Dietary fibre fractions in hulled and naked winter oat grain: effects of cultivar and various agronomic factors

The dietary fibre fractions in two winter cultivars each of hulled oats and naked oats grown on three sites under different agronomic conditions in two years were studied. Overall, soluble non‐starch polysaccharides (NSP) represented some 540 g kg⁻¹ of total NSP, and this did not vary greatly among cultivars. There was a significant (P < 0.001) positive relationship between total and soluble NSP. Within cultivars there was much greater variability in the concentrations of β‐glucans than in soluble NSP, and overall there was no relationship between the concentrations of the two related fractions. Oat cultivar and factors such as year and site where grown significantly (P < 0.01) affected soluble NSP contents. There were some indications that environmental factors such as temperature, rainfall and sunshine hours may have been responsible for the apparent effects of site and year. On a dehulled basis, traditional hulled cultivars contained significantly (P < 0.05) more β‐glucans than the naked types, and the results suggest that selection of oats for dietary or plant‐breeding purposes should be based on β‐glucan rather than soluble NSP concentrations. © 2000 Society of Chemical Industry     

Isolation,structural features and rheological properties of water‐extractable β‐glucans from different Greek barley cultivars

β‐Glucans were isolated from six Greek barley cultivars (Persefoni, Kos, Thessaloniki, Athinaida, Dimitra and Triptolemos) by water extraction at 47 °C, enzymatic removal of starch and protein and subsequent precipitation of the water‐soluble β‐glucans with 37% (w/v) ammonium sulfate saturation. The purity of barley β‐glucans was high (>93% dry basis) with some small contamination by protein (<3.84%). The molecular size of the β‐glucan isolates was determined by high‐performance size‐exclusion chromatography (HPSEC); the weight‐average molecular weights and the intrinsic viscosities ranged between 0.45 × 10⁶ and 1.32 × 10⁶ and 2.77 and 4.11 dl g^?1, respectively. Structural features of barley β‐glucans were revealed by ¹³C NMR spectroscopy and high‐performance anion‐exchange chromatography (HPAEC) of the oligomers released by the hydrolytic action of lichenase. Lichenase degradation showed that β‐glucans from all barley cultivars consisted of blocks of cellotriosyl and cellotetraosyl units, accounting for 90.6–92.3% of the total oligomers released, with a molar proportion of these units between 2.31 and 2.77. Rheological measurements of aqueous solutions/dispersions of β‐glucans showed the behaviour of non‐interacting polysaccharides and a transition from the typical viscoelastic response to gel‐like properties after a time period that depended on the molecular size of the polysaccharide. The lowest molecular size β‐glucans from the Triptolemos cultivar showed shorter gelation times than their higher molecular weight counterparts. The effect of sugar incorporation (glucose, fructose, sucrose, xylose and ribose), at a concentration of 30% (w/v), to the β‐glucans gels (6% w/v) on compression parameters seemed to be related to the type of sugar used; the pentose sugars substantially reduced gel firming. Copyright © 2004 Society of Chemical Industry     

Turbidity and Haze Formation in Beer — Insights and Overview

Beer is a complex mixture of over 450 constituents. In addition, it contains macromolecules such as proteins, nucleic acids, polysaccharides and lipids. Proteins influence the entire brewing process with regard to enzymes, which degrade starch, β‐glucans and proteins; with protein‐protein linkages that stabilize foam and are responsible for mouthfeel and flavour stability; and in combination with polyphenols, thought to form haze. With this complexity, problems in processability are as various as the constituents. Several substances in beer are responsible for haze formation. Organic components such as proteins, polyphenols and carbohydrates (α‐glucans, β‐glucans) are known to form haze. In addition, inorganic particles such as filter aids and label remains can cause increased turbidity. In this article only non‐microbiological induced hazes are described. Many studies have been conducted on the identification of haze and foam active components in beer. Hence the aim of this work was to survey the different possibilities of haze formation and for haze identification. A summary is provided on methods for haze identification including dyeing methods, microscopic analyses and size exclusion chromatography.     

