The potential use of cereal (1→3,1→4)-β-d-glucans as functional food ingredients

β-Glucan content increase in Waxy-mutated barley is closely associated with positive stress responses and is regulated by ASR1

Mixed-linkage (1,3; 1,4)-β-D-glucan (MLG) impacts the food and industrial end-uses of barley, but the molecular mechanism of variations in MLG content remains unclear. MLG content usually increases in Waxy-mutated barley. This study applied transcriptomic, proteomic, and metabolomic analyses to Waxy-mutated recombinant inbred lines with higher MLG content and wild-type lines with lower MLG content, and identified candidate genes and pathways regulating MLG content through combining preliminary gene function analysis. MLG biosynthesis differed significantly during late grain development in the Waxy-mutated and wild-type barley lines. The MLG increase was closely associated with strongly active sugar and starch metabolism and stress-responsive plant hormones, particularly abscisic acid (ABA) signaling process. Stress-responsive transcript factors ILR3, BTF3, RGGA, and PR13 protein bind to CslF6, which is critical for barley MLG biosynthesis, and the stress-responsive gene ASR1 also had a positive effect on MLG increase. Waxy mutation enhances barley stress responses by activating ABA- or other stress-responsive plant hormones signaling processes, which facilitates MLG biosynthesis. This study provides a new approach for elucidating the variations in MLG content of barley grains.

Effect of quinoa (Chenopodium quinoa W.) flour supplementation in breads on the lipid profile and glycemic index: an in vivo study

Quinoa is a gluten-free pseudocereal, with an excellent nutrient profile containing considerable amounts of fiber and minerals and rich in antioxidants such as polyphenols. The purpose of this research was to investigate the effects of quinoa bread on physical, chemical, bioactive components, glycaemic index (GI), and biochemical parameters. Human subjects aged between 20 and 50 years with the absence of morbid factors were fed daily with quinoa bread for 3 months in order to study its pre-and post-treatment effects on blood glucose, glycosylated haemoglobin, and lipid profile. The effort was made to incorporate the maximum amount of quinoa into the bread without compromising the acceptability of the bread. Of the 14 formulations, TQ13, containing 20% quinoa flour with 3% wheat bran, was selected for further analysis. The GI study revealed that quinoa bread peaked at 45 min with a gradual increase after ingestion of the bread and a steady decline thereafter. The observed value for blood glucose levels, before and after supplementation with quinoa-incorporated bread, was 86.96 ± 15.32 mg/dL and 84.25 ± 18.26 mg/dL, respectively. There was a statistically significant (p ≤ 0.05) decrease in levels of triglycerides, total cholesterol, low-density lipoprotein (LDL), and very-LDL (VLDL) level before and after supplementation. However, non-significant changes were observed for high-density lipoprotein levels from the pre- and post-treatment with the quinoa-incorporated bread. Quinoa-incorporated bread possessed low GI (42.00 ± 0.83) compared to control (69.20 ± 1.84) and long-term consumption proved to contain functional efficacies in terms of hypolipidemic effect.

Cereal β-d-Glucans in Food Processing Applications and Nanotechnology Research

Cereal (1,3)(1,4)-β-d-glucans, known as β-d-glucans, are cell wall polysaccharides observed in selected plants of grasses, and oats and barley are their good natural sources. Thanks to their physicochemical properties β-d-glucans have therapeutic and nutritional potential and a specific place for their functional characteristics in diverse food formulations. They can function as thickeners, stabilizers, emulsifiers, and textural and gelation agents in beverages, bakery, meat, and extruded products. The objective of this review is to describe the primary procedures for the production of β-d-glucans from cereal grains, to define the processing factors influencing their properties, and to summarize their current use in the production of novel cereal-based foods. Additionally, the study delves into the utilization of β-d-glucans in the rapidly evolving field of nanotechnology, exploring potential applications within this technological realm.

Effect of diet on postprandial glycemic and insulin responses in healthy dogs

Introduction

Dog owners have gradually changed their approach, paying more attention to the nutrition and health of their animals. Various pet foods with different ingredients and nutritional characteristics are available on the market. The present study aimed to evaluate the administration of three diets, namely, two grain-free (GF1 and GF2) and one grain-based (CB), with different sources of carbohydrates that can influence the glycemic and insulin postprandial responses in healthy dogs.

Materials

Fifteen healthy dogs were dived in three groups and alternatively fed each diet for 50 days. Blood samples were collected at beginning of each feeding period. Glycemia and insulin were measured before and after 120, 240 and 360 minutes diet administration to evaluate postprandial responses.

Results

GF2 diet showed the highest level of albumin and mean insulin concentration (p < 0.001). Furthermore, the GF1 diet caused the smallest (p < 0.001) glucose and insulin area under the curve (AUC) and the lowest (p < 0.05) glucose nadir. Otherwise, GF1 showed the highest (p < 0.01) insulin time to peak. The GF2 diet showed the highest level of albumin while reporting the lowest amount of fructosamine (p < 0.05). The diet GF2 registered the highest (p < 0.001) level of insulin zenith. The cereal-based (CB) diet reported the highest amount of fructosamine (p < 0.05). The CB diet had the highest levels of glucose and the highest (p < 0.001) glucose and insulin mean concentrations. Diet CB reported the lowest (p < 0.001) insulin nadir.

Discussion

Diets with different carbohydrate sources and chemical compositions could modulate the glycemic response in healthy dogs. Bearing in mind that glycemic/insulin postprandial responses influence energy availability and that different dogs have specific lifestyles, it may be preferable to also consider these aspects when choosing a maintenance diet for animals.

Effects of β-glucan with vitamin E supplementation on the growth performance, blood profiles, immune response, fecal microbiota, fecal score, and nutrient digestibility in weaning pigs

OBJECTIVE

This study was conducted to evaluate effects of β-glucan with vitamin E supplementation on the growth performance, blood profiles, immune response, fecal microbiota, fecal score, and nutrient digestibility in weaning pigs.

