Effect of barley β-glucan on postprandial glycaemic response in the healthy human population: A meta-analysis of randomized controlled trials

Genetic Approaches to Increase Arabinoxylan and β-Glucan Content in Wheat

Wheat is one of the three staple crops feeding the world. The demand for wheat is ever increasing as a relatively good source of protein, energy, nutrients, and dietary fiber (DF) when consumed as wholemeal. Arabinoxylan and β-glucan are the major hemicelluloses in the cell walls and dietary fiber in wheat grains. The amount and structure of DF varies between grain tissues. Reducing post-prandial glycemic response as well as intestinal transit time and contribution to increased fecal bulk are only a few benefits of DF consumption. Dietary fiber is fermented in the colon and stimulates growth of beneficial bacteria producing SCFA, considered responsible for a wide range of health benefits, including reducing the risk of heart disease and colon cancer. The recommended daily intake of 25-30 g is met by only few individuals. Cereals cover nearly 40% of fiber in the Western diet. Therefore, wheat is a good target for improving dietary fiber content, as it would increase the fiber intake and simultaneously impact the health of many people. This review reflects the current status of the research on genetics of the two major dietary fiber components, as well as breeding approaches used to improve their quantity and quality in wheat grain.

Application of Mass Spectrometry-Based Proteomics to Barley Research

Barley (Hordeum vulgare) is the fourth most cultivated crop in the world in terms of production volume, and it is also the most important raw material of the malting and brewing industries. Barley belongs to the grass (Poaceae) family and plays an important role in food security and food safety for both humans and livestock. With the global population set to reach 9.7 billion by 2050, but with less available and/or suitable land for agriculture, the use of biotechnology tools in breeding programs are of considerable importance in the quest to meet the growing food gap. Proteomics as a member of the "omics" technologies has become popular for the investigation of proteins in cereal crops and particularly barley and its related products such as malt and beer. This technology has been applied to study how proteins in barley respond to adverse environmental conditions including abiotic and/or biotic stresses, how they are impacted during food processing including malting and brewing, and the presence of proteins implicated in celiac disease. Moreover, proteomics can be used in the future to inform breeding programs that aim to enhance the nutritional value and broaden the application of this crop in new food and beverage products. Mass spectrometry analysis is a valuable tool that, along with genomics and transcriptomics, can inform plant breeding strategies that aim to produce superior barley varieties. In this review, recent studies employing both qualitative and quantitative mass spectrometry approaches are explored with a focus on their application in cultivation, manufacturing, processing, quality, and the safety of barley and its related products.

Preliminary Investigations on the Use of a New Milling Technology for Obtaining Wholemeal Flours

Wholemeal flours from various cereals and pseudocereals are a valuable source of nutritionally important fiber components, especially beta-glucans and arabinoxylans, as well as bioactive substances accompanying dietary fiber. Most types of whole-wheat flours have unfavorable baking and sensory properties. The finest granulation of bran particles in the flour has a significant effect on reducing or eliminating these deficiencies. Special disintegration equipment is required to achieve fine granulation of the bran particles. In this study, we have tested a special type of impact mill (originally intended for grinding of plastics) to produce special finely ground wholemeal flours with lower starch damage and higher farinographic absorption. Moisture content in the studied flours was significantly lower (7.4–9.8%) than is common in standard flour (13–14%). According to the results of flour analyses obtained from several cereal sources, it seems that especially in rye and wheat, this technology is suitable for both achieving fine granulation of bran particles and in terms of not very substantial damage of starch granules.

Emerging science on benefits of whole grain oat and barley and their soluble dietary fibers for heart health, glycemic response, and gut microbiota

The aim of this work is to review the major mechanisms by which consumption of whole grain oats and barley, and β-glucans, reduces the risk of coronary heart disease, type 2 diabetes, and other noncommunicable chronic conditions. These effects have been predominantly explained by the role of soluble dietary fibers and smaller bioactive compounds, such as phenolic compounds, in oats and barley. These help to reduce the level of serum low-density lipoprotein cholesterol, decreasing postprandial blood glucose and modulating gut microbiota. In the present review, the role of viscosity development of the intestinal content by β-glucans in these mechanisms is discussed, as well as the impact of processing conditions altering the composition or the physicochemical characteristics of β-glucans.

Inhibitors of α-amylase and α-glucosidase: Potential linkage for whole cereal foods on prevention of hyperglycemia

The strategy of reducing carbohydrate digestibility by controlling the activity of two hydrolyzing enzymes (α-amylase and α-glucosidase) to control postprandial hyperglycemia is considered as a viable prophylactic treatment of type 2 diabetes mellitus (T2DM). Thus, the consumption of foods rich in hydrolyzing enzyme inhibitors is recommended for diet therapy of diabetes. Whole cereal products have gained increasing interests for plasma glucose-reducing effects. However, the mechanisms for whole cereal benefits in relation to T2DM are not yet fully understood, but most likely involve bioactive components. Cereal-derived phenolic compounds, peptides, nonstarch polysaccharides, and lipids have been shown to inhibit α-amylase and α-glucosidase activities. These hydrolyzing enzyme inhibitors seem to make whole cereals become nutritional strategies in managing postmeal glucose for T2DM. This review presents an updated overview on the effects provided by cereal-derived ingredients on carbohydrate digestibility. It suggests that there is some evidence for whole cereal intake to be beneficial in amelioration of T2DM through inhibiting α-glucosidase and α-amylase activities.

