Water Unextractable Solids Research Articles

Investigation of combined effects of xylanase and glucose oxidase in whole wheat buns making based on reconstituted model dough system

The combined effects of xylanase (XYL) and glucose oxidase (GOX) during whole wheat buns making was investigated based on the reconstituted model dough system including starch, gluten, and water-unextractable solids (WUS). The results showed that the combinations of GOX and XYL significantly (P < 0.05) increased free sulfhydryl (SH) contents (14.93–70.18%) and glutenin macropolymer (GMP) content (2.82%–6.15%) compared with the individual GOX. The XYL-GOX modified dough significantly (P < 0.05) increased glutenin (5.71%–13.04%) and gliadin solubility (3.57%–6.01%), leading to a decrease in the dough viscoelasticity and a more open gluten matrix structure. Additionally, XYL800GOX80 modified dough exhibited the highest α-helix (40.22%) and β-sheet (43.78%) contents among all the samples. However, when the level of XYL increased from 800 μg/g to 2400 μg/g, the α-helix and β-sheet in the XYL2400GOX40 and XYL2400GOX80 showed a significant downward trend (α-helix: 3.87–7.81%; β-sheet: 11.38–19.90%; P < 0.05). Therefore, the study indicated that the synergistic effects of XYL and GOX on the whole wheat dough were quite dependent on the hydrolysis degrees of WUS.

Improving the physicochemical properties of whole wheat model dough by modifying the water-unextractable solids

Most studies on improving the quality of wheat flour products have been based on eliminating the adverse effects of water-unextractable arabinoxylan (WUAX) using pentosanase (Pn), but the interactions between the arabinoxylan released from WUAX and gluten have rarely been studied. The results demonstrated that Pn decreased the molecular weight of soluble AX released from water-unextractable solids (57,120–18,450 g mol−1). The released AX increased the amount of glutenin macropolymer, accompanied by a decrease in glutenin solubility, but made it more difficult for the free sulfhydryl to form disulfide bonds between glutenin proteins. This might be beneficial to the formation of uniform and fine crumb structures, and produced whole wheat Chinese steamed bread (CSB) with higher volume and lower firmness. However, the gluten network became more open and easier to fracture at higher level of Pn, which made it different to the further improvement in the texture of CSB.

Acetyl Xylan Esterase Axe1 (T. reesei, Carbohydrate Esterase Family 5) Supplemented to a (Hemi)cellulolytic Preparation Enhances Degradation of Recalcitrant Corn Silage Polysaccharides

The increase in hydrolytic activity towards corn silage water unextractable solids by supplementation of acetyl xylan esterase 1 (T. reesei, TrAxe1), belonging to arbohydrate esterase (CE) family 5, to an A. niger / T. emersonii enzyme preparation is presented. TrAxe1 was cloned and expressed in A niger. The hydrolytic activity of TrAxe1 was analysed with a p-nitrophenyl-acetate standard assay and by the measurement of the acetic acid released from neutral and acidic eucalyptus xylo-oligosaccharides. The activity obtained for TrAxe1 was compared to acetyl xylan esterases belonging to CE families 1, 5 and 16 from A. niger. High activities were obtained for the CE5 classified acetyl xylan esterases from T. reesei and A. niger. The data obtained confirm the suggested increase in hydrolytic activity by supplementation of CE5 classified acetyl xylan esterases to the (hemi)cellulolytic A. niger / T. emersonii preparation (Neumuller et al. 2014b)

Trichoderma longibrachiatum acetyl xylan esterase 1 enhances hemicellulolytic preparations to degrade corn silage polysaccharides.

Supplementation of a Trichoderma longibrachiatum preparation to an industrial Aspergillus niger/Talaromyces emersonii enzyme mixture demonstrated synergy for the saccharification of corn silage water-unextractable solids (WUS). Sub-fractions of the crude T. longibrachiatum preparation obtained after chromatography were analyzed regarding their hydrolytic activity. An acetyl xylan esterase 1 [Axe1, carbohydrate esterase (CE) family 5]-enriched sub-fraction closely mimicked the hydrolytic gain as obtained by supplementation of the complete, crude enzyme mixture (increase of 50%, 62% and 29% for Xyl, Ara and Glc, respectively). The acetic acid released from model polysaccharides (WUS) and oligosaccharides [neutral (AcXOS) and acidic (AcUXOS) xylo-oligosaccharides] by Axe1 was two and up to six times higher compared to the acetic acid released by acetyl xylan esterase A (AxeA, CE 1). Characterization of Axe1 treated AcXOS and AcUXOS revealed deacetylation of oligosaccharides that were not deacetylated by AxeA or the A. niger/T. emersonii preparation.