METHODS

A total of 200 weaning pigs with an average body weight (BW) of 7.64±0.741 kg were allotted to five treatment groups and were divided based on sex and initial BW in four replicates with ten pigs per pen in a randomized complete block design. The experimental diets included a corn‒soybean meal-based basal diet with or without 0.1% or 0.2% β-glucan and 0.02% vitamin E. The pigs were fed the diets for 6 weeks. A total of 15 barrows were used to evaluate the nutrient digestibility by the total collection method. The BW and feed intake were measured at the end of each phase. Blood samples were collected at the end of each phase, and fecal samples were collected at the end of the experiment.

RESULTS

The addition of β-glucan with vitamin E to weaning pig feed increased BW, average daily gain, and average daily feed intake. A significant decrease in yeast and mold and Proteobacteria and a tendency for Lactobacillus to increase compared to the control was shown when 0.1% β-glucan and 0.02% vitamin E were added. The fecal score in weaning pigs was lower in the treatments supplemented with 0.1% or 0.2% β-glucan and 0.02% vitamin E compared to the control. In addition, vitamin E was better supplied to weaning pigs by increasing the concentration of α-tocopherol in the blood of weaning pigs when 0.02% vitamin E was supplemented. However, there was no significant difference in either the immune response or nutrient digestibility.

CONCLUSION

Inclusion of 0.1% β-Glucan with 0.02% vitamin E in a weaning pig's diet were beneficial to the growth performance of weaning pigs by improving intestinal microbiota and reducing the incidence of diarrhea.

High β-Glucans Oats for Healthy Wheat Breads: Physicochemical Properties of Dough and Breads

Bread is a highly consumed food whose nutritional value can be improved by adding an oat flour (Avena sativa L.-variety Bonaerense INTA Calen-Argentina) to a high-industrial quality wheat flour (Triticum aestivum L.). This cultivar of oat contains high amounts of β-glucans, which act as a prebiotic fiber. Wheat flour was complemented with different amounts of oat flour (5, 15, and 25%). A contribution of hydrophilic components from oat flour was evident in the oat-wheat mixtures. At the same time, the high content of total dietary fiber led to changes in the rheological properties of the dough. Mixtures with a higher proportion of oats showed an increase in alveographic tenacity (stiffer dough), higher stability, and a lower softening degree in farinographic assays. The dough showed significant increases in hardness and gumminess, without significant changes in cohesiveness, i.e., no disruption to the gluten network was observed. Relaxation tests showed that the blends with a higher oat content yielded 10 times higher stress values compared to wheat dough. Analysis of the oat-wheat breads showed improvements in nutritional parameters, with slight decreases in the volume and crust color. The crumb showed significant increases in firmness and chewing strength as the amount of oats added increased. Nutritional parameters showed that lipids, dietary fiber, and β-glucans were significantly increased by the addition of oats. Sensory analysis achieved high response rates with good-to-very good ratings on the hedonic scale set. Thus, the addition of oats did not generate rejection by the consumer and could be accepted by them. Breads with wheat and oats showed nutritional improvements with respect to wheat bread, since they have higher dietary fiber content, especially in β-glucans, so they could be considered functional breads.

Barley in the Production of Cereal-Based Products

Barley (Hordeum vulgare L.) is unjustly neglected today as a food grain. Interest in the use of barley in the food industry has increased recently. The reason for this is its content of dietary fibre, especially β-glucan, which has been shown to reduce blood cholesterol and lower blood sugar levels. The main nutritional components of barley and barley products, besides the mentioned β-glucan, are starch, sugar, proteins, fat and ash. Although not common in the production of bakery products, barley can be very easily involved in the production of the same products, and such products have improved nutritional characteristics and acceptable sensory characteristics, which make them desirable. Barley has great potential for use in a wide range of cereal-based foods as a partial or full replacement for currently used grains (such as wheat, oats, rice and corn). This article provides basic and general information about the use of barley in food and the processing of barley grains for use in the manufacturing of cereal-based products, with particular attention to the use of barley in the manufacturing of bread (flatbread and leavened bread), noodles and pasta, muffins and cakes and cookies and biscuits.

Evaluation of graded levels of corn-fermented protein on stool quality, apparent nutrient digestibility, and palatability in healthy adult cats

Dried distillers' grains, coproducts from the ethanol industry, may provide sustainable ingredients for pet food. Due to new post-fermentation separation techniques, corn-fermented protein (CFP) is higher in protein and lower in fiber compared with traditional dried distillers' grains, increasing its appeal for inclusion into pet food. Therefore, the objectives of this study were to determine the effects of increasing levels of CFP on stool quality, apparent total tract digestibility (ATTD), and palatability in adult cats. Four extruded diets were fed to 11 adult cats in an incomplete 4 × 4 replicated Latin square design. The control diet contained 15% soybean meal (0C) and CFP was exchanged for soybean meal at either 5%, 10%, or 15% (5C, 10C, 15C). Cats were fed each dietary treatment for 9-d adaption followed by 5-d total fecal collection. Feces were scored on a 1 to 5 scale, with 1 representing liquid diarrhea and 5 representing hard pellet-like (Carciofi et al., 2008). A fecal score of 3.5 to 4 was considered ideal. Titanium dioxide was added to all diets (0.4%) as a marker to estimate digestibility. Data were analyzed using a mixed model in SAS (version 9.4, SAS Institute, Inc., Cary, NC) with treatment as a fixed effect and cat and period as random effects. Fecal dry matter percent and dry fecal output were greater (P < 0.05) at elevated levels of CFP. Stool scores were maintained (P > 0.05) throughout treatments (average; 4). Dry matter, organic matter, crude protein, and gross energy ATTD decreased when cats were fed 15C. There was no difference in ATTD of fat or total dietary fiber among treatments. For palatability assessment, cats preferred 5C over 0C but had no preference with increased CFP inclusion. These results suggest that CFP is comparable to SBM, but there may be a maximum inclusion level of 10% when fed to cats.

