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Among cereals, barley ( Hordeum vulgare L.) is notable for its high content of bioactives such as β-glucan and phenolic compounds, but it is not used as widely in human nutrition as wheat. To compare the impact of food formulation and processing on barley bioactives, crackers, cookies, and fresh pasta were prepared combining wheat and barley flour. After quantification of β-glucan and PCs in the barley flour and barley-based products, their behavior during in vitro gastrointestinal digestion and colonic fermentation was studied. The β-glucan and PCs were not drastically affected by processing. The amount of bioaccessible compounds after gastrointestinal digestion was lower than the amount retained in the undigested fraction. After in vitro colonic fermentation, β-glucan was mainly metabolized to acetic and propionic acids and PCs to phenylpropionic and phenylacetic acids. Based on the results of the study, the daily ingestion of barley-based foods may contribute to the intake of beneficial bioactive compounds.

Pleurotus ostreatus, P. eryngii, and P. nebrodensis were cultivated on nonconventional substrates containing grape marc (GMC) or olive mill byproducts (OMB); wheat straw (WHS) served as control. GMC-based media demonstrated equal/better mushroom productivity than WHS for P. eryngii and P. nebrodensis, while the cultivation performance of P. eryngii was improved in OMB-based media. Both GMC and OMB substrates led to large increase of fruit-bodies content in phenolic acids, resveratrol, triterpenic compounds, and ergosterol; in particular, P. eryngii mushrooms presented significantly more total phenolics and exhibited much higher antioxidant activity (2- to 8-fold increase). Furthermore, substrates containing GMC or OMB presented up to 27% increase in mushroom β-glucans. Overall, Pleurotus species responded in a different and mostly substrate-specific manner by selectively absorbing organic compounds. Phenolics and squalene content of substrates correlated very well with mushrooms antioxidant activity and ergosterol, respectively; the same was observed for triterpenics' content of substrates and mushrooms.

Some β-glucans have attracted attention due to their functionality as an immunostimulant and have been used in processed foods. However, accurately measuring the β-glucan content of processed foods using existing methods is difficult. We demonstrate a new method, the Sodium hypochlorite Extracting and Enzymatic Digesting (SEED) assay, in which β-glucan is extracted using sodium hypochlorite, dimethyl sulfoxide, and 5 mol/L sodium hydroxide and then digested into β-glucan fragments using Westase which is an enzyme having β-1,6- and β-1,3 glucanase activity. The β-glucan fragments are further digested into glucose using exo-1,3-β-d-glucanase and β-glucosidase. We measured β-glucan comprising β-1,3-, -1,6-, and -1,(3),4- bonds in various polysaccharide reagents and processed foods using our novel method. The SEED assay was able to quantify β-glucan with good reproducibility, and the recovery rate was >90% for food containing β-glucan. Therefore, the SEED assay is capable of accurately measuring the β-glucan content of processed foods.

This study was conducted to evaluate the behavior of a white teff variety called Witkop during malting by using different parameters (germination temperature and duration) and to identify the best malting program. Samples were evaluated for standard quality malt and wort attributes, pasting characteristics, β-glucan and arabinoxylan content, and sugar profile. It was concluded that malting teff at 24 °C for 6 days produced acceptable malt in terms of quality attributes and sugar profile for brewing. The main attributes were 80.4% extract, 80.9% fermentability, 1.53 mPa s viscosity, 7.4 EBC-U color, 129 mg/L FAN, and 72.1 g/L of total fermentable sugars. Statistical analysis showed that pasting characteristics of teff malt were negatively correlated with some malt quality attributes, such as extract and fermentability. Witkop teff appeared to be a promising raw material for malting and brewing. However, the small grain size may lead to difficulties in handling malting process, and a bespoke brewhouse plant should be developed for the production at industrial scale.

Two hulled barley varieties have been sequentially pearled for one to eight cycles, each with 5% removal. The derived fractions were analyzed for their bioactive compound content. The dietary fiber (DF) decreased from the external to the internal layers, whereas β-glucans showed an inverse trend. Deoxynivalenol contamination was concentrated in the outer layers. The total antioxidant activity (TAA) was higher in the 15-25% fractions, which were used to prepare bread. Five mixtures of refined wheat flour, with an increasing replacement of this pearled barley fraction, were compared with a control for the bioactive compound content, as well as for the rheological and physical bread properties. The inclusion of pearled fractions with up to a 10% substitution leads to a clear enhancement of the DF and TAA, with only minor detrimental effects on the physical parameters. Selected byproducts of barley pearling could be proposed as functional ingredients for bakery products rich in DF and TAA.

