Analysis of β-glucan content in barley cultivars from different locations of China

Effect of three polysaccharides with different charge characteristics on the properties of highland barley starch gel

Highland barley, a nutritious whole grain, faces limited market utilization due to the poor heating stability of its starch. The aim of this study was to investigate the effects of three differently charged ionic polysaccharides-guar gum (GG), xanthan gum (XG), and carboxymethyl chitosan (CMC)-on the gel properties of highland barley starch (HBS). GG and XG notably increased pasting viscosity, viscoelasticity, hardness, and strength of HBS gels. Conversely, CMC resulted in decreased gel properties. All three polysaccharides enhanced OH tensile vibration (3000-3800 cm-1), with GG and XG promoting denser honeycomb network structures and lower spin-spin relaxation time (T2), indicating improved structural integrity. In contrast, low concentrations of CMC led to disorder and loose structure. Hydrogen bonding and electrostatic interactions were the main forces by which polysaccharides influenced the properties of starch gels. This research contributes to enhancing the properties of HBS gel during heating and expanding its commercial applications. It also provides some insights to understand the interaction between different charged polysaccharides and starch.

Genotypic and environmental effects on quality and nutritional attributes of Moroccan barley cultivars and elite breeding lines

Although barley is mainly used for livestock feed and beverages, its use as human feed can enrich human diets with some health benefits. The development of new hulless varieties rich in β-glucans and micronutrients can enhance the use of barley as food, but little is known about the effects of the environment on these nutritional traits. In this study, we evaluated five Moroccan varieties and two elite breeding lines of barley at four locations in Morocco during the 2016-2017 and 2017-2018 cropping seasons. The results showed highly significant differences between genotypes for β-glucan, protein, iron, and selenium contents, as well as 1000 kernel weight, but not zinc content; significant to highly significant differences between environments for all traits except β-glucan content; and significant to highly significant interactions for all traits. The highest level of β-glucan content has reached 11.57% observed at the Sidi El Aydi site during the growing season 2017-2018 for the hulless variety Chifaa. This variety has shown the highest content of β-glucan (6.2-11.57%) over all environments except at Tassaout during the 2016-2017 seasons. The breeding line M9V5 has achieved significantly higher protein content at all the locations during the two growing seasons, ranging from 12.38 to 20.14%. Most hulless lines had significantly higher β-glucan and protein contents, but lower 1000 kernel weight. For micronutrients, the content ranges were 28.94 to 38.23 ppm for Fe, 28.78 to 36.49 ppm for Zn, and 0.14 to 0.18 ppm for Se, with the highest content for Fe and Zn shown by the breeding line M9V5 and Chifaa showing average contents of 33.39 ppm, 35.34 ppm, and 0.18 ppm for Fe, Zn, and Se, respectively. The GGE biplot confirmed the high and relatively stable content of β-glucan and acceptable micronutrient contents of the Chifaa variety and identified Marchouch as the most discriminant site to breed for biofortified barley varieties.

Comparison of Nutritional Composition and Antioxidant Properties of Pulverized and Unutilized Portions of Waxy Barley

To promote the use of waxy barley bran, an underutilized resource, samples of waxy barley were divided into three parts: polished waxy barley powder (PWBP), inner bran layer powder (IBLP), and outer bran layer powder (OBLP). The color and appearance, general properties, minerals, vitamins, β-glucan, antioxidant properties, and aroma of each part were compared. In terms of appearance and color, IBLP and OBLP appeared more yellow than PWBP; general components that were more abundant in IBLP and OBLP compared with PWBP were protein, fat, and ash. IBLP and OBLP had characteristically high values of Mg and Zn, monounsaturated and polyunsaturated fatty acids, vitamin B₁, total polyphenol content, H-ORAC, and DPPH. In particular, the vitamin B₁ content of OBLP was approximately 10 times higher than that of PWBP, and Mg and Zn content was more than five times higher than in PWBP. The β-glucan content of IBLP and OBLP was lower than that of PWBP, but relatively high. GC-MS analysis revealed that hexanal was the aroma component common to all three samples, and the peak areas were in the order of PWBP > OBLP > IBLP.