Analyses of Fatty Acids, Proteins, Ascorbic Acid, Bioactive Phenolic Compounds and Antioxidant Activity of Canadian Barley Cultivars and Elite Germplasm

Barley (Hordeum vulgare L.) grain is rich in fiber and antioxidant phytochemicals, including fatty acids, proteins, phenolic compounds, vitamins, and minerals, that offer various health benefits. Research on identifying different barley genotypes based on their health attributes is very limited. In this study, we performed an analysis of fatty acids, proteins, ascorbic acid, phenolic compounds, and antioxidant activity of several Canadian barley cultivars and elite breeding lines. Linoleic acid (C18:2) was the predominant fatty acid present in the tested barley cultivars. The cultivar CDC Bold contained the highest amount of ascorbic acid, while the highest protein content was in CDC Mindon. An assessment of the free and bound phenolic compounds of barley grains showed quantitative changes among different genotypes of Canadian barley. Catechin is the most abundant molecule in free phenolics, while ferulic acid and para-coumeric acid are the most abundant in bound phenolics. Ferulic acid and vanillic acid were molecules detected in the soluble free fraction of all genotypes. Para-coumeric acid was detected only in genotypes such as CDC Copeland, CDC Bold, Lowe, and elite breeding Line 5 of both free and bound fractions of barley. Breeding Line 5 had the lowest antioxidant activity. An analysis of the above molecules and parameters of Canadian barley would help to uncover potential biomarkers in order to distinguish individual barley genotypes.

Mechanism of mixed-linkage glucan biosynthesis by barley cellulose synthase-like CslF6 (1,3;1,4)-β-glucan synthase

Mixed-linkage (1,3;1,4)-β-glucans, which are widely distributed in cell walls of the grasses, are linear glucose polymers containing predominantly (1,4)-β-linked glucosyl units interspersed with single (1,3)-β-linked glucosyl units. Their distribution in cereal grains and unique structures are important determinants of dietary fibers that are beneficial to human health. We demonstrate that the barley cellulose synthase-like CslF6 enzyme is sufficient to synthesize a high-molecular weight (1,3;1,4)-β-glucan in vitro. Biochemical and cryo-electron microscopy analyses suggest that CslF6 functions as a monomer. A conserved "switch motif" at the entrance of the enzyme's transmembrane channel is critical to generate (1,3)-linkages. There, a single-point mutation markedly reduces (1,3)-linkage formation, resulting in the synthesis of cellulosic polysaccharides. Our results suggest that CslF6 monitors the orientation of the nascent polysaccharide's second or third glucosyl unit. Register-dependent interactions with these glucosyl residues reposition the polymer's terminal glucosyl unit to form either a (1,3)- or (1,4)-β-linkage.

HvGBSSI mutation at the splicing receptor site affected RNA splicing and decreased amylose content in barley

Granule-bound starch synthase I (HvGBSSI) is encoded by the barley waxy (Wx-1) gene and is the sole enzyme in the synthesis of amylose. Here, a Wx-1 mutant was identified from an ethyl methane sulfonate (EMS)-mutagenized barley population. There were two single-base mutations G1086A and A2424G in Wx-1 in the mutant (M2-1105). The G1086A mutation is located at the 3' splicing receptor (AG) site of the fourth intron, resulting in an abnormal RNA splicing. The A2424G mutation was a synonymous mutation in the ninth intron. The pre-mRNA of Wx-1 was incorrectly spliced and transcribed into two abnormal transcripts. The type I transcript had a 6 bp deletion in the 5' of fifth exon, leading to a translated HvGBSSI protein lacking two amino acids with a decreased starch-binding capacity. In the type II transcript, the fourth intron was incorrectly cleaved and retained, resulting in the premature termination of the barley Wx-1 gene. The mutations in the Wx-1 decreased the enzymatic activity of the HvGBSSI enzyme and resulted in a decreased level in amylose content. This work sheds light on a new Wx-1 gene inaction mechanism.

An Updated Review on Prebiotics: Insights on Potentials of Food Seeds Waste as Source of Potential Prebiotics

Prebiotics are a group of biological nutrients that are capable of being degraded by microflora in the gastrointestinal tract (GIT), primarily Lactobacilli and Bifidobacteria. When prebiotics are ingested, either as a food additive or as a supplement, the colonic microflora degrade them, producing short-chain fatty acids (SCFA), which are simultaneously released in the colon and absorbed into the blood circulatory system. The two major groups of prebiotics that have been extensively studied in relation to human health are fructo-oligosaccharides (FOS) and galactooligosaccharides (GOS). The candidature of a compound to be regarded as a prebiotic is a function of how much of dietary fiber it contains. The seeds of fruits such as date palms have been reported to contain dietary fiber. An increasing awareness of the consumption of fruits and seeds as part of the daily diet, as well as poor storage systems for seeds, have generated an enormous amount of seed waste, which is traditionally discarded in landfills or incinerated. This cultural practice is hazardous to the environment because seed waste is rich in organic compounds that can produce hazardous gases. Therefore, this review discusses the potential use of seed wastes in prebiotic production, consequently reducing the environmental hazards posed by these wastes.

An Update Regarding the Bioactive Compound of Cereal By-Products: Health Benefits and Potential Applications

Cereal processing generates around 12.9% of all food waste globally. Wheat bran, wheat germ, rice bran, rice germ, corn germ, corn bran, barley bran, and brewery spent grain are just a few examples of wastes that may be exploited to recover bioactive compounds. As a result, a long-term strategy for developing novel food products and ingredients is encouraged. High-value compounds like proteins, essential amino acids, essential fatty acids, ferulic acid, and other phenols, tocopherols, or β-glucans are found in cereal by-products. This review aims to provide a critical and comprehensive overview of current knowledge regarding the bioactive compounds recovered from cereal by-products, emphasizing their functional values and potential human health benefits.