Milling properties, water uptake, and modification in malting were studied in 14 barley (Hordeum vulgare L.) lots from two consecutive crop years. In all barley lots studied, grains with lower β-glucan and protein content and higher starch content produced finer flours upon milling. Grains with lower β-glucan content also hydrated more rapidly during steeping. A detailed study of two cultivars from two crop years indicated that similar environmental conditions could induce a higher β-glucan content and concentration of aggregated B hordein in the peripheral endosperm and a lower proportion of C hordein entrapped among aggregated hordeins deeper within the endosperm. These characteristics were associated with production of coarser flours during milling as well as with slower water uptake and lower modification. However, the data do not distinguish between the effect of β-glucan content and that of hordein localization. Distribution of β-glucan or total protein within the kernel was not linked to hydration or modification.

The present work aimed to assess the effect of the following treatments on the medicinal potential (β-glucan content) and agronomical performance (yield) of Agaricus subrufescens: five different fungal strains, three cultivation substrates (compost), four casing layers, and four cultivation environments. Two experiments were performed, and the results indicate that the greatest contribution to the variation in β-glucan content was the strain (35.8%), followed by the casing layer (34.5%), the cultivation environment (15.7%), and the type of compost (9.9%). On the other hand the variation in yield was affected most by the cultivation environment (82.1%), followed by the strain (81.3%), casing layer (49.1%), and compost type (15.2%). These findings underscore the importance of developing a production protocol that employs specific cultivation practices for improving mushroom yield as well as β-glucan content.

Barley is primarily grown for feed and malt, but in some regions of the world it is also considered to be a staple food. Some barley types such as high-amylose barley have also gained importance as health-promoting foods. Starch that is not readily digested in the upper mammalian gastrointestinal system, or resistant starch (RS), is considered to be valuable because it prevents some diet-related diseases such as colon cancer. RS was quantified in a diverse collection of 209 spring barley varieties released in Europe during the past 100 years. The RS content varied from <1% to >15% in the collection, with 13 varieties having high RS content (>11%) and 15 varieties below 1%. Combined with genome-wide association scanning (GWAS), SNP markers and candidate genes controlling the RS content in grains were identified. This identified 40 SNP markers with a LOD score above 2, located on chromosomes 2H, 3H, 5H, and 6H, respectively. Among these SNPs, 10 genes with a known role in starch biosynthesis were associated on the basis of synteny conservation to the rice genome. The β-glucan content was quantified in 61 varieties selected to represent extreme as well as medium RS values. The β-glucan amount in the 15 varieties with RS <1% ranged from 1.7 to 3.2%, ranged from 1.76 to 2.54% in the 13 varieties with RS >11%, and ranged from 1.95 to 2.82% for those with 1%< RS < 11%. No statistically significant correlation between RS content and β-glucan content was found. This association analysis of commercial varieties revealed a large variation in RS content and identified a number of SNP markers that can be explored for selection and further dissection of the pathway and control of RS phenotype.

Rye bran and aleurone, wheat bran and aleurone, and oat bran and cell wall concentrate were compared in their in vitro gut fermentation patterns of individual phenolic acids and short-chain fatty acids, preceded by enzymatic in vitro digestion mimicking small intestinal events. The formation of phenolic metabolites was the most pronounced from the wheat aleurone fraction. Phenylpropionic acids, presumably derived from ferulic acid (FA), were the major phenyl metabolites formed from all bran preparations. The processed rye, wheat, and oat bran fractions contained more water-extractable dietary fiber (DF) and had smaller particle sizes and were thus more easily fermentable than the corresponding brans. Rye aleurone and bran had the highest fermentation rate and extent probably due to high fructan and water-extractable arabinoxylan content. Oat samples also had a high content of water-extractable DF, β-glucan, but their fermentation rate was lower. Enzymatic digestion prior to in vitro colon fermentation changed the structure of oat cell walls as visualized by microscopy and increased the particle size, which is suggested to have retarded the fermentability of oat samples. Wheat bran was the most slowly fermentable among the studied samples, presumably due to the high proportion of water-unextractable DF. The in vitro digestion reduced the fructan content of wheat samples, thus also decreasing their fermentability. Among the studied short-chain fatty acids, acetate dominated the profiles. The highest and lowest production of propionate was from the oat and wheat samples, respectively. Interestingly, wheat aleurone generated similar amounts of butyrate as the rye fractions even without rapid gas production.

