Whole Grain Barley Research Articles

Metabolic profiling of (poly)phenolic compounds in mouse urine following consumption of hull-less and purple-grain barley.

The present study attempted for the first time to investigate the metabolic fate of (poly)phenolic compounds provided by a hull-less and purple grain barley genotype biofortified in anthocyanins. Balb/c mice were supplemented either with standard purified diet (SD) or whole-grain barley supplemented diet (WGB) for six weeks. Subsequently, (poly)phenolic metabolites were determined in urine samples by UPLC-MS/MS, and the principal metabolic pathways were elucidated. Thirty-nine (poly)phenolics compounds were identified in WGB which were distributed between the free (58%) and bound (42%) fractions, encompassing anthocyanins, phenolic acids, flavan-3-ols and flavones. Upon WGB intake, forty-two (poly)phenolic metabolites were identified, predominantly comprising phase-II sulphate, glucuronide, and/or methylated conjugates, along with colonic catabolites. Noteworthy metabolites included peonidin-3-O-glucuronide, peonidin-3-O-6''-O-malonylglucoside, and peonidin-3-O-glucoside among anthocyanins; hydroxyphenylpropanoic acid-O-sulphate among phenolic acids; and 5-(3',4'-dihydroxyphenyl)-γ-valerolactone-O-sulphate among flavan-3-ols. Metabolites like phenylpropionic, phenylacetic, hydroxybenzoic, and hippuric acids were found in both WGB and SD groups, with higher levels after barley consumption, indicating both endogenous and polyphenolic metabolism origins. Overall, this study offers valuable insights into the metabolism of (poly)phenols in purple barley, setting the stage for future investigations into the health benefits linked to the consumption of purple grain barley.

Fecal Metabolites as Biomarkers for Predicting Food Intake by Healthy Adults

The fecal metabolome is affected by diet and includes metabolites generated by human and microbial metabolism. Advances in -omics technologies and analytic approaches have allowed researchers to identify metabolites and better utilize large data sets to generate usable information. One promising aspect of these advancements is the ability to determine objective biomarkers of food intake. We aimed to utilize a multivariate, machine learning approach to identify metabolite biomarkers that accurately predict food intake. Data were aggregated from 5 controlled feeding studies in adults that tested the impact of specific foods (almonds, avocados, broccoli, walnuts, barley, and oats) on the gastrointestinal microbiota. Fecal samples underwent GC-MS metabolomic analysis; 344 metabolites were detected in preintervention samples, whereas 307 metabolites were detected postintervention. After removing metabolites that were only detected in either pre- or postintervention and those undetectable in ≥80% of samples in all study groups, changes in 96 metabolites relative concentrations (treatment postintervention minus preintervention) were utilized in random forest models to 1) examine the relation between food consumption and fecal metabolome changes and 2) rank the fecal metabolites by their predictive power (i.e., feature importance score). Using the change in relative concentration of 96 fecal metabolites, 6 single-food random forest models for almond, avocado, broccoli, walnuts, whole-grain barley, and whole-grain oats revealed prediction accuracies between 47% and 89%. When comparing foods with one another, almond intake was differentiated from walnut intake with 91% classification accuracy. Our findings reveal promise in utilizing fecal metabolites as objective complements to certain self-reported food intake estimates. Future research on other foods at different doses and dietary patterns is needed to identify biomarkers that can be applied in feeding study compliance and clinical settings.

Explainable Artificial Intelligence in the Early Diagnosis of Gastrointestinal Disease