Synergistic action of enzyme preparations towards recalcitrant corn silage polysaccharides

Corn silage, its water unextractable solids (WUS) and enzyme recalcitrant solids (ErCS) and an industrial corn silage-based anaerobic fermentation residue (AFR) represent corn substrates with different levels of recalcitrance. Compositional analysis reveals different levels of arabinoxylan substitution for WUS, ErCS and AFR, being most pronounced regarding acetic acid, glucuronic acid- and arabinose content. By screening for enzymatic degradation of WUS, ErCS and AFR, enzyme preparations exhibiting high conversion rates were identified. Furthermore significant synergistic effects were detected by blending Aspergillus niger/Talaromyces emersonii culture filtrates with various enzymes. These findings clearly highlight a necessity for a combinatorial use of enzyme preparations towards substrates with high recalcitrance characteristics to reach high degrees of degradation. Enzyme blends were identified, outperforming the individual commercial preparations. These enzyme preparations provide a basis for new, designed enzyme mixtures for corn polysaccharide degradation as a source of necessary, accessory enzyme activities.

Interaction of water unextractable solids and xylanase with gluten protein: effect of wheat cultivar

A previously proposed explanation for the change in gluten properties on addition of pentosans to doughs was based on data for only one wheat cultivar. Using three wheat cultivars, Scipion, Soissons and Amazon, differing in technological quality from weak to strong we have obtained results that support the previous explanation. In addition to standard techniques for characterizing gluten and glutenin macropolymer (GMP) yield, composition and properties, a new technique (particle size analysis) was applied that provides further detail on GMP particle size distribution. For each of the three wheat cultivars the effect of WUS and xylanase on gluten and GMP yield, composition and properties followed the trend previously observed. However, WUS and xylanase affected gluten yield and properties more strongly for Scipion and Soissons than for Amazon. Amazon flour contains more protein and less pentosans. The analysis of GMP particles demonstrates that the volume surface average particle diameter D 3,2 of GMP particles from Amazon wheat is larger than those from Scipion and Soissons. Amazon has the ability to form larger and stickier particles. These factors may explain why the effects of pentosans and xylanase on gluten yield and properties are smaller for this wheat.

How gluten properties are affected by pentosans

During the wet separation of starch and gluten, both water extractable pentosans (WEP) and water unextractable solids (WUS) have a negative effect on gluten yield. Gluten properties are also affected: the gluten becomes less extensible. In comparison to the control, addition of WUS or WEP resulted in less gluten with a higher maximum resistance to extension ( R max ) and a smaller extensibility at maximum resistance ( E at R max ). The corresponding glutenin macropolymer (GMP) gel was more elastic, and the specific volume of the GMP particles was larger and their tendency to aggregate was lower. In contrast, the use of xylanase or ferulic acid (FA) resulted in a higher gluten yield and a larger E at R max of gluten. Here, the GMP was characterised by a more viscous gel structure, a smaller specific volume of the GMP particles and a larger tendency of GMP particles to aggregate. Correlations between gluten properties ( R max , E at R max ) and GMP particle properties ([ η ], K ′) were observed. Based on these observations, we propose a possible explanation for the effect of pentosans on gluten formation and properties. Both a physical effect and a chemical effect are involved. The physical effect is related to viscosity and likely also to depletion attraction between protein particles. The chemical effect is related to a FA-mediated effect and ‘controls’ the tendency of the particles to aggregate ( K ′). The contribution of physical and chemical effects leads to a partial agglomeration of GMP particles and shifts the GMP particle size distribution to a higher value. Since GMP particle properties could be directly related to gluten rheological properties, this explains the change in quality observed.

How gluten properties are affected by pentosans

During the wet separation of starch and gluten, both water extractable pentosans (WEP) and water unextractable solids (WUS) have a negative effect on gluten yield. Gluten properties are also affected: the gluten becomes less extensible. In comparison to the control, addition of WUS or WEP resulted in less gluten with a higher maximum resistance to extension (Rmax) and a smaller extensibility at maximum resistance (E at Rmax). The corresponding glutenin macropolymer (GMP) gel was more elastic, and the specific volume of the GMP particles was larger and their tendency to aggregate was lower. In contrast, the use of xylanase or ferulic acid (FA) resulted in a higher gluten yield and a larger E at Rmax of gluten. Here, the GMP was characterised by a more viscous gel structure, a smaller specific volume of the GMP particles and a larger tendency of GMP particles to aggregate. Correlations between gluten properties (Rmax, E at Rmax) and GMP particle properties ([η], K′) were observed. Based on these observations, we propose a possible explanation for the effect of pentosans on gluten formation and properties. Both a physical effect and a chemical effect are involved. The physical effect is related to viscosity and likely also to depletion attraction between protein particles. The chemical effect is related to a FA-mediated effect and 'controls' the tendency of the particles to aggregate (K′). The contribution of physical and chemical effects leads to a partial agglomeration of GMP particles and shifts the GMP particle size distribution to a higher value. Since GMP particle properties could be directly related to gluten rheological properties, this explains the change in quality observed. © 2004 Elsevier Ltd. All rights reserved.