Recent breeding advances have led to the development of several barley lines and cultivars with significant reductions (50% or greater) in phytate levels. Low-phytate (LP) grain is distinguished by containing not only a reduced level of phytate P but also an increased level of inorganic P, resulting in greater bioavailability of P and mineral cations in animal diets. It is important to determine whether other nutritional characteristics are altered by breeding for the low-phytate trait. This study was designed to investigate if breeding for reduced phytate content in barleys had any effect on the contents of other attributes measured by comparing mean and range values of the levels of protein, oil, ash, total carbohydrate, starch, and β-glucan, fatty acid composition, and levels of tocopherols and tocotrienols between five LP and five normal-phytate barleys grown in three Idaho locations. Results show that only the phytate level in the LP group was substantially lower than that of the normal-phytate group and that all other attributes measured or calculated were substantially equivalent between the two groups of barleys. Therefore, the phytate level had little effect on the levels of protein, oil, ash, total carbohydrate, starch, and β-glucan, fatty acid composition, and levels of tocopherols and tocotrienols in barley seeds.

The in vitro starch digestion rate and estimated glycemic index (GI) of oat flours and oat starches from typical and high β-glucan oat lines were evaluated along with the impact of heating on starch digestion. Flour from oat lines ('Jim', 'Paul', IA95, and N979 containing 4.0, 5.3, 7.4, and 7.7% β-glucan, respectively) was digested by pepsin and porcine pancreatin. To determine the impact of heating on starch digestion, oat slurries were prepared by mixing oat flour and water (1:8 ratio) and heating for 10 min prior to digestion. Viscosity, as measured on a Rapid Visco Analyzer, increased with increases in concentration and molecular weight of β-glucan. The in vitro starch digestion of oat flours and a control, white bread made from wheat flour, increased as the digestion time increased. Starch digestion of oat flour was slower than that of the control (p < 0.05). Heat treatment of oat-flour slurries increased the starch digestion from a range of 31-39% to a range of 52-64% measured after 180 min of in vitro digestion. There were no differences in starch digestibility among oat starches extracted from the different oat lines. The GI, estimated by starch hydrolysis of oat flours, ranged from 61 to 67, which increased to a range of 77-86 after heating. Oat-flour slurries prepared from IA95 and N979 lines with high β-glucan concentrations had lower GI values than did slurries made from Jim and Paul lines. Starch digestion was negatively correlated with β-glucan concentrations in heated oat-flour slurries (R(2) = 0.92). These results illustrate that the oat soluble fiber, β-glucan, slowed the rate of starch digestion. This finding will help to develop new food products with low GI by using oat β-glucan.

The separation of a compound of interest from its structurally similar homologues is an important and challenging problem in producing high-purity natural products, such as the separation of genistein from other soybean isoflavone aglycone (SIA) homologues. The present work provided a novel method for separating genistein from its structurally similar homologues by ionic liquid (IL)-based liquid-liquid extraction using hydrophobic IL-water or hydrophilic IL/water-ethyl acetate biphasic systems. Factors that influence the distribution equilibrium of SIAs, including the structure and concentration of IL, pH value of the aqueous phase, and temperature, were investigated. Adequate distribution coefficients and selectivities over 7.0 were achieved with hydrophilic IL/water-ethyl acetate biphasic system. Through a laboratory-scale simulation of fractional extraction process containing four extraction stages and four scrubbing stages, genistein was separated from the SIA homologues with a purity of 95.3% and a recovery >90%.

Barley byproducts obtained by air classification have been used to produce a different barley functional spaghetti, which were compared to different commercial whole semolina samples. Total, insoluble, and soluble fiber and β-glucan contents of the barley spaghetti were found to be greater than those of commercial samples. Furthermore, it was proved that barley spaghetti reached the FDA requirements, which could allow these pastas to deserve the health claims "good source of dietary fiber" and "may reduce the risk of heart disease". When the barley coarse fraction was used, a flavan-3-ols enrichment and an increase of antioxidant activity were reported, while commercial samples showed the absence of flavan-3-ols and a higher presence of phenolic acids and tannins. Whole semolina commercial spaghetti had a significantly higher content of phenolic acids than semolina spaghetti samples. Besides, it was observed that when vital gluten was added to the spaghetti formulation, phenolic compounds were blocked in the gluten network and were partially released during the cooking process.