This study reviews the recent progress of explainable artificial intelligence for the early diagnosis of gastrointestinal disease (GID). The source of data was eight original studies in PubMed. The search terms were "gastrointestinal" (title) together with "random forest" or "explainable artificial intelligence" (abstract). The eligibility criteria were the dependent variable of GID or a strongly associated disease, the intervention(s) of artificial intelligence, the outcome(s) of accuracy and/or the area under the receiver operating characteristic curve (AUC), the outcome(s) of variable importance and/or the Shapley additive explanations (SHAP), a publication year of 2020 or later, and the publication language of English. The ranges of performance measures were reported to be 0.70-0.98 for accuracy, 0.04-0.25 for sensitivity, and 0.54-0.94 for the AUC. The following factors were discovered to be top-10 predictors of gastrointestinal bleeding in the intensive care unit: mean arterial pressure (max), bicarbonate (min), creatinine (max), PMN, heart rate (mean), Glasgow Coma Scale, age, respiratory rate (mean), prothrombin time (max) and aminotransferase aspartate (max). In a similar vein, the following variables were found to be top-10 predictors for the intake of almond, avocado, broccoli, walnut, whole-grain barley, and/or whole-grain oat: Roseburia undefined, Lachnospira spp., Oscillibacter undefined, Subdoligranulum spp., Streptococcus salivarius subsp. thermophiles, Parabacteroides distasonis, Roseburia spp., Anaerostipes spp., Lachnospiraceae ND3007 group undefined, and Ruminiclostridium spp. Explainable artificial intelligence provides an effective, non-invasive decision support system for the early diagnosis of GID.

Theoretical and experimental determination of number of impacts required for caryopsis destruction

The article presents theoretical and experimental studies to determine the number of impacts to destroy the caryopsis. To substantiate the number of shock impacts, the Rebinder’s equation for determining the work on grinding was taken as the basis for theoretical studies. The transformation and development of the Rebinder’s equation enabled to theoretically obtain expressions for determining the amount of work required for guaranteed destruction of the caryopsis when a single impact was applied. An equation for determining the work of a particle destruction during a multiple number of impacts was also obtained. Its transformation enabled to obtain a function and implement a theoretical nomogram. The performed theoretical analysis of the obtained nomogram enabled to consider the energy costs when determining the required number of impacts for guaranteed caryopsis destruction at certain voltages. To validate the theoretical studies, the experiments on breaking down whole grains of wheat and barley were carried out. To conduct the experiments, an experimental setup to perform a series of experiments was developed. As a result of experimental studies, the value of the limiting stresses, at which no grain destruction is observed with any number of impacts, was determined. The magnitude of the stress for a single impact for guaranteed destruction of the caryopsis was determined. The main result of the experiments is the determination of the number of impacts for the destruction of barley and wheat kernels with minimal energy consumption.

Effects of whole-grain barley and oat β-glucans on postprandial glycemia and appetite: a randomized controlled crossover trial.

This study aimed to determine the postprandial effects of barley bread (BB) and oat bread (OB), grain sources of β-glucans, on glycaemia and appetite by comparison with white bread (WB) and whole-wheat bread (WWB). This randomized controlled crossover trial included 20 healthy individuals (10 males and 10 females) who consumed WB, WWB, BB, and OB with a standard breakfast followed by an ad libitum lunch. Postprandial glucose and appetite responses were quantified as the incremental area under the curve (iAUC). Although the iAUC for glycaemic response was lower by 23.7%, 29.9%, and 27.9% after the consumption of BB, OB, and WWB compared with WB (p = 0.023), no differences were observed between BB, OB, and WWB (p > 0.05). BB had a lower iAUC for appetite sensation by 21.5%, 23.9%, and 55.7% compared with WB, WWB, and OB (p = 0.005). OB had no effect on appetite and was also less palatable than BB. Subsequent food intakes were similar after the consumption of all test breads (p > 0.05). The encouragement of healthier bread formulations that can beneficially modulate postprandial glycemia and appetite may contribute to the promotion of public health. This trial was registered at ClinicalTrials.gov as NCT04749498.