Association between Dietary Patterns and Metabolic Syndrome and Modification Effect of Altitude: A Cohort Study of Tibetan Adults in China

Little is known about the longitudinal association between dietary patterns (DPs) and metabolic disorders in people living at high altitude areas, such as Tibetans. We constructed the first open cohort, with 1832 Tibetans, and collected data in 2018 and in 2022. The metabolic syndrome (MetS) prevalence was 30.1% (32.3% in men and 28.3% in women). Three different DPs were identified: modern DP (pulses, poultry, offal, and processed meat), urban DP (vegetables, refined grain, beef/mutton, and eggs), and pastoral DP (Tibetan cheese, tsamba, butter/milk tea, and desserts). Participants within the third tertile of the urban DP had a 3.42-fold (95% CI 1.65-7.10) higher risk of MetS than those with the first tertile. Modern DP was positively associated with elevated blood pressure (BP) and elevated triglycerides (TAG), while it was inversely associated with low HDL-C. The urban DP was associated with a higher risk of low HDL-C, but a lower risk of impaired fasting blood glucose (FBG). The pastoral DP was a risk factor for impaired FBG, but protective for central obesity and elevated BP. Associations of modern DP with elevated BP, and pastoral DP with low HDL-C, were modified by altitude. In conclusion, among Tibetan adults, DPs were associated with MetS and its components, and the associations were modified by altitude among Tibetans.

Barley: a potential cereal for producing healthy and functional foods

Barley is the fourth largest cereal crop in the world. It is mainly used for feeding, beer production and food. Barley is receiving more attention from both agricultural and food scientists because of its special chemical composition and health benefits. In comparison with other cereal crops, including wheat, rice and maize, barley grains are rich in dietary fiber (such as β-glucan) and tocols, which are beneficial to human health. It is well proved that diets rich in those chemicals can provide protection against hypertension, cardiovascular disease, and diabetes. Barley has been widely recognized to be great potential as a healthy or functional food. In this review, we present the information about the studies on physical structure of barley grain and the distribution of main chemical components, nutrient and functional composition of barley grain and their health benefits, and the approaches of improving and utilizing the nutrient and functional chemicals in barley grain. With the development of processing technologies, functional components in barley grains, especially β-glucan, can be efficiently extracted and concentrated. Moreover, nutrient and functional components in barley grains can be efficiently improved by precise breeding and agronomic approaches. The review highlights the great potential of barley used as healthy and functional foods, and may be instructive for better utilization of barley in food processing.

Beneficial Effects of Partly Milled Highland Barley on the Prevention of High-Fat Diet-Induced Glycometabolic Disorder and the Modulation of Gut Microbiota in Mice

The nutritional functions of highland barley (HB) are superior to those of regular cereals and have attracted increasing attention in recent years. The objective of this study was to investigate whether partly milled highland barley (PHB) can regulate the serum glucose and lipid disorders of mice fed a high-fat diet (HFD) and to further explore their potential gut microbiota modulatory effect. Our results showed that PHB supplementation significantly reduced fasting blood glucose (FBG) and improved oral glucose tolerance. Histological observations confirmed the ability of PHB to alleviate liver and intestine damage. Furthermore, the results of 16S amplicon sequencing revealed that PHB prevented a HFD-induced gut microbiota dysbiosis, enriching some beneficial bacteria, such as Lactobacillus, Bifidobacterium, and Ileibacterium, and reducing several HFD-dependent taxa (norank_f_Desulfovibrionaceae, Blautia, norank_f_Lachnospiraceae, unclassified_f_Lachnospiraceae, and Colidextribacter). In addition, the increase of Lactobacillus and Bifidobacterium presence has a slightly dose-dependent relationship with the amount of the added PHB. Spearman correlation analysis revealed that Lactobacillus and Bifidobacterium were negatively correlated with the blood glucose level of the oral glucose tolerance test. Overall, our results provide important information about the processing of highland barley to retain its hypoglycemic effect and improve its acceptability and biosafety.

