No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Determination of β-Glucan in Barley and Oats by Streamlined Enzymatic Method: Summary of Collaborative Study
Abstract
A collaborative study was conducted involving 8 laboratories (including the authors' laboratories) to validate the streamlined enzymatic method for determination of β-D-glucan in barley and oats. In the method, the flour sample is cooked to hydrate and gelatinize β-glucan, which is subsequently hydrolyzed to soluble fragments with the lichenase enzyme. After volume and pH adjustments and filtration, the solution is treated with β-glucosidase, which hydrolyzes β-gluco-oligosaccharides to D-glucose. D-Glucose is measured with glucose oxidase-peroxidase reagent. Other portions of lichenase hydrolysate are treated directly with glucose oxidase-peroxidase reagent to measure free glucose in test sample. If levels of free glucose are high, the sample is extracted first with 80% ethanol. For all samples analyzed, the repeatability relative standard deviation (RSDr) values ranged from 3.1 to 12.3% and the reproducibility relative standard deviation (RSDR) values ranged from 6.6 to 12.3%. The streamlined enzymatic method for determination of β-D-glucan in barley and oats has been adopted first action by AOAC INTERNATIONAL.
... After that soluble and total β-glucan contents of cereal samples were determined by this improved method. The method of McCleary-Mugford [8], which is recognized as AOAC International Reference Method, was also used to measure the β-glucan contents of the samples. The correlation between the results of AOAC Official Reference Method and the improved method in this study was determined for testing the utility of the new method. ...
... β-glucan assay of samples with the McCleary method. The soluble and total β-glucan contents of the samples were also determined using the McCleary Method, according to AOAC Official Method 995.16 [8]. ...
... Soluble and total β-glucan contents of samples were also measured using the AOAC International Reference Method [8] and the results are given in Table 1. It is clearly seen that the results of these two methods for different samples were totally matched, with high correlation (R 2 =0.992). ...
A rapid method for determination of the soluble and total amount of #-glucan was investigated. #-Glucan was extracted from the samples with the modified extraction method and then incubated with lichenase and #-glucosidase. The optimum incubation parameters were determined by using pure #-glucan solutions as follows: lichenase concentration, 0.04 international units (IU) ml-1; #-glucosidase concentration, 0.125 IU ml-1; reaction time, 20 min; reaction temperature, 50 °C; reaction acidity, pH 6. After enzymatic incubation, free D-glucose produced by the action of enzymes on soluble and total #-glucans was measured with an amperometric glucose electrode. The linearity of the #-glucan assay was determined as 8.0% (w/w) under the considered enzymatic reaction condition. In the last part of the study, soluble and total #-glucan contents of certain samples were determined by both the improved method and the AOAC Official Method. A high correlation (R2: 0.992) between the results of these two methods was observed.
... A determinação de β−glucanas foi conduzida como descrito por Mc CLEARY e MURGFORD [16] que é o método oficial da AOAC, utilizando o kit da Megazyme International Ireland Ltd., Irlanda, que contém as enzimas que hidrolisam β−glucanas, liquenase (EC 3.2.1.73) e β−glucosidase (EC 3.2.1.21): ...
... Uma curva padrão com 10 100µg de glicose acompanhou todas as determinações. As amostras comerciais que continham açúcar, foram previamente tratadas com etanol 80% [16]. Em todas as amostras foi realizada análise da composição centesimal, sendo: umidade, cinzas e lípides como recomendado pelo Instituto Adolfo Lutz [13]. ...
... A determinação de β−glucanas foi conduzida como descrito por Mc CLEARY e MURGFORD [16] ...
... Uma curva padrão com 10 100µg de glicose acompanhou todas as determinações. As amostras comerciais que continham açúcar, foram previamente tratadas com etanol 80% [16]. Em todas as amostras foi realizada análise da composição centesimal, sendo: umidade, cinzas e lípides como recomendado pelo Instituto Adolfo Lutz [13]. ...
Foi utilizado o método enzimático recomendado pela AOAC para determinação de beta-glucanas em cereais e alimentos que os contém. O método, utiliza liquenase (EC 3.2.1.73) e beta-glucosidase (EC 3.2.1.21) para hidrólise debeta-glucanas, é rápido, fácil de executar e específico para beta-glucanas com ligações beta(1->3) e beta(1->4). As sementes analisadas foram subministradas pelo Instituto Agronômico de Campinas (IAC) e os alimentos adquiridos nos supermercados. Aveia e cevada são os grãos com maior conteúdo de beta-glucanas. Na aveia os teores determinados foram 6,48 e 5,94%. Nos 10 cultivares de cevada os teores de beta-glucanas oscilaram entre 2,04 e 9,68%. Trigo e triticale apresentaram teores de b-glucanas menores que 1%. Nos produtos comerciais o teor de beta-glucanas estava relacionado ao tipo de cereal da fórmula. O produto comercial de maior conteúdo de beta-glucanas é o farelo de aveia. As beta-glucanas são ingredientes funcionais em potencial e a conveniência ou não de estimular sua incorporação em alimentos deve ser mais estudada. Quanto à composição centesimal dos grãos de cereais, o teor de proteínas foi o que apresentou a maior variação e isso se reflete na composição dos produtos comerciais.
... In addition, the percentage of β-glucan was determined using the Megazyme mixed-linkage β-glucan assay kit (AOAC method 995.16; Wicklow, Ireland) (McCleary & Mugford, 1997). Furthermore, the concentration of ferulic acid was quantified using a HPLC system (1260 Infinity, Agilent Technologies, Inc., Santa Clara, CA, USA), which was carried out on an XBridge C18 column (4.6 × 250 mm, 5 μm particle size; Waters Co., Auckland, New Zealand) at 30°C and detection wavelength of 320 nm. ...
... Total β-glucan composition of dry powder extracts was determined by the method of McCleary and Mugford (1997)) using the mixed linkage β-glucan assay kit from Megazyme (Wicklow, Ireland) with modifications for samples with high content of β-glucan. ...
β-Glucans are considered candidates for the medication in different human pathologies. In this work, we have purified β-glucan from a selected barley line and tested their effects in primary human dermal fibroblasts. Unexpectedly, we have observed that this compound promoted a short-transitory proliferation arrest at 24 h after its addition on the medium. We have determined that this transitory arrest was dependent on the cell-cycle regulator protein Retinoblastoma. Moreover, dermal fibroblasts increase their migration capacities at 24 h after barley β-glucan addition. Also, we have described that barley β-glucan strongly reduced the ability of fibroblasts to attach and to spread on cell plates. Our data indicates that barley β-glucan signal induces an early response in HDF cells favoring migration versus proliferation. This feature is consistent with our observation that the topical addition of our barley β-glucan in vivo accelerates the wound closure in mouse skin.
