Ultrafine grinding improves the nutritional, physicochemical, and antioxidant activities of two varieties of whole-grain highland barley

Effects of ultrafine grinding on the nutritional profile, physicochemical properties, and antioxidant activities of whole-grain highland barley (HB) including white highland barley (WHB) and black highland barley (BHB) were studied. Whole-grain HB was regularly ground and sieved through 80 mesh get 80 M powder, and HB was ultrafine grounded and sieved through 80 mesh, 150 mesh, and 200 mesh get 80UMM, 150UMM, and 200UMM samples. Particle size of WHB and BHB reduced significantly after ultrafine grinding. As the particle size decreased, moisture content of WHB and BHB decreased significantly, whereas fat content increased significantly. Redistribution of fiber components in WHB and BHB from insoluble to soluble fractions was also observed. Wherein, content of soluble pentosan of WHB and BHB increased significantly from 0.56% and 0.78% (80 M) to 0.91% and 1.14% (200UMM), respectively. Damaged starch of WHB and BHB increased significantly from 8.16% and 8.21% (80 M) to 10.29% and 10.07% (200UMM), respectively. Content of phenolic acid and flavonoid of WHB and BHB and associated antioxidant capacity were increased after ultrafine grinding. Color of L* value increased significantly, a* and b* values decreased significantly, indicating the whiteness of WHB and BHB was increased after ultrafine grinding. Pasting temperature of WHB and BHB decreased, whereas peak viscosity increased. X-ray diffraction patterns of HB showed typical A- and V-style polymorphs and the relative crystallinity of HB decreased as the particle size decreased. Taken together, ultrafine grinding has shown great potential in improving the nutritional, physiochemical, and antioxidant properties of whole-grain HB. Our research findings could help better understand the ultrafine grinded whole grain HB in food industry.

The Quality Evaluation of Highland Barley and Its Suitability for Chinese Traditional Tsampa Processing

The physicochemical traits of highland barley prominently affect the quality of Tsampa. To find out the relevance between the physicochemical properties of raw material and the texture parameters of processed products, twenty-five physicochemical traits and ten quality parameters for seventy-six varieties of highland barley were measured and analyzed. The results showed that there was a significant difference between the physicochemical indexes for highland barleys of various colors. The dark highland barley generally has more fat, protein, total dietary fiber, phenolic, Mg, K, Ca, and Zn and less amylose, Fe, Cu, and Mo than light colored barley. Then, these highland barleys were made into Tsampa. A comprehensive quality evaluation model based on the color and texture parameters of Tsampa was established through principal component analysis. Then, cluster analysis was used to classify the tested samples into three edible quality grades predicated on the above evaluation model. At last, the regression analysis was applied to establish a Tsampa quality predictive model according to the physicochemical traits of the raw material. The results showed that amylose, protein, β-Glucan, and a* and b* could be used to predict the comprehensive quality of Tsampa. The predicted results indicated that 11 of 14 validated samples were consistent with the actual quality, and the accuracy was above 78.57%. Our study built the approach of the appropriate processing varieties evaluation. It may provide reference for processing specific highland barley.

Structural Characterization and Antioxidant Activity of β-Glucans from Highland Barley Obtained with Ultrasonic-Microwave-Assisted Extraction

In order to efficiently extract β-glucan from highland barley (HBG) and study its structural characterization and antioxidant activity, ultrasonic-microwave-assisted extraction (UME) was optimized by the response surface method (RSM). Under the optimal extraction conditions of 25.05 mL/g liquid-solid ratio, 20 min ultrasonic time, and 480 W microwave intensity, the DPPH radical scavenging activity of HBG reached 25.67%. Two polysaccharide fractions were purified from HBG, namely HBG-1 and HBG-2. Structural characterization indicated that HBG-1 and HBG-2 had similar functional groups, glycosidic linkages, and linear and complex chain conformation. HBG-1 was mainly composed of glucose (98.97%), while HBG-2 primarily consisted of arabinose (38.23%), galactose (22.01%), and xylose (31.60%). The molecular weight of HBG-1 was much smaller than that of HBG-2. Both HBG-1 and HBG-2 exhibited concentration-dependent antioxidant activity, and HBG-1 was more active. This study provided insights into the efficient extraction of HBG and further investigated the structure and antioxidant activities of purified components HBG-1 and HBG-2. Meanwhile, the results of this study imply that HBG has the potential to be an antioxidant in foods and cosmetics.