β-Glucan Extracted from Highland Barley Alleviates Dextran Sulfate Sodium-Induced Ulcerative Colitis in C57BL/6J Mice

Inflammatory bowel disease (IBD), which significantly affects human health, has two primary presentations: Crohn's disease and ulcerative colitis (UC). Highland barley is the most common food crop for Tibetans and contains much more β-glucan than any other crop. Highland barley β-glucan (HBBG) can relieve the gastrointestinal dysfunction and promote intestines health. This study aimed to evaluate whether HBBG can relieve UC in mice. A mouse model of UC was established by adding 2% dextran sulfate sodium (DSS) to drinking water for 1 week. UC was alleviated after the introduction of the HBBG diet, as indicated by reductions in the disease activity index (DAI) score, histopathological damage, and the concentration of colonic myeloperoxidase (MPO), along with an improvement in colonic atrophy. Furthermore, we found that HBBG can increase the relative transcriptional levels of genes encoding ZO-1, claudin-1, occludin, and mucin2 (MUC2), thereby reducing intestinal permeability. Additionally, HBBG maintained the balance of proinflammatory and anti-inflammatory cytokines and modulated the structure of the intestinal flora.

Changes in the Nutrient Composition of Barley Grain (Hordeum vulgare L.) and of Morphological Fractions of Sprouts

The objectives of the current study were (1) to evaluate the effect of sprouting on protein, amino acids, fats, fatty acids, starch, total soluble carbohydrates, and ß-D-glucan content of barley grains and (2) to know the content of these nutrients in the morphological fractions of sprouts: green shoot, residual structure of sprouted grain (RSSG), residual structure of sprouted grain plus unsprouted grain (RSSG plus UG), and root fractions and to determine the proportion of each of these fractions (on fresh and dry basis) in the sprout biomass. Barley grain was sprouted in a commercial germination chamber for a period of 6 days. Raw grain was used as a control. Results showed that crude protein, ether extract, total soluble carbohydrates, and cellulose content increased, whereas starch and ß-D-glucan content decreased in sprouted when compared with the control grain. Amino acid and fatty acid profiles were also affected. Thus, aspartic acid, threonine, alanine, valine, isoleucine, lysine, and tryptophan content increased and only that of glutamic acid decreased after sprouting. Regarding fatty acids, an increase in the relative concentration of C18 : 0 and C18:3n-3 and a decrease in that of C18:1n-9 were detected. Partitioning of sprouted barley into three morphological component fractions showed that the residual structures of sprouted grains plus unsprouted grain fraction made up 82.9% and 93.6% of sprout biomass, on fresh and DM basis, respectively, and the remainder was provided by the root fraction, 10.3% and 3.2%, respectively, and by the green shoot fraction, 6.8% and 3.1%, respectively. The three morphological fractions differed in the content of the most analyzed nutrients.

Bioactive Components in Oat and Barley Grain as a Promising Breeding Trend for Functional Food Production

Cereal crops, such as oats and barley, possess a number of valuable properties that meet the requirements for functional diet components. This review summarized the available information about bioactive compounds of oat and barley grain. The results of studying the structure and physicochemical properties of the cell wall polysaccharides of barley and oat are presented. The main components of the flavonoids formation pathway are shown and data, concerning anthocyanins biosynthesis in various barley tissues, are discussed. Moreover, we analyzed the available information about structural and regulatory genes of anthocyanin biosynthesis in Hordeum vulgare L. genome, including β-glucan biosynthesis genes in Avena sativa L species. However, there is not enough knowledge about the genes responsible for biosynthesis of β-glucans and corresponding enzymes and plant polyphenols. The review also covers contemporary studies about collections of oat and barley genetic resources held by the N.I. Vavilov All-Russian Institute of Plant Genetic Resources (VIR). This review intended to provide information on the processes of biosynthesis of biologically active compounds in cereals that will promote further researches devoted to transcription factors controlling expression of structural genes and their role in other physiological processes in higher plants. Found achievements will allow breeders to create new highly productive varieties with the desirable properties.