Anti‐inflammatory properties of high pressure‐assisted extracts of Grifola frondosa in lipopolysaccharide‐activated RAW 264.7 macrophages

The aim of this study was to determine the in vitro anti‐inflammatory properties of the shake extract (SE) and the high pressure‐assisted extract (PE) of the mycelia of Grifola frondosa in a lipopolysaccharide‐stimulated RAW 264.7 macrophage model. The content of total polysaccharides and β‐glucans of PE at 600 MPa (PE‐600) was 41.2 and 6.2 mg g^?1 dry weight, respectively, which were significantly higher than SE extracts. The results showed that treatment with 500 μg mL^?1 of PE by 600 MPa (PE‐600) did not reduce RAW 264.7 cell viability but did significantly inhibit the production of LPS‐induced NO, PGE₂ and intracellular ROS. The PE‐600 inhibited the activation of NF‐kB and then reduced the production of LPS‐induced TNF‐α, IL‐6 and IL‐1β in a dose‐dependent manner. Thus, the PE could be used as an alternative extraction method for improving the extraction efficacy of G. frondosa and serve as an alternative source of anti‐inflammatory agents.     

Myricetin attenuates lipopolysaccharide‐stimulated activation of mouse bone marrow‐derived dendritic cells through suppression of IKK/NF‐κB and MAPK signalling pathways

BACKGROUND: Myricetin is a naturally occurring flavonoid that is found in many fruits, vegetables, teas and medicinal herbs. It has been demonstrated to have anti‐inflammatory properties, but, to date, no studies have described the immunomodulatory effects of myricetin on the functions of dendritic cells (DCs). The aim of this study was to evaluate the potential for myricetin to modulate lipopolysaccharide (LPS)‐stimulated activation of mouse bone marrow‐derived DCs. RESULTS: Our experimental data showed that treatment with myricetin up to 10 µg mL⁻¹ does not cause cytotoxicity in cells. Myricetin significantly decreased the secretion of tumour necrosis factor‐α, interleukin‐6 and interleukin‐12p70 by LPS‐stimulated DCs. The expression of LPS‐induced major histocompatibility class II, CD40 and CD86 on DCs was also inhibited by myricetin, and the endocytic and migratory capacity of LPS‐stimulated DCs was blocked by myricentin. In addition, LPS‐stimulated DC‐elicited allogeneic T‐cell proliferation was reduced by myricetin. Moreover, our results confirmed that myricetin attenuates the responses of LPS‐stimulated activation of DCs via suppression of IκB kinase/nuclear factor‐κB and mitogen‐activated protein kinase‐dependent pathways. CONCLUSION: Myricetin has novel immunopharmacological activity, and modulation of DCs by myricetin may be an attractive strategy for the treatment of inflammatory and autoimmune disorders, and for transplantation. Copyright © 2012 Society of Chemical Industry     

β‐1,3/1,6‐Glucans and Immunity: State of the Art and Future Directions

The innate immune system responds in a rapid and non‐specific manner against immunologic threats; inflammation is part of this response. This is followed by a slower but targeted and specific response termed the adaptive or acquired immune response. There is emerging evidence that dietary components, including yeast‐derived β‐glucans, can aid host defense against pathogens by modulating inflammatory and antimicrobial activity of neutrophils and macrophages. Innate immune training refers to a newly recognized phenomenon wherein compounds may “train” innate immune cells, such that monocyte and macrophage precursor biology is altered to mount a more effective immunological response. Although various human studies have been carried out, much uncertainty still exists and further studies are required to fully elucidate the relationship between β‐glucan supplementation and human immune function. This review offers an up‐to‐date report on yeast‐derived β‐glucans as immunomodulators, including a brief overview of the current paradigm regarding the interaction of β‐glucans with the immune system. The recent pre‐clinical work that has partly decrypted mode of action and the newest evidence from human trials are also reviewed. According to pre‐clinical studies, β‐1,3/1,6‐glucan derived from baker's yeast may offer increased immuno‐surveillance, although the human evidence is weaker than that gained from pre‐clinical studies.     

Milling of barley to obtain β‐glucan enriched products

The methods for laboratory and commercial milling of dehulled barley grain are described. In the laboratory‐scale barley at 10%, 12% and 14% moisture, was milled to produce three fine‐products (flours) and two coarse‐products (grits). The yield of flours and grits was about 40% and 60%, respectively. Increased products yield and the β‐glucan content in products with increasing moisture of ground grain were observed. Barley at 14% moisture was milled under commercial conditions to produce the following end‐products: fine‐ and coarse‐grained flours, middlings and fine grits. These products differed in their average contents of β‐glucans, total dietary fiber, ash and protein. The fine‐grained grit from impact milling coarse grit had the highest contents of β‐glucans, total dietary fiber, ash and protein. This product, with a weight yield of 18.6%, contained 6.72% β‐glucans, 25.12% total dietary fiber, 2.19% ash, and 15.83% protein. All these values were at about 50%, 72%, 55% and 24%, respectively higher than in dehulled barley. Lowest contents of chemical components in fine‐grained flours were found. Developed method of commercial milling of barley will allow to obtain new, nutritionally valuable barley products, which have potential for use in human foods.     

