Gomes PW, Fernández-Ochoa Á, Simões Larraz Ferreira M. Overview of the Metabolite Composition and Antioxidant Capacity of Seven Major and Minor Cereal Crops and Their Milling Fractions

Cereal grains play an important role in human health as a source of macro- and micronutrients, besides phytochemicals. The metabolite diversity was investigated in cereal crops and their milling fractions by untargeted metabolomics ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) of 69 samples: 7 species (barley, oat, pearl millet, rye, sorghum, triticale, and wheat), 23 genotypes, and 4 milling fractions (husk, bran, flour, and wholegrain). Samples were also analyzed by in vitro antioxidant activity. UHPLC-MS/MS signals were processed using XCMS, and metabolite annotation was based on SIRIUS and GNPS libraries. Bran and husk showed the highest antioxidant capacity and phenolic content/diversity. The major metabolite classes were phenolic acids, flavonoids, fatty acyls, and organic acids. Sorghum, millet, barley, and oats showed distinct metabolite profiles, especially related to the bran fraction. Molecular networking and chemometrics provided a comprehensive insight into the metabolic profiling of cereal crops, unveiling the potential of coproducts and super cereals such as sorghum and millet as sources of polyphenols.

Exploring a maize-derived dietary fiber-phenolic acid complex with prebiotic effects

The structural, functional, and prebiotic properties of three maize-derived cell wall dietary fiber-phenolic acid complexes (CWDFPC1, CWDFPC2, and CWDFPC3) were investigated. The results showed that all three CWDFPCs had similar proximate composition and XRD pattern (type I). However, there were significant differences in the phytochemical profiles of their phenolic compounds (PC). Although the testa was the primary source of bound PC (BPC) in all three CWDFPCs, CWDFPC2 had the highest BPC content (15.41 mg GAE/g) and exhibited the greatest antioxidant activity in vitro (DPPH and ABTS assays). The water holding capacity of CWDFPC1 (6.53 g/g) and CWDFPC3 (6.86 g/g) was higher than CWDFPC2 (4.84 g/g), and three CWDFPCs had similar nitrite ion adsorption capacity, bile adsorption capacity, and cation-exchange capacity. After 48 h of in vitro fecal fermentation, CWDFPC2 produced more short-chain fatty acids (46.33 mM) compared to CWDFPC1 and CWDFPC3 (40.26 mM and 44.20 mM, respectively).

Dynamic changes in ferulic acid and diferulic acids in wheat flour doughs during the breadmaking process

Ferulic acid (FA), a phytochemical concentrated in wheat bran, influences structural characteristics of arabinoxylan (AX) and rheological properties of wheat dough. This study investigates the dynamic changes in FA and diferulic acids, closely associated with AX molecular weight, during the breadmaking process. FA predominantly exists in a tightly bound state within the arabinoxylan matrix, with a substantial increase in free FA content observed during the initial fermentation phase. Furthermore, this research identified four specific wheat-derived diferulic acids: 8-5'-DFA, 5-5'-DFA, 8-O-4'-DFA, and 8-5'-DFA (benzofuran form), tracking their variations throughout breadmaking. The notable upsurge in diferulic acid levels in the early fermentation stages suggests that the cleavage of ferulic acid moieties may not be the primary factor contributing to the reduction in AX molecular weight. Future investigations into the effects of FA and diferulic acids on arabinoxylan and wheat dough properties promise to enhance understanding of the intricacies of the breadmaking process.

Nutritional assessment of nixtamalized maize tortillas produced from dry masa flour, landraces, and high yield hybrids and varieties