Characteristics of Highland Barley-Wheat Composite Flour and Its Effect on the Properties of Coating Batter and Deep-Fried Meat

Highland barley flour-based coating batter has rarely been reported, although highland barley flour is promising due to its high β-glucan and amylose content. In this study, highland barley flour was used to substitute 40% to 80% of wheat flour to form a highland barely-wheat composite flour used in the coating batter. The characteristics of the highland barley-wheat composite flour and its effect on the properties of coating batter and deep-fried meat were analyzed. Results showed that the composite flour significantly improved water holding capacity, oil absorbing capacity, and water solubility index. In contrast, no significant change was observed in the water absorption index or swelling power. The incorporation of highland barley flour significantly changed the pasting properties of the composite flour. Compared with the wheat flour, the viscosity and the pickup of the coating batter made with composite flour increased from 4905 Pa·s and 0.53% to more than 12,252 Pa·s and 0.63%, respectively, and its water mobility decreased. These changes were closely related to the substitution rate of highland barley flour. The composite flour significantly increased the moisture content from 27.73% to more than 33.03% and decreased the oil content of the crust from 19.15% to lower than 16.44%, respectively. It decreased L* and increased a* of the crust and decreased the hardness, adhesiveness, and springiness of the deep-fried meat. A spongy inner structure with a flatter surface was formed in all composite flour-based crusts, and the substitution rate influenced the flatness of the crust. Thus, highland barley flour could be used for batter preparation with partial substitution, enhancing the quality of deep-fried meat and acting as an oil barrier-forming ingredient for fried batter foods.

Whole-Grain Highland Barley Attenuates Atherosclerosis Associated with NLRP3 Inflammasome Pathway and Gut Microbiota in ApoE-/- Mice

The efficacy and mechanism of highland barley in the treatment of atherosclerosis have received little attention. Herein, we aimed to explore whether highland barley supplementation can prevent atherosclerosis progression and improve gut microbiota disorder in apolipoprotein E knockout (ApoE-/-) mice. Male ApoE-/- mice were fed a high-fat diet with whole-grain highland barley (WHB) or refined highland barley for 18 weeks. WHB substantially inhibited the formation of atherosclerotic plaques, reduced serum tumor necrosis factor-α, and downregulated the expression of NLRP3 in the aorta. Furthermore, the 16S rRNA analysis revealed that highland barley supplementation helped to restore the dysregulation of the gut microbiota, as evidenced by an increase in the relative abundance of specific beneficial bacteria known for their anti-inflammatory properties, such as Lachnospiraceae, Lactobacillus, Muribaculaceae, and Bifidobacterium. Highland barley supplementation might alleviate atherosclerotic plaque formation by modulating the NLRP3 inflammasome pathway and the synthesis of anti-inflammatory metabolites by the gut microbiota.

The Composition, Structure, and Functionalities of Prolamins from Highland Barley

The composition, structure, and functionalities of prolamins from highland barley were investigated. These parameters were compared with those of the commonly applied prolamins (zein). There are more charged and hydrophilic amino acids in highland barely prolamins than zein. The molecular weight of highland barely prolamins was between 30 and 63 kDa, which was larger than that of zein (20 and 24 kDa). The main secondary structure of highland barely prolamins was β-turn helices, while α-helical structures were the main secondary structure in zein. The water holding capacity, thermal stability, emulsifying capacity, and stability of prolamins from highland barley were significantly higher than in zein, while the opposite results were observed for oil absorption capacity between the two. The diameter of fibers prepared using highland barely prolamins was almost six times that of zein, while highland barely prolamins formed ribbon structures instead of fibers. Therefore, the results provide guidance for applications of prolamins from highland barley.