Effects of β‐glucans on properties of soya bean protein isolate thermal gels

The effects of concentration and molecular weight of oat β‐glucans on properties of soya bean protein isolate (SPI) thermal gels prepared by heating at 90℃for 30 min were investigated. Compared with control (free of β‐glucan) formulations, the presence of β‐glucans (0.5–1.5%, w/v) largely enhanced storage modulus (G′) and texture properties of SPI (12%, w/v) thermal gels measured by dynamic oscillatory rheometry and texture profile analysis, which were developed as increasing β‐glucan concentration and molecular weight. It is possible that β‐glucans could cause the formation of protein aggregates to produce gels through hydrophobic interactions. Mixed gel systems at low ionic strength showed higher G′ resulting from the lower denaturation temperature of SPI, which was beneficial to the formation of gel structure. In addition, although adding a certain amount of β‐glucan into SPI reduced water‐holding capacity of mixed gels, high molecular weight of β‐glucan improved their water‐holding capacity compared to control formulations attributed to the improvement of the structural integrity of the mixed gel network.     

PUFFING AND JET COOKING AFFECT SOLUBILITY AND MOLECULAR WEIGHT OF BARLEY β‐GLUCANS

Foods containing barley or oats are often marketed as healthy because of the dietary fiber (1→3) (1→4)‐β‐D‐glucan. Processing conditions can affect the molecular structure of these dietary fibers, which in turn affect quality and properties of the products. In this study, the effect of puffing and jet cooking conditions on changes in the solubility and molecular weight of barley β‐glucans was investigated. Barley flour was processed in a pasta extruder to produce particles similar in size and shape to rice. These particles were puffed at 230, 250 and 270C for 6, 8 and 10 s in a rice cake machine. Solubility and molecular weight of barley β‐glucans were determined by using water extracts (25 or 65C). The amount of β‐glucan extracted in water at 25C increased from 41.1% in cakes puffed at 230C/6 s to 69.7% in cakes puffed at 270C/10 s. The amount of β‐glucan extracted in water at 65C increased from 63.6% in samples puffed at 230C/6 s to 99.1% in samples puffed at 270C/10 s. The molecular weight of β‐glucans in barley was reduced by puffing and jet cooking treatments.     

Evaluation of baking procedures for incorporation of barley roller milling fractions containing high levels of dietary fibre into bread

BACKGROUND: Roller milling of hull‐less barley generates fibre‐rich fractions (FRF) enriched in non‐starch polysaccharides from the endosperm cell walls (β‐glucans and arabinoxylans). This investigation was initiated to compare the suitability of different baking processes and to determine the optimal conditions for incorporation of barley FRF into pan bread. RESULTS: Addition of FRF from waxy and high‐amylose starch hull‐less barley genotypes was evaluated in pan bread prepared from Canada Western Red Spring (CWRS) and Canada Western Extra Strong (CWES) wheat flour. Three bread processes were used: Canadian short process (CSP), remix‐to‐peak, and sponge‐and‐dough. Addition of 20% FRF (equivalent to enrichment with 4.0 g of arabinoxylans and β‐glucans per 100 g of flour) disrupted dough properties and depressed loaf volume. CSP was not suitable for making FRF‐enriched bread because dough could not be properly developed. FRF‐enriched remix‐to‐peak bread was better, especially for the stronger CWES flour. The better bread quality compared to CSP was probably due to redistribution of water from non‐starch polysaccharides to gluten during fermentation prior to remixing and final proof. The sponge‐and‐dough process produced the best FRF‐enriched bread because of the positive effect of sponge fermentation on gluten development and hydration. FRF was added at the dough stage to fully developed dough. CONCLUSION: The method of bread production strongly influences bread quality. Pre‐hydration of FRF improved bread quality. CWRS and CWES flour produced comparable FRF‐enriched sponge‐and‐dough bread. Addition of xylanase to the sponge‐and‐dough formula improved the loaf volume, appearance, crumb structure and firmness of FRF‐enriched bread. Copyright © 2007 Society of Chemical Industry     

Do cereal mixed‐linked β‐glucans possess immune‐modulating activities?