In the scientific literature there are different analyses of the nutritional profiles of maize tortillas, whether they are landraces or hybrid maize versus those made with dry masa flour (DMF). In general terms, there is agreement in the reported content of moisture. However, for the other nutrients, a great disparity is reported for each type of tortilla which may be due to various factors such as the type of maize or processing methods. In this study, the nutritional aspects of maize tortillas made with different genotypes (five hybrids, two varieties, five landraces, six hybrid mixtures and six dry masa flours) under controlled conditions, were compared. More than 30 characteristics were analyzed. High performance hybrids and varieties (HPHV) and landraces had the highest (p < 0.05) antioxidant capacity (58.8% free, 150.2% bound). In terms of vitamins contents, the tortillas produced from DMF contained 11.2 and 3.5 times more B1, 18.6 and 7.8 times more B2, and 2.7 and 5.3 times more B3 than HPHV and landraces respectively; and only in these samples was detected folic acid. DMF tortilla samples contained 1.75 times more sodium and 2.75 times more iron than the other groups, and 0.75 times less calcium than HPHV. Zinc was present in higher concentration (p < 0.05) in DMF tortilla samples. The landraces had the highest protein content (average 10.28%), but the tortillas produced from DMF presented the highest protein quality evaluated by protein digestibility-corrected amino acid score (PDCAAS) (p < 0.05) that represents 27, 25 and 19% more than hybrids mixture, HPHV and landraces, respectively. This work gives valuable information on how different types of grains differ in the nutritional quality affecting the final product to provide more elements in the decision-making of processors. There is no a perfect maize, but there are genotypes that can be combined as mixtures and the processing method to design superior nutritional tortillas and related products for populations that highly consume them and improve their human health.

Effect of Particle Size of Wheat and Barley Grain on the Digestibility and Fermentation of Carbohydrates in the Small and Large Intestines of Growing Pigs

The objective of this investigation was to study the effects of different cereal types, barley and wheat, with different particle sizes (PS) on the recovery of ileal digesta and fecal excretion, digestion of nutrients and fiber components, mean transit time (MTT), and short-chain fatty acid content and composition in growing pigs studied in two experiments. Five barrows with ileal cannulas (initial BW 35.9 ± 1.5 kg) in Experiment 1 and thirty-two castrated pigs (30.8 ± 1.3 kg) in Experiment 2 were fed four different diets: barley fine, barley coarse, wheat fine and wheat coarse diets. The cereal type and PS did not influence the relative weight of the small and large intestines and pH of digesta, whereas MTT in the large intestine of pigs fed the coarse barley diet was lower compared to pigs fed other diets (p < 0.05). Pigs fed the coarse barley diet had lower apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of nutrients and fiber (p < 0.05), whereas pigs fed the fine barley diet had similar AID and ATTD to pigs fed wheat fine and coarse diets (p < 0.05). In conclusion, the barley diet was more influenced by PS in comparison to wheat, thereby inducing lower AID and ATTD of nutrient.

The Phenolic Compounds' Role in Beer from Various Adjuncts

BACKGROUND

The present article considers the influence of malt with various adjuncts on beer organic compounds and taste profile composition, with more attention paid to the phenol complex change. The topic under consideration is relevant since it studies the interactions of phenolic compounds with other biomolecules, and expands the understanding of the adjuncts organic compounds contribution and their joint effect on beer quality.

METHODS

Samples of beer were analyzed at a pilot brewery using barley and wheat malts, barley, rice, corn and wheat, and then fermented. The beer samples were assessed by industry-accepted methods and using instrumental analysis methods (high-performance liquid chromatography methods-HPLC). The obtained statistical data were processed by the Statistics program (Microsoft Corporation, Redmond, WA, USA, 2006).

RESULTS

The study showed that at the stage of hopped wort organic compounds structure formation, there is a clear correlation between the content of organic compounds and dry substances, including phenolic compounds (quercetin, catechins), as well as isomerized hop bitter resines. It is shown that the riboflavin content increases in all adjunct wort samples, and mostly with the use of rice-up to 4.33 mg/L, which is 9.4 times higher than the vitamin levels in malt wort. The melanoidin content in the samples was in the range of 125-225 mg/L and its levels in the wort with additives exceeded the malt wort. Changes in β-glucan and nitrogen with thiol groups during fermentation occurred with different dynamics and depending on the adjunct's proteome. The greatest decrease in non-starch polysaccharide content was observed in wheat beer and nitrogen with thiol groups content-in all other beer samples. The change in iso-α-humulone in all samples at the beginning of fermentation correlated with a decrease in original extract, and in the finished beer there was no correlation. The behavior of catechins, quercetin, and iso-α-humulone has been shown to correlate with nitrogen with thiol groups during fermentation. A strong correlation was shown between the change in iso-α-humulone and catechins, as well as riboflavin and quercetin. It was established that various phenolic compounds were involved in the formation of taste, structure, and antioxidant properties of beer in accordance with the structure of various grains, depending on the structure of its proteome.

CONCLUSIONS

The obtained experimental and mathematical dependences make it possible to expand the understanding of intermolecular interactions of beer organic compounds and take a step toward predicting the quality of beer at the stage of using adjuncts.