Talbina as a functional food and a source of health-beneficial ingredients: a narrative review

During the past two decades, several researchers have claimed that traditional foods are healthier products and better sources of micronutrients. Talbina is a well-known traditional food in North Africa, Middle East and South East Asia. Talbina is made by adding 1-2 tablespoons of barley (100% wholegrain barley) to cup of water. Cook on low heat for15 minutes in a water bath. After that a cup of Laban (fermented milk) or milk is added. It can be sweetened with honey. This broth can be used as a stock for soups or stews or as a thickener. Talbina is a healthy food helps in depression and stress relief. It has high antioxidant activity as well as anti-inflammatory. Its consumption regularly proves to be an effective and safe strategy for treating different chronic diseases. It is a rich source of different essential nutrients and antimicrobials, both of which have been linked to a reduction in chronic disease. However, Talbina has not been well studied or defined by the scientific community. This review defines Talbina and discusses the various bioactive compounds in this food and their health benefits. Keywords: Barley wholegrain; fermented milk; natural honey; functional food; nutraceutical ingredients.

Fecal Bacteria as Biomarkers for Predicting Food Intake in Healthy Adults

ABSTRACTBackgroundDiet affects the human gastrointestinal microbiota. Blood and urine samples have been used to determine nutritional biomarkers. However, there is a dearth of knowledge on the utility of fecal biomarkers, including microbes, as biomarkers of food intake.ObjectivesThis study aimed to identify a compact set of fecal microbial biomarkers of food intake with high predictive accuracy.MethodsData were aggregated from 5 controlled feeding studies in metabolically healthy adults (n = 285; 21–75 y; BMI 19–59 kg/m2; 340 data observations) that studied the impact of specific foods (almonds, avocados, broccoli, walnuts, and whole-grain barley and whole-grain oats) on the human gastrointestinal microbiota. Fecal DNA was sequenced using 16S ribosomal RNA gene sequencing. Marginal screening was performed on all species-level taxa to examine the differences between the 6 foods and their respective controls. The top 20 species were selected and pooled together to predict study food consumption using a random forest model and out-of-bag estimation. The number of taxa was further decreased based on variable importance scores to determine the most compact, yet accurate feature set.ResultsUsing the change in relative abundance of the 22 taxa remaining after feature selection, the overall model classification accuracy of all 6 foods was 70%. Collapsing barley and oats into 1 grains category increased the model accuracy to 77% with 23 unique taxa. Overall model accuracy was 85% using 15 unique taxa when classifying almonds (76% accurate), avocados (88% accurate), walnuts (72% accurate), and whole grains (96% accurate). Additional statistical validation was conducted to confirm that the model was predictive of specific food intake and not the studies themselves.ConclusionsFood consumption by healthy adults can be predicted using fecal bacteria as biomarkers. The fecal microbiota may provide useful fidelity measures to ascertain nutrition study compliance.

Highland Barley Whole Grain (Hordeum vulgare L.) Ameliorates Hyperlipidemia by Modulating Cecal Microbiota, miRNAs, and AMPK Pathways in Leptin Receptor-Deficient db/db Mice

The mechanisms of highland barley whole grain (BWG) with rich phenolics on obese db/db mice were investigated in this study. Oral consumption of BWG reduced food intake, body weight, organ/body weight indexes of liver and fat, levels of serum and hepatic lipids, liver injury, and oxidative stress. Furthermore, BWG recovered the disorder of cecal microbiota by augmenting the Bacteroidetes/Firmicutes ratio and Alistipes abundance and decreasing the abundances of Bacteroides and Desulfovibrionaceae to modulate lipid metabolism-related genes. BWG inhibited fatty acid biosynthesis via upregulating the phosphorylation of AMP-activated protein kinase α, while downregulating sterol regulatory element binding protein-1c, fatty acid synthase (FAS), and stearoyl-CoA desaturase 1 levels. BWG also significantly downregulated miRNA-122, miRNA-33, miRNA-34a, and miRNA-206 levels. Accordingly, BWG exhibited hypolipidemic potential through modulating cecal microbiota, AMPK/SREBP-1c/FAS pathway, and related miRNAs, triggering the alleviation of dyslipidemia. These findings suggested BWG as an effective candidate to ameliorate the symptoms of hyperlipidemia.

Effects of the addition of waxy and normal hull-less barley flours on the farinograph and pasting properties of composite flours and on the nutritional value, textural qualities, and in vitro digestibility of resultant breads.