Estimation of Iron Availability in Modified Cereal β-Glucan Extracts by an in vitro Digestion Model

For cereal-based foods rich in dietary fibers, iron bioavailability is known to be poor. For native cereal β-glucan extracts, literature has demonstrated that the main factor impacting the bioavailability is phytic acid, which is often found in association with dietary fibers. During food processing, β-glucan can undergo modifications which could potentially affect the equilibrium between phytic acid, fiber, and iron. In this study, an in vitro digestion was used to elucidate the iron dialysability, and hence estimate iron availability, in the presence of native, chelating resin (Chelex)-treated, oxidised, or partially hydrolysed oat and barley β-glucan extracts (at 1% actual β-glucan concentration), with or without phytase treatment. It was confirmed that pure, phytic acid-free β-glucan polysaccharide does not impede iron availability in cereal foods, while phytic acid, and to a smaller extent, also proteins, associated to β-glucan can do so. Neither Chelex-treatment nor partial hydrolysis, 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) or NaIO4 oxidation significantly influenced the phytic acid content of the β-glucan extracts (ranging 2.0-3.9%; p > 0.05). Consequently, as long as intrinsic phytic acid was still present, the β-glucan extracts blocked the iron availability regardless of source (oat, barley) or Chelex-treatment, partial hydrolysis or NaIO4-oxidation down to 0-8% (relative to the reference without β-glucan extract). Remarkably, TEMPO-oxidation released around 50% of the sequestered iron despite unchanged phytic acid levels in the modified extract. We propose an iron-mobilising effect of the TEMPO product β-polyglucuronan from insoluble Fe(II)/phytate/protein aggregates to soluble Fe(II)/bile salt units that can cross the dialysis membrane. In addition, Chelex-treatment was identified as prerequisite for phytase to dramatically diminish iron retention of the extract for virtually full availability, with implications for optimal iron bioavailability in cereal foods.

Potential health effects of brewers' spent grain as a functional food ingredient assessed by markers of oxidative stress and inflammation following gastro-intestinal digestion and in a cell model of the small intestine

Brewer's spent grains (BSG) are a by-product of the beer-brewing industry, often employed as animal feeding stuffs. With BSG being rich not only in proteins, lipids, and dietary fiber but also in certain phytochemicals, it constitutes a potentially valuable food source that could be employed as a functional food, e.g. against chronic inflammatory diseases. Several types of bread were prepared with various amounts of BSG as flour replacement (0, 10, 20, 40, 60, 80 and 100%), either employing wet BSG or dried BSG after pressing. Total phenolics, flavonoids, insoluble dietary fiber, as well as antioxidant capacity (FRAP, ABTS) were measured in the bread, before and after simulated gastro-intestinal digestion. Furthermore, we investigated digested BSG and bread-containing BSG for their capability to alter oxidative stress (Nrf2, malondialdehyde) and inflammation (IL-6, IL-8, NO, and PGE2) in a Caco-2 cell culture model of the small intestine. Incorporation of BSG significantly and dose-dependently enhanced the amount of dietary fiber in the product, as well as total phenolics, flavonoids, and antioxidant capacity, by over 10-fold, 3-fold, 4-fold and 5-fold, respectively, when replacing all of the flour with BSG. This pattern remained after in vitro digestion. However, digesta failed to show significant antioxidant or anti-inflammatory effects on the biomarkers observed in the cell model. Consuming 150 g of such a BSG-bread (wet based) would supply the proposed RDA of 25 g d^-1 dietary fiber and could be a healthy product valorizing BSG.

More Prominent Inflammatory Response to Pachyman than to Whole-Glucan Particle and Oat-β-Glucans in Dextran Sulfate-Induced Mucositis Mice and Mouse Injection through Proinflammatory Macrophages

(1→3)-β-D-glucans (BG) (the glucose polymers) are recognized as pathogen motifs, and different forms of BGs are reported to have various effects. Here, different BGs, including Pachyman (BG with very few (1→6)-linkages), whole-glucan particles (BG with many (1→6)-glycosidic bonds), and Oat-BG (BG with (1→4)-linkages), were tested. In comparison with dextran sulfate solution (DSS) alone in mice, DSS with each of these BGs did not alter the weight loss, stool consistency, colon injury (histology and cytokines), endotoxemia, serum BG, and fecal microbiome but Pachyman-DSS-treated mice demonstrated the highest serum cytokine elicitation (TNF-α and IL-6). Likewise, a tail vein injection of Pachyman together with intraperitoneal lipopolysaccharide (LPS) induced the highest levels of these cytokines at 3 h post-injection than LPS alone or LPS with other BGs. With bone marrow-derived macrophages, BG induced only TNF-α (most prominent with Pachyman), while LPS with BG additively increased several cytokines (TNF-α, IL-6, and IL-10); inflammatory genes (iNOS, IL-1β, Syk, and NF-κB); and cell energy alterations (extracellular flux analysis). In conclusion, Pachyman induced the highest LPS proinflammatory synergistic effect on macrophages, followed by WGP, possibly through Syk-associated interactions between the Dectin-1 and TLR-4 signal transduction pathways. Selection of the proper form of BGs for specific clinical conditions might be beneficial.

Retention of bioactive compounds during extrusion processing and storage

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Significant retention of beta-glucans was reported in fortified extrudates.

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Lowest rentention was found in extrudates fortified with oryzanol at high level.

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In storage studies at higher relative humidities, lowest retention was observed.

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L* and b* values decreased when extrudates were kept at high relative humidities.

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a* value increased when extrudates were kept at high relative humidities.