Omics data reveals the phenolic fingerprint of Brazilian whole wheat flours of different technological qualities

Common wheat (Triticum aestivum) is one of the most consumed staple foods used for bakery products. Outer layers of grain present a great diversity of bioactive compounds, especially phenolic compounds (PC). Free and bound PC were extracted from eight genotypes of whole wheat flours (WWF) presenting different technological classifications. These extracts were comprehensively characterized through untargeted metabolomics applying ultra-high-performance liquid chromatography-mass spectrometry (UHPLC-MSE) and spectrophotometric analyses. Chemical composition and colorimetry were also determined by classical analyses. Thirty-eight PC were tentatively identified by UHPLC-MSE belonging to three classes (phenolic acids, flavonoids, and other polyphenols), some of them identified in all WWF samples. Bound hydroxycinnamic acids were the main PC found in WWF, especially the trans-ferulic acid and its isomer. No difference was found in starch and protein contents, whereas low-quality flours showed a higher ash content than the superior and medium-quality flours. Total phenolic content (TPC) ranged between 124.5 and 171.4 mg GAE/100 g WWF, which bound PC were responsible for 60% of TPC. Omics data and multivariate statistical analyses were successfully applied to discern the phenolic profile of WWF from different genotypes and technological qualities.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-023-05665-8.

Integrated metabolite analysis and health-relevant in vitro functionality of white, red, and orange maize (Zea mays L.) from the Peruvian Andean race Cabanita at different maturity stages

The high maize (Zea mays L.) diversity in Peru has been recognized worldwide, but the investigation focused on its integral health-relevant and bioactive characterization is limited. Therefore, this research aimed at studying the variability of the primary and the secondary (free and dietary fiber-bound phenolic, and carotenoid compounds) metabolites of three maize types (white, red, and orange) from the Peruvian Andean race Cabanita at different maturity stages (milk-S1, dough-S2, and mature-S3) using targeted and untargeted methods. In addition, their antioxidant potential, and α-amylase and α-glucosidase inhibitory activities relevant for hyperglycemia management were investigated using in vitro models. Results revealed a high effect of the maize type and the maturity stage. All maize types had hydroxybenzoic and hydroxycinnamic acids in their free phenolic fractions, whereas major bound phenolic compounds were ferulic acid, ferulic acid derivatives, and p-coumaric acid. Flavonoids such as luteolin derivatives and anthocyanins were specific in the orange and red maize, respectively. The orange and red groups showed higher phenolic ranges (free + bound) (223.9-274.4 mg/100 g DW, 193.4- 229.8 mg/100 g DW for the orange and red maize, respectively) than the white maize (162.2-225.0 mg/100 g DW). Xanthophylls (lutein, zeaxanthin, neoxanthin, and a lutein isomer) were detected in all maize types. However, the orange maize showed the highest total carotenoid contents (3.19-5.87 μg/g DW). Most phenolic and carotenoid compounds decreased with kernel maturity in all cases. In relation to the primary metabolites, all maize types had similar fatty acid contents (linoleic acid > oleic acid > palmitic acid > α-linolenic acid > stearic acid) which increased with kernel development. Simple sugars, alcohols, amino acids, free fatty acids, organic acids, amines, and phytosterols declined along with grain maturity and were overall more abundant in white maize at S1. The in vitro functionality was similar among Cabanita maize types, but it decreased with the grain development, and showed a high correlation with the hydrophilic free phenolic fraction. Current results suggest that the nutraceutical characteristics of orange and white Cabanita maize are better at S1 and S2 stages while the red maize would be more beneficial at S3.

Natural Polyphenol Recovery from Apple-, Cereal-, and Tomato-Processing By-Products and Related Health-Promoting Properties