Study on the Changes in Volatile Flavor Compounds in Whole Highland Barley Flour during Accelerated Storage after Different Processing Methods

The effect of heat processing on the flavor characteristics of highland barley flour (HBF) in storage was revealed by analyzing differences in volatile compounds associated with flavor deterioration in HBF using GC-MS identification and relative odor activity values (ROAVs). Hydrocarbons were the most abundant in untreated and extrusion puffed HBFs, while heterocycles were found to be the most abundant in explosion puffed, baked, and fried HBFs. The major contributors to the deterioration of flavor in different HBFs were hexanal, hexanoic acid, 2-pentylfuran, 1-pentanol, pentanal, 1-octen-3-ol, octanal, 2-butyl-2-octanal, and (E,E)-2,4-decadienal. Amino acid and fatty acid metabolism was ascribed to the main formation pathways of these compounds. Baking slowed down the flavor deterioration in HBF, while extrusion puffing accelerated the flavor deterioration in HBF. The screened key compounds could predict the quality of HBF. This study provides a theoretical basis for the regulation of the flavor quality of barley and its products.

Impact of Processing Methods on the In Vitro Protein Digestibility and DIAAS of Various Foods Produced by Millet, Highland Barley and Buckwheat

Cereals are rich sources of dietary protein, whose nutritional assessments are often performed on raw grains or protein isolates. However, processing and gastrointestinal digestion may affect amino acid (AA) compositions, then change the protein quality. In this study, we determined the digestibility and AA compositions of various foods produced by whole grains (PG) or flour (PF) from three cereals (millet, highland barley and buckwheat) and analyzed the impact of processing methods on the digestible indispensable amino acid score (DIAAS) using the INFOGEST protocol. The in vitro protein digestibility of cereal-based foods was lower than raw grains, and PF showed a better digestion property than PG. The intestinal digestibility of individual AA within a food varied widely, and the digestibility of Cys and Ile was the lowest among all AAs. The DIAAS values of PG were lower than those of PF in each kind of cereal, and PF of buckwheat had the highest DIAAS value, followed by highland barley. The first limiting AA was still Lys for millet and highland barley compared to the raw grains; however, for buckwheat it was Leu. This study provided nutritional information on cereal products and helped to guide the collocation of different foods in diets.

Physicochemical Characterizations, Digestibility, and Lipolysis Inhibitory Effects of Highland Barley Resistant Starches Prepared by Physical and Enzymatic Methods

This study aimed to investigate the differences in the physicochemical and structural characteristics, digestibility, and lipolysis inhibitory potential in vitro of highland barley resistant starches (HBRSs) prepared by autoclaving (HBSA), microwave-assisted autoclaving (HBSM), isoamylase (HBSI) and pullulanase (HBSP) debranching modifications. Results revealed that the resistant starch content of native starch was significantly elevated after modifications. HBSA and HBSM showed distinctly higher swelling power and water-binding capacities along with lower amylose amounts and solubilities than those of HBSI and HBSP (p < 0.05). Fourier transform infrared spectroscopy and X-ray diffraction exhibited that HBSP displayed the highest degree of the ordered crystalline region and crystallinity with a mixture of C_B- and V-type polymorphs. Meanwhile, HBSA and HBSM were characterized by their high degree of the amorphous region with a mixture of B- and V-type polymorphs. Physical and enzymatic modifications resulted in different functionalities of HBRSs, among which HBSP showed the lowest digestibility and HBSM exhibited the highest inhibitory activity on lipolysis due to their structure and structure-based morphology and particle size. This study provided significant insights into the development of native starch from highland barley as an alternative functional food.

Impacts of Proanthocyanidin Binding on Conformational and Functional Properties of Decolorized Highland Barley Protein

The impacts of interaction between proanthocyanidin (PC) and decolorized highland barley protein (DHBP) at pH 7 and 9 on the functional and conformational changes in DHBP were investigated. It was shown that PC strongly quenched the intrinsic fluorescence of DHBP primarily through static quenching. PC and DHBP were mainly bound by hydrophobic interactions. Additionally, free sulfhydryl groups and surface hydrophobicity obviously decreased in DHBP after combining with PC. The zeta potential of DHBP-PC complexes at pH 7 increased significantly. A change in the structure of DHBP was caused by interactions with PC, resulting in an increase in the number of β-sheets, a decrease in the number of α-helixes, and a spectral shift in the amide Ⅱ band. Furthermore, the presence of PC enhanced the foaming properties and antioxidant activity of DHBP. Overall, this study suggests that DHBP-PC complexes at pH 7 could be designed as a stable additive, and illustrates the potential applications of DHBP-PC complexes in the food industry.