Retention of bioactive compounds (beta-glucans, lignans and gamma oryzanol) was analyzed after extrusion and during storage period of three months under four relative humidities using saturated salt solutions such as potassium carbonate (43.26%), magnesium nitrate (52.60%), potassium chloride (84.36%) and potassium nitrate (93.58%). The control sample comprising a corn and rice flour blend (50 g each) was substituted with beta-glucans at 3 g/100 g and 6 g/100 g, flaxseed lignans at 6.67 g/kg and 11.67 g/kg and gamma oryzanol at 1.5 g/100 g and 3.0 g/100 g at low and high levels, respectively. After extrusion, beta-glucan was retained up to 82.67 and 90.83%, lignans were retained at 86.31 and 66.66% whereas retention of gamma oryzanol was 71.33 and 51.67% at low and high level of substitution, respectively. Retention of bioactive compounds was the lowest along with a decrease in L* and b* values and an increase in a* value was observed under higher relative humidity (84.36% and 93.58%) storage conditions.

Metabolic variables of obese dogs with insulin resistance supplemented with yeast beta-glucan

Background

Obesity is one of the most common nutritional disorders in dogs and cats and is related to the development metabolic comorbidities. Weight loss is the recommended treatment, but success is difficult due to the poor satiety control. Yeast beta-glucans are known as biological modifiers because of their innumerable functions reported in studies with mice and humans, but only one study with dogs was found. This study aimed to evaluate the effects of a diet supplemented with 0.1% beta-glucan on glucose, lipid homeostasis, inflammatory cytokines and satiety parameters in obese dogs. Fourteen dogs composed three experimental groups: Obese group (OG) with seven dogs with body condition score (BCS) 8 or 9; Lean group (LG) included seven non-obese dogs with a BCS of 5; and Supplemented Obese group (SOG) was the OG dogs after 90 days of consumption of the experimental diet.

Results

Compared to OG, SOG had lower plasma basal glycemic values (p = 0.05) and reduced serum cholesterol and triglyceride levels. TNF-α was lower in SOG than in OG (p = 0.05), and GLP-1 was increased in SOG compared to OG and LG (p = 0.02).

Conclusion

These results are novel and important for recognizing the possibility of using beta-glucan in obesity prevention and treatment.

A stress-responsive transcription factor PeNAC1 regulating beta-D-glucan biosynthetic genes enhances salt tolerance in oat

A Populus euphratica NAC gene regulates (1,3; 1,4)-β-D-glucan content in oat developing seed and improves the spikelet number and grain number per spike in transgenic oat under salinity conditions Salinity is the major factor affecting the production and quality of oat, and improving oat salt tolerance to increase yield and quality is vital. (1,3;1,4)-β-D-glucan in Gramineae is the key component in response to various environmental signals, and it is the most important functional ingredient in oat grain. The NAC transcription factors are important candidate genes used in genetic engineering to improve plant abiotic stress tolerance. In this study, we introduced Populus euphratica PeNAC1, controlled by its own promoter, into hexaploid cultivated oat and produced six transgenic lines. Compared to the non-transgenic control, the expression of PeNAC1 significantly improved the seed germination rate, seedling survival rate, and leaf chlorophyll content in the transgenic plants under salt stress. These physiological changes increased the spikelet number and grain number per spike in the transgenic oat under salinity conditions and reduced the yield loss per plant. The results indicated that the heterologous expression of PeNAC1 plays an effective role in improving the salt tolerance in transgenic oat. In addition, overexpressing PeNAC1 significantly increased the (1,3;1,4)-β-D-glucan content as well as the expression level of the (1,3;1,4)-β-D-glucan biosynthetic genes AsCslF3, AsCslF6, and AsCslF9 in the transgenic lines under salt stress, which suggested that PeNAC1 regulates the synthesis of (1,3;1,4)-β-D-glucan. Our research should assist in the discovery of the diverse action modes of NAC proteins, while PeNAC1 will be useful for improving the salt tolerance and quality of oat through molecular breeding.

Comparison of β-Glucan Content in Milled Rice, Rice Husk and Rice Bran from Rice Cultivars Grown in Different Locations of Thailand and the Relationship between β-Glucan and Amylose Contents

β-glucan is a dietary fiber that is beneficial to human health, and its content varies according to its different parts, type of cereal grain, and growing environment. In this study, the β-glucan of milled rice, rice husk, and rice bran fractions, as well as the amylose content of milled rice fraction, from 38 selected rice-paddy grains from six regions of Thailand were quantitatively determined. The milled rice of the Sakon Nakhon (SN) cultivar grown in the northeast contained the highest β-glucan content (0.88 ± 0.03%), followed by the milled rice of the Jow Khao Chiangmai (JKC) cultivar (0.71 ± 0.03%) and rice bran of the Sew Mae Jan (SMJ) cultivar (0.67 ± 0.03%) grown in the north. The results reveal that the rice cultivars from each region showing variation in the β-glucan level in each fraction, which is mainly found in milled rice and rice bran, are similar to those found in other cereal grains, although low amounts are found in the husk. The amylose and β-glucan contents in the milled rice fraction showed a strong negative correlation (r = −0.805; p < 0.0001). This new information about the β-glucan content of Thai rice cultivars could be used for the development of cereal-based functional food.

Consumer Choices in the Pasta Market: The Importance of Fiber in Consumer Decisions

The aim of the current study was two-fold: (1) to identify consumer segments based on pasta selection motives and (2) to examine the differences between the identified segments in terms of perception of pasta and pasta with added fiber and information on the food label. The data were collected using a CAPI (computer-assisted personal interview) survey on a sample of 1013 consumers. The k-means clustering method was used to identify four clusters of consumers, namely, quality-oriented, sensory-oriented, convenience-oriented, and neutral consumers. The quality-oriented group was the group that expressed the most positive opinions about the pasta and about the addition of fiber to pasta. Moreover, they appreciated the information placed on the pasta label the most. Consumers in the sensory-oriented segment were the least likely to agree that the addition of fiber to pasta deteriorated its taste and to agree that it looked worse compared to pasta without fiber. These findings are of significance for those involved in the public nutrition sector as well as for those responsible for preparing well-targeted marketing messages. The conclusions may constitute invaluable insights for those devising educational initiatives and campaigns.