Polyphenols of plant origin are a broad family of secondary metabolites that range from basic phenolic acids to more complex compounds such as stilbenes, flavonoids, and tannins, all of which have several phenol units in their structure. Considerable health benefits, such as having prebiotic potential and cardio-protective and weight control effects, have been linked to diets based on polyphenol-enriched foods and plant-based products, indicating the potential role of these substances in the prevention or treatment of numerous pathologies. The most representative phenolic compounds in apple pomace are phloridzin, chlorogenic acid, and epicatechin, with major health implications in diabetes, cancer, and cardiovascular and neurocognitive diseases. The cereal byproducts are rich in flavonoids (cyanidin 3-glucoside) and phenolic acids (ferulic acid), all with significant results in reducing the incidence of noncommunicable diseases. Quercetin, naringenin, and rutin are the predominant phenolic molecules in tomato by-products, having important antioxidant and antimicrobial activities. The present understanding of the functionality of polyphenols in health outcomes, specifically, noncommunicable illnesses, is summarized in this review, focusing on the applicability of this evidence in three extensive agrifood industries (apple, cereal, and tomato processing). Moreover, the reintegration of by-products into the food chain via functional food products and personalized nutrition (e.g., 3D food printing) is detailed, supporting a novel direction to be explored within the circular economy concept.

A Comparative Study of Physicochemical Attributes of Pigmented Landrace Maize Varieties

Maize has been cultivated and continues to be cultivated for its usability in calorie supply to humans and livestock. There has been great interest in pigmented landrace maize varieties (PLMVs) due to their importance in the pharmaceutical industry. Landraces are to a large extent a repository of the gene pool that enriches biodiversity and maintains but also stabilizes the ecosystem in a sustainable way. PLMVs are still being cultivated by smallholder farmers in smaller portions of their fields and home surroundings despite the high adoption of white hybrid maize. This study examined the ash, moisture, mineral, crude protein, fat, and carbohydrate content of three different PLMVs from central (Ntcheu and Dedza districts) and northern (Mzimba district) Malawi. The mineral content of soils from fields where PLMVs were grown was also analyzed. The study areas experience a warm temperate climate and higher rainfall in summer than in winter but they differ in that Ntcheu has the highest average annual temperature of 20.3°C while Dedza receives the highest annual precipitation of about 1010 mm. Mzimba’s average annual temperature and precipitation are 20.1°C and 915 mm, respectively. The study showed that orange maize from Dedza had a significantly higher content of calcium (71.00 ± 0.58 mg·kg−1), magnesium (819.00 ± 0.58 mg·kg−1), and phosphorus (2720.35 ± 0.03 mg·kg−1). Significantly higher contents of zinc (54.61 ± 0.43 mg·kg−1) and potassium (808.58 ± 0.27 mg·kg−1) were observed in purple maize from Dedza and Ntcheu, respectively. Red maize from Dedza had a significantly higher content of iron (59.80 ± 0.26 mg·kg−1). Purple maize from Dedza has significantly higher carbohydrate content (65.52 ± 0.07%). The findings also revealed that red maize from Dedza provenance had a high content of crude protein (12.57 ± 0.07%) and fat (10.73 ± 0.14%). Moisture (17.30 ± 0.21%) and ash (2.28 ± 0.02%) were significantly higher in orange maize from Dedza. Dedza’s provenance revealed a high content of the analyzed attributes in PLMVs. Mineral analysis showed different levels of mineral bioavailability in different PLMVs and in the soils where maize was grown. It can, therefore, be concluded that production location and maize variety have an influence on the attributes of PLMVs. Understanding the physicochemical attributes of PLMVs and its maximum utilization have the potential of improving food and nutrition security in Sub-Saharan African countries and globally.

Integrated Technology for Cereal Bran Valorization: Perspectives for a Sustainable Industrial Approach

Current research focuses on improving the bioaccessibility of functional components bound to cereal bran cell walls. The main bioactive components in cereal bran that have major biological activities include phenolic acids, biopeptides, dietary fiber, and novel carbohydrates. Because of the bound form in which these bioactive compounds exist in the bran matrix, their bioaccessibility is limited. This paper aims to comprehensively analyze the functionality of an integrated technology comprising pretreatment techniques applied to bran substrate followed by fermentation bioprocesses to improve the bioaccessibility and bioavailability of the functional components. The integrated technology of specific physical, chemical, and biological pretreatments coupled with fermentation strategies applied to cereal bran previously-pretreated substrate provide a theoretical basis for the high-value utilization of cereal bran and the development of related functional foods and drugs.