Oat products are abundant in β-glucan, which could lower the glycemic index of products or foods. A low glycemic index is beneficial in the control of postprandial glycemia. The study examined the hypoglycemic effects of oat products that had the same percentage of oat β-glucan and were added into the diet fed to streptozotocin-induced diabetic mice for 6 weeks, and potential mechanisms are discussed here. Oat products significantly decreased fasting blood glucose and glycosylated serum protein (p < 0.05), but the hypoglycemic effect was not more than that of metformin (p > 0.05). Oat products increased glycogen, hormone, and nuclear receptor levels (p < 0.05), decreased free fatty acid content and succinate dehydrogenase activity (p < 0.05), and inhibited pancreatic apoptosis (p < 0.05). The results showed oat products had hypoglycemic effects. Hypoglycemic effects of oat products might be regulating glucose and fat metabolisms, stimulating hormone secretion, activating the nuclear receptor, and protecting organ function.

To assess the effect of food processing on the capacity of oat beta-glucan to attenuate postprandial glycemia, isocaloric crisp bread, granola, porridge, and pasta containing 4 g of beta-glucan as well as control products with low beta-glucan content were prepared. The physicochemical properties (viscosity, peak molecular weight (M(p)), and concentration (C)) of beta-glucan in in-vitro-digestion extracts were evaluated, and fasting and postprandial blood glucose concentrations were measured in human subjects. Porridge and granola had the highest efficacy in attenuating the peak blood glucose response (PBGR) because of their high M(p) and viscosity. beta-Glucan depolymerization in bread and pasta reduced beta-glucan bioactivity. Pastas, known to have low glycemic responses, showed the lowest PBGR. The analyses of these products with previously reported data indicated that 73% of the bioactivity in reducing PBGR can be explained by M(p) x C. Characterizing the physicochemical properties of beta-glucan in bioactive foods aids functional food development.

This study investigates the release of selected strawberry flavor compounds from aqueous solutions of two barley and oat beta-glucan products at concentrations of 5, 10, and 15% (w/w). The flavor release of 12 esters and 3 alcohols was measured by dynamic headspace GC-MS. For each compound the ratio of the flavor release from the beta-glucan solution to the release from aqueous solution, A(rel), was recorded. In general, esters were retained in the beta-glucan matrices in a mass-dependent manner where heavier molecules were retained more. A(rel) for alcohols was found to be significantly larger than for the esters. Whereas A(rel) values for esters were always below unity, this parameter was above unity for alcohols in some preparations of beta-glucan. This implies that relative to esters, alcohols were rejected from some matrices. An increase in the concentration of the beta-glucan products was associated with an increased retention of alcohols and esters. For solutions of oat and barley beta-glucan products at the same concentration, the oat product retained the flavor compounds more strongly. This difference was more pronounced at low concentrations of the beta-glucan products. To investigate the potential of a multivariate approach for the analysis of the flavor release from beta-glucan products, partial least-squares regression was employed on a large selection of calculated molecular descriptors, yielding simple QSPR models capable of explaining the variation in A(rel). The robustness of the QSPR models was verified by cross-validation and permutation tests. The results indicate that the multivariate modeling approach might provide a useful tool for the investigation of flavor release systems similar to those studied here.

Sparassis crispa and Phellinus linteus are edible/medicinal mushrooms that have remarkably high contents of beta-(1-->3)-D-glucan, which acts as a biological response modifier, but difficulty in cultivating the fruiting bodies and extraction of beta-D-glucan have restricted detailed studies. Therefore, a novel process for nanoparticle extraction of Sparan, the beta-D-glucan from Sparassis crispa, and Phellin, the beta-D-glucan from Phellinus linteus, has been investigated using insoluble tungsten carbide as a model for nanoknife technology. This is the first report showing that the nanoknife method results in high yields of Sparan (70.2%) and Phellin (65.2%) with an average particle size of 150 and 390 nm, respectively. The extracted Sparan with beta-(1-->3) linkages showed a remarkably high water solubility of 90% even after 10 min of incubation at room temperature. Therefore, it is likely that this nanoknife method could be used to produce beta-D-glucan for food, cosmetic, and pharmaceutical industries.