... The total β-glucan content was determined according to the AOAC Method 991.43 using the Megazyme mixed linkage β-glucan assay kit (Mccleary and Mugford, 1997). ...
... The determination of total dietary fiber of re-milled semolina, milling by-products, and bread was carried out by means of the enzymatic-gravimetric procedure according to the AOAC method 991.43 (AOAC, 1995). The total β-glucan concentration of re-milled semolina, milling by-products, and breads was determined according to the AOAC method 995.16 (McCleary & Mugford, 1997), using the Megazyme mixed-linkage β-glucan assay kit (Megazyme International Ltd., Bray, Ireland). ...
We evaluated the bread making ability of meals composed of re-milled semolina and either 100 g/kg or 200 g/kg of i) residuals of the second and third debranning steps of durum wheat (DB), ii) the micronized and air-classified thin fraction obtained from the same residuals (MB), or iii) coarse bran obtained from conventional roller milling of non-debranned durum wheat (B). Dietary fibers, proteins, total soluble phenolic compounds, ferulic acid, and antioxidant activity were significantly higher (P < 0.05) in MB and DB than B. The addition of by-products to re-milled semolina lowered the alveograph W and increased the P/L ratio, with stronger effects at higher doses. Particularly negative were the effects of B on P/L and farinograph dough-development time. Bread containing 100 g/kg of MB did not show significant differences (P < 0.05) in specific volume, crumb hardness, resilience, and chewiness with pure re-milled semolina bread but had higher dietary fiber, phenolics and antioxidant activity.
... The total -glucan content of whole meal was determined using the Megazyme mixed-linkage -glucan assay kit (Megazyme International Ltd, Bray, Ireland), in accordance with the protocol of McCleary and Mugford. 28 The analyses were carried out in triplicate. ...
Background:
Several studies had evaluated the effects of composted sewage sludge on barley, and found a positive influence on crop productivity. No studies investigated the effects of composted sewage sludge on functional compounds of the caryopsis, such as phenolics and β-glucans. The former play a role in plant defence mechanism and both could be influenced by variations of kernel size related to fertilization intensity. The aim of this study was to evaluate the effect of different doses (3-12 Mg ha(-1) ) of composted sewage sludge applied alone or in combination with mineral fertilization on morpho-physiological and yield, qualitative parameters, especially phenolics and β-glucans contents of the grains, in barley.
Results:
Increasing fertilization rates, irrespective of fertilizer type, improved morpho-physiological and yield parameters, whereas the phenolic compounds and the related antioxidant activity significantly decreased (P < 0.05). The β-glucans and the main color indices did not show significant differences. The combined application of 6 Mg ha(-1) sewage sludge and nitrogen was not significantly different from mineral fertilization. Morpho-physiological and qualitative parameters, and bioactive compounds, were all significantly correlated with nutrient levels, with higher r values for N.
Conclusion:
Composted sewage sludge had a similar effect compared to mineral fertilization.
... Both enzymatic and fluorimetric methods have been included in Analytica-EBC (59), and a fluorimetric method has been included as an American Society of Brewing Chemists (ASBC) method (6). An enzymatic method has been adopted by Association of Official Analytical Chemists (AOAC) International (116). ...
Beta-glucan polymers originating from barley endosperm cell walls are one of the major concerns in the brewing industry. The amount and molecular weight of beta-glucans in malt affect brewhouse extract yield and wort and beer viscosities, as well as lautering, diatomaceous earth, and membrane filtrations. Barley beta-glucans are also associated with beer hazes. Precipitation and gel formation of beta-glucan polymers can be enhanced by factors such as ethanol concentration, and freezing and thawing, as well as by turbulent shear. Understanding the properties and degradation of beta-glucans and the aggregation mechanisms of these polymers helps brewers adopt preventative and corrective operations to minimize the beta-glucan-related processing difficulties.
... The sterilization was used to preserve the beer concentrate. The concentrated beer was cooled and kept at 50°C followed by adding lichenase (Megazyme) at 0.1 Units/mL (27) to hydrolyze β-glucan for 30 min until the residual β-glucans were undetectable by Congo red dye. The enzyme was then inactivated by autoclaving beer in Erlenmeyer flasks covered with four layers of aluminum foil at 121°C for 15 min. ...
An extended filtration test with 0.45-μm membranes was employed in this study to investigate the influence of β-glucan polymers, shearing, pH, ethanol content, and storage time on beer filterability. Results indicated that the presence of β-glucans caused lower beer filterability. The maximum amount of beer filtered through a membrane filter (Vmax) and the initial filtration rate (Qinit) decreased with the addition of higher β-glucan molecular weight at higher concentrations. Shearing beer at 0-10°C resulted in lower Vmax and Qinit values. Higher pH values were found to improve beer filterability. Compared with nonalcohol beer samples, beers containing 5 and 10% (v/v) of ethanol showed lower Q init and higher Vmax values. However, the addition of ethanol at 5 and 10% (v/v) decreased the relative Vmax (%) value of beer samples containing β-glucans compared with β-glucan-free beers. Filtration tests also suggested that a cold storage at 4°C for two weeks did not affect filterability in β-glucan treated beers.
... The total b-glucan concentration was determined by the AOAC method 995.16 (McCleary & Mugford, 1997), by using the Megazyme mixed-linkage b-glucan assay kit (Megazyme International Ltd., Bray, Ireland). ...
In a future scenario where the world population will have doubled by 2050, legumes will be playing an important role in human nutrition since they are an inexpensive, protein-rich food source. In order to increase legume consumption, innovative solutions are needed to meet the needs of modern consumers. In this context, the aim of this study has been to set up pre-cooked legume-based burgers that couple high nutritional value and good sensory features and to evaluate their chemical, nutritional and textural profile, as well as the consumers acceptance based on the type of cereal used.
The proposed legume-based burgers were characterized by fatty-acid and amino–acid profile fulfilling the dietary guidelines. Mono-unsaturated fatty acids accounted for about 61% of the total fatty acids, so that more than 20% of the total energy values of the burgers were provided by MUFA. Moreover, fiber content was comprised between 5.58% and 7.88% of fresh matter, so as to meet the requirements for ‘high fiber’ and/or for ‘source of fiber’ nutritional claims. Through a careful choice of the ingredient ratios we achieved a good level of consumer's appreciation, with scores higher than 6.5 for all the parameters considered, indicating good possibilities for industrial upscaling.