Polyphenols and Their Nanoformulations: Protective Effects against Human Diseases

Polyphenols are the secondary metabolites synthesized by the plants as a part of defense machinery. Owing to their antioxidant, anti-inflammatory, anticancerous, antineoplastic, and immunomodulatory effects, natural polyphenols have been used for a long time to prevent and treat a variety of diseases. As a result, these phytochemicals may be able to act as therapeutic agents in treating cancer and cardiovascular and neurological disorders. The limited bioavailability of polyphenolic molecules is one issue with their utilization. For the purpose of increasing the bioavailability of these chemicals, many formulation forms have been developed, with nanonization standing out among them. The present review outlines the biological potential of nanoformulated plant polyphenolic compounds. It also summarizes the employability of various polyphenols as nanoformulations for cancer and neurological and cardiovascular disease treatment. Nanoencapsulated polyphenols, singular or in combinations, effective both in vitro and in vivo, need more investigation.

Maize Silk Biogenic Nanoceria (CeO2NPs) Enhanced Sequential Injection-Chemiluminescence Detection of Ferulic, Sinapic and p-Coumaric in Yellow Maize Kernels

The current study demonstrated the capability of using maize silk as a green, simple, clean, safe, and cost-effective platform for the biosynthesis of cerium oxide (CeO₂NPs). Several spectroscopic and microscopic analyses were employed to characterize the resulted biogenic nanoceria. When the concentration of the CeO₂NPs was elevated from 25 to 100 ug mL⁻¹, the CeO₂NPs exhibited strong scavenging potential ranging from 60.21 to 75.11% and 56 to 77% for 1,1-diphenyl-2- picrylhydrazyl (DPPH•) and 2-2′-azino-bis(3-ethyl benzothiazoline-6-sulphonic acid) (ABTS) tests, respectively. The quantitative determination of ferulic, sinapic, and p-coumaric acids was carried out using an eco-friendly, cost-effective, and optimized ultrasensitive nanoceria enhanced sequential injection-chemiluminescence (SIA-CL) system. The highest amount was presented by the ferulic acid (1636 ± 2.61 ug/g_dw), followed by p-coumaric acid (206 ± 1.12 ug/g_dw) and sinapic acid (123 ± 2.15 ug/g_dw). The intrinsic capabilities of the biogenic CeO₂NPs in enhancing the developed system reveal its potential role in detecting phenolic compounds with great sensitivity.

Broa, an Ethnic Maize Bread, as a Source of Phenolic Compounds

Maize is an important source of phenolic compounds, specially hydroxycinnamic acids, which are widely known for their antioxidant activity and associated health benefits. However, these effects depend on their bioaccessibility, which is influenced by the different techniques used for food processing. Several traditional products can be obtained from maize and, in Portugal, it is used for the production of an ethnic bread called broa. In order to evaluate the effect of processing on maize phenolic composition, one commercial hybrid and five open-pollinated maize flours and broas were studied. The total phenolic content and antioxidant activity were evaluated by the Folin-Ciocalteu and ORAC assays, respectively. The major phenolics, namely ferulic and p-coumaric acids (in their soluble-free, soluble-conjugated and insoluble forms), insoluble ferulic acid dimers and soluble hydroxycinnamic acid amides were quantitated. Results show that the total phenolic content, antioxidant activity and hydroxycinnamic acids resisted traditional processing conditions used in the production of broas. The content in soluble-free phenolics increased after processing, meaning that their bioaccessibility improved. Portuguese traditional broas, produced with open-pollinated maize varieties, can be considered an interesting dietary source of antioxidant compounds due to the higher content in hydroxycinnamic acids and derivatives.

Valorization of Heat-Treated Brewers' Spent Grain Through the Identification of Bioactive Phenolics by UPLC-PDA and Evaluation of Their Antioxidant Activities

Thermal processing not only disrupts cell membranes and cell walls, but also cleaves covalent bonds releasing low molecular phenolic. This study examined the impact of various heat treatments (100, 140, and 160°C) on the composition of phenolic acids and antioxidant activities in extracts obtained from defatted brewers spent grain (BSG) meal. Heating BSG at 160°C resulted in a 2-fold increase in total phenolic content [TPC, 172.98 ± 7.3 mg Gallic acid equivalent (GAE)/100 g defatted meal] and total flavonoid content [TFC, 16.15 ± 2.22 catechin equivalents (CE)/100 g defatted meal] compared to the untreated BSG extracts. The antioxidant activities of treated BSG extracts, determined by radical scavenging and ferric reducing antioxidant power (FRAP) were significantly (p < 0.5) higher than the corresponding untreated BSG extracts. Eleven phenolic acids were identified and quantified in BSG extracts by Ultra Performance Liquid Chromatography with Photodiode Array (UPLC-PDA). The amounts varied significantly (p < 0.05) depending on the degree of toasting BSG was subjected to. Chlorogenic acid, an ester of caffeic and quinic acid was the predominant phenolic acid present in all fractions. Significant (p < 0.05) increases in TPC, TFC, individual phenolic acids and antioxidant activity were observed in BSG extracts exposed to increasing oven temperatures. These results confirm the ability of heat processing to release bioactive phenolic from their bound forms thereby enhancing the phenolic acids and the digestibility of BSG meal in the intestinal tract.