Enzyme inactivation induced by thermal stabilization in highland barley and impact on lipid oxidation and aroma profiles

Thermal stabilization is efficient for slowing lipid degradation and prolonging the shelf life of highland barley, but the impacts of different thermal stabilized treatments on highland barley and possible chemical reactions remain unclear. The effects of thermal stabilization treatments (bake, far-infrared, fry, microwave and steam) on the enzymes, lipids and aroma profiles of highland barley flour (HBF) were investigated in this study. Thermal stabilization significantly decreased the contents of ash and GABA. Baked HBF exhibited the lowest fatty acid value and peroxide value. Untreated HBF had higher lipase and lipoxygenase activities and fried mostly inactivated these enzymes. All thermal stabilization treatments increased the catalase activities and fried showed the higher level. Thus, fried might be an effective method to stabilize the HBF. The high temperatures during stabilizing triggered the complex reactions, leading to the loss of some volatile compounds, and in the meantime the formation of others such as furans and aldehydes. These productions contributed to the unique aroma profiles of different HBFs. Furthermore, a chemometric approach was used to analyze the changes of thermal stabilized treated HBFs and to identity six key volatile compounds, which provided important knowledge on possible chemical reactions caused by thermal stabilization. Overall, these results provide the theoretical basis for the wider application of thermal stabilization technologies in highland barley processing.

Integrated transcriptomic and metabolomic analyses of the molecular mechanisms of two highland barley genotypes with pyroxsulam responses

Highland barley is one of the few crops that can be grown at high elevations, making it a key resource within the Tibet Plateau. Weeds are a significant threat to highland barley production, and new herbicides and tolerant barley varieties are needed to control this ever-growing problem. A better understanding of existing herbicide resistance mechanisms is therefore needed. In this study, transcriptomic and metabolomic analyses were used to identify molecular and physiological changes in two highland barley genotypes with differing sensitivities to the herbicide pyroxsulam. We identified several stress-responsive metabolites, including flavonoids and antioxidants, which accumulated to significantly higher levels in the pyroxsulam-resistant genotype. Additionally, we found key genes in both the flavonoid biosynthesis pathway and the antioxidant system that were up-regulated in pyroxsulam-resistant barley. This work significantly expands on the current understanding of the molecular mechanisms underlying differing pyroxsulam tolerance among barley genotypes and provides several new avenues to explore for breeding or engineering tolerant barley.

Deciphering the core seed endo-bacteriome of the highland barley in Tibet plateau

Highland barley (Hordeum vulgare var. nudum (L.) Hook.f., qingke) has unique physical and chemical properties and good potential for industrial applications. As the only crop that can be grown at high altitudes of 4200-4500 m, qingke is well adapted to extreme habitats at high altitudes. In this study, we analysed the seed bacterial community of 58 genotypes of qingke grown in different regions of Tibet, including qingke landraces, modern cultivars, and winter barley varieties, and characterised endophytic bacterial communities in seeds from different sources and the core endo-bacteriome of qingke. This study aim to provide a reference for the application of seed endophytes as biological inoculants for sustainable agricultural production and for considering microbe-plant interactions in breeding strategies. A total of 174 qingke seed samples from five main agricultural regions in Tibet were collected and subjected to investigation of endophytic endo-bacteriome using high-throughput sequencing and bioinformatics approaches. The phyla of endophytic bacteria in qingke seeds from different sources were similar; however, the relative proportions of each phylum were different. Different environmental conditions, growth strategies, and modern breeding processes have significantly changed the community structure of endophytic bacteria in seeds, among which the growth strategy has a greater impact on the diversity of endophytic bacteria in seeds. Seeds from different sources have conserved beneficial core endo-bacteriome. The core endo-bacteriome of qingke seeds dominated by Enterobacteriaceae may maintain qingke growth by promoting plant growth and assisting plants in resisting pests and diseases. This study reveals the core endo-bacteriome of qingke seeds and provides a basis for exploiting the endophytic endo-bacteriome of qingke seeds.