Hull-less barley (HLB), especially waxy HLB, contains many physiologically active ingredients; however, its poor processing performance and end-product quality are unfavorable. In this study, 80% waxy or normal HLB wholegrain flour (WGF) and 20% wheat flour were used for baking bread. The farinograph and pasting properties of composite powders, and the nutritional value, textural properties, and in vitro hydrolysis of resultant breads were evaluated. The addition of a high proportion of HLB WGFs significantly increased the nutritional value of breads, especially the β-glucan contents of waxy HLB breads. The addition of HLB WGFs and a suitable amount of wheat gluten led to a lower degree of softening of HLB bread flours but improved its farinograph characteristics, such as higher water absorption rate, development time, stability time, and farinograph quality number. Although the sensory profiles of HLB breads were considerably lower than those of wheat bread, they still received a good overall acceptability from a panel of sensory evaluators. HLB breads, particularly the waxy types, exhibited higher hardness, gumminess, chewiness, and lower specific volume, glycemic index and equilibrium concentration in starch hydrolysis. After baking, the starch crystallinity of dough changed from A to V type, and the relative crystallinity decreased. Overall, waxy HLB breads had more nutritional value than normal HLB breads. Higher β-glucan and total dietary fiber content in HLB might have a positive effect on the nutritional value of the resultant breads. However, high β-glucan and total dietary fiber was also accompanied by a negative effect on the sensory quality and processing performance of the end product. PRACTICAL APPLICATION: The composite flour with 80g hull-less barley wholegrain flour, 20g wheat flour, and 30g wheat gluten can be substituted in breadmaking. Compared to wheat bread, hull-less barley bread exhibited different but acceptable sensory properties and had more nutritional value, particularly the waxy one. Therefore, a high proportion of hull-less barley could be recommended for bread production.

Combined effect of vital wheat gluten, ascorbic acid and emulsifier addition on the quality characteristics of whole grain barley bread.

There is a renewed attention in barley for being used in food products due to its nutritional benefits. Unfortunately barley breads are still inferior in their quality characteristics when compared to their wheat counterparts. The present work studied the individual and interactive effects of three bread improvers (i.e. vital wheat gluten VWG, ascorbic acid AA and sodium stearoyl-2-lactylate SSL) on the quality characteristics of wholegrain barley bread. Results showed significant effects of such improvers on both bread specific volume and overall sensory acceptability. VWG-AA and AA- SSL interactive effects were positively correlated with bread overall acceptability. Inclusion of bread improvers according to the obtained optimized formula showed a positive effect on bread with regard to its dough rheological properties (longer stability time, lower degree of softening and higher extensibility), physical (specific volume), textural (hardness and springiness), and crumb DIA characteristics of bread. Chemical analysis showed higher nutrient contents (protein, fiber and minerals) in the optimized barley bread when compared to their wheat counterparts. The overall sensory characteristics of the optimized barley bread were acceptable by the panelists with scores corresponded to “like moderately” compared to “extremely like/like very much” in case of wheat bread.

Studies on the Effect of Low Glycemic Index for Multi-Whole Grain Formulated Flour Samples in Type 2 Diabetic Patients

Different types of corns are used as staple food in Bangladesh, core source of nutrients from food stuffs for metabolic energy. Ready to eat or processed food stuffs that contains totally different macro and micronutrients such as Tocopherol , Thiamine , Riboflavin , Pyroxene, Mg and Zn etc. within the recipes for sample preparation, were incorporated different whole grains of wheat, wheat bran, rye, maize, soya, barley, chickpeas and plantain husk in numerous ratios. Developed flours were subjected to nutritionally active diet for diabetic patients, the extent of glucose when consumption of diets could be an essential issue. Protein, fat, crude fiber and energy values of developed multi grains combined and market flours were MFS- 1: (11.00%, 3.77%, 2.69%, 387.25); MFS- 2:(14.16%, 3.71%,3.21%, 385.73); MFS-3:(12.40%, 3.33%, 2.87%,385.24);MFS- 4: (11.31%, 2.16%, 2.45%, 382.83) and market flour samples CS-A: (12.04%, 2.05%,1.64%,358.37) and CS-B:(14.90%,2.06%,1.46%,350.82) respectively. Amongst, MFS- 3 sample resulted the preferences in hedonic sensory evaluation. Glycemic index (GI) resolved mistreatment normal methodology for MFS-3 and normal sugar. The GI worth of MFS- 3 sample (46.86) showed lowest postprandial aldohexose like compared to plain. once the analysis of all four mixed recipes compared to market samples, it showed that MFS- 3sample possessed the simplest preferences because the different useful diet for type- 2 diabetic patients. Aims of the analysis works were recipe preparation of samples, product acceptances and determination of Glycemic Index (GI) for four mixed multi-wholegrain flours compared with 2 market multi-grain flours within the market.

