Biochemical characterization of oat (Avena sativa L.) genotypes with high nutritional potential

The role of fermentation with lactic acid bacteria in quality and health effects of plant-based dairy analogues

The modern food industry is undergoing a rapid change with the trend of production of plant-based food products that are more sustainable and have less impact on nature. Plant-based dairy analogues have been increasingly popular due to their suitability for individuals with milk protein allergy or lactose intolerance and those preferring a plant-based diet. Nevertheless, plant-based products still have insufficient nutritional quality, undesirable structure, and earthy, green, and bean-like flavor compared to dairy products. In addition, most plant-based foods contain lesser amounts of essential nutrients, antinutrients limiting the bioavailability of some nutrients, and allergenic proteins. Novel processing technologies can be applied to have a homogeneous and stable structure. On the other hand, fermentation of plant-based matrix with lactic acid bacteria can provide a solution to most of these problems. Additional nutrients can be produced and antinutrients can be degraded by bacterial metabolism, thereby increasing nutritional value. Allergenic proteins can be hydrolyzed reducing their immunoreactivity. In addition, fermentation has been found to reduce undesired flavors and to enhance various bioactivities of plant foods. However, the main challenge in the production of fermented plant-based dairy analogues is to mimic familiar dairy-like flavors by producing the major flavor compounds other than organic acids, yielding a flavor profile similar to those of fermented dairy products. Further studies are required for the improvement of the flavor of fermented plant-based dairy analogues through the selection of special microbial cultures and formulations.

Characterization of Seven New Steroidal Saponins from Korean Oat Cultivars by UPLC-QTOF-MS and UPLC-MS/MS

Oat saponins are composed of triterpenoid and steroidal saponins, and their potential biological activities, such as antibacterial, antifungicidal, osteogenic, and anticancer activities, have been reported. In this study, qualitative and quantitative analyses of oat saponins were conducted by using UPLC-QToF-MS and UPLC-Triple Q-MS/MS. A total of 22 saponins were analyzed in seven Korean oat cultivars. Among them, 7 saponins were identified as new compounds in this source, which were tentatively confirmed as nuatigenin-type saponins with 26-O-diglucoside and 3-O-malonylglucoside forms and (25S)-furost-5-en-3β,22,26-triol-type saponins. In addition, the total content of these saponins ranged from 70.61 to 141.38 mg/100 g dry weight, and it was affected by the type of oat cultivar and the presence or absence of hulling. These detailed profiles will be suggested as fundamental data for breeding superior oat cultivars, evaluating of related products, and various industries.

Spatiotemporal deposition of cell wall polysaccharides in oat endosperm during grain development

Oat (Avena sativa) is a cereal crop whose grains are rich in (1,3;1,4)-β-D-glucan (mixed-linkage glucan or MLG), a soluble dietary fiber. In our study, we analyzed oat endosperm development in 2 Canadian varieties with differing MLG content and nutritional value. We confirmed that oat undergoes a nuclear type of endosperm development but with a shorter cellularization phase than barley (Hordeum vulgare). Callose and cellulose were the first polysaccharides to be detected in the early anticlinal cell walls at 11 days postemergence (DPE) of the panicle. Other polysaccharides such as heteromannan and homogalacturonan were deposited early in cellularization around 12 DPE after the first periclinal walls are laid down. In contrast to barley, heteroxylan deposition coincided with completion of cellularization and was detected from 14 DPE but was only detectable after demasking. Notably, MLG was the last polysaccharide to be laid down at 18 DPE within the differentiation phase, rather than during cellularization. In addition, differences in the spatiotemporal patterning of MLG were also observed between the 2 varieties. The lower MLG-containing cultivar AC Morgan (3.5% w/w groats) was marked by the presence of a discontinuous pattern of MLG labeling, while labeling in the same walls in CDC Morrison (5.6% w/w groats) was mostly even and continuous. RNA-sequencing analysis revealed higher transcript levels of multiple MLG biosynthetic cellulose synthase-like F (CSLF) and CSLH genes during grain development in CDC Morrison compared with AC Morgan that likely contributes to the increased abundance of MLG at maturity in CDC Morrison. CDC Morrison was also observed to have smaller endosperm cells with thicker walls than AC Morgan from cellularization onwards, suggesting the processes controlling cell size and shape are established early in development. This study has highlighted that the molecular processes influencing MLG content and deposition are more complex than previously imagined.