Polyphenol and Anthocyanin Composition and Activity of Highland Barley with Different Colors

In this research, the composition of free phenols, bound phenols, and anthocyanins and their in vitro antioxidant activity and in vitro α-glucosidase inhibiting activity were observed in different barley colors. The outcomes revealed that the contents of total phenols (570.78 mg/100 gDW), total flavonoids (47.08 mg/100 gDW), and anthocyanins (48.07 mg/100 g) were the highest in purple barley. Furthermore, the structure, composition, and concentration of phenolics differed depending on the colors of barley. The types and contents of bound total phenolic acids and flavonoids were greater than those of free total phenolic acids and flavonoids. The main phenolic acids in blue barley were cinnamic acid polyphenols, whereas in black, yellow, and purple barley, benzoic acid polyphenols were the main phenolic acids, and the main types of flavonoids in black and blue barley were chalcones and flavanones, respectively, whereas flavonol was the main type of flavonoid in yellow and purple barley. Moreover, cornflower pigment-3-glucoside was the major anthocyanin in blue, yellow, and purple barley, whereas the main anthocyanin in black barley was delphinidin-3-glucoside. The dark color of barley indicated richness in the anthocyanins. In addition, the free polyphenol fractions had stronger DPPH and ABTS radical scavenging capacity as compared to the bound ones. In vitro α-glucosidase-inhibiting activity was greater in bound polyphenols than in free polyphenols, with differences between different varieties of barley. Purple barley phenolic fractions had the greatest ABTS radical scavenging and iron ion reduction capacities, as well as the highest α-glucosidase-inhibiting activity. The strongest DPPH radical scavenging capacity was found in yellow barley, while the strongest in vitro α-glucosidase-inhibiting activity was found in anthocyanins isolated from black barley. Furthermore, in different colors of barley, there was a strong association between the concentration of specific phenolic compounds and antioxidant and α-glucosidase-inhibiting activities. The outcomes of this study revealed that all colored barley seeds tested were high in phenolic compounds, and had a good antioxidant impact and α-glucosidase-inhibiting activity. As a result, colored barley can serve as an antioxidant and hypoglycemic food. Polyphenols extracted from purple barley and anthocyanins extracted from black barley stand out among them.

Effect of an Environment Friendly Heat and Relative Humidity Approach on γ-Aminobutyric Acid Accumulation in Different Highland Barley Cultivars

In this study, heat and relative humidity (HRH) treatment was applied in highland barley for γ-aminobutyric acid (GABA) accumulation. Tibetan highland barley cultivars (25) were selected for comparison and analysis. HRH treatment could accumulate GABA in several hours with low moisture content and high temperature, and the grains were treated for 2.5 h at 65 °C in this study. The GABA content of processed grains under HRH optimal condition ranged from 26.91 to 76.28 mg·100 g−1, which was significantly higher than the initial content (12.78−43.00 mg·100 g−1). The highest GABA accumulation capacity was observed in two-row yellow cultivars (YT1), increasing from 36.52 to 76.28 mg·100 g−1. Correlation analysis showed that the accumulation of GABA after HRH treatment was positively and significantly (p < 0.05) correlated with the contents of protein (0.52), total free amino acids (0.68), threonine (0.53), serine (0.51), glutamate (0.69), glycine (0.49), alanine (0.46), cysteine (0.57), tyrosine (0.50), lysine (0.53), proline (0.40), and glutamate decarboxylase (GAD) activity (0.62), which were closely related to GABA-shunt pathway. The polyamines contents, diamine oxidase (DAO) and polyamine oxidase (PAO) activities, as the substrates and critical enzymes of polyamine degradation pathway, showed no significant correlation with GABA accumulation. The results suggested that the main pathway of GABA accumulation in highland barley under HRH treatment was GABA-shunt pathway.