β‐glucans are known for their immune‐modulating properties. However, the heterogeneity of these glucose polymers makes a distinction between the different sources and structures necessary—a fact that has been little allowed for in the literature. We have focused on β‐glucans from cereals as they are already used as functional food ingredients due to their established cholesterol lowering effect. Cereal β‐glucans have shown in vitro activity on cytokine secretion, phagocytic activity and cytotoxicity of isolated immune cells, and activation of the complement system. Animal studies suggest a possible protective effect against an intestinal parasite, against bacterial infection, and a synergistic effect in antibody‐dependent cellular cytotoxicity. Animal studies have shown activity of orally applied cereal β‐glucans indicating uptake or interaction with cells of the gastrointestinal tract. However, uptake is still debated, interaction with intestinal epithelial cells has been suggested but not clarified, and mechanisms of action remain largely unknown. So far, cereal β‐glucans have not shown immune modulation in the few conducted human studies and further studies are needed to clarify their effect.     

(1-3)(1-6)-β-glucan-enriched materials from Lentinus edodes mushroom as a high-fibre and low-calorie flour substitute for baked foods

BACKGROUND: Extensive physiological and biological emphasis has been placed on pharmaceutical and medicinal uses of mushrooms containing β‐glucans, but their incorporation into processed functional foods is quite limited. Thus, low‐grade Lentinus edodes mushrooms were utilised to produce β‐glucan‐enriched materials (BGEMs), which were evaluated as a high‐fibre and low‐calorie substitute for wheat flour. RESULTS: The fractions obtained from Lentinus edodes mushrooms contained 514 g kg^?1 of (1–3)‐β‐glucans with (1–6)‐β‐linked side chains and the chemical structure was confirmed by ¹³C NMR and FTIR spectroscopy. Replacement of a portion of the wheat flour with BGEMs resulted in the solutions with lower values of pasting parameters and also caused significant changes in starch gelatinisation. When BGEMs were incorporated into cake formulations, batter viscosity increased with more shear‐thinning behaviours and elastic properties improved. Overall, the cakes containing more BGEMs showed decreased volume and increased hardness while no significant differences were observed between the control and BGEM cakes containing 1 g of β‐glucan per serving. CONCLUSION: As a wheat flour substitute, the BGEMs that were prepared from low‐grade Lentinus edodes mushrooms, could be successfully used to produce cakes containing 1 g of β‐glucan per serving with quality attributes similar to those of the control. Copyright © 2011 Society of Chemical Industry     

Non-enzymatic Depolymerization of Carrot Pectin: Toward a Better Understanding of Carrot Texture During Thermal Processing

ABSTRACT Pretreated carrot discs were thermally processed (90 °C to 110 °C) in closed containers and the resulting textural characteristics were analyzed. The pretreatment conditions used include conventional high‐temperature blanching (90 °C, 4 min), low‐temperature blanching (LTB = 60 °C, 40 min), LTB combined with 0.5% calcium chloride soaking, LTB combined with 2% sodium chloride soaking, high pressure pretreatment (HP = 400 MPa, 60 °C, 15 min), HP combined with 0.5% calcium chloride soaking, and control (non‐pretreated sample). Alcohol insoluble residues (AIR) from the pretreated carrot discs were characterized in terms of degree of methoxylation (DM). The AIR samples were further subjected to fractionation into water‐soluble pectin (WSP), chelator‐soluble pectin (CSP), and sodium carbonate‐soluble pectin (NSP). Heat depolymerization patterns and β‐elimination kinetics were investigated on the different pectin fractions. Thermal texture degradation was strongly influenced by the pretreatment condition used and the processing temperature during subsequent thermal treatment. Pretreatment conditions that showed a significant reduction in DM exhibited decreased WSP content, reduced β‐elimination, and consequently superior textural characteristics. β‐elimination was markedly pronounced in the highly methoxylated WSP fractions. CSP and NSP fractions were insensitive to β‐elimination. A strong correlation (r> 0.95) between thermal texture loss of carrots and β‐elimination kinetics exists. Overall, the benefits of controlled pectinmethylesterase activity in carrot processing were pointed out.     