The Effect of the Addition of Fiber Preparations on the Color of Medium-Grounded Pasteurized and Sterilized Model Canned Meat Products

A beneficial aspect of the use of fiber preparations in the meat industry is the improvement of some quality characteristics of meat products. However, the preparation added in the amount of 3 or 6% may affect their color. The effect of the addition of barley, wheat and oat fiber preparations with different fiber lengths, in quantities allowing the product to be indicated as “high in fiber” or “source of fiber”, to pasteurized or sterilized medium-grounded canned meat products on their color, was determined. In the obtained canned meat products, the basic chemical composition and the L*, a* and b*, C* (Chroma) and h* (hue angle) color components were determined. The addition of the barley fiber preparation BG 300 to the model canned meat products caused a significant (p ≤ 0.05) darkening and an increase in the proportion of yellow color. In an industrial practice, this may result in poorer consumer acceptance of the meat product. Fiber length of wheat and barley fiber had no effect on the color components of products. The 6% addition of the wheat fiber preparations WF 200R and WF 600R or the oat fiber preparations HF 200 and HF 600 caused an apparent lightening of their color (ΔE > 2) compared to the control products.

Wheat, Barley, and Oat Breeding for Health Benefit Components in Grain

Cereal grains provide half of the calories consumed by humans. In addition, they contain important compounds beneficial for health. During the last years, a broad spectrum of new cereal grain-derived products for dietary purposes emerged on the global food market. Special breeding programs aimed at cultivars utilizable for these new products have been launched for both the main sources of staple foods (such as rice, wheat, and maize) and other cereal crops (oat, barley, sorghum, millet, etc.). The breeding paradigm has been switched from traditional grain quality indicators (for example, high breadmaking quality and protein content for common wheat or content of protein, lysine, and starch for barley and oat) to more specialized ones (high content of bioactive compounds, vitamins, dietary fibers, and oils, etc.). To enrich cereal grain with functional components while growing plants in contrast to the post-harvesting improvement of staple foods with natural and synthetic additives, the new breeding programs need a source of genes for the improvement of the content of health benefit components in grain. The current review aims to consider current trends and achievements in wheat, barley, and oat breeding for health-benefiting components. The sources of these valuable genes are plant genetic resources deposited in genebanks: landraces, rare crop species, or even wild relatives of cultivated plants. Traditional plant breeding approaches supplemented with marker-assisted selection and genetic editing, as well as high-throughput chemotyping techniques, are exploited to speed up the breeding for the desired genotуpes. Biochemical and genetic bases for the enrichment of the grain of modern cereal crop cultivars with micronutrients, oils, phenolics, and other compounds are discussed, and certain cases of contributions to special health-improving diets are summarized. Correlations between the content of certain bioactive compounds and the resistance to diseases or tolerance to certain abiotic stressors suggest that breeding programs aimed at raising the levels of health-benefiting components in cereal grain might at the same time match the task of developing cultivars adapted to unfavorable environmental conditions.

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.

Characterization of β-glucan gum for food applications as influenced by genotypic variations in three hulless barley varieties

Three hulless barley varieties were grown under normal conditions during 2017/2018 and 2018/2019, to improve their agronomic yield, and to assess how the genotype influences β-glucan contents, and its structural, thermal, rheological, and functional properties, as intended to be used in food applications. The extracted gums with hot water at 55 °C and pH 8.0, showed contents from 5.75% to 6.41% (w/w), and concentrations from 68.55% to 79.29% of β-glucan, with some starch and protein impurities. The results of the agronomic trail indicated the highly significant (P ≤ 0.01) influence of the genotype on all studied characteristics, and on the β-glucan contents (0.28^** and 0.33^** ) at both seasons. The morphology of the three gums was significantly different in the distribution and structure of networks. Peak intensities of the -OH and -CH groups and CH₂ stretching were higher and wider in Giza129 and Giza131. β-Glucan networks melt from 71.5 to 87.18 °C, and Giza131 exhibited the highest thermal stability. The aqueous dispersions (1%) of β-glucan gums exhibited a non-Newtonian behavior, and Giza130 presented the highest significant (P ≤ 0.05) apparent viscosity (η) and foaming stability. Giza129 showed the highest significant water and fat binding capacities, whereas Giza131 showed the highest significant foaming capacity. β-Glucan gums showed different potentials in food applications as fat replacers, stabilizers, thickeners, and foaming agents in food systems. This study suggests planting the proper barley variety in breeding and genetic improvement programs to supply the food industry with the expected β-glucan content with consistent structural, thermal, rheological, and functional properties. PRACTICAL APPLICATION: β-Glucans play an important technological role in processed foods. Little current information is available on β-glucan contents, and its potentiality on food applications, as influenced by variability among hulless barley genotypes. Accordingly, knowledge of β-glucan levels in barley varieties is a valuable attribute for both consumers and food processors, and it will create an opportunity for scientific cooperation between food technologist and breeders to identify the suitable barley varieties to be used in breeding programs, to obtain barley with required β-glucan contents, targeted for specific end uses.