... After dilution and centrifugation (10 min at 15,000 × g), an aliquot of the supernatant was incubated with β-glucosidase in acetate buffer at pH 4.5 and 40°C for 15 min. The glucose released was assayed with hexokinase/glucose-6-phosphate dehydrogenase 17,18 . ...
This study used a recombinant Saccharomyces cerevisiae strain, which expressed both β-glucanase enzyme and reduced Pro-teinase A expression during wort fermentations. The genetic stability and fermentation features of the strain were examined. The recombinant strain's proteinase A activity was reduced compared to the parent strain; β-glucanase was produced throughout the fermentation. The fermentation with the recombinant S. cerevisiae strain exhibited a larger reduction in β-glucan content than what was observed with the control strain, with β-glucan degradation above 80%. The foam stability period was reduced when the beer produced by the recombinant S. cerevisiae was stored for 3 months. SDS-PAGE analysis of the beer proteins indicated that lipid transfer protein 1 had disappeared. Fermentation studies indicated that based on the parameters examined, this recombinant strain was suitable for industrial beer production.
... Dietary fibre analysis was performed on four replicate samples. Total b-glucan content was determined by the method of McCleary and Mugford (1997) using the Megazyme (Megazyme International, Wicklow, Ireland) mixed linkage b-glucan assay kit and same conditions as Mikkelsen et al. (2010). The content of total starch along with total (TDF), soluble (SDF) and insoluble dietary fibres (IDF) was determined according to the Megazyme procedures provided with the test kits (Approved Methods 76-13 and 32-07, AACC 2000). ...
Health effects of β-glucan are typically related to dose, size and viscosity without taking the specific molecular structure into account. High β-glucan mutant barley, mother barley and oat β-glucans were large-scale extracted by comparable protocols using hot water, enzyme assisted hydrolysis and ethanol precipitation leading to similar molecular masses (200-300kDa). Multivariate data analysis on all compositional, structural and functional features demonstrated that the main variance among the samples was primarily explained by block structural differences as determined by HPSEC-PAD. In particular the barley high β-glucan mutant proved to exhibit a unique block structure with DP3 and DP4 contributions of: 78.9% and 16.7% as compared to the barley mother (72.1% and 21.4%) and oat (66.1% and 29.1%). This unique block structure was further confirmed by the (1)H NMR determination of the β-1,4 to β-1,3 linkage ratio. Low solubility of the barley samples was potentially an effect of substructures consisting of longer repetitive cellotriosyl sequences. FT-Raman and NMR spectroscopy were useful in measuring sample impurities of α-glucans and prediction of β-linkage characteristics.
... The b-glucan contents of the CB and WB samples were determined with the AOAC 995.16 method (McCleary & Codd, 1991;McCleary & Mugford, 1997). In this method, the lichenase and b-glucosidase enzymes were used for hydrolysis of b-glucan and the amount of b-D-glucose was spectrophotometrically measured with glucose oxidase-peroxidase reagent. ...
The acid and enzymatic hydrolyses of oat β-glucan were compared for commercial oat β-glucan and β-glucan isolated from oat grain and oat bran. The resulting mono- and oligosaccharides were analysed by high-performance anion-exchange chromatography, combined with pulsed amperometric detection. The acid hydrolysis was studied with HCl, TFA and H2SO4 at two concentrations, with three durations of hydrolysis and at three temperatures.Under the mildest acid conditions (37 °C and pH 1, corresponding to those in the human stomach) no degradation of β-glucan was observed with HCl over a 12 h period. At 120 °C, total hydrolysis to glucose occurred with high-concentration acids. Total recovery was also achieved with lichenase hydrolysis. Hydrolysis, with lichenase and β-glucosidase together, produced glucose, which was analysed spectrophotometrically according to the AOAC 995.16 method. Since the results with the original method were not satisfactory, the method was further modified to determine the best conditions for samples with high β-glucan content and poor solubility.
... The concentrated beer was cooled and held at 50°C while lichenase at 0.1 U/mL (Megazyme, Bray, IRL) was added to hydrolyze -glucan for 30 min until the residual -glucans were undetectable by Congo red dye. One lichenase activity unit (U) is defined as the amount of enzyme required to release 1 µmol of glucose per min from a barley -glucan substrate at 10 mg/mL 35 . The enzyme was then inactivated by autoclaving in Erlenmeyer flasks covered with 4 layers of aluminum foil at 121°C for 15 min. ...
J. Inst. Brew. 110(2), 104–116, 2004 This paper reports on the influence of molecular weight and con-centration of barley -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, -glucans in-creased 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 -glucans fol-lowed the Mark-Houwink relationship. Shearing wort and beer at approximately 13,000 s –1 for 35 s was found to increase the wort viscosity but reduce beer viscosity. Shearing wort at 20°C influenced -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 -glucans in wort but had no effect in beer. Higher concentrations of maltose in wort and ethanol in beer also increased the viscosity of -glucan poly-mers. It was found that -glucans had higher intrinsic viscosities in beer than in wort (5°C), and lower critical overlap concentra-tions (C*) in beer than in wort.
... Crude-protein concentration of grain was estimated as Kjeldahl N × 6.25. (1-3), (1-4)-b-D-Glucan was determined by a modification of the McCleary enzymatic method (McCleary and Mugford, 1997), in which oil was extracted prior to enzymatic hydrolysis. ...
Oat consumption has been rapidly increased worldwide because its high β-glucan concentration may lower the level of blood cholesterol. The rates of β-glucan accumulation in two husk and two nude oats were determined with an interval of 5 d after anthesis in a pot experiment. The results showed that a higher nitrogen level increased oat grain yield per plant, thousand-grain weight, and concentrations of protein and β-glucan. β-glucan concentration generally increased with development of grain after anthesis, whereas the accumulation rate of β-glucan was greater at the early stage of grain development and reached a maximum around 25 d after anthesis. We also found a larger β-glucan concentration when plants were grown with NO-N as compared to NH-N. This study may suggest that the agronomic approaches such as nutrient management by optimizing the time and the level of nitrogen application and a higher ratio of NO-N to NH-N can play an important role in enhancing β-glucan concentration in oat grains.
... For balanced sample preparation, 5-grams of seed was ground in a ball mill with a 0.5-mm mesh screen. Total β -glucan content of each line was determined by McCleary method which was dependent on a streamlined enzymatic reaction and absolutely specific for mixed-linkage β -glucan (McCleary and Mugford 1997). ...