Nutritional and Phytochemical Composition and Associated Health Benefits of Oat (Avena sativa) Grains and Oat-Based Fermented Food Products

Oats (Avena sativa L.) are a popular functional cereal grain due to their numerous health benefits. This review article summarized the information on the chemical composition and phytonutrients of oats grown in different countries. It also reviewed recently developed fermented oat products to highlight their potential for human health. Oats have an interesting nutritional profile that includes high-quality protein, unsaturated fats, soluble fiber, polyphenolic compounds, and micronutrients. Oat grain has a unique protein composition, with globulins serving as the primary storage protein, in contrast to other cereals, where prolamins are the main storage proteins. Oats have the highest fat content of any cereal, with low saturated fatty acids and high essential unsaturated fatty acid content, which can help reduce the risk of cardiovascular diseases. Oats are a good source of soluble dietary fiber, particularly β-glucan, which has outstanding functional properties and is extremely important in human nutrition. β-Glucan has been shown to lower blood cholesterol and glucose absorption in the intestine, thereby preventing diseases such as cardiovascular injury, dyslipidemia, hypertension, inflammatory state, and type 2 diabetes. Oats also contain high concentration of antioxidant compounds. Avenanthramides, which are unique to oats, are powerful antioxidants with high antioxidative activity in humans. Recognizing the nutritional benefits of oats, oat-based fermented food products are gaining popularity as functional foods with high probiotic potential.

The Role of Ancient Grains in Alleviating Hunger and Malnutrition

Meeting the United Nation's sustainable development goals for zero hunger becomes increasingly challenging with respect to climate change and political and economic challenges. An effective strategy to alleviate hunger and its severe implications is to produce affordable, nutrient-dense, and sustainable food products. Ancient grains were long-forgotten due to the dominance of modern grains, but recently, they have been rediscovered as highly nutritious, healthy and resilient grains for solving the nutrition demand and food supply chain problems. This review article aims to critically examine the progress in this emerging field and discusses the potential roles of ancient grains in the fight against hunger. We provide a comparative analysis of different ancient grains with their modern varieties in terms of their physicochemical properties, nutritional profiles, health benefits and sustainability. A future perspective is then introduced to highlight the existing challenges of using ancient grains to help eradicate world hunger. This review is expected to guide decision-makers across different disciplines, such as food, nutrition and agronomy, and policymakers in taking sustainable actions against malnutrition and hunger.

Impact of Oats on Appetite Hormones and Body Weight Management: A Review

PURPOSE OF REVIEW

This study aims to review the hunger hormones in obesity management and the impact of oats in regulating these hormones for hunger suppression and body weight management. In this review, the impact of various edible forms of oats like whole, naked, sprouted, or supplemented has been investigated for their appetite hormones regulation and weight management.

RECENT FINDINGS

The onset of obesity has been greatly associated with the appetite-regulating hormones that control, regulate, and suppress hunger, satiety, or energy expenditure. Many observational and clinical studies prove that oats have a positive effect on anthropometric measures like BMI, waist circumference, waist-to-hip ratio, lipid profile, total cholesterol, weight, appetite, and blood pressure. Many studies support the concept that oats are rich in protein, fiber, healthy fats, Fe, Zn, Mg, Mn, free phenolics, ß-glucan, ferulic acid, avenanthramides, and many more. Beta-glucan is the most important bioactive component that lowers cholesterol levels and supports the defense system of the body to prevent infections. Hence, several clinical studies supported oats utilization against obesity, appetite hormones, and energy regulation but still, some studies have shown no or little significance on appetite. Results of various studies revealed the therapeutic potentials of oats for body weight management, appetite control, strengthening the immune system, lowering serum cholesterol, and gut microbiota promotion by increased production of short-chain fatty acids.