Interaction of water unextractable solids with gluten protein: effect on dough properties and gluten quality

In a previous study, we have shown that water unextractable solids (WUS) interfere with gluten formation and affect the quality of the resulting gluten. In this study we aim to explain how WUS can affect the process of gluten formation. To this end, WUS were modified with NaOH, xylanase, horseradish peroxidase (HRP) and hydrogen peroxide (H2O2). Effects of modified WUS on gluten yield, dough properties, and gluten and glutenin macropolymer (GMP) composition and properties were studied. The results showed that addition of WUS to wheat flour led to a lower gluten yield and gluten starch yield, a higher Rmax and a lower E at Rmax of gluten and a more concentrated and elastic GMP gel. Pretreatment of WUS by NaOH, xylanase, HRP and H2O2 cannot correct its negative effect on gluten yield, but addition of xylanase or free ferulic acid (FA) during gluten separation can remove or prevent the negative effect of WUS on gluten yield. Compared to addition of only WUS, addition of WUS and FA together to wheat flour resulted in a higher gluten yield, a higher E at Rmax of gluten, and a less concentrated and elastic GMP gel. Similar to water extractable pentosans (WEP), FA bound WUS plays a key role in the effect of WUS on gluten yield and properties. It appears that there is a common mechanism regarding the effect of WUS and WEP that the oxidative cross-linking during gluten formation could be prevented by FA addition. The difference between both is that WUS have a higher water binding capacity, which is reflected in a higher Rmax of dough and gluten in the presence of WUS.

Effect of Water Unextractable Solids on Gluten Formation and Properties: Mechanistic Considerations

A miniaturised set-up for gluten-starch separation was used to systematically study the effect of water unextractable solids (WUS) on the formation and properties of gluten. The results showed that WUS not only have a negative effect on gluten yield, but also affect gluten and glutenin macropolymer (GMP) composition and rheological properties. The negative effect of WUS on gluten yield could be compensated for to a large extent, but not completely, by increasing mixing time and mixing water. Adding xylanase can effectively counteract the effect of WUS. On the basis of these results we hypothesize that WUS interfere with gluten formation in both a direct and an indirect way. WUS interfere indirectly by competing for water and thus changing conditions for gluten development. This effect can be corrected for by the combination of adding more 0.2% NaCl solution during dough mixing and a longer mixing time. The particulate nature of WUS requires that the direct effect occurs through an interaction between WUS particles and gluten particles. Both effects of WUS can be counteracted through the use of xylanase. © 2003 Published by Elsevier Science Ltd.

EFFECT OF CONCENTRATION ON THE RHEOLOGY AND SERUM SEPARATION OF TOMATO SUSPENSIONS

ABSTRACTThe °Brix value of the tomato concentrate, from which tomato suspensions were prepared, was shown to have a large effect on the resulting apparent viscosity and storage modulus. The apparent viscosity of a tomato suspension prepared from a 30 °Brix tomato concentrate was only 35% of that of a suspension prepared from a 4.9 °Brix juice, both standardized on the same water unextractable solids (WUS) (0.65%) and total tomato solids (TS) level. After homogenizing the difference in apparent viscosity was only about 10–15%. A similar trend was found for the dynamic moduli. The decrease in rheological parameters of the nonhomogenized suspensions is probably partly related to the decrease in diameter of the tomato particles due to the concentration process. Moreover, microscopic fracture of the cellulosic, microfibrillar network of the cell wall plays a part. Serum separation of diluted nonhomogenized tomato suspensions was higher if made from a concentrate that was concentrated to a higher °Brix value. This phenomenon is discussed in terms of variations in uniaxial compression of the network in the diluted tomato suspensions caused by gravitational force.

The CDTA-soluble pectic substances from soybean meal are composed of rhamnogalacturonan and xylogalacturonan but not homogalacturonan.

Structural characteristics of pectic substances extracted from soybean meal cell walls (water unextractable solids) with a chelating agent-containing buffer (0.05M 1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid (CDTA) and 0.05M NH(4)-oxalate in 0.05M NaOAc buffer) were studied. The arabinogalactans present as side chains to the rhamnogalacturonan backbone were largely removed by enzymatic hydrolysis using endo-galactanase, exo-galactanase, endo-arabinanase, and arabinofuranosidase B. The remaining pectic backbone appeared to be resistant to enzymatic degradation by pectolytic enzymes. After partial acid hydrolysis of the isolated pectic backbone, one oligomeric and two polymeric populations were obtained by size-exclusion chromatography. Monosaccharide and linkage analyses, enzymatic degradation, and NMR spectroscopy of these populations showed that the pectic substances in the original extract contain both rhamnogalacturonan and xylogalacturonan regions, while homogalacturonan is absent.