Growth-Promoting Effect of Cava Lees on Lactic Acid Bacteria Strains: A Potential Revalorization Strategy of a Winery By-Product

The growing trend of circular economy has prompted the design of novel strategies for the revalorization of food industry by-products. Cava lees, a winery by-product consisting of non-viable cells of Saccharomyces cerevisiae rich in β-glucans and mannan-oligosaccharides, can be used as a microbial growth promoter, with potential food safety and health applications. The aim of this study was to assess in vitro the effect of cava lees on the growth of 21 strains of lactic acid bacteria (LAB) species commonly used as starter cultures and/or probiotics. Firstly, 5% of cava lees was selected as the most effective amount for enhancing microbial counts. After screening different LAB, statistically significantly (p < 0.05) higher microbial counts were found in 12 strains as a consequence of cava lees supplementation. Moreover, a greater and faster reduction in pH was observed in most of these strains. The growth-promoting effects of cava lees on LAB strains supports the potential revalorization of this winery by-product, either to improve the safety of fermented products or as a health-promoting prebiotic that may be selectively fermented by probiotic species.

Compositional profile of barley landlines grown in different regions of Gilgit-Baltistan

The current investigation was performed to explore the nutritional and functional composition of four landlines of barley denoted as LB1 (Gilgit), LB2 (Nagar), LB3 (Skardu), and LB4 (Shigar) from different regions of Gilgit-Baltistan. The samples were examined for nutritional profile and antioxidant attributes. Total phenolic values and total flavonoid results were in the range of 1.2 to 3.1 mg/g and 0.41 to 0.55 mg/g, respectively. Nutritional profile as crude starch, fiber, protein, ash, and fat ranged from 56.3%-50.80%, 16.50%-11.73%, 16.20%-11.53%, 2.8%-2.1%, and 2.63%-1.63%, respectively. The mineral composition in terms of Mg (527-616 mg/kg) was higher in the landlines followed by Ca (312-368 mg/kg), Na (122.6-146.6 mg/kg), Fe (43.3-65.6 mg/kg), and Zn (22.5-26.6 mg/kg). It was concluded that the indigenous barley landlines had immense nutritional potential and functional attributes. Thus, it can be used for value-added food products and the development of cottage industry in the region.

The detection, purity and structural properties of partially soluble mushroom and cereal β-D-glucans: A solid-state NMR study

β-D-glucans are proposed to have many health benefits. It is therefore important to have methods which can distinguish these from other carbohydrates present in natural products, as well as giving glucan content and structural information. Correlations between features in the CP/MAS spectra of β-D-glucans and enzyme assay determined β-D-glucan content were generally found to be poor. The β-D-glucan in dry and hydrated forms of the mushroom Ganoderma lucidum was investigated in detail by spectral peak fitting to the anomeric carbon C1 region in CP/MAS NMR spectra. Hydrated samples gave spectra with enhanced resolution and suggested that a clear distinction between β-D-glucans and other carbohydrates could be possible in the anomeric carbon C1 region. Chemical shift values for a range of carbohydrate polymers, which can be found alongside β-D-glucans, as well as the values for various linkages are given. Contamination by other carbohydrates and buffer salts is discussed.

Anti-Inflammatory and Immune Modulatory Effects of Synbio-Glucan in an Atopic Dermatitis Mouse Model

Many trials have been conducted to treat atopic dermatitis (AD), but these therapies are generally unsuccessful because of their insufficiency or side effects. This study examined the efficacy of β-glucan derived from oats with fermented probiotics (called Synbio-glucan) on an AD-induced mouse model. For the experiment, Nc/Nga mice were exposed to a house dust mite extract (HDM) to induce AD. The mice were placed in one of four groups: positive control group, Synbio-glucan topical treatment group, Synbio-glucan dietary treatment group, and Synbio-glucan topical + dietary treatment group. The experiment revealed no significant difference in the serum IgE concentration among the groups. Serum cytokine antibody arrays showed that genes related to the immune response were enriched. A significant difference in the skin lesion scores was observed between the groups. Compared to the control group tissue, skin lesions were alleviated in the Synbio-glucan topical treatment group and Synbio-glucan dietary treatment group. Interestingly, almost normal structures were observed within the skin lesions in the Synbio-glucan topical + dietary treatment group. Overall, the β-glucan extracted from oats and fermented probiotic mixture is effective in treating atopic dermatitis.

Structures, Biosynthesis, and Physiological Functions of (1,3;1,4)-β-D-Glucans

(1,3;1,4)-β-d-Glucans, also named as mixed-linkage glucans, are unbranched non-cellulosic polysaccharides containing both (1,3)- and (1,4)-β-linkages. The linkage ratio varies depending upon species origin and has a significant impact on the physicochemical properties of the (1,3;1,4)-β-d-glucans. (1,3;1,4)-β-d-Glucans were thought to be unique in the grasses family (Poaceae); however, evidence has shown that (1,3;1,4)-β-d-glucans are also synthesized in other taxa, including horsetail fern Equisetum, algae, lichens, and fungi, and more recently, bacteria. The enzyme involved in (1,3;1,4)-β-d-glucan biosynthesis has been well studied in grasses and cereal. However, how this enzyme is able to assemble the two different linkages remains a matter of debate. Additionally, the presence of (1,3;1,4)-β-d-glucan across the species evolutionarily distant from Poaceae but absence in some evolutionarily closely related species suggest that the synthesis is either highly conserved or has arisen twice as a result of convergent evolution. Here, we compare the structure of (1,3;1,4)-β-d-glucans present across various taxonomic groups and provide up-to-date information on how (1,3;1,4)-β-d-glucans are synthesized and their functions.