Understanding the influence of genotype and temperature on proteolytic activity in distinct barley genotypes

This study aimed at investigating the effects of genotype and temperatures on the proteolytic activity in green malt of 48 barley genotypes, including 19 mutants, 15 hulled, 4 hulless, and 10 wild using enzyme assays based on casein, as substrate. During malting, insoluble barley protein must be hydrolyzed into soluble peptides and free amino acids to supply the brewing yeast with sufficient nutrients to grow rapidly and metabolize glucose and other sugars into alcohol through fermentation. However, the relatively hot temperatures employed during kilning usually denature the proteolytic enzymes due to their thermolabile nature. Even though the hydrolytic activity of most of the proteases is destroyed during the kilning process, the malt includes a small fraction of thermostable proteases that can further degrade protein in the subsequent mashing process. Considering the higher temperature range employed in industrial kilning and mashing, three temperatures (37, 50, and 70°C) were selected to identify the genotypes possessing high activity at the higher range of temperatures as well as thermostable variant of the enzyme. The proteolytic activity in all the genotypes declined after 50°C depicting its optimum temperature. Overall proteolytic activity was observed to be positively correlated with the amino acids and negatively correlated with protein content. Three mutant (BL2086, BL2091, and BL2079) and one wild (WS 237) genotypes possessing proteolytic activity in a higher range at all the studied temperatures have the potential to be exploited in the breeding programs for incorporating trait of thermostable proteolytic activity into low malting efficiency cultivars. PRACTICAL APPLICATION: The optimal hydrolytic activities of carbohydrases and proteases during mashing are essential for producing high-quality wort from malted barley to ensure that hydrolyzed molecules are available to brewers' yeast to support fermentative metabolism. In this study, several barley cultivars were grown under identical environmental conditions but assayed at different temperatures. As result, four genotypes had been obtained that possessed optimal proteolytic activities at a higher temperature range and can be of great interest to breeders and maltsters for altering wort amino acid profiles and better exposure of starch to mashing enzymes, thereby increasing the fermentable sugar yield from the malt.

The comparison of polymorphism among Avena species revealed by retrotransposon-based DNA markers and soluble carbohydrates in seeds

Here, we compared the polymorphism among 13 Avena species revealed by the iPBS markers and soluble carbohydrate profiles in seeds. The application of seven iPBS markers generated 83 bands, out of which 20.5% were polymorphic. No species-specific bands were scored. Shannon's information index (I) and expected heterozygosity (H_e) revealed low genetic diversity, with the highest values observed for A. nuda (I = 0.099; He = 0.068). UPGMA clustering of studied Avena accessions and PCoA results showed that the polyploidy level is the main grouping criterion. High-resolution gas chromatography revealed that the studied Avena accessions share the same composition of soluble carbohydrates, but significant differences in the content of total (5.30-22.38 mg g^-1 of dry weight) and particular sugars among studied samples were observed. Sucrose appeared as the most abundant sugar (mean 61.52% of total soluble carbohydrates), followed by raffinose family oligosaccharides (31.23%), myo-inositol and its galactosides (6.16%), and monosaccharides (1.09%). The pattern of interspecific variation in soluble carbohydrates, showed by PCA, was convergent to that revealed by iPBS markers. Thus, both methods appeared as a source of valuable data useful in the characterization of Avena resources or in the discussion on the evolution of this genus.