High wholegrain barley β-glucan lowers food intake but does not alter small intestinal macronutrient digestibility in ileorectostomised rats

Using barley cultivars differing widely in β-glucan content, we aimed to determine their effects on small intestinal macronutrient digestion in 24 ileorectostomised rats. The rats were fed 1 of 4 experimental diets, each containing a different barley variety, for 11 d. The diets had a content of 0, 2.1, 2.6 and 4.3 g of β-glucan/100 g. Feed intake and faecal excretion of fat, protein, starch, and non-starch polysaccharides were determined in the final 5 d of the study and apparent macronutrient digestibility calculated. Higher dietary levels of β-glucan (2.6% and 4.3%) lowered feed intake (by 15 and 19%, respectively) but final body weight was only lowered by the 4.3% β-glucan diet relative to rats fed the 0% β-glucan diet (all ps < 0.05). Protein, lipid and starch digestibility was unrelated to the dietary β-glucan content. Higher dietary levels of barley β-glucan lower feed intake of ileorectostomised rats, which is independent of intestinal fermentation and unrelated to macronutrient digestibility.

Influence of α-amylase and xylanase on the chemical, physical and volatile compound properties of wheat bread supplemented with wholegrain barley flour

The Irish barley variety “Sanette” was incorporated at 30 % inclusion levels into a wheat bread formulation. Baking enzymes were used to improve the baking characteristics of the final breads. The enzymes studied were fungal α-amylase, xylanase and a combination of the two enzymes. Volume, cell structure, crumb texture, compositional analysis and volatile compounds of the baked breads were evaluated. Experiments were replicated thrice, and the data were analysed using a one-way ANOVA for significant differences less than p < 0.05. Baking results illustrated that using xylanase on its own and in combination with fungal α-amylase resulted in breads with a larger loaf volume (3.16 and 3.05 mL/g) in comparison with the control (2.69 mL/g, p < 0.006). Crumb softness increased following the addition of the α-amylase and xylanase combination (6.94 N) compared to the control (11.17 N, p < 0.001). The use of barley flour in the breads increased the concentration of isoamyl alcohol from the alcohol group and decreased the concentration of compounds from the pyrazine and sulphur groups. Using the enzyme combination resulted in volatile compounds similar to the 30 % wholegrain wheat bread, e.g. 2-methyl butanal and 2,3-butanedione. The incorporation of barley into a wheat bread formulation on a 30 % replacement basis in combination with the two enzymes (α-amylase and xylanase) increased the total amount of fibre present in the bread (6.3 %) compared to the 30 % wholegrain wheat bread (4.8 %).

Investigation of physicochemical, sensory characteristics, cooking and texture properties of whole grain pasta

The consumption of whole-grain products, such as pasta, has been linked to the reduced risks of some illnesses. Nutritional benefits include dietary fibre, minerals, and phytochemicals. Traditionally, whole-grain products tend to be darker in colour, fiber can interfere with the drying process affecting production processes. The purpose of the current research was to investigate the colour, cooking properties and texture of the whole-grain pasta. For pasta production, flour blends were made from wheat flour type 405 in combination with whole-grain flours as whole-grain wheat, triticale, rye and hull-less barley flour in previously determined proportions. In experiments, the whole-grain Italpasta (Italy) was used as a control sample. The colour, cooking properties and texture of the obtained pasta were tested using standard methods. The results of the present experiments demonstrate that the cooking time of control, whole-grain triticale and wheat pasta was longer than the cooking time of whole-grain rye and hull-less barley pasta. The colour of control, whole-triticale and whole-wheat pasta samples was darker as compared with whole-rye and hull-less barley pasta samples. However, more firmness had pasta samples made from whole-rye and hull-less barley whole-grain flour. DOI: http://dx.doi.org/10.5755/j01.ct.66.1.12364

Effect of Whole-Grain Barley on the Human Fecal Microbiota and Metabolome.