Purification, Preliminary Structural Characterization, and In Vitro Inhibitory Effect on Digestive Enzymes by β-Glucan from Qingke (Tibetan Hulless Barley)

Background and Objective. Qingke (Tibetan hulless barley, Hordeum vulgare L.) contains a high content of β-glucan among all the cereal varieties. Although β-glucan has multiple physiological functions, the physiological function of qingke β-glucan was few studied. In this study, the β-glucan was isolated, purified, determined the structural characterization, and measured the inhibitory activity to enzymes correlating blood sugar and lipid. Methods. β-Glucan was isolated from enzymatic aqueous extract of qingke by using deproteinization, decolorization, DEAE-52 column chromatography, and sepharose CL-4B agarose gel column chromatography. The structure of the β-glucan was determined using FT-IR and 13C-NMR spectra analysis, and molecular mass by use of HPSEC-dRI-LS. The kinematic viscosity was measured. The inhibitory effects of this β-glucan on four enzymes were investigated. Results. This β-glucan had a uniform molecular weight of 201,000 Da with β-(1⟶4) as the main chain and β-(1⟶3) as a side chain. The β-glucan presented a relatively strong inhibitory activity on α-glucosidase, moderate inhibition on invertase, and a weak inhibition on α-amylase, whereas it did not inhibit lipase. Conclusion. The study indicates that the enzymatic β-glucan from qingke has the potential as natural auxiliary hypoglycemic additives in functional medicine or foods.

IRS-1/PI3K/Akt pathway and miRNAs are involved in whole grain highland barley (Hordeum vulgareL.) ameliorating hyperglycemia of db/db mice

The present investigation further unravels the underlying molecular mechanism of WGH on T2DM: IRS-1/PI3K/Akt pathway and related miRNA expression.

Genetic variation of HvXYN1 associated with endoxylanase activity and TAX content in barley (Hordeum vulgare L.)

BACKGROUND

Endo-β-1,4-xylanase1 (EA), the key endoxylanase in plants, is involved in the degradation of arabinoxylan during grain germination. In barley (Hordeum vulgare L.), one gene (HvXYN-1) that encode a endo-beta-1,4-xylanase, has been cloned. However, the single nucleotide polymorphisms (SNPs) that affect the endoxylanase activity and total arabinoxylan (TAX) content have yet to be characterized. The investigation of genetic variation in HvXYN1 may facilitate a better understanding of the relationship between TAX content and EA activity in barley.

RESULTS

In the current study, 56 polymorphisms were detected in HvXYN1 among 210 barley accessions collected from 34 countries, with 10 distinct haplotypes identified. The SNPs at positions 110, 305, 1045, 1417, 1504, 1597, 1880 bp in the genomic region of HvXYN1 were significantly associated with EA activity (P < 0.0001), and the sites 110, 305, and 1045 were highly significantly associated with TAX content. The amount of phenotypic variation in a given trait explained by each associated polymorphism ranged from 6.96 to 9.85%. Most notably, we found two variants at positions 1504 bp and 1880 bp in the second exon that significantly (P < 0.0001) affected EA activity; this result could be used in breeding programs to improve beer quality. In addition, African accessions had the highest EA activity and TAX content, and the richest germplasm resources were from Asia, indicating the high potential value of Asian barley.

CONCLUSION

This study provided insight into understanding the relationship, EA activity, TAX content with the SNPs of HvXYN1 in barley. These SNPs can be applied as DNA markers in breeding programs to improve the quality of barley for beer brewing after further validation.