Content of dietary fiber and dietary fiber components in whole-grain rye (n = 18) were analyzed. The average total content, when fructan was included, was for dietary fiber 19.9% (range of 18.7-22.2%) and for extractable dietary fiber 7.4% (range of 6.9-7.9%). Arabinoxylan was the main dietary fiber component, with an average total content of 8.6%, followed by fructan (4.1%). During baking of whole-grain rye bread, only small changes in total content of arabinoxylan, arabinogalactan, and beta-glucan occurred, while the content of resistant starch increased and the content of fructan decreased in a baking-method-dependent manner. The molecular-weight distribution of extractable arabinoxylan in the flour was analyzed with a new method and ranged from 4 x 10(4) to 9 x 10(6) g/mol, with a weight average molecular weight of about 2 x 10(6) g/mol. During crisp bread making, only a limited degradation of arabinoxylan molecular weight was detected, while a notable degradation was observed in sour-dough bread. The molecular weight of extractable beta-glucan in the whole-grain rye flour ranged from 10(4) to 5 x 10(6) g/mol, with a weight average molecular weight of 0.97 x 10(6) g/mol. During bread making, the molecular weight of the beta-glucan was substantially degraded.

Within the HEALTHGRAIN diversity screening program, the variation in the content of dietary fiber and components thereof in different types of wheat was studied. The wheat types were winter (131 varieties) and spring (20 varieties) wheats (both Triticum aestivum L., also referred to as common wheats), durum wheat (Triticum durum Desf., 10 varieties), spelt wheat (Triticum spelta L., 5 varieties), einkorn wheat (T. monococcum L., 5 varieties), and emmer wheat (Triticum dicoccum Schubler, 5 varieties). Common wheats contained, on average, the highest level of dietary fiber [11.5-18.3% of dry matter (dm)], whereas einkorn and emmer wheats contained the lowest level (7.2-12.8% of dm). Intermediate levels were measured in durum and spelt wheats (10.7-15.5% of dm). Also, on the basis of the arabinoxylan levels in bran, the different wheat types could be divided this way, with ranges of 12.7-22.1% of dm for common wheats, 6.1-14.4% of dm for einkorn and emmer wheats, and 10.9-13.9% of dm for durum and spelt wheats. On average, bran arabinoxylan made up ca. 29% of the total dietary fiber content of wheat. In contrast to what was the case for bran, the arabinoxylan levels in flour were comparable between the different types of wheat. For wheat, in general, they varied between 1.35 and 2.75% of dm. Einkorn, emmer, and durum wheats contained about half the level of mixed-linkage beta-glucan (0.25-0.45% of dm) present in winter, spring, and spelt wheats (0.50-0.95% of dm). All wheat types had Klason lignin, the levels of which varied from 1.40 to 3.25% of dm. The arabinoxylan contents in bran and the dietary fiber contents in wholemeal were inversely and positively related with bran yield, respectively. Aqueous wholemeal extract viscosity, a measure for the level of soluble dietary fiber, was determined to large extent by the level of water-extractable arabinoxylan. In conclusion, the present study revealed substantial variation in the contents of dietary fiber and constituents thereof between different wheat types and varieties.

Extruded breakfast cereals (EBC), processed from two oat lines, N979-5-2-4 (N979) and "Jim", with beta-glucan concentrations of 8.7 and 4.9%, respectively, were used to determine the impact of dry solids (DS) and bile acid (BA) concentrations on in vitro BA binding efficiency. A full fractional factorial design with levels for BA concentrations of 0.20, 0.47, 0.95, 2.37, and 4.73 micromol/g of total EBC slurry and for DS in the slurries of 0.8, 2, 3, and 4% (w/w) was selected. The absolute amount of BA bound (micromol) was measured for each trial in the experiment design. The percentage (%) of BA bound based on the total amount of BA added and BA bound per gram of DS of the EBC (micromol/g) were also presented and discussed. N979 in vitro digestion slurries had greater BA binding (micromol) than Jim slurries at different DS and BA concentrations, with greater differences at DS of 3% or above and at BA concentrations of 2.37 micromol/g or above. No difference in the absolute amount of BA bound (micromol) and percentage (%) BA bound occurred between the EBC slurries made from the two oat types at the lowest DS of 0.8% or the lowest BA concentration of 0.20 micromol/g. The efficiency of BA binding by beta-glucan in these two EBC became more distinguishable at 3% DS or above and BA concentrations of 2.37 micromol/g or above, indicating that these two conditions can be employed to measure BA capacities for similar foods. Also, the beta-glucan in the EBC produced from the N979 oat line was more soluble than that from the EBC produced from the Jim oat line. Thus, greater BA binding capacity may have been caused by both a greater amount of beta-glucan and a greater solubility of beta-glucan in N979 than in Jim EBC.

