with native brown rice powder, steam explosion at 0.5 MPa for 7 min increased the water-extractable arabinoxylans (5.77%), reducing sugar content (21.04%), and iodine blue value (30.38%), which indicated steam explosion that destroyed the intact cells of brown rice. Later the crystalline structure of brown rice powder was destroyed into an amorphous structure by steam explosion. Steam explosion enhanced the degree of gelatinization (4.76~351.85%) and solvent retention capacity (SRC) of brown rice powder, compared with native sample. The effect on the intact cells and starch structure of brown rice caused the starch digestibility enhancement remarkable. Viscoelastic profiles confirmed that steam explosion weakened the paste strength and elasticity corresponded with hardness and cohesiveness by increasing the loss factor (tanδ). This work provided important information for brown rice powder modified by steam explosion (0.5 MPa, 7 min) with good nutritional property (nutrients and digestibility) and processability (SRC, textural, and rheological property). Steam exploded brown rice powder (0.5 MPa, 7 min) could serve as a potential ingredient widely used in food products.

Effects of malting process on molecular weight distribution and content of total and water-extractable arabinoxylan in barley

This work aims to evaluate the effects of the malting process on the malt total and water-extractable (WE) arabinoxylan (AX), also considering the barley cultivar and year of cultivation. The WEAX molecular properties were characterized by high-pressure size exclusion chromatography (HPSEC) - triple detector array (TDA). Most of the barley malt WEAX showed a molecular weight over 4.0 × 105 Da with a random coil conformation. Compared to raw barley, the malts show analogous content of AX and WEAX, similar intrinsic viscosity, less rigid conformation, and higher polydispersity. The WEAX content of malt was highly and negatively related to the common quality parameters, resulting in a useful indicator of malt modification, even more representative than the total AX content. WEAX is highly positively related to the Congress wort viscosity, and thus, lautering could be more significantly affected by WEAX rather than total AX content.

Enhancing of nutritional properties of quinoa fermented by probiotics

Fermentation of quinoa by probiotics provides higher nutritional value and can be considered as a significant source of bioactive compounds and alive probiotics for the human body. Moringa leaves powder (MLP) at the levels of 0.25 and 0.50% were used as an additional prebiotic source to supply quinoa fermentation by Lactobacillus plantaram ATCC 14917 and Lactobacillus delbrueckii ssp. Bulgaricus EMCC 11102 and produce healthier quinoa products. The results indicated that supplementation of fermented quinoa products with MLP at bath levels increased its contents of free phenolics and water extractable arabinoxylans as well as enhanced its antioxidant activity and phytate degradation. Fermented quinoa products with 0.50% MLP showed better chemical properties than fermented quinoa products with 0.25% MLP. Furthermore, supplementation of fermented quinoa products with MLP (0.50%) displayed positive effects on blood glucose levels of the experimental rats. Further studies are required on the test of more kinds of probiotics with different concentration of MLP in quinoa fermentation in the future.

The microbiome modulating potential of superheated steam (SHS) treatment of dietary fibres

In this study, wheat and oat bran fibres were used to investigate the potential beneficial prebiotic-enhancing effects of superheated steam (SHS) treatment. Following SHS treatment of fibres, in-vitro simulated gastric and intestinal digestion followed by batch culture fermentation was performed. 16S rRNA gene sequencing and short chain fatty acid analysis were conducted, which demonstrated that SHS treatment was associated with significant differences in beta diversity and the relative abundances of several microbial taxa. Principal Coordinate Analysis (PCoA) revealed significant separation between SHS-treated oat and non-treated oat (p = 0.013), and between SHS-treated wheat and non-treated wheat following in vitro batch fermentation (p = 0.042). Abundances of Ruminococcus were found to be significantly higher by 1.09-log in SHS-treated oat when compared with non-treated oat while abundances of Escherichia_Shigella, and Alistipes were significantly lower by 1.47-log and 0.39-log, respectively in the SHS-treated oat samples than the non-treated oat samples (p = 6.85E-06, p = 0.002037, p = 0.002458; respectively). These data demonstrate that SHS treatment of dietary fibre enhanced its effectiveness to modulate the gut microbiome.Industrial Relevance: Superheated steam (SHS) treatment has emerged as an effective method to improve the shelf-life of grains by reducing lipid hydrolysis and oxidation. Our results revealed that SHS treatment of wheat and oat brans led to increased physiological and chemical properties including higher water-binding capacity, water-extractable arabinoxylan, and total phenolics as well as improvement in human gut microbiota. Our results suggest that this method could be implemented in the food industry in order to improve beneficial properties of oat and wheat brans.

Morenga leaves for promotion the healthy benefits of oat fermented by probiotic bacteria: The first investigation

This is the first study that evaluates the effect of supplementation with Moringa leaves powder (MLP) as a source of prebiotics to produce healthier fermented oat products. MLP at the levels of 0.25 and 0.50% (w/w) were used as an additional prebiotic source to improve the oat fermentation by Lactobacillus plantaram ATCC 14,917 and Lactobacillus delbrueckii ssp. Bulgaricus EMCC 11,102. The results indicated that supplementation of fermented oat products with MLP at bath levels enhanced the antioxidant activity and phytate degradation and increased the contents of total phenolics and water extractable arabinoxylan. Interestingly, fermented oat products supplemented with the higher level of MLP presented higher cholesterol lowering effect and reduced the coliform group counts of experimental rat feces. Supplementation with MLP improved the healthy benefits of oat products fermented by selected probiotic bacteria and may have a potential role as effective vehicles for probiotics and control of hypercholesterolemia disease in the future.