In this study, we compared the fecal microbiota and metabolomes of 26 healthy subjects before (HS) and after (HSB) 2 months of diet intervention based on the administration of durum wheat flour and whole-grain barley pasta containing the minimum recommended daily intake (3 g) of barley β-glucans. Metabolically active bacteria were analyzed through pyrosequencing of the 16S rRNA gene and community-level catabolic profiles. Pyrosequencing data showed that levels of Clostridiaceae (Clostridium orbiscindens and Clostridium sp.), Roseburia hominis, and Ruminococcus sp. increased, while levels of other Firmicutes and Fusobacteria decreased, from the HSB samples to the HS fecal samples. Community-level catabolic profiles were lower in HSB samples. Compared to the results for HS samples, cultivable lactobacilli increased in HSB fecal samples, while the numbers of Enterobacteriaceae, total coliforms, and Bacteroides, Porphyromonas, Prevotella, Pseudomonas, Alcaligenes, and Aeromonas bacteria decreased. Metabolome analyses were performed using an amino acid analyzer and gas chromatography-mass spectrometry solid-phase microextraction. A marked increase in short-chain fatty acids (SCFA), such as 2-methyl-propanoic, acetic, butyric, and propionic acids, was found in HSB samples with respect to the HS fecal samples. Durum wheat flour and whole-grain barley pasta containing 3% barley β-glucans appeared to be effective in modulating the composition and metabolic pathways of the intestinal microbiota, leading to an increased level of SCFA in the HSB samples.

Modulation of gut microbiota in rats fed high-fat diets by processing whole-grain barley to barley malt.

The gut microbiota is linked with human health, and by manipulating its composition, health conditions might be improved. The aim of this study was to investigate whether two barley products, whole-grain barley and barley malt, caused differentiation of the cecal microbiota in rats fed high-fat diets and whether there were correlations with the short-chain fatty acids formed. Male Wistar rats were given barley or malt (7-8 dietary fiber/100 g) for 4 weeks. Cellulose was used as a control, and the cecal microbiota was analyzed with next-generation sequencing of 16S rDNA. The barley group had higher abundances of Verrucomicrobia and Actinobacteria and lower abundances of Firmicutes and Deferribacteres than the control group; the alpha diversity was also lower. At the genus level, the barley group had higher abundances of Akkermansia, Ruminococcus, Blautia, and Bilophila. Turicibacter and Roseburia were more abundant in the malt group, and Parabacteroides, Dorea and rc4-4 were enriched in the control group. Most genera correlated with acetic and propionic acids, but Roseburia and Turicibacter instead correlated with butyric acid. Succinic acid correlated with Clostridium and Akkermansia. Bioprocessing is a potential method to modulate the gut microbiota for enhanced effects on human health.

Effects of two whole-grain barley varieties on caecal SCFA, gut microbiota and plasma inflammatory markers in rats consuming low- and high-fat diets