The effects of Trametes hirsuta laccase and Pentopan Mono BG xylanase and their combination on oat, wheat, and mixed oat-wheat doughs and the corresponding breads were investigated. Laccase treatment decreased the content of water-extractable arabinoxylan (WEAX) in oat dough due to oxidative cross-linking of feruloylated arabinoxylans. Laccase treatment also increased the proportion of water-soluble polysaccharides (WSNSP) apparently due to the beta-glucanase side activity present in the laccase preparation. As a result of the laccase treatment, the firmness of fresh oat bread was increased. Xylanase treatment doubled the content of WEAX in oat dough and slightly increased the amount of WSNSP. Increased stiffness of the dough and firmness of the fresh bread were detected, probably because of the increased WEAX content, which decreased the amount of water available for beta-glucan. The combination of laccase and xylanase produced slight hydrolysis of beta-glucan by the beta-glucanase side activity of laccase and enhanced the availability of AX for xylanase with concomitant reduction of the amount and molar mass of WSNSP. Subsequently, the volume of oat bread was increased. Laccase treatment tightened wheat dough, probably due to cross-linking of WEAX to higher molecular weight. In oat-wheat dough, laccase slightly increased the proportion of WSNSP between medium to low molecular weight and increased the specific volume of the bread. Xylanase increased the contents of WEAX and WSNSP between medium to low molecular weight in oat-wheat dough, which increased the softness of the dough, as well as the specific volume and softness of the bread. The results thus indicate that a combination of laccase and xylanase was beneficial for the textures of both oat and oat-wheat breads.

In vitro fermentabilities of the oat flour digestion residues (ODR) from two commercial oat lines with 4.7 and 5.3% beta-glucan and from two high-beta-glucan experimental lines with 7.6 and 8.1% beta-glucan were evaluated and compared with fermentations of lactulose, purified oat beta-glucan (POBG), and purified oat starch (POS). Substrates were fermented by using an in vitro batch fermentation system under anaerobic conditions for 24 h. The progress of the fermentation was studied by following the change in pH of the fermentation medium, production of short-chain fatty acids (SCFA) and gases, and consumption of carbohydrates. The substrate from the flour with the greatest amount of beta-glucan tended to have the greatest pH decline and the greatest total SCFA production. A significant correlation occurred between gas production and SCFA formation (R 2 = 0.89-0.99). Acetate was produced in the greatest amounts by all of the substrates except POBG, by which butyrate was produced in the greatest amount. More propionate and butyrate, but less acetate, were produced from high-beta-glucan ODR. With the given fermentation conditions, >80% of the total carbohydrate was depleted by the bacteria after 24 h. Glucose was the most rapidly consumed carbohydrate among other available monosaccharides in the fermentation medium. Overall, the high-beta-glucan experimental lines provided the best conditions for optimal in vitro gut fermentations.

An important determinative of malt quality is the malt beta-glucan content, which in turn depends on the initial barley beta-glucan content as well as the beta-glucan depolymerization by beta-glucanase (EC 3.2.1.73) during malting. Another enzyme, named beta-glucan solubilase, has been suggested to act prior to beta-glucanase; its existence, however, has not been unequivocally proven. We monitored changes in beta-glucan levels and in the development of beta-glucan-degrading enzymes during malting of five lots of contrasting barley genotypes. Two models of in vivo kinetics for beta-glucan degradation were then compared as follows: (i) a biphasic model based on the sequential action of beta-glucan solubilase and beta-glucanase and (ii) a monophasic model assuming that all beta-glucans are depolymerized by beta-glucanase without the previous intervention of another enzyme. Confirmatory regression analysis was used to test the fit of the models to the observed data. Our results show that beta-glucan degradation is mostly monophasic, although some enzyme other than beta-glucanase seems to be required for the early solubilization of a small fraction of insoluble beta-glucans (on average, 7% of total beta-glucans). Furthermore, the genotype-dependent kinetic rate constant (indicating beta-glucan degradability), in addition to beta-glucanase activity, is suggested to play a major role in malting quality.