Procyanidin B1 and p-Coumaric Acid from Highland Barley Grain Showed Synergistic Effect on Modulating Glucose Metabolism via IRS-1/PI3K/Akt Pathway

INTRODUCTION

Phenolic extract in highland barley grain has showed hypoglycemic effect, while little information is available about the active compounds and whether there exist additive or synergistic effect on modulating glucose metabolism.

METHODS AND RESULTS

Procyanidin B1 (PB) and p-coumaric acid (CA) are the active compounds in highland barley grain and show synergistic effect on improving glucose uptake and glycogen synthesis by upregulating glucose transporter (GLUT4) and downregulating glycogen synthase kinase-3β (GSK-3β) protein expression, respectively. The mechanism may be attributed to target insulin receptor (IRβ) and regulate insulin receptor substrate-1 (IRS-1)/phosphatidylinositol 3-kinase (PI3K)/ protein kinase B (Akt) pathway. Furthermore, PB + CA exhibits synergistic effect on restoring glucose intolerance and insulin resistance, and improving hepatic glycogen synthesis in impaired glucose tolerance (IGT) mice. The postprandial blood glucose (PBG), homeostasis model assessment (HOMA)-IR values and serum insulin contents in PB + CA-treated IGT mice with dosage of 300 mg kg^-1 BW are reversed to normal levels. Additionally, PC + CA shows additive effect on inhibiting gluconeogenesis in vitro and in vivo.

CONCLUSION

PB + CA in highland barley grain synergistically modulate glucose metabolism. These results may provide evidence of whole highland barley grain diet achieve superior effect on restoring IGT than isolated components.

Identification, Characterization, and Stress Responsiveness of Glucose-6-phosphate Dehydrogenase Genes in Highland Barley

G6PDH provides intermediate metabolites and reducing power (nicotinamide adenine dinucleotide phosphate, NADPH) for plant metabolism, and plays a pivotal role in the cellular redox homeostasis. In this study, we cloned five G6PDH genes (HvG6PDH1 to HvG6PDH5) from highland barley and characterized their encoded proteins. Functional analysis of HvG6PDHs in E. coli showed that HvG6PDH1 to HvG6PDH5 encode the functional G6PDH proteins. Subcellular localization and phylogenetic analysis indicated that HvG6PDH2 and HvG6PDH5 are localized in the cytoplasm, while HvG6PDH1, HvG6PDH3, and HvG6PDH4 are plastidic isoforms. Analysis of enzymatic activities and gene expression showed that HvG6PDH1 to HvG6PDH4 are involved in responses to salt and drought stresses. The cytosolic HvG6PDH2 is the major isoform against oxidative stress. HvG6PDH5 may be a house-keeping gene. In addition, HvG6PDH1 to HvG6PDH4 and their encoded enzymes responded to jasmonic acid (JA) and abscisic acid (ABA) treatments, implying that JA and ABA are probably critical regulators of HvG6PDHs (except for HvG6PDH5). Reactive oxygen species analysis showed that inhibition of cytosolic and plastidic G6PDH activities leads to increased H₂O₂ and O₂⁻ contents in highland barley under salt and drought stresses. These results suggest that G6PDH can maintain cellular redox homeostasis and that cytosolic HvG6PDH2 is an irreplaceable isoform against oxidative stress in highland barley.

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.

Assessment of the Phenolic Profiles, Hypoglycemic Activity, and Molecular Mechanism of Different Highland Barley (Hordeum vulgare L.) Varieties

The phenolic profiles, hypoglycemic activity, and molecular mechanism of the effect on type 2 diabetes mellitus (T2DM) of four highland barley varieties were investigated in the present study. The fundamental phenolics in highland barley were ferulic acid, naringin, and catechin, which mainly existed in bound form. These varieties showed favorable hypoglycemic activity via inhibition of α-glucosidase and α-amylase activities, enhancement of glucose consumption, glycogen accumulation and glycogen synthase 2 (GYS2) activity, and down-regulation of glucose-6-phosphatase (G6Pase) and phosphoenolpyruvate carboxykinase (PEPCK) activities. Specifically, ZQ320 variety exhibited the strongest hypoglycemic activity compared to the other varieties. Highland barley phenolics could inhibit gluconeogenesis and motivate glycogen synthesis via down-regulating the gene expression of G6Pase, PEPCK, and glycogen synthase kinase 3β (GSK3β), while activating the expression of insulin receptor substrate-1 (IRS-1), phosphatidylinositol 3 kinase (PI3K), serine/threonine kinase (Akt), GYS2, and glucose transporter type 4 (GLUT4). Therefore, phenolics from highland barley could be served as suitable candidates for therapeutic agent in T2DM to improve human health.