Hypocholesterolaemic effect of whole-grain highland hull-less barley in rats fed a high-fat diet

Whole-grain highland hull-less barley (WHLB) contains high amounts of bioactive compounds that potentially exhibit cholesterol-lowering effects. This study investigated the hypocholesterolaemic effect of WHLB. A total of seventy-two male Sprague–Dawley rats were divided into four groups and were fed with the normal control diet, high-fat diet (HFD) and HFD containing low or high dose (10 or 48·95 %) of WHLB. High dose of WHLB significantly decreased the organ indexes of liver and abdominal fat and lipid levels of plasma and liver in HFD rats. The lipid regulation effect of WHLB, which was reconfirmed through hepatocyte morphologic observation, was accompanied by a large excretion of bile acids in the small intestinal contents and the faeces. Real-time PCR analyses, which were further reconfirmed through Western blot analyses, revealed that a high dose of WHLB significantly enhanced the hepatic expressions of AMP-activated protein kinase α, cholesterol 7α-hydroxylase, LDL receptor, liver X receptor, and PPARα and decreased the expression of 3-hydroxy-3-methylglutaryl coenzyme A reductase. It also enhanced the ileal expression of farnesoid X receptor and resulted in the decrease of expression of apical sodium-dependent bile acid transporter. WHLB exhibited hypocholesterolaemic effects mainly by inhibiting cholesterol synthesis, cholesterol accumulation in peripheral tissue, and bile acid reabsorption and by stimulating bile acid synthesis.

Free and Bound Phenolic Compound Content and Antioxidant Activity of Different Cultivated Blue Highland Barley Varieties from the Qinghai-Tibet Plateau

In this study, the polyphenols composition and antioxidant properties of 12 blue highland barley varieties planted on the Qinghai-Tibet Plateau area were measured. The contents of the free, bound and total phenolic acids varied between 166.20–237.60, 170.10–240.75 and 336.29–453.94 mg of gallic acid equivalents per 100 g of dry weight (DW) blue highland barley grains, while the free and bound phenolic acids accounted for 50.09% and 49.91% of the total phenolic acids, respectively. The contents of the free, bound and total flavones varied among 20.61–25.59, 14.91–22.38 and 37.91–47.98 mg of catechin equivalents per 100 g of dry weight (DW) of blue highland barley grains, while the free and bound flavones accounted for 55.90% and 44.10% of the total flavones, respectively. The prominent phenolic compounds in the blue hulless barley grains were gallic acid, benzoic acid, syringic acid, 4-coumaric acid, naringenin, hesperidin, rutin, (+)-catechin and quercetin. Among these, protocatechuic acid, chlorogenic acid and (+)-catechin were the major phenolic compounds in the free phenolics extract. The most abundant bound phenolics were gallic acid, benzoic acid, syringic acid, 4-coumaric acid, benzoic acid, dimethoxybenzoic acid, naringenin, hesperidin, quercetin and rutin. The average contribution of the bound phenolic extract to the DPPH^• free radical scavenging capacity was higher than 86%, that of free phenolic extract to the ABTS^•+ free radical scavenging capacity was higher than 79%, and that of free phenolic (53%) to the FRAP antioxidant activity was equivalent to that of the bound phenol extract (47%). In addition, the planting environment exerts a very important influence on the polyphenol composition, content and antioxidant activity of blue highland barley. The correlation analysis showed that 2,4-hydroxybenzoic acid and protocatechuic acid were the main contributors to the DPPH^• and ABTS^•+ free radical scavenging capacity in the free phenolic extract, while chlorogenic acid, vanillic acid, ferulic acid and quercetin were the main contributors to the free radical scavenging capacity in the bound phenol extract. The study results show that the blue highland barley grains have rich phenolic compounds and high antioxidant activity, as well as significant varietal differences. The free and bound phenolic extracts in the blue hulless barley grains have an equivalent proportion in the total phenol, and co-exist in two forms. They can be used as a potential valuable source of natural antioxidants, and can aid in enhancing the development and daily consumption of foods relating to blue highland barley.