β-glucan is the soluble dietary fiber component and occurs at its highest in barley. This study aims to evaluate the inheritance
of β-glucan content in barley grains and to map quantitative trait loci (QTL) associated with this trait. F5-derived 107 lines from the cross of the six-rowed waxy hulless barley, ‘Yonezawa Mochi’ and the six rowed non-waxy hulless
barley,’ Neulssalbori’ were measured for their agronomic traits and β-glucan level at four different environments. These recombinant lines showed significant genotypic variation (P < 0.01) and normal distribution for β-glucan content with a range of 43.6–62.1 g kg−1 across environments. A significant genotype-by-environment interaction was also found. The broad-sense heritability estimates
for β-glucan content ranged from 0.42 to 0.82 across environments. Using one-factor analysis and composite interval mapping, a
main effect of QTL associated with β-glucan content was identified in the genomic region near waxy gene (wx) and HVM4 on chromosome 7H. The major QTL at this region explained on average 44.4% of the variation for the mean of β-glucan content across environments with LOD values that ranged from 5.7 in Suwon in 2001 to 13.9 in Suwon in 2003. Two minor
QTLs were identified but their significance of association with β-glucan content was inconsistent across environments.
Key wordsbarley–β-glucan–DNA marker–mapping–QTL
... Standard reference samples were included in all chemical analysis and the methods proved to be accurate. Total βglucan content was determined by the method of McCleary and Mugford (1997) using the Megazyme (Megazyme International Ltd., Bray, Ireland) mixed linkage β-glucan assay kit with a sample amount of 10 mg instead of 80-120 mg and 3 h of lichenase hydrolysis instead of 1 h. The extended hydrolysis time was suggested by Johansson et al. (2006) for concentrated β-glucan samples and the smaller sample amount was based on an internally pre-study. ...
The rheology of crude and purified barley (BBG) and oat (OBG) β-glucan samples were characterized. Sample content and major impurities was characterized by Fourier-transform near infrared Raman and infrared (FT-IR) spectroscopy revealing substantial differences between the β-glucan samples. The purification procedure increased the β-glucan content from 66.7 to 82.4% and from 30.1 to 68.4% for BBG and OBG, respectively. Proton nuclear magnetic resonance (1H NMR) analysis was applied to estimate the β-(1 → 3) to β-(1 → 4) linkage ratio of the β-glucans. The molar mass of BBG and OBG was determined by high performance size-exclusion chromatography (HPSEC) using β-glucan standards and was found to be 126 and 355 kDa, respectively.The viscosity of crude and purified β-glucans was studied at various concentrations (2.5, 5% w/v), temperatures (10–80 °C) and shear rates (1–100 s− 1). BBG was characterized as a low-viscosity β-glucan with Newtonian flow behavior while OBG was characterized as a high-viscosity β-glucan with shear thinning flow behavior. At equivalent β-glucan concentration in solutions the viscosity for OBG was found to be ~ 100 fold higher than for BBG. A direct viscosity dependence on exact β-glucan content regardless of amount and composition of α-glucan impurities was found for both OBG and BBG. This study suggests that the structural characteristics of the β-glucan polymers such as molar mass are of greater functional importance than the presence of lager amounts of starch/α-dextrins as long as the β-glucan samples are compared at equivalent β-glucan doses.
... For the determination of -glucan, sample material was suspended in phosphate buffer (pH 6.5) and mixed for 5 min at 100°C. The diluted suspension was hydrolyzed with lichenase (Megazyme International, Bray, Ireland) for 60 min at 40°C (16). After dilution and centrifugation (10 min at 1500 ϫ g), a part of the supernatant was incubated with -glucosidase (Megazyme) in acetate buffer at pH 4.5 and 40°C for 15 min. ...
The objective of this study was to investigate the effects of barley-rich diets in the intestinal tract of rats. Four test groups (A-D) of 10 young male Wistar rats were fed diets containing 50 g/100 g barley extrudates (A, B and D) or mixtures (C) for 6 wk; the control diet contained no barley. The barley-containing supplements in the test diets were: A = cultivar "HiAmi"; B = "HiAmi" and "Prowashonupana" (50:50); C = "Prowashonupana" and Novelose (50:50); D = "Prowashonupana" and amylose from maize (60:40). These supplements contained 7-12 g/100 g beta-glucan and 7-24 g/100 g resistant starch. Additionally, 5 g microcrystalline cellulose/100 g was present in all diets. Carbohydrate utilization (indirect calorimetry) was lower (P < 0.05) in rats fed the barley-containing diets C or D than in the controls. In the test groups, the following differences from the controls were found: greater food intake in the last 2 wk (P < 0.05); increased weight gain in wk 6 (P < 0.05); greater mass of the ceca (groups B-D; P < 0.05) and colons (P < 0.001) as well as masses of cecal (groups C and D; P < 0.01) and colon contents (P < 0.001); greater concentrations of resistant starch in cecal and most of the colon contents (P < 0.05); and more beta-glucan in the small intestine, cecum and colon (P < 0.05). The numbers of coliforms and Bacteroides were lower than in the controls in groups B-D and those of Lactobacillus were greater in all test groups (P < 0.05). Short-chain fatty acids (SCFA) were higher in the cecal contents of the test groups (> or = 800 micro mol/g DM; P < 0.001) compared with the controls ( approximately 200 micro mol/g DM). Similarly, SCFA were higher in colon and feces of the test groups. The concentrations of excreted bile acids increased up to 30% during the feeding period. The proportions of secondary bile acids were lower and the amounts of neutral sterols (P < 0.001) were greater in feces of rats fed the barley-containing diets for 6 wk than in the controls. Diets containing more soluble macromolecular dietary fibers such as beta-glucans affected the excretion of bile acids and neutral sterols the most, whereas the fermentation of dietary fiber, including resistant starch, influenced the steroids in feces. These results suggest that dietary fiber-rich barley-containing diets have beneficial physiologic effects.
... For the determination of b-glucan, sample material was suspended in phosphate buffer (pH 6·5) and mixed for 5 min at 1008C. The diluted suspension was hydrolysed with lichenase (Megazyme International, Bray, Ireland) for 60 min at 40 8C (McCleary & Mugford, 1997). After dilution and centrifugation (10 min at 1500 g), a part of the supernatant was incubated with b-glucosidase (Megazyme) in acetate buffer at pH 4·5 and 408C for 15 min. ...