β-Glucans as a panacea for a healthy heart? Their roles in preventing and treating cardiovascular diseases

Cardiovascular diseases (CVDs) are the leading cause of death worldwide. Factors increasing the risks for CVD development are related to obesity, diabetes, high blood cholesterol, high blood pressure and lifestyle. CVD risk factors may be treated with appropriate drugs, but prolonged can use cause undesirable side-effects. Among the natural products used in complementary and alternative medicines, are the β-ᴅ-glucans; biopolymers found in foods (cereals, mushrooms), and can easily be produced by microbial fermentation. Independent of source, β-glucans of the mixed-linked types [(1 → 3)(1 → 6)-β-ᴅ-glucans - fungal, and (1 → 3)(1 → 4)-β-ᴅ-glucans - cereal] have widely been studied because of their biological activities, and have demonstrated cardiovascular protective effects. In this review, we discuss the roles of β-ᴅ-glucans in various pathophysiological conditions that lead to CVDs including obesity, dyslipidemia, hyperglycemia, oxidative stress, hypertension, atherosclerosis and stroke. The β-glucans from all of the sources cited demonstrated potential hypoglycemic, hypocholesterolemic and anti-obesogenicity activities, reduced hypertension and ameliorated the atherosclerosis condition. More recently, β-glucans are recognized as possessing prebiotic properties that modulate the gut microbiome and impact on the health benefits including cardiovascular. Overall, all the studies investigated unequivocally demonstrated the dietary benefits of consuming β-glucans regardless of source, thus constituting a promising panaceutical approach to reduce CVD risk factors.

Analysis of β-d-glucan biosynthetic genes in oat reveals glucan synthesis regulation by light

BACKGROUND AND AIMS

Oat (Avena sativa) has human health benefits when consumed as a whole-grain food, attributed to the high content of (1,3;1,4)-β-d-glucan (mixed-linkage glucan [MLG]), but little is known about the synthase genes and synthesis mechanism of MLG polysaccharides in this species.

METHODS

The concentration of oat MLGs under different light intensities was measured by a standard enzymatic approach and further verified by immunoelectron microscopy. The effect of light intensity on MLG synthase genes was examined by RT-qPCR and western blot analyses. The pattern of expression directed by the promoter of the oat MLG synthase gene was also investigated by histochemical β-glucuronidase (GUS) analysis.

KEY RESULTS

The oat orthologues of genes implicated in the synthesis of MLG in other cereals, including cellulose synthase-like (Csl) F, H and J gene families, were defined. Transcript profiling of these genes across oat tissues indicated that AsCslF6 transcripts dominated. Under high light intensities, the expression of AsCslF6, a major isoform of the MLG synthase genes, increased to >30 % of the dark growth control. The amount of MLG in oat rose from 0.07 to 1.06 % with increased light intensity. Histochemical tests showed that the AsCslF6 gene promoter preferentially directs GUS expression under high light intensity conditions.

CONCLUSIONS

Oat MLG synthesis is regulated by light. High light intensity upregulates the expression of the MLG synthase AsCslF6 gene, leading to an increase in the amount of MLG in oat leaves.

Comparative study of nutritional and technological quality aspects of minor cereals

In order to have a better insight into the quality of minor cereals, the aim of this research was to evaluate the nutritional, biochemical, physical and rheological properties of barley, rye, triticale, oat, sorghum and millet flours. Generally, all flours could be divided into two groups according to mineral content, ω-6/ω-3 fatty acids ratio and amino acid composition. Sorghum flour was characterized by the highest total phenolic content and was the only flour which contained detectable amounts of tannins. Sorghum and millet flours differed from other flours by lower water absorption index and higher temperature of starch gelatinization. Additionally, sorghum and millet flours could be analysed by Mixolab only using constant hydration and require more time to obtain complete hydration than other flours. All flours would require modification of standard breadmaking process in order to obtain quality of product similar to those already present at the market.

Spent Brewer's Yeast as a Source of Insoluble β-Glucans

In the brewing process, the consumption of resources and the amount of waste generated are high and due to a lot of organic compounds in waste-water, the capacity of natural regeneration of the environment is exceeded. Residual yeast, the second by-product of brewing is considered to have an important chemical composition. An approach with nutritional potential refers to the extraction of bioactive compounds from the yeast cell wall, such as β-glucans. Concerning the potential food applications with better textural characteristics, spent brewer’s yeast glucan has high emulsion stability and water-holding capacity fitting best as a fat replacer in different food matrices. Few studies demonstrate the importance and nutritional role of β-glucans from brewer’s yeast, and even less for spent brewer’s yeast, due to additional steps in the extraction process. This review focuses on describing the process of obtaining insoluble β-glucans (particulate) from spent brewer’s yeast and provides an insight into how a by-product from brewing can be converted to potential food applications.

Targeted mutation of barley (1,3;1,4)-β-glucan synthases reveals complex relationships between the storage and cell wall polysaccharide content

Barley (Hordeum vulgare L) grain is comparatively rich in (1,3;1,4)-β-glucan, a source of fermentable dietary fibre that protects against various human health conditions. However, low grain (1,3;1,4)-β-glucan content is preferred for brewing and distilling. We took a reverse genetics approach, using CRISPR/Cas9 to generate mutations in members of the Cellulose synthase-like (Csl) gene superfamily that encode known (HvCslF6 and HvCslH1) and putative (HvCslF3 and HvCslF9) (1,3;1,4)-β-glucan synthases. Resultant mutations ranged from single amino acid (aa) substitutions to frameshift mutations causing premature stop codons, and led to specific differences in grain morphology, composition and (1,3;1,4)-β-glucan content. (1,3;1,4)-β-Glucan was absent in the grain of cslf6 knockout lines, whereas cslf9 knockout lines had similar (1,3;1,4)-β-glucan content to wild-type (WT). However, cslf9 mutants showed changes in the abundance of other cell-wall-related monosaccharides compared with WT. Thousand grain weight (TGW), grain length, width and surface area were altered in cslf6 knockouts, and to a lesser extent TGW in cslf9 knockouts. cslf3 and cslh1 mutants had no effect on grain (1,3;1,4)-β-glucan content. Our data indicate that multiple members of the CslF/H family fulfil important functions during grain development but, with the exception of HvCslF6, do not impact the abundance of (1,3;1,4)-β-glucan in mature grain.