Evaluation of barley and triticale as feed ingredients in growing Iberian pigs: amino acid and carbohydrate ileal digestibility

BACKGROUND: Iberian pig production is linked to the use of the Mediterranean woodland, where the use of local feed resources is of paramount importance for the sustainability of the system. The aim of the present work was to explore the potential of triticale cv. Camarma as compared to barley cv. Esgueva in Iberian pig feeding by studying their respective ileal digestibilities of amino acids and carbohydrates in animals cannulated at the end of the ileum. RESULTS: Leu, Met and Tyr had (P < 0.05) greater standardised ileal digestibilities (SID) in pigs fed triticale diet. There was a trend (P = 0.07) towards greater SID of Thr in pigs fed the barley diet. The least digestible indispensable amino acids were Ile (74.6% SID) for barley and Thr (78.9% SID) for triticale. Except for β‐glucans, apparent ileal digestibilities (AIDs) of individual non‐starch polysaccharide (NSP), sugars and starch were greater in pigs fed triticale (P < 0.05). Nevertheless, total amounts of NSP digested were greater in pigs fed the barley diet (P < 0.05). CONCLUSION: Overall, triticale cv. Camarma had greater amino acid and carbohydrate AID than barley cv. Esgueva and may represent a valuable grain for Iberian pig feeding. Copyright © 2008 Society of Chemical Industry     

Relationship Between Grain Hardness and Malting Quality of Barley (Hordeum vulgare L.)

In a three‐year period, protein content, polysaccharides and values of the selected malting parameters were determined in 12 varieties of barley. Hardness was assessed using the particle size index (PSI) and a Do‐Corder apparatus (BRA). Significant differences in the levels of hardness between the varieties were detected. Hardness was affected by variety from 37% (PSI) and 71% (BRA). Significant correlations were determined between the PSI and extract content (0.64^***), Kolbach index (0.66^***), friability (0.57^***), β‐glucans in wort (?0.51^***) and colour of malt (0.57^***). Significant correlations were found between BRA and content of non‐starch polysaccharides in caryopses (0.64^***), extract (?0.62^***), Kolbach index (?0.70^***), friability (?0.70^***), β‐glucans in wort (0.79^***) and wort colour (?0.56^***). Correlation was determined between hardness and malting quality index (PSI 0.51^***, BRA ?0.71^***).     

Cereal β-glucan immune modulating activity depends on the polymer fine structure

ScopeThe relationship between the immune modulatory properties of different mixed linkage β-glucans from plant and microbial origin and their physico-chemical properties is elusive. By the use of murine dendritic cells and multivariate data analysis, this study examines the importance of the physico-chemical characteristics of β-glucans for their capacity to modulate immune responses.Methods and resultsA total of 23 different β-glucan samples characterised with respect to compositional, molecular, structural and rheological properties were investigated for their immune modulatory properties. Most of the β-glucans showed a decrease in the LPS induced IL-12 production and an increase in the LPS induced IL-10 levels in dendritic cells. When the dendritic cells were stimulated with the probiotic Lactobacillus acidophilus NCFM, the β-glucans up-regulate the IL-12 production but showed no effect on the IL-10 levels. The modulation of the cytokine responses was shown to depend on the β-glucan block structure as expressed by the ratio of cellotriosyl to cellotetraosyl units in the molecule as well as the polymer solubility and aggregation in solution.ConclusionThis comparative study reveals that the β-glucan fine structure and in turn the intermolecular organisation in solution are key factors that determine their immune modulatory capacity.     

Effects of β‐Glucans and Environmental Factors on the Viscosities of Wort and Beer

This paper reports on the influence of molecular weight and concentration of barley β‐glucans on the rheological properties of wort and beer. Environmental conditions such as pH, maltose level in wort, ethanol content of beer, shearing and shearing temperature were also examined for their effects on wort and beer viscosities. In the range of 50–1000 mg/L, β‐glucans increased solution viscosity linearly with both molecular weights (MW) of 31, 137, 250, 327, and 443 kDa and concentration. The influence of MW on the intrinsic viscosity of β‐glucans followed the Mark‐Houwink relationship. Shearing wort and beer at approximately 13,000 s^?1for 35 s was found to increase the wort viscosity but reduce beer viscosity. Shearing wort at 20°C influenced β‐glucan viscosity more than shearing at 48°C and 76°C whereas the shearing temperature (0, 5 and 10°C) did not effect the viscosity of beer. At lower pHs, shearing was found to reduce the viscosity caused by β‐glucans in wort but had no effect in beer. Higher concentrations of maltose in wort and ethanol in beer also increased the viscosity of β‐glucan polymers. It was found that β‐glucans had higher intrinsic viscosities in beer than in wort (5°C), and lower critical overlap concentrations (C^*) in beer than in wort.