Wistar rats (ten per group) were fed either an oat-free control diet or a dietary fibre-rich test diet containing 500 g oat-based products/kg for 6 weeks. The oat-based products, containing 4-128 g/kg resistant starch, 30-92 g/kg beta-glucan and 122-304 g/kg total dietary fibre, were oat flour extrudate, flour/Novelose (commercial resistant starch) extrudate (80:20 w/w), oat bran, bran/Novelose extrudate (80:20 w/w) and autoclaved oat flour. Serum total cholesterol decreased in the groups fed flour, flour/Novelose and bran/Novelose (P<0.05). In most of the test groups, count numbers of bifidobacteria were higher (P<0.001) and of coliforms were lower (P<0.05). The mass of the caecum walls and contents was greater in groups fed Novelose- and bran-containing diets (P<0.005). In all the test groups, pH values were lower in the intestinal contents (P<0.001), and caecal concentrations of acetate (P<0.001), propionate (P<0.05), butyrate (P<0.005) and total SCFA (P<0.001) were higher. The lowest concentrations of steroids were found in rats fed the autoclaved flour. In the other test groups, more bile acids appeared in the caecal (P<0.001) and colonic contents (P<0.005), as well as in the faeces, at week 6 (P<0.001). The highest bile acid excretion was found after feeding bran-containing diets. In the intestinal contents of all the test groups, more primary bile acids (P<0.001) appeared than in the control group. The excretion of steroids increased within the experimental period. Using extrusion technology, dietary fibre-rich oat-based products, which have beneficial physiological effects in rats, can be produced. Oat flour and bran are excellent sources for the preparation of directly edible oat products. Their nutritional properties can be further improved by the addition of resistant starch.
... Coefficients of variation (CV) in duplicate samples from food and ileostomy excreta were 3.6% for cholesterol and 3.4% for bile acids. Analysis of b-glucans in the oat bran cereals was carried out by the manufacturer (Finn Cereal Ltd, Vantaa, Finland), according to the AOAC method 995.16 (McCleary and Mugford, 1997). To correct for the amount of b-glucan hydrolysed to glucose monomer during the processing or enzymatic hydrolysing step, glucose content of the final product was determined according to the same procedure but omitting the lichenase hydrolysis step, and the values obtained subtracted from the results of the analyses where lichenase was used. ...
To study whether oat bran with native beta-glucans increases bile acid excretion and bile acid synthesis as measured by serum concentrations of 7alpha-hydroxy-4-cholesten-3-one (7alpha-HC).
Short-term interventional crossover study evaluating cholesterol absorption, ileal excretion of cholesterol and bile acids, and serum levels of cholesterol and bile acid metabolites. Differences between diets evaluated with Wilcoxon's signed rank-sum test.
Outpatients at a metabolic-ward kitchen.
Nine volunteers with conventional ileostomies.
Two 3-day-diet periods, with controlled, blinded basal diet including 75 g extruded oat bran breakfast cereal daily, with either 11.6 g native or hydrolysed beta-glucans.
Native oat bran increased median excretion of bile acids by 144% (P=0.008). Cholesterol excretion remained unchanged, cholesterol absorption decreased by 19% (P=0.013), whereas the sum of bile acid and cholesterol excretion increased by 40% (P=0.008) compared with hydrolysed oat bran. 7alpha-HC reflecting bile acid synthesis increased by 57% (P=0.008) within 24 h of consumption, whereas serum lathosterol concentration reflecting cholesterol synthesis increased by 12% (P=0.015).
Oat bran with native beta-glucans increases bile acid excretion within 24 h of consumption and this increase can also be detected by rising serum concentrations of 7alpha-HC. Thus, 7alpha-HC could be used for rapid detection of dietary effects on bile acid metabolism. These effects could possibly be explained by entrapment of whole micelles in the gut owing to higher viscosity.
Legumes are a popular grain-free alternative carbohydrate source in canine diets, however, information on their fermentative characteristics have not been established. Thus, the objectives of the present study were to (1) quantify the chemical compositions and (2) fermentative profile of select legumes using canine fecal inoculum. Five legume varieties, whole yellow peas (WYP), green lentils (GL), black bean grits (BBG), navy bean powder (NBP), and garbanzo beans, were analyzed and compared to a positive control, beet pulp (BP). Substrates were analyzed for gross energy (GE), dry and organic matter, crude protein (CP), acid hydrolyzed fat, and total dietary fiber (TDF) fractions, beta-glucans, starch, free and hydrolyzed sugars, as well as fermentative characteristics: pH, short-chain fatty acids (SCFA), branched-chain fatty acids (BCFA), total gas, hydrogen, and methane. Substrates then underwent a two-stage in vitro digestion and subsequent fermentation using canine fecal inoculum for 0, 3, 6, 9, and 12 h. All test substrates contained approximately 8-9% moisture and 4.5 kcal/g GE. The highest CP content was observed in GL (27%). Analyzed TDF content of test substrates was greatest for WYP (32%) and GL (36%). Total starch content was greatest for GL (58%) and WYP (56%). Sucrose and stachyose were the most predominant free sugars and glucose was the most predominant hydrolyzed sugar among test substrates. After 3 and 6 h of fermentation, a net negative change in pH was observed among most substrates with a net negative change in all substrates after 9 and 12h. Values for SCFA did not differ among substrates after 3 or 6 h of fermentation with BP and WYP among the greatest acetate (1,656 and 1,765 umol/g, respectively) and propionate production values (157.7 and 126.1, respectively) after 9 h. All substrates produced greater total gas volumes than WYP after 3 h, with no differences observed after any other time points. However, BP hydrogen production values were greater after 9 and 12 h (P < 0.0001; 726,042 and 394,675 ng/g, respectively) with greater methane production values after 12 h (P < 0.0001; 54,291 ng/g) than all test substrates. These data suggest that legumes offer a diverse macronutrient profile and appear to be a source of slowly fermentable fiber, which may have beneficial implications on the ratios of saccharolytic to proteolytic fermentation towards the distal colon.