Whole Tibetan Hull-Less Barley Exhibit Stronger Effect on Promoting Growth of Genus Bifidobacterium than Refined Barley In Vitro

The gut microbiota has recently become a new route for research at the intersection of diet and human health. The aim of this study was to investigate whether whole Tibetan hull-less barley (WHB) and refined Tibetan hull-less barley (RHB) caused differentiation of the fecal microbiota in vitro. The microbiota-accessible ingredients in the 2 barley samples were studied using an in vitro enzymatic digestion procedure. After in vitro digestion, insoluble dietary fiber, phenolic compounds, proteins, and β-glucans were 93.2%, 103.4%. 18.8%, and 10.2% higher provided by WHB flour as compared with RHB flour based on the same mass amount. However, due to the significantly higher content of insoluble dietary fiber, WHB digesta had lower percentage contents of fast fermentable substrates including dietary fiber and starch as compared with RHB digesta. The results of Next-generation sequencing of the bacterial 16SrRNA gene showed that both WHB and RHB fermentation had significantly promoted the growth of Bifidobacterium and inhibited the growth of pathogenic bacteria such as Dorea, Escherichia, Oscillopira, and Ruminococcus. Moreover, in response to WHB fermentation, the relative abundance of Bifidobacterium increased by 78.5% and 92.8% as compared with RHB and fructo-oligosaccharides (FOs). Both WHB and RHB are good sources of fermentable dietary fiber with the ability to yield high concentration of short chain fatty acids (SCFAs) as compared to FOs. However, the higher fraction of soluble fiber in RHB digesta increase higher amounts of SCFA compared with WHB digesta. Our findings shed light on the complex interactions of whole cereals with gut microbiota and the possible impact on host health.

PRACTICAL APPLICATION

Until now, only few reports have regarded the impact of in vitro digestion in components of whole grain with complex food matrix. Moreover, our findings shed light on the complex interactions of whole cereals with gut microbiota and the possible impact on host health.

Physio-biochemical and molecular mechanism underlying the enhanced heavy metal tolerance in highland barley seedlings pre-treated with low-dose gamma irradiation

Heavy metal pollution, as a consequence of rapid industrialization and urbanization, poses a threat to highland barley grown in Tibet. This study investigates the effect of different doses of gamma irradiation (50–300 Gy) on the physio-biochemical and molecular mechanism of highland barley under heavy metal stress. Growth data showed that 50-Gy gamma irradiation had the maximal beneficial effects on the highland barley seedlings under lead/cadmium stress. The results of oxidative parameters demonstrated that 50-Gy gamma-irradiated seedlings had lower hydrogen peroxide and malondialdehyde contents under lead/cadmium stress compared to non-irradiated seedlings. Moreover, the activities of antioxidant enzyme and proline levels in 50-Gy gamma-irradiated seedlings were drastically higher than those in non-irradiated seedlings under lead/cadmium stress. Additionally, transmission electron microscopy results revealed that the 50-Gy gamma-irradiated seedlings exhibited improved chloroplasts ultrastructure compared with non-irradiated seedlings exposed to lead/cadmium stress. Notably, transcriptional expression analysis showed that 50-Gy gamma irradiation could significantly affect the expression of genes related to heavy metal transport and abscisic acid metabolism under lead/cadmium stress. Collectively, these results provide insights into the physio-biochemical and molecular mechanisms of low-dose-gamma-irradiation-enhanced heavy metal tolerance in highland barley seedlings, thus proposing gamma irradiation as a potential technology to mitigate heavy metal toxicity in crops.

Effect of Whole Grain Qingke (Tibetan Hordeum vulgare L. Zangqing 320) on the Serum Lipid Levels and Intestinal Microbiota of Rats under High-Fat Diet

This study investigated the hypolipidemic effect of whole grain Qingke (WGQ) and its influence on intestinal microbiota. Changes in the serum lipid, intestinal environment, and microbiota of Sprague-Dawley rats fed high-fat diets supplemented with different doses of WGQ were determined. Results showed that high doses of WGQ significantly decreased (P < 0.05) the Lee's index, serum total cholesterol, low-density lipoprotein cholesterol, and non-high-density lipoprotein cholesterol levels whereas they increased the body weight of the rats. Cecal weight and short-chain fatty acid (SCFA) concentration increased with increasing WGQ dose. An Illumina-based sequencing approach showed that the relative abundance of putative SCFA-producing bacteria Prevotella and Anaerovibrio increased in the rats fed the WGQ diet. Principal component analysis revealed a significant difference in intestinal microbiota composition after the administration of the WGQ diet. These findings provide insights into the contribution of the intestinal microbiota to the hypolipidemic effect of WGQ.