Glucuronoarabinoxylans from maize kernel cell walls are more complex than those from sorghum kernel cell walls

Water-unextractable solids (WUS) were isolated from maize kernels. They contained 7% of protein, 8% of starch and 57% of non-starch polysaccharides (NSP). These NSP were composed mainly of glucose, xylose, arabinose, and glucuronic acid. Sequential extractions with a saturated Ba(OH) 2-solution (BE1 extract), and distilled water (BE2 extract) were used to solubilise glucuronoarabinoxylans from maize WUS. Cellulose remained in the insoluble residue. The glycosidic linkage composition of the extracts and their resistance to endo-xylanase treatment indicated that the extracted glucuronoarabinoxylans were highly substituted. In the maize BE1 extract 25% of the xylose was unsubstituted, 38% was monosubstituted and 15% was disubstituted. A new measure for the degree of substitution is defined. The resulting degree of substitution for maize BE1 arabinoxylan (87%) is higher than for sorghum BE1 arabinoxylan (70%). The glucuronoarabinoxylans in maize BE1 can be degraded by a sub-fraction of Ultraflo, a commercial enzyme preparation from Humicola insolens. The digest contains a number of series of oligomers: pentose n , pentose n GlcA, pentose n hexose, and pentose n GlcA 2.

Enzymatic degradation of cell wall polysaccharides from soybean meal

Soybean meal, soybean water unextractable solids (WUS) and extracts thereof, which contain particular cell wall polysaccharides, were incubated with a number of cell wall degrading enzymes. The intact cell wall polysaccharides in the meal and WUS were hardly degradable, while the extracts from WUS were well degraded. The arabinogalactan side chains in the pectin-rich ChSS fraction (Chelating agent Soluble Solids) could to a large extent be removed from the pectins by the combined action of endo-galactanase, exo-galactanase, endo-arabinanase and arabinofuranosidase B. The remaining polymer was isolated and represented 30% of the polysaccharides in the ChSS fraction. Determination of the sugar composition showed these polymers to be very highly substituted pectic structures. It still contained 5 mol% of arabinose and 12 mol% of galactose, representing 7% and 12%, respectively, of the arabinose and galactose present in the ChSS fraction before degradation. Further, the presence of uronic acid (50 mol%) and of xylose (18 mol%) indicated the presence of a xylogalacturonan.

Cell wall polysaccharides from soybean ( Glycine max.) meal. Isolation and characterisation

Cell wall material was isolated as water unextractable solids (WUS) from soybean meal. The isolation of WUS yields a fraction that contains 92% of the polysaccharides present in soybean meal and only a few other components. Arabinose, galactose, uronic acids and glucose (cellulose) were the major constituent sugars. WUS was sequentially extracted with chelating agent (chelating agent soluble solids, ChSS), dilute alkali (dilute alkali soluble solids, DASS), 1 m alkali (1 m alkali soluble solids, 1 m ASS) and 4 m alkali (4 m alkali soluble solids, 4 m ASS) to leave a cellulose-rich residue (RES). ChSS was the major extract, yielding 38% of the polysaccharides present in the WUS. All extracts and the residue were characterised by their sugar composition and their molecular-weight distribution. The extracts ChSS and DASS were fractionated by anion exchange chromatography. They showed identical elution patterns: an unbound fraction, five bound fractions of which one fraction eluted only with alkali. Anion exchange chromatography was also performed after saponification of both pectin-rich extracts, again resulting in identical elution patterns.

In Vitro Accessibility of Untreated, Toasted, and Extruded Soybean Meals for Proteases and Carbohydrases

The in vitro accessibility of the water unextractable solids (WUS) from untreated, toasted, and extruded soybean meals toward different enzyme activities was studied. WUS was incubated with seven c...

Consistency, Polysaccharidase Activities and Non-Starch Polysaccharides Content of Soya Beans During Tempe Fermentation

The relation between consistency of soya beans, polysaccharidase activities and the non-starch polysaccharides (NSP) content of soya beans was investigated during tempe fermentation. The fermentations were carried out in a rotating drum reactor (RDR) as well as in the traditional stationary tempe process. The firmness of the soya beans decreased rapidly during the first day of incubation. At increased incubation temperatures the hardness of the beans decreased more rapidly. In the RDR glycosidase activities became significantly higher beyond 48 h of incubation compared with the traditional process. This might have resulted from (a) the better control of temperature and gas composition in the RDR, and/or (b) the agitation in the RDR. The content of arabinose, galactose and uronic acids in the water-unextractable solids of NSP decreased more rapidly than that of glucose, mannose, xylose and fucose. These results indicate that during enzymatic maceration of soya beans in tempe fermentation, the arabinogalactan and pectin fractions are preferentially solubilised. © 1997 SCI.