抄録
【目的】高脂肪食の摂取は，白色脂肪組織の活性酸素種（ROS）の生成を促進し，酸化ストレスを増大して動脈硬化の発症を促進する可能性があることが示唆されている。本研究では，新規に育種された国産の高β-グルカン含有大麦ならびにβ-グルカン欠失大麦の摂取が，自然発症ApoE欠損マウスの脂肪組織の炎症と動脈硬化に及ぼす影響を比較することにより，大麦中のβ-グルカンの作用を評価した。
【方法】5週齢のC57BL/6 系統のApoE欠損マウスに高コレステロール・高脂肪食を与えた。飼料中のβ-グルカン含量は，高β-グルカン含有大麦群が2.1 ％，β-グルカン欠失大麦群が0.0％となった。各飼料と水は55日間自由摂取させた。心臓の大動脈弁の切片はOil Red Oで，摘出した大動脈はズダンIVで染色した。脂肪組織の炎症に関わるmRNA発現量はリアルタイムPCR法，血清インスリン濃度はELISA法にて分析した。
【結果】活性酸素を生成するNADPHオキシダーゼを構成するサブユニットp67phox，p47phox，p40phox，脂肪組織の炎症に関わるMCP-1，F4/80，TNF-αのmRNA発現量ならびに血清インスリン濃度は，高β-グルカン含有大麦群がβ-グルカン欠失大麦群に比べて，有意に低かった。また，心臓の大動脈弁の脂質沈着面積は，高β-グルカン含有大麦群がβ-グルカン欠失大麦群に比べて，有意に低値を示した。一方，大動脈の脂質沈着面積には各群間に有意差が見られなかった。
【結論】大麦中のβ-グルカンが脂肪組織の抗炎症作用ならびに抗動脈硬化作用に関与している可能性が示唆された。
There is an unmet need for appealing and functional barley β-glucan (BG) food matrices that can provide sufficient and active BG doses to consumers. We investigated how molecular mass and oligomer structure important for BG food and health properties affected plasma lipids and gut parameters in hypercholesterolemic rats. Following 3 weeks on a high-cholestrol diet, rats were given a high-cholesterol diet supplemented with either cellulose (control) or purified barley BGs with low (100 or 150 kDa; glucagel or lowBG, respectively) or medium (530 kDa; mediumBG) molecular masses varying in cellotriosyl/cellotetraosyl oligomer ratio for 4 weeks. All four diets (control, glucagel, lowBG or mediumBG) reduced plasma triacylglycerol and cholesterols from week 3 to 7. The BG diets increased cecal production of short-chain fatty acids (SCFAs) compared to the control diet. The glucagel and lowBG diets stimulated the number of Bifidobacterium in the cecum, whereas the mediumBG diet reduced numbers of both Bacteroides/Prevotella and Lactobacillus in the cecum compared to the control diet. In conclusion, barley BGs at 6.5-7.5% of the diet independent of molecular mass and oligomer block structure showed no additional effect compared to the control treatment on blood cholesterol and triacylglycerol levels in this hypercholesterolemic rat model. Furthermore, the cecal fermentation pattern and microbial composition did not seem to affect plasma lipid composition.
The aim of this study was to determine wheat constituents in bread and pasta that might result in intestinal gas production. Fructans, water-soluble arabinoxylans, arabinogalactan proteins and fermentable sugars were followed in bread and pasta made with ancient (Khorasan wheat; emmer) and modern wheats (common wheat; durum). After fermentation for 180 min, 80% of fructans were eliminated and higher levels of fructose than glucose accumulated in bread dough supplemented with sucrose. Whole-grain Khorasan wheat and emmer flours inhibited yeast fermentative activity. Half of fructans, arabinogalactan proteins and sugars were washed out in cooking water for pasta. Water-soluble wheat arabinoxylans increased in bread and cooked pasta. With very low levels (0.3-0.8%, dry basis), fructans in cooked pasta and, in particular, long-fermentation bread prepared with modern or ancient wheat would unlikely act as major gas-forming triggers of gastrointestinal discomfort associated with noncoeliac gluten sensitivity. Noncoeliac gluten sensitivity: in ancient and modern wheats, fructans (g per 100 g flour, dry basis) from bread and pasta are unlikely factors because very small amounts remain after pasta cooking and, in particular, long bread dough fermentation (180 min at 35 °C). International Journal of Food Science and Technology
Barley germplasm including released varieties in India were evaluated for their β-glucan content and wort filteration rate. Wide range of variability was observed for these qualify traits among these genotypes. β-glucan content varied from 2.8% to 7.1% with the mean value of 4.8% and wort filteration rate from 80 ml/hr to 335 ml/hr with the mean value of 192 ml/hr. β-glucan content and wort filteration rate showed significant negative correlation (r=-0.51, P<.001). The t-test analysis of the lines grown at two locations indicated significant environmental influence (at 5% level) on wort filteration rate and non-significant effect on β-glucan content.
This study focuses on the identification and characterization of wild mushrooms grown on the campus of Rakuno Gakuen University, using DNA sequencing and analysis of functional metabolites. Forty-eight samples of fruiting bodies were collected between June 2012 and November 2014. The samples were hot-air dried and powdered, and subsequently extracted with alkaline hot water to obtain beta-glucans, or 50% ethanol for total polyphenols (TPP) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity. Functional metabolites were assessedby colorimetric assays, using Congo Redreagent for beta-glucans, Folin-Denis reagent for TPP level, and DPPH radical scavenging for antioxidant activity. Total DNA was extracted from each sample and subjected to DNA sequencing for the inter spacer regions of ribosomal RNA gene. Sequencing analysis identified 27 independent species or genus of mushrooms. Beta-glucan contents showed clear differences between species. The TPP levels andDPPH radical scavenging activity showed similar tendencies and were significantly correlated(p<0.0001).
It is well accepted that dietary fibres, especially mixed linkage (1→3, 1→4)-β-D-glucans (β-glucan) from barley and oat, have beneficial effects on health and prevent modern lifestyle diseases. Even though recent research has shed some light on the mechanisms of action and structure-functionality relationship of β-glucans, the exact functional principle remain elusive. The overall aim of this project was to provide new knowledge into the relation between β-glucan and health at a molecular level. For the first time two barley and one oat fractions of well-defined and structurally different β-glucans were compared in a human intervention study. The work first focussed on large-scale extraction and physico-chemical characterisation of barley and oat β-glucans. The second step was to investigate the in vitro health effects of barley and oat β-glucans in relation to their physico-chemical properties. Finally, health effects from barley and oat β-glucans were studied in vivo in humans using traditional biomarkers and plasma metabolomics.
Results from Paper I demonstrated that structural characteristics and viscous properties of barley and oat β-glucans dominate the functional traits over the presence of α-glucan impurities. Paper II identified a structurally unique barley high β-glucan variety with an extraordinary high amount of cellotriosyl units and showed that the oligomer block structure of barley and oat β-glucans influence their solubility. The main findings from Papers III and IV in vitro studies were that small molecule interaction with barley and oat β-glucans is influenced by degree of polymerisation and β-glucan fine structure whereas β-glucan solubility and aggregation are key elements for understanding their immune modulating capacity. Results from the Paper V in vivo human study showed that consumption of 3.3 g/day extracted barley and oat β-glucan for 3 weeks does not significantly lower total and LDL cholesterol levels in young healthy adults. However, an indicated potential effect of oat suggests the importance of solubility for β-glucan interference with the cholesterol metabolism. The findings from Paper VI confirmed the general absence of barley and oat β-glucan effect on blood metabolites but showed the existence of subject unique lipoprotein profiles depended on gender, BMI and diet.