Biochemical assessment of oat genotypes revealed variability in grain quality with nutrition and crop improvement implications

Oat is a potent source of nutrients and bioactive compounds offering potential health benefits and role in combating micronutrient malnutrition problems. To exploit nutritional and quality traits of oats, a biochemical assessment of 112 oat genotypes was conducted. The high range of variability for total phenol (1.7-31.3 mg/g), β-glucan (1.0-8.0 mg/g), calcium (1.91-4.34 mg/g), zinc (3.80-6.50 mg/100 g), iron (0.66-4.89 mg/100 g) and manganese (2.88-8.0 mg/100 g) was revealed among genotypes. A higher amount of iron and zinc was found in genotypes OS-6, HFO-638, HFO-915 & HFO-918, whereas, elevated levels of manganese and zinc were recorded in genotypes OS-403 & OL-1804. The results revealed groups of low phytic acid oat genotypes containing high crude protein (HFO-52, HFO-270, HFO-330), β-glucan (HFO-62, HFO-588, HFO-926). A significant positive correlation was obtained between copper with iron, manganese, and calcium content. These findings could be useful for developing value-added oat food products and novel oat varieties.

Genetic diversity in nutritional composition of oat (Avena sativa L.) germplasm reported from Pakistan

In the present study, 30 potential germplasm of oat (Avena sativa L.) were subjected to proximate, elemental, and HPLC analysis to provide a scientific basis to genetic diversity present among them. The extracts of the selected germplasms were also evaluated for their antioxidant potentials through DPPH and ABTS assays. Proximate analysis showed protein contents to be in the range 8.35–17.72% with the highest protein contents in the accession line 22,365 (17.72 ± 0.38%). The genotype-725 showed the highest carbohydrate, and dry matter (53.35 ± 0.01 and 93.50 ± 0.07% respectively) contents whereas, the germplasm-830 contained the highest fat (7.88 ± 0.12%) contents while the highest moisture contents were there in germplasm-22348 (11.95 ± 0.06%). The crude fiber contents (19.67 ± 0.19%) were found high in germplasm-832. The mentioned contents were also correlated to each other where a negative (−0.431*) correlation was noted for crude protein and carbohydrate while ash content to crude protein has a positive (0.38*) correlation. A positive and a negative correlation were there in Crude fats/crude protein (0.30*) and crude fats/moisture contents (−0.39*) respectively. Principal component analysis showed an Eigenvalue of 0.76 with a total variation of 85.01% when applied to proximate components. Based on cluster analysis to proximate composition all the oat germplasms were divided into 5 sub-clusters, where accession numbers 769 and 817 were found to be the most diverse genotypes. The elemental analysis confirmed the presence of magnesium (2.89–7.62 mg/L), sodium (3.71–8.03 mg/L), manganese (0.93–3.71 mg/L), copper (0.35–3.36 mg/L), iron (2.15–6.82 mg/L), zinc (1.30–3.37 mg/L), chromium (0.37–3.34 mg/L), and potassium (50.70–59.60 mg/L) in the selected germplasms. Principal component analysis for elemental composition showed the total variation of 73.75% with the Eigenvalue of 0.97. Cluster analysis on an elemental basis divided all the oat germplasms into 7 sub-clusters where accession numbers 769 and 22,350 were found to be the most diverse germplasm. Phytochemical analysis performed through HPLC resulted in the identification of nine possible compounds (malic acid, epigallocatechin gallate, quercetin, morin, ellagic acid, catechin hydrate, rutin, pyrogallol, and mandelic acid) in various germplasm of oat. A concentration-dependent antioxidant response was recorded when extracts were tested as an inhibitor of DPPH and ABTS free radicals. The results revealed that oat grains are a good source of nutrients, minerals, and phytochemicals that can be used as nutraceuticals and as food. The genetic differences revealed that this plant can be grown under varied environmental conditions.