Debranching enzymes in corn/soybean meal-based poultry feeds: a review

This review discusses the complex nature of the primary nonstarch polysaccharide (NSP) in corn with respect to the merit of debranching enzymes. Celluloses, hemicelluloses, and pectins comprise the 3 major categories of NSP that make up nearly 90% of plant cell walls. Across cereals, the hemicellulose arabinoxylan exists as the primary NSP, followed by cellulose, glucans, and others. Differences in arabinoxylan structure among cereals and cereal fractions are facilitated by cereal type, degree and pattern of substitution along the xylan backbone, phenol content, and cross-linkages. In particular, arabinoxylan (also called glucuronoarabinoxylan) in corn is heavily fortified with substituents, being more populated than in wheat and other cereal grains. Feed-grade xylanases - almost solely of the glycoside hydrolase (GH) 10 and GH 11 families - require at least 2 or 3 contiguous xylose units to be free of attachments to effectively attack the xylan chain. This canopy of attachments, along with a high phenol content and the insoluble nature of corn glucuronoarabinoxylan, confers a significant resistance to xylanase attack. Both in vitro and in vivo studies demonstrate that debranching enzymes appreciably increase xylanase access and fiber degradability by removing these attachments and breaking phenolic linkages. The enzymatic degradation of the highly branched arabinoxylan can facilitate disassembly of other fibers by increasing exposure to pertinent carbohydrases. For cereals, the arabinofuranosidases, α-glucuronidases, and esterases are some of the more germane debranching enzymes. Enzyme composites beyond the simple core mixes of xylanases, cellulases, and glucanases can exploit synergistic benefits generated by this class of enzymes. A broad scope of enzymatic activity in customized mixes can more effectively target the resilient NSP construct of cereal grains in commercial poultry diets, particularly those in corn-based feeds.

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

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

The effect of the amylose content and milling fractions on the physico-chemical features of co-extruded snacks from corn

The suitability of corn fractions (break meal: 250-500 µm; flour: < 150 µm) from hybrids with different amylose contents (conventional: 18%; high-amylose: 42%; waxy: 2%) and their blends, to produce co-extruded snacks was assessed. Corn flour exhibited a higher content in total soluble phenolic acids (+34%) than break meal. The high-amylose hybrid maintained a higher antioxidant capacity and phenolic acid content (+52% for soluble and + 54% for cell-wall bound phenolic acids), even after extrusion, than the conventional one. Because of its gelatinization properties (high pasting and peak temperatures; low maximum viscosity), the high-amylose hybrid produced co-extruded snacks characterized by low section areas and large inner areas. The blends led to snacks whose features (sections and inner areas, porosity and hardness) did not follow a linear trend with the amylose content, suggesting the need for further studies to better understand the starch interactions that take place among the various hybrids.

Hydroxycinnamic Acids and Their Derivatives in Broa, a Traditional Ethnic Maize Bread

Maize is one of the most interesting dietary sources of hydroxycinnamic acids, widely known for their beneficial health effects, namely antioxidant properties. This work aims to identify hydroxycinnamic acids and their derivatives in broa, a Portuguese traditional ethnic maize bread, and corresponding maize flours. Soluble and insoluble phenolic fractions of diverse maize flours and corresponding broas were prepared and analysed by HPLC-DAD-MS/MS (high-performance liquid chromatography coupled with diode array detector and tandem mass spectrometry). Besides free hydroxycinnamic acids, mainly ferulic and p-coumaric acids, several structural isomers and stereoisomers of insoluble ferulic acid dehydrodimers (n = 18) and trimers (n = 11), were also identified. Hydroxycinnamic acid amides consisting of coumaroyl and feruloyl conjugates (n = 22) were present in both soluble and insoluble fractions of maize flours and breads, in different isomeric forms. A new compound was putatively identified as bis-N,N′-diferuloyl putrescine. Additionally, more complex and