In conclusion, the results show that barley and oat β-glucan fine structures are of great importance for their functionality. β-Glucan solubility and polymer aggregation in solution is dependent on the block structural pattern and differently structured β-glucans may exert various functional and bioactive properties in our body. It is important to account for these diverse effects in the future evaluation of β-glucan effectiveness in functional foods and health.
Oat β-glucan (OG) is a linear non-starch polysacchride which is usually concentrated in the inner aleurone and subaleurone endosperm cell walls, and it exhibits good physiological and functional properties. In this paper soy protein isolate (SPI) which is widely used in the food industry was mixed with OG, then the gel properties and micromechanism of the mixture were studied for a better understanding of the interaction between β-glucan and protein in food. The results showed that, compared with the single OG or SPI, OG/SPI mixture easily formed thermoreversible gels in 4 °C and 25 °C, which reduced the gel forming time; this would be conducive to improve β-glucans application in food production. The glass transition temperature (Tg) and the thermal stability were increased. Scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) were used to analyze the microstructure of the mixture of OG/SPI, and showed that the gathering and interaction of oat β-glucan and soy protein isolate affected the forming of gels. The molecular simulations of the microstructure of OG and OG/SPI mixed system inferred the interaction between OG and SPI were mainly hydrogen bonds.
β-glucans are mixed linkage β-(1,3;1,4)-D-glucan polymers that account for the majority of oat soluble dietary fiber and 3–6% of oat grain weight. Although other cereals such as barley and wheat also contain β-glucans, oat β-glucans have unique physicochemical properties (solubility, molecular weight, gelation properties, etc.). These features are intimately linked to the physiological properties of oat β-glucans, such as bile acid binding, viscosity accumulation in the gastrointestinal tract, and colonic fermentability. Subsequent beneficial physiological activities, such as reduction in cholesterol and postprandial blood glucose levels, have been shown in clinical studies. All of these features have put oat β-glucans under intense scrutiny. This chapter is intended to review their physiological properties with respect to their physicochemical characteristics, in comparison with other cereal β-glucans.
The major targets in malting and brewing are to obtain maximum extract yield, enough nutrients for yeast growth, fermentable
sugars for alcohol production and a balanced combination of high molecular weight compounds to achieve a beautiful and stable
foam and smooth mouth feel in beer and to avoid haze formation during storage. Wort and beer filtration difficulties frequently
happen in beer processing because of insufficient hydrolysis of cell wall components. It is well documented that insufficient
degradation of cell walls hinders the diffusion of germination enzymes, the mobilization of kernel reserves and hence reduces
malt extract. β-glucans and arabinoxylans are the major components of endosperm cell walls. In general, insufficient degradation of cell
walls is closely related to more residues of these sugars, which may lead to highly viscous wort and beer, giving rise to
filtration problems in the brewery. In malt barley breeding, low β-glucan and arabinoxylans contents, or high activities of β-glucanase and xylosidase, which degrade β-glucan and arabinoxylans respectively, have been considered as an important target.
The quest for optimum methodology for any analyte often includes a study of the method in multiple independent laboratories. Evaluation of the results of these studies is typically subjective; however, various attempts have been made to increase the objectivity of the evaluation. Among the objective propositions is the use of the Horwitz Ratio (HorRat) as applied to collaborative study statistics. A historical review of fiber method validation studies performed since 1940 shows that the Horwitz curve does not effectively predict the results of dietary fiber collaborative studies, either retrospectively or prospectively. Consequently, use of the HorRat as a criterion for accepting or rejecting dietary fiber methods is contraindicated. An alternative, objective statistical approach is proposed that may also apply to collaborative studies of other empirical analytical methods in general.
A series of extrudates was prepared from oat meal, oat bran and Novelose 330®, differing in concentrations of individual dietary fibre (DF) components, such as β-glucan and resistant starch, as well as total DF. After simulated digestion, the digested DF-rich oat-based extrudates were used to evaluate their physiological effects in vitro. A strong interaction occurred between the digested extrudates and bile acids (BA). The binding of BA increased with increasing proportions of oat bran, total DF, insoluble DF and β-glucan in the extrudates. Dihydroxy-BA was more strongly bound to the extrudates than trihydroxy-BA. Interactions at pH 5.0 were greater than at pH 6.5. During fermentation of digested extrudates with human faecal samples, concentrations of short-chain fatty acid (SCFA) formed and the molar proportion of butyrate increased continuously. Higher SCFA concentrations were found when extrudates contained more oat bran, soluble and insoluble DF and β-glucan. Extrudates, on the basis of oat, have several beneficial nutritional and protective effects in vitro. Therefore, physiological effects occurring in the small and large intestine are also related to the DF composition of the cereal products.
Products with new functional and nutritional properties are a precondition for a higher acceptance of barley in human nutrition. Amylose can be partly converted into enzyme-resistant starch (RS) by technological treatments. Optimal conditions for generation of RS from barley using a single-screw laboratory extruder were the following: feed moisture approximately 20%, mass temperature approximately 150 °C, screw speed approximately 200 rev/min and a relatively wide die. Extrusion followed by freeze-storage resulted in formation of RS up to 6%. Under these conditions, the macromolecular state of β-glucan was preserved. Functional and physico-chemical properties of extruded preparations and of their extracts were determined and compared to an autoclaved product. In extracts, high viscosities and a pseudoplastic behaviour were found. Viscosity and flow behaviour were temperature- but not pH-dependent. Water binding properties and the acid-extract viscosity were influenced by process parameters during extrusion. The molecular weights of β-glucans isolated from extrudates were between 80 000 and 125 000. Extruded products interacted with glycoconjugated bile acids (pH 5·0–6·5). During in vitro fermentation of pancreatin-digested extruded or autoclaved products with human faeces flora, the production of short-chain fatty acids and the molar portion of butyrate were more increased compared with pancreatin-digested barley meal.