Mass Spectrometric Imaging of Wheat (Triticum spp.) and Barley (Hordeum vulgare L.) Cultivars: Distribution of Major Cell Wall Polysaccharides According to Their Main Structural Features

Arabinoxylans (AX) and (1→3),(1→4)-β-glucans (BG) are the main components of cereal cell walls and influence many aspects of their end uses. Important variations in the composition and structure of these polysaccharides have been reported among cereals and cultivars of a given species. In this work, the spatial distribution of AX and BG in the endosperm of mature grains was established for nine wheat varieties and eight barley varieties using enzymatically assisted mass spectrometry imaging (MSI). Important structural features of the AX and BG polymers that were previously shown to influence their physicochemical properties were assessed. Differences in the distribution of AX and BG structures were observed, both within the endosperm of a given cultivar and between wheat and barley cultivars. This study provides a unique picture of the structural heterogeneity of AX and BG polysaccharides at the scale of the whole endosperm in a series of wheat and barley cultivars. Thus, it can participate meaningfully in a strategy aiming at understanding the structure-function relationships of these two polymers.

Response of soil respiration to experimental warming in a highland barley of the Tibet

Highland barley is an important dominant crop in the Tibet and the croplands of the Tibet are experiencing obvious climatic warming. However, information about how soil respiration will respond to climatic warming in the highland barley system is still lacking. A field warming experiment using infrared heaters with two warming magnitudes was conducted in a highland barley system of the Tibet in May 2014. Five daily cycles of soil respiration was measured using a CO₂ flux system (Li-8100, Li-COR Biosciences, Lincoln, NE, USA) during the period from early June to early September in 2014. The high and low experimental warming significantly increased soil temperature by 1.98 and 1.52 °C over the whole study period, respectively. The high experimental warming significantly decreased soil moisture. Soil respiration and its temperature sensitivity did not significantly change under both the high and low experimental warming. The response of soil respiration to experimental warming did not linearly correlate with warming magnitudes because a greater experimental warming resulted in a higher soil drying. Our findings suggested that clarifying the response of soil CO₂ production and its temperature sensitivity to climatic warming need consider water availability in the highland barley system of the Tibet.

Purification and characterisation of arabinoxylan arabinofuranohydrolase I responsible for the filterability of barley malt

Dan'er is a widely grown malt barley cultivar in China, but its filterability defects have severely impeded its application in beer brewing. Previous investigations have suggested that we should identify the malt filterability correlated proteins, one of which was postulated to be arabinoxylan arabinofuranohydrolase I (AXAH-I). To verify this hypothesis, we purified AXAH-I from Dan'er malt, characterised its enzyme performance, and investigated its influence on filterability by adding different amounts of purified enzyme to the mash. With 6 mU g(-1) malt AXAH-I supplemented, the wort separation rate increased by 31.8%, viscosity decreased by 3.6%, and the endosperm reserve contents declined concomitantly. Unexpectedly, the wort turbidity increased with increasing AXAH-I. We also tried to optimise the use of currently available commercial enzyme products for filterability improvement in beer brewing, by supplementing them with purified AXAH-I and β-amylase. AXAH-I could be a functional component for novel commercial enzyme products in the beer industry.

Intake of Tibetan hull-less barley is associated with a reduced risk of metabolic related syndrome in rats fed high-fat-sucrose diets

The objective of this study was to assess the effects of whole grain Tibetan hull-less barley on metabolic related syndrome induced by high-fat-sucrose diets in rats. The diets were designed to reflect the dietary patterns of Chinese individuals (>30% energy fat) with refined wheat flour (HFS-W) or Tibetan hull-less barley (HFS-THB) as the main carbohydrate sources. Rats fed HFS-W had increased body weight, abdominal fat deposition, liver weight, liver fat deposition, triglyceride (TG), fasting blood glucose (FBG), serum fasting insulin (FINS), and homeostasis model assessment of insulin resistance (HOMA-IR) scores, and decreased low-density lipoprotein cholesterol (LDL-C) levels compared to rats fed a basal diet (BD). However, rats fed HFS-THB had reduced body weight gain, dyslipidemia, and insulin resistance. These findings indicate that whole Tibetan hull-less barley is a functional food that can reduce the prevalence of metabolic related syndrome induced by high-fat-sucrose diets.