Green Hydrothermal Synthesis of N-doped Carbon Dots from Biomass Highland Barley for the Detection of Hg2

Totally water-soluble N-doped Carbon dots (N-CDs) were synthesized by a green hydrothermal method from biomass using Highland barley as a carbon source and ethanediamine as nitrogen source. TEM and XRD showed the graphitic amorphous structure and narrow diameter distribution of these N-CDs. N-doping to the crystal lattice and carrying many hydrophilic groups on the surface of N-CDs were verified by XPS and FT-IR. The as-synthesized N-CDs emitted strong blue fluorescence at 480 nm and owned a relatively high quantum yield of 14.4%. The product also could sensitively and selectively detect Hg2+ ions in the range of 10-160 μM and the limit of detection was equal to 0.48 μM.

Dipeptidyl Peptidase IV Inhibitory Peptides Derived from Oat (Avena sativa L.), Buckwheat (Fagopyrum esculentum), and Highland Barley (Hordeum vulgare trifurcatum (L.) Trofim) Proteins

Peptides released from oat, buckwheat, and highland barley proteins were examined for their in vitro inhibitory effects on dipeptidyl peptidase IV (DPP4), an enzyme that deactivates incretin hormones involved in insulin secretion. All of the hydrolysates exhibited DPP4 inhibitory activities, with IC50 values ranging from 0.13 mg/mL (oat glutelin alcalase digestion) to 8.15 mg/mL (highland barley albumin tryptic digestion). The lowest IC50 values in gastrointestinal, alcalase, and tryptic digestions were 0.99 mg/mL (oat flour), 0.13 mg/mL (oat glutelin), and 1.83 mg/mL (highland barley glutelin). In all, 35 peptides of more than seven residues were identified in the tryptic hydrolysates of oat globulin using liquid chromatography-mass spectroscopy. Peptides LQAFEPLR and EFLLAGNNK were synthesized and their DPP4 inhibitory activities determined. LQAFEPLR showed high in vitro DPP4 inhibitory activity with an IC50 value of 103.5 μM.

Postprandial Differences in the Amino Acid and Biogenic Amines Profiles of Impaired Fasting Glucose Individuals after Intake of Highland Barley

The aim of this study was to measure the postprandial changes in amino acid and biogenic amine profiles in individuals with impaired fasting glucose (IFG) and to investigate the changes of postprandial amino acid and biogenic amine profiles after a meal of highland barley (HB). Firstly, 50 IFG and 50 healthy individuals were recruited for the measurement of 2 h postprandial changes of amino acid and biogenic amine profiles after a glucose load. Secondly, IFG individuals received three different loads: Glucose (GL), white rice (WR) and HB. Amino acid and biogenic amine profiles, glucose and insulin were assayed at time zero and 30, 60, 90 and 120 min after the test load. The results showed fasting and postprandial amino acid and biogenic amine profiles were different between the IFG group and the controls. The level of most amino acids and their metabolites decreased after an oral glucose tolerance test, while the postprandial level of γ-aminobutyric acid (GABA) increased significantly in IFG individuals. After three different test loads, the area under the curve for glucose, insulin, lysine and GABA after a HB load decreased significantly compared to GL and WR loads. Furthermore, the postprandial changes in the level of GABA between time zero and 120 min during a HB load were associated positively with 2 h glucose and fasting insulin secretion in the IFG individuals. Thus, the HB load produced low postprandial glucose and insulin responses, which induced changes in amino acid and biogenic amine profiles and improved insulin sensitivity.