The cereal dietary fibre β-glucan has outstanding functional and nutritional properties, because of its viscosity in aqueous systems and in the intestinal tract. The rheological behaviour of β-glucan (concentrations: 2% and 4%) isolated from extruded and autoclaved oat meal and from oat bran was evaluated using oscillatory and rheological measurements. In frequency sweep, the storage and loss moduli G′ and G″ of β-glucan preparations from extruded meal and from bran increased continuously with increasing frequency, showing a dominantly viscous behaviour. With increasing frequency, the elastic properties improved. β-Glucan from autoclaved meal also showed elastic behaviour. With the exception of β-glucan from autoclaved meal, G′ and G″ were not influenced by deformation in the amplitude sweep. Complex viscosities decreased with frequency (in all samples) and were independent of deformation (in extruded meal and bran). In shear experiments, β-glucan solutions were structurally viscous non-Newtonian solutions with rheostable behaviour. β-Glucan (2%) from bran had the highest and that from autoclaved meal had the lowest apparent and process viscosities. Fluid dynamic parameters may influence the flow, diffusion or transport behaviour of β-glucan during digestion processes in the small intestine, but the influence of the viscous behaviour is limited.
The current enzymatic assay approach (AACC International Approved Method 32-23) for the measurement of mixed-linkage β-glucan in small grains was modified to a cost-efficient and high-throughput format without compromising the accuracy of the results. Ten barley (Hordeum vulgare L.) genotypes used in the study represented a wide range of β-glucan content levels. A reduced reaction volume is used in the new protocol to adapt to a 96-well plate format. The volume of key components lichenase and β-glucosidase were reduced to 25% of the volume required in the original protocol and the cost per sample was reduced to 22% of that in the original protocol. Labor cost was also decreased to 25% of the original protocol as a result of format changes. The accuracy of the measurement from the modified protocol was comparable to the current standard enzymatic procedure. β-Glucan measurement accuracy of the modified and original protocols were also compared using 21 oat (Avena sativa L.) samples. The results indicated that the new protocol consistently produced accurate measurements in both barley and oat.
1. A diet with addition to normal barley of malt from transgenic barley expressing a protein engineered, thermotolerant Bacillus (1,3-1,4)-beta-glucanase during germination has previously been demonstrated to provide a broiler chicken weight gain comparable to maize diets. It also reduced dramatically the number of birds with adhering sticky droppings, but did not entirely eliminate sticky droppings. One of the objectives of the broiler chicken trials reported here was to determine if higher concentrations of transgenic malt could alleviate the sticky droppings. 2. Another aim was to investigate the feasibility of using mature transgenic grain containing the thermotolerant (1,3-1,4)-beta-glucanase as feed addition and to compare diets containing transgenic grain to a diet with the recommended amount of a commercial beta-glucanase-based product. 3. Inclusion of 75 or 151 g/kg transgenic malt containing 4.7 or 98 mg/kg thermotolerant (1,3-1,4)-beta-glucanase with 545 or 469 g/kg non-transgenic barley instead of maize yielded a weight gain in Cornish Cross broiler chickens indistinguishable from presently used maize diets. The gene encoding the enzyme is expressed in the aleurone with a barley alpha-amylase gene promoter and the enzyme is synthesised with a signal peptide for secretion into the endosperm of the malting grain. 4. Equal weight gain was achieved, when the feed included 39 g/kg transgenic barley grain [containing 66 mg/kg thermotolerant (1,3-1,4)-beta-glucanase] and 581 g/kg non-transgenic barley instead of maize. In this case, the gene encoding the enzyme has been expressed with the D-hordein gene (Hor3-1) promoter during grain maturation. The enzyme is synthesised as a precursor with a signal peptide for transport through the endoplasmic reticulum and targeted into the storage vacuoles. Deposition of the enzyme in the prolamin storage protein bodies of the endosperm protects it from degradation during the programmed cell death of the endosperm in the final stages of grain maturation and provides extraordinary heat stability. The large amount of highly active (1,3-1,4)-beta-glucanase in the mature grain allowed the reduction of the transgenic grain ingredient to 0.2 g/kg diet, thus making the ingredient comparable to that of the trace minerals added to standard diets. 5. A direct comparison using transgenic grain supplement at the level of 1 g/kg of feed with the standard recommended addition of the commercial enzyme preparation Avizyme 1100 at 1 g/kg yielded equal weight gain, feed consumption and feed efficiency in birds fed a barley-based diet. 6. The production of sticky droppings characteristic of broilers fed on barley diets was avoided with all 9 experimental diets and reduced to the level observed with a standard maize diet by supplementation with transgenic barley. 7. The excellent growth and normal survival of the 400 broilers tested on barley diets supplemented with transgenic grain or malt showed the grain and malt not to be toxic. 8. The barley feed with added transgenic grain or malt containing thermotolerant (1,3-1,4)-beta-glucanase provides an environmentally friendly alternative to enzyme additives, as it uses photosynthetic energy for production of the enzyme in the grain and thus avoids use of non-renewable energy for fermentation. The deposition of the enzyme in the protein bodies of the grain in the field makes coating procedures for stabilisation of enzyme activity superfluous. 9. Barley feed with the small amount of transgenic grain as additive to normal barley provides an alternative for broiler feed in areas where grain maize cannot be grown for climatic reasons or because of unsuitable soil and thus has to be imported.
The aim of the present study was to investigate the influence of dietary-fibre (DF)-rich barley-based diets on bile acids (BA) and neutral sterols (NS) in the intestinal tract of rats. For this purpose, young male Wistar rats (n 50; ten per group) weighing about 67 g were fed either a barley-free diet (control group) or diets containing 500 g barley meal extrudates/kg or a barley meal-Novelose mixture (groups A-D) for 6 weeks. These barley products contained 7-24 g resistant starch/100 g and 7-12 g (1 --> 3),(1 --> 4)-beta-glucan/100 g. More steroids were transported towards the lower parts of the intestinal tract when higher concentrations of macromolecular DF were present in the diets (P < 0.001). Tauroconjugated and primary BA dominated in the contents of the small intestine. Intense enzymic conversion of BA occurred in the caecum and colon. The fermentation of DF affected indirectly the amount of formed secondary BA. The main BA present in the caecal contents were muricholic acids, hyodeoxycholic acid and cholic acid. The BA spectrum in the colonic contents was different from that in the caecum. A higher concentration of NS appeared in the intestinal contents of the groups fed the barley-based diets than in the controls (P < 0.005). The microbial conversion of cholesterol to coprostanol, cholestanone and coprostanone was influenced by the amount and composition of the DF in the gut. DF in the diet may affect the concentration and spectrum of steroids in the intestinal tract. The results are relevant for the discussion of mechanisms behind the cholesterol-lowering effects of DF.
ResearchGate has not been able to resolve any references for this publication.