Mixed-linkage β-glucans are fermented by the colon microbiota that give rise to SCFA. Propionic and butyric acids have been found to play an important role in colonic health, as well as they may have extraintestinal metabolic effects. The aim of the present study was to investigate how two whole-grain barley varieties differing in dietary fibre and β-glucan content affected caecal SCFA, gut microbiota and some plasma inflammatory markers in rats consuming low-fat (LF) or high-fat (HF) diets. Barley increased the caecal pool of SCFA in rats fed the LF and HF diets compared with those fed the control diet, and the effect was generally dependent on fibre content, an exception was butyric acid in the LF setting. Furthermore, whole-grain barley reduced plasma lipopolysaccharide-binding protein and monocyte chemoattractant protein-1, increased the caecal abundance of Lactobacillus and decreased the Bacteroides fragilis group, but increased the number of Bifidobacterium only when dietary fat was consumed at a low level. Fat content influenced the effects of barley: rats fed the HF diets had a higher caecal pool of acetic and propionic acids, higher concentrations of amino acids and higher amounts of lipids in the portal plasma and liver than rats fed the LF diets; however, less amounts of butyric acid were generally formed. Interestingly, there was an increase in the caecal abundance of Akkermansia and the caecal pool of succinic acid, and a decrease in the proportion of Bifidobacterium and the Clostridium leptum group. In summary, whole-grain barley decreased HF diet-induced inflammation, which was possibly related to the formation of SCFA and changes in microbiota composition. High β-glucan content in the diet was associated with reduced plasma cholesterol levels.

Properties of enzyme preparations and homogeneous enzymes - endoglucanases EG2 Penicillium verruculosum and LAM Myceliophthora thermophila.

The genes of endoglucanases EG2 (36.2kDa) Penicillium verruculosum and LAM (30.8kDa) Myceliophthora thermophila were cloned in P. verruculosum recombinant strain. New enzyme preparations with highly stable activity against β-glucan and laminarin were obtained and investigated, homogeneous enzymes EG2 (EC 3.2.1.4) and LAM (EC 3.2.1.6) being purified and characterized. For β-glucan, the EG2 Km value was found to be 10 times higher than that for LAM; however, EG2 demonstrated greater processivity due to its higher kcat. The pH and temperature optima of EG2 and LAM activity against barley β-glucan overlapped and were 4.3-4.9 and 61-67°C, respectively, and EG2 appeared to be more stable than LAM. Oligosaccharides with degree of polymerization 2-10 were formed by hydrolysis of β-glucan and laminarin by the studied enzymes. The recombinant enzyme preparations were faster and more effective in decreasing the reduced viscosity of wholegrain barley extract than some commercial enzyme preparations. Thus, the new enzyme preparations seem to be rather perspective as feed additives for degradation of non-starch polysaccharides in grain animal feed.

Wholegrain barley β-glucan fermentation does not improve glucose tolerance in rats fed a high-fat diet

Fermentation of oat and barley β-glucans is believed to mediate in part their metabolic health benefits, but the exact mechanisms remain unclear. In this study, we sought to test the hypothesis that barley β-glucan fermentation raises circulating incretin hormone levels and improves glucose control, independent of other grain components. Male Sprague-Dawley rats (n = 30) were fed a high-fat diet for 6 weeks and then randomly allocated to 1 of 3 dietary treatments for 2 weeks. The low– (LBG, 0% β-glucan) and high– (HBG, 3% β-glucan) β-glucan diets contained 25% wholegrain barley and similar levels of insoluble dietary fiber, available carbohydrate, and energy. A low-fiber diet (basal) was included for comparison. Immediately prior to the dietary intervention, gastric emptying rate (using the 13C-octanoic breath test) and postprandial glycemic response of each diet were determined. At the end of the study, circulating gut hormone levels were determined; and a glucose tolerance test was performed. The rats were then killed, and indices of cecal fermentation were assessed. Diet did not affect live weight; however, the HBG diet, compared to basal and LBG, reduced food intake, tended to slow gastric emptying, increased cecal digesta mass and individual and total short-chain fatty acid pools, and lowered digesta pH. In contrast, circulating levels of glucose, insulin, gastric-inhibitory peptide, and glucagon-like peptide-1, and glucose tolerance were unaffected by diet. In conclusion, wholegrain barley β-glucan suppressed feed intake and increased cecal fermentation but did not improve postprandial glucose control or insulin sensitivity.

Wholegrain barley β-glucan reduced diet intake but did not improve glucose tolerance despite increasing fermentation in rats

Wholegrain barley β-glucan reduced diet intake but did not improve glucose tolerance despite increasing fermentation in rats