Whole flours from four oat lines with different amounts of beta-glucan (4.8-8.1%) were examined for their antioxidant activity and total phenolic and lignin concentrations. These data, along with the beta-glucan percentages, were compared with bile acid (BA) binding. Only the lignin concentrations of the flours significantly (P < 0.01) correlated with the BA binding values. The oat flours also were fractionated into bran, protein concentrate, starch, layer above starch, and soluble beta-glucan (SBG)-free flour, and their BA binding capacities were evaluated. The bran fractions were the only fractions that bound greater BA than did the whole oat flours on dry matter basis. Extraction of the soluble beta-glucan to create the SBG-free flour significantly (P < 0.01) decreased the BA binding of the remaining flour. These data suggest that BA binding of the oat flours involves the synergistic interactions of the oat components, with beta-glucan and lignin (insoluble fiber) having a great impact.

Protection of barley grain against contamination by fungi such as Fusarium spp., particularly by those producing mycotoxins, secondary metabolites with adverse health effects, is of principal importance. Fungicides applied immediately after full heading of spring barley is one method of direct protection. In this work, extensive two-year field experiments combined with a detailed chemical laboratory analysis (barley and malt) were performed with the aim to study the effect of previous crops, different fungicides, and other conditions on the selected barley and malt quality parameters (content of beta-glucans, pentosans, oxalic acid, deoxynivalenol, and gushing), while the main task was to follow the effect of the fungicide (used as a treatment to protect against pathogens, mostly Fusarium) on changes of the chemical composition in barley and malt, and gushing. It was found that the relationship between the studied factors and the parameters usually applied to the evaluation of barley and malt quality is quite complex and not straightforward. The responses show typical features of a multifactorial influence with both positive and negative correlations resulting in a decrease or increase in grain quality (concentrations of beta-glucans, pentosans, deoxynivalenol, and other studied parameters). The role of previous crops was also found to be important. The fungicides should be applied at the time of heading but not at the very beginning of this period.

Surfactants were used to disperse oat beta-glucan. Atomic force microscopy (AFM) images of the resulting samples revealed a distribution of extended chainlike molecules and allowed, for the first time, direct visualization of single oat beta-glucan molecules with cross-sectional heights of about 0.44 nm. The number-average contour length (L(n)) and root-mean-square end-to-end distance ((R(ee)2)(1/2)) measured from the AFM images were 938 and 912 nm, respectively. The calculated persistence length (L(p)) was 526 nm. The weight-average molecular weight (M(w)) calculated from single beta-glucan molecules was 4.43 x 10(5). Samples without surfactant showed a strong tendency to form aggregates. The sample concentration, reserving time, and calcofluor as well as freezing could affect the formation of aggregates. These aggregates were visualized by both AFM and confocal scanning laser microscopy. The shape of the aggregates changed from small dots with diameters of approximately 20-50 nm to microfibrils over 3 microm long with the increasing of the concentration of oat beta-glucan from 10 to 100 microg/mL. The particle size distribution obtained by a laser particle size analyzer was 926 nm, which confirmed the size of oat beta-glucan molecules obtained from AFM images.

Two new oat beta-glucan hydrocolloids (designated C-trim20 and C-trim30) obtained through a thermal-shearing process were evaluated for their potential use in food products as functional ingredients. Their rheological characteristics were investigated using steady and dynamic shear measurements. Both samples exhibited typical shear-thinning and viscoelastic properties of random coil polysaccharides. The Cross equation was also used to examine the dependence of their apparent viscosity on shear rates. Furthermore, the effects of flour replacement with C-trim20 on the physical, rheological, and sensory properties of cookies were studied. The cookies containing C-trim20 exhibited reduced spreading characteristics compared with the control due to their increased elastic properties. Also, higher water content and water activity were observed in the C-trim20 cookies. However, flour replacement with C-trim20 up to 10% produced cookies with instrumental texture properties similar to those of the control, which was in good agreement with the sensory results.

Preparation of three novel dietary fibers (DFs) from mushroom sclerotia, namely, Pleurotus tuberregium, Polyporous rhinocerus, and Wolfiporia cocos, by a scale-up modified AOAC procedure using industrial enzymes was investigated. A remarkably high level of total dietary fiber (TDF) ranging from 81.7 to 96.3% sample dry matter (DM), in which a content of nonstarch polysaccharide (NSP) ranging from 86.6 to 94.3% sclerotial TDF DM, was obtained from the three sclerotia. All sclerotial DFs were rich in beta-glucan (the glucose residue ranged from 89.7 to 94.5% NSP DM) with a very low level of resistant glycogen (ranged from 3.77 to 3.94% sclerotial TDF DM). All three novel sclerotial DFs also exhibited similar, if not better, physicochemical and functional properties (pH, color, water binding capacity, oil holding capacity, and emulsifying properties) as those of barely DF control and commercial DF-rich ingredients. The potential use of the three mushroom sclerotial DFs as a new beta-glucan type DF-rich ingredient in the food industry was discussed.