Physicochemical, Sensory, and Cooking Qualities of Pasta Enriched with Oat β-Glucans, Xanthan Gum, and Vital Gluten

The functional properties of β-glucans derived from oats and barley are confirmed by numerous in vitro and in vivo studies. This study aimed to assess the effect of adding 0, 5, 10, 15, and 20% oat (1,3)(1,4)-β-D-glucans to physicochemical properties, as well as the cooking and sensory qualities of durum wheat pasta. Additionally, to improve the cooking and sensory qualities of pasta, we added 5% of xanthan gum and vital gluten. The present study showed that the addition of β-glucans led to an increase of the water absorption index (WAI), water solubility index (WSI), and viscosity of products. At the same time, an increase in the content of fat, ash, and dietary fiber was observed. The addition of (1,3)(1,4)-β-D-glucans influenced the cooking quality of the pasta, extending the minimum cooking time and increasing the loss of dry matter. At the same time, the color of the product changed. In the case of cooked pasta, the addition of β-glucans decreased the brightness and increased the yellowness and redness. It was found that the products enriched with 10–15% of β-glucans, as well as 5% of xanthan gum and vital gluten would yield functional pasta that may offer health benefits beyond its nutritional value. Further, this could influence high cooking and sensory quality.

Acceptance of Fresh Pasta with β-Glucan Addition: Expected Versus Perceived Liking

The aim was to recognize the effect of oat β-glucan fiber addition on expected and perceived liking of fresh pasta. Durum wheat semolina was enriched with oat β-glucan fiber in proportions: 0, 4, 8, 12 and 16% in relation to wheat flour. The evaluation of pasta samples was carried out by a group of 150 consumers and 10 panelists. Consumers evaluated pasta samples to assess the expected and perceived liking and the trained panelists established sensory profile.The consumers’ evaluation of cooked pasta with different oat β-glucan fiber additions showed that the sample with 16% oat β-glucan fiber addition was most liked (6.4 in a 1–9 scale). Consistency between expected and perceived liking increased with the increase in oat β-glucan fiber addition and was the highest for the sample enriched with 16% β-glucan. The sensory profile established by the trained panelists compared with the results of the consumers’ assessment showed that an increase in intensity of bran odor and flavor (up to value 4.08 for odor note and 5.31 for flavor) could have been related to higher perceived liking by the consumers. The increased amount of oat β-glucan fiber powder (16%), which provides fiber-rich products, is a promising ingredient for fresh pasta formulation.

Antioxidant Properties of Sourdoughs Made with Whole Grain Flours of Hull-Less Barley or Conventional and Pigmented Wheat and by Selected Lactobacilli Strains

The use of sourdough fermentation and whole grain flours in baked goods manufacturing are known to enhance their functional and nutritional features. In this context, it is necessary to select the most suitable lactic acid bacteria strains and flour combination to achieve this goal. A characterization of 70 lactobacilli strains based on pro-technological and nutritional properties was carried out. The screening allowed the selection of 10 strains that were used to ferment sourdoughs made with two varieties of common wheat, the conventional red-grained cv Aubusson, a blue-grained variety rich in anthocyanins cv Skorpion, and a hull-less barley variety, cv Rondo. From each fermented sourdough, a water soluble extract was obtained and evaluated for its antioxidant activity performed on cultured cells (RAW 264.7 murine macrophage) by assaying Reactive Oxygen Species (ROS) content. Sourdoughs made with pigmented wheat and barley, had an antioxidant activity greater than that recovered in those made with conventional wheat flour, in spite they have been inoculated with the same LAB strains. Results highlighted the interdependence between flour and the inoculated lactic acid bacteria that has to be taken into account for the development of healthy breads exploiting high functional value cereals through biotechnological processes.

Non-Starch Polysaccharides in Durum Wheat: A Review

Durum wheat is one of most important cereal crops that serves as a staple dietary component for humans and domestic animals. It provides antioxidants, proteins, minerals and dietary fibre, which have beneficial properties for humans, especially as related to the health of gut microbiota. Dietary fibre is defined as carbohydrate polymers that are non-digestible in the small intestine. However, this dietary component can be digested by microorganisms in the large intestine and imparts physiological benefits at daily intake levels of 30–35 g. Dietary fibre in cereal grains largely comprises cell wall polymers and includes insoluble (cellulose, part of the hemicellulose component and lignin) and soluble (arabinoxylans and (1,3;1,4)-β-glucans) fibre. More specifically, certain components provide immunomodulatory and cholesterol lowering activity, faecal bulking effects, enhanced absorption of certain minerals, prebiotic effects and, through these effects, reduce the risk of type II diabetes, cardiovascular disease and colorectal cancer. Thus, dietary fibre is attracting increasing interest from cereal processors, producers and consumers. Compared with other components of the durum wheat grain, fibre components have not been studied extensively. Here, we have summarised the current status of knowledge on the genetic control of arabinoxylan and (1,3;1,4)-β-glucan synthesis and accumulation in durum wheat grain. Indeed, the recent results obtained in durum wheat open the way for the improvement of these important cereal quality parameters.