Survey of Freshly Harvested Oat Grains from Southern Brazil Reveals High Incidence of Type B Trichothecenes and Associated Fusarium Species

The current study investigated the fungal diversity in freshly harvested oat samples from the two largest production regions in Brazil, Paraná (PR) and Rio Grande do Sul (RS), focusing primarily on the Fusarium genus and the presence of type B trichothecenes. The majority of the isolates belonged to the Fusarium sambucinum species complex, and were identified as F. graminearum sensu stricto (s.s.), F. meridionale, and F. poae. In the RS region, F. poae was the most frequent fungus, while F. graminearum s.s. was the most frequent in the PR region. The F. graminearum s.s. isolates were 15-ADON genotype, while F. meridionale and F. poae were NIV genotype. Mycotoxin analysis revealed that 92% and 100% of the samples from PR and RS were contaminated with type B trichothecenes, respectively. Oat grains from PR were predominantly contaminated with DON, whereas NIV was predominant in oats from RS. Twenty-four percent of the samples were contaminated with DON at levels higher than Brazilian regulations. Co-contamination of DON, its derivatives, and NIV was observed in 84% and 57.7% of the samples from PR and RS, respectively. The results provide new information on Fusarium contamination in Brazilian oats, highlighting the importance of further studies on mycotoxins.

Process-Induced Changes in the Quantity and Characteristics of Grain Dietary Fiber

Daily use of wholegrain foods is generally recommended due to strong epidemiological evidence of reduced risk of chronic diseases. Cereal grains, especially the bran part, have a high content of dietary fiber (DF). Cereal DF is an umbrella concept of heterogeneous polysaccharides of variable chemical composition and molecular weight, which are combined in a complex network in cereal cell walls. Cereal DF and its distinct components influence food digestion throughout the gastrointestinal tract and influence nutrient absorption and other physiological reactions. After repeated consumption of especially whole grain cereal foods, these effects manifest in well-demonstrated health benefits. As cereal DF is always consumed in the form of processed cereal food, it is important to know the effects of processing on DF to understand, safeguard and maximize these health effects. Endogenous and microbial enzymes, heat and mechanical energy during germination, fermentation, baking and extrusion destructurize the food and DF matrix and affect the quantity and properties of grain DF components: arabinoxylans (AX), beta-glucans, fructans and resistant starch (RS). Depolymerization is the most common change, leading to solubilization and loss of viscosity of DF polymers, which influences postprandial responses to food. Extensive hydrolysis may also remove oligosaccharides and change the colonic fermentability of DF. On the other hand, aggregation may also occur, leading to an increased amount of insoluble DF and the formation of RS. To understand the structure–function relationship of DF and to develop foods with targeted physiological benefits, it is important to invest in thorough characterization of DF present in processed cereal foods. Such understanding also demands collaborative work between food and nutritional sciences.

Metabolic adjustments during compatible interaction between barley genotypes and stripe rust pathogen

Stripe rust is a fungal disease that has devastated the barley production for a long time. The present study focused on the role of β-glucan, PR proteins, diamine oxidase (DAO), polyamine oxidase (PAO), key enzymes and metabolites of phenol and proline metabolism in the stripe rust resistance of barley. RD2901 with resistant behavior against stripe rust showed increased levels of PR proteins, phenylalanine ammonia lyase (PAL), tyrosine ammonia lyase (TAL) along with the accumulation of β-glucan and lignin which strengthen the plant cell wall during plant-pathogen interaction. It also depicted the enhanced activities of glutamate dehydrogenase (GDH) and ornithine aminotransferase (OAT) coupled with the increased amounts of proline, glycine betaine and choline after infection with M-race of P. striiformis f. sp. hordei. On the contrary, the sensitive genotype Jyoti was unable to enhance the activities of most of these enzymes except PAL and OAT so that it showed an increase in lignin and choline contents only. Secondly, the increase in lignin content was less as compared to the tolerant genotype. Hence, it can be inferred that these key metabolites and enzymes of various metabolic pathways may contribute to the resistance of barley against stripe rust pathogen. This study suggested that these key enzymes and their metabolites could serve as markers for the characterization of plant defensive state that is essential for crop protection.