Two experimental high beta-glucan oat (Avena sativa) lines (7.64 and 8.05%) and two traditional lines (4.77 and 5.26% beta-glucan) were used to evaluate the effect of beta-glucan quantity and molecular weight on bile acid (BA) binding. The oat flour samples were digested by an in vitro system that simulated human digestion. No significant differences among oat type were found in the overall beta-glucan, starch, and pentosan digestibilities. Considering the standard, cholestyramine, as 100% bound, the relative BA binding for the oat flour samples on a dry matter basis was in the range of 7.5-14.8%, which is higher than the values determined for some other grains and plant materials in the literature. Although the high beta-glucan flours bound a high amount of BA, no significant correlations were found between beta-glucan content in the flours and BA binding. Significant correlations were found between BA binding and insoluble dietary fiber content. Partial hydrolysis with lichenase of the beta-glucan molecules did not affect the BA binding. A summary of all data suggested that BA binding is a multicomponent-dependent process.

The FT-IR fingerprint of wheat endosperm arabinoxylan (AX) was investigated using a set of polysaccharides exhibiting variation of their degree of substitution and xylo-oligosaccharides comprising xylose units mono- or disubstituted by arabinose residues. Substitution of the xylose backbone by arabinose side units was more particularly studied in the 1000-800 cm(-1) spectral region, by taking advantage of second-derivative enhancement. The 920-1020 cm(-1) spectral region revealed two absorption bands at 984 and 958 cm(-1), the intensities of which varied according to the degree of substitution. Whereas the intensity of the band at 958 cm(-1) increased with the degree of substitution, that at 984 cm(-1) decreased. The second-derivative spectral data of xylo-oligosaccharides indicated that these changes could be attributed to substitution of the xylan backbone by arabinose residues, and the band at 958 cm(-1) was ascribed to the presence of disubstituted xylose residues. Principal component analysis of FT-IR spectra of model mixtures of AX, beta-glucans, and arabinogalactans suggested that it is possible to evaluate the relative proportions of the polymers and degree of substitution of AX in complex mixtures such as the cell wall of cereal grains.

Select mushrooms were analyzed for proximate constituents and carbohydrate profiles either raw or cooked and at different stages of maturity. White button mushrooms (Agaricus biporus) contained high concentrations of ash (12.5 and 11.9% for immature and mature mushrooms, respectively). Starch and total dietary fiber (TDF) concentrations were higher in maitake (Grifola frondosa) and shiitake (Lentinus edodes) mushrooms. Crude protein (CP) and acid-hydrolyzed fat (AHF) were highest in crimini (Agaricus bisporus) and white button and maitake mushrooms, respectively. Chitin concentrations were highest in portabella (Agaricus bisporus) and enoki (Flammulina velutipes) mushrooms (8.0 and 7.7%, respectively). Oligosaccharides were found in low concentrations in some mushrooms. CP and TDF accounted for 86.4 and 49.3% of mushroom organic matter. Cooking increased starch, TDF, and AHF but decreased CP and chitin concentrations. The chitin concentration increased with mushroom maturity. These results detail the complete carbohydrate profile of several important mushroom varieties.

beta-(1-->3),(1-->4)-D-Glucan (beta-glucan) was extracted from 93 Swedish and 41 American oat samples using hot water containing CaCl(2) and thermostable alpha-amylase. The samples showed a large variation in both the content of extractable beta-glucan (0.76-3.68%) and the average molecular weight ((1.25-1.78) x 10(6) g mol(-1)). An analysis of the variance of beta-glucan content and the molecular weight of Swedish oat samples grown in 2000 and 2001 was done with cultivar and harvest year as factors. It showed that the extractable beta-glucan content was a heritable trait whereas molecular weight depended more on environmental factors. The American oat samples had a higher average content of extractable beta-glucan (2.24%) and a somewhat higher average molecular weight (1.58 x 10(6) g mol(-1)) than the Swedish oat samples (1.43% and 1.49 x 10(6) g mol(-1)).