Conversion of hulled into naked barley by Cas endonuclease-mediated knockout of the NUD gene

BACKGROUND

The naked caryopsis character in barley is a domestication-associated trait defined by loss-of-function of the NUD gene. The functional NUD gene encodes an Apetala 2/Ethylene-Response Factor (AP2/ERF) controlling the formation of a cementing layer between pericarp and both lemma and palea. The downstream genes regulated by the NUD transcription factor and molecular mechanism of a cementing layer formation are still not sufficiently described. A naturally occurring 17-kb deletion in the nud locus is associated with the emergence of naked barley. Naked barley has been traditionally used for food and nowadays is considered as a dietary component for functional nutrition.

RESULTS

In the present study, we demonstrate that targeted knockout of the NUD gene using RNA-guided Cas9 endonuclease leads to the phenotype conversion from hulled to naked barley. Using in vivo pre-testing systems, highly effective guide RNAs targeting the first exon of the NUD gene were selected. Expression cassettes harboring the cas9 and guide RNA genes were used to transform barley cv. Golden Promise via Agrobacterium-mediated DNA transfer. The recessive naked grain phenotype was observed in 57% of primary transformants, which indicates a frequent occurrence of homozygous or biallelic mutations. T-DNA-free homozygous lines with independently generated mutations in the NUD gene were obtained in the T1 generation. At homozygous state, all obtained mutations including one- and two-amino acid losses with the translational reading frame being retained invariably caused the naked grain phenotype.

CONCLUSIONS

The hulled and naked barley isogenic lines generated are a perfect experimental model for further studies on pleiotropic consequences of nud mutations on overall plant performance under particular consideration of yield-determining traits. Due to the high β-glucan content of its grains, naked barley is considered as being of particular dietary value. The possibility to convert hulled into naked barley cultivars by targeted mutagenesis allows breeders to extend the potential utilization of barley by the provision of functional food.

Predicting Glycemic Index and Glycemic Load from Macronutrients to Accelerate Development of Foods and Beverages with Lower Glucose Responses

Low glycemic index (GI) and/or low glycemic load (GL) are associated with decreased risks of type-2 diabetes and cardiovascular disease. It is therefore relevant to consider GI and GL in the early phases of the development of packaged foods and beverages. This paper proposes a model that predicts GI and GL from macronutrient composition, by quantifying both the impact of glycemic carbohydrates and the GI-lowering effects of nutrients such as proteins, fats and fibers. The precision of the model is illustrated using data on 42 breakfast cereals. The predictions of GI (r = 0.90, median residual = 2.0) and GL (r = 0.96, median residual = 0.40 g) compete well with the precision of the underlying in-vivo data (Standard Error SE = 3.5 for GI). This model can guide product development towards lowering GI and GL, before final confirmation by in vivo testing.

Ingestion of Non-digestible Carbohydrates From Plant-Source Foods and Decreased Risk of Colorectal Cancer: A Review on the Biological Effects and the Mechanisms of Action

The hypothesis that links the increase in the intake of plant-source foods to a decrease in colorectal cancer (CRC) risk has almost 50 years. Nowadays, systematic reviews and meta-analysis of case-control and cohort studies confirmed the association between dietary patterns and CRC risk, in which the non-digestible carbohydrates (NDC) from plant-source foods are known to play beneficial effects. However, the mechanisms behind the physicochemical properties and biological effects induced by NDC on the decrease of CRC development and progression remain not fully understood. NDC from plant-source foods consist mainly of complex carbohydrates from plant cell wall including pectin and hemicellulose, which vary among foods in structure and in composition, therefore in both physicochemical properties and biological effects. In the present review, we highlighted the mechanisms and described the recent findings showing how these complex NDC from plant-source foods are related to a decrease in CRC risk through induction of both physicochemical effects in the gastrointestinal tract, fermentation-related effects, and direct effects resulting from the interaction between NDC and cellular components including toll-like receptors and galectin-3. Studies support that the definition of the structure-function relationship-especially regarding the fermentation-related effects of NDC, as well as the direct effects of these complex carbohydrates in cells-is crucial for understanding the possible NDC anticancer effects. The dietary recommendations for the intake of NDC are usually quantitative, describing a defined amount of intake per day. However, as NDC from plant-source foods can exert effects that vary widely according to the NDC structure, the dietary recommendations for the intake of NDC plant-source foods are expected to change from a quantitative to a qualitative perspective in the next few years, as occurred for lipid recommendations. Thus, further studies are necessary to define whether specific and well-characterized NDC from plant-source foods induce beneficial effects related to a decrease in CRC risk, thereby improving nutritional recommendations of healthy individuals and CRC patients.

Obesity and neurological disorders: Dietary perspective of a global menace

Obesity is considered a major public health concern throughout the world among children, adolescents, as well as adults and several therapeutic, preventive and dietary interventions are available. In addition to life style changes and medical interventions, significant milestones have been achieved in the past decades in the development of several functional foods and dietary regimens to reduce this menace. Being a multifactorial phenomenon and related to increased fat mass that adversely affects health, obesity has been associated with the development of several other co-morbidities. A great body of research and strong scientific evidence identifies obesity as an important risk factor for onset and progression of several neurological disorders. Obesity induced dyslipidaemia, metabolic dysfunction, and inflammation are attributable to the development of a variety of effects on central nervous system (CNS). Evidence suggests that neurological diseases such as Parkinson's disease and Alzheimer's disease could be initiated by various metabolic changes, related to CNS damage, caused by obesity. These metabolic changes could alter the synaptic plasticity of the neurons and lead to neural death, affecting the normal physiology of CNS. Dietary intervention in combination with exercise can affect the molecular events involved in energy metabolism and synaptic plasticity and are considered effective non-invasive strategy to counteract cognitive and neurological disorders. The present review gives an overview of the obesity and related neurological disorders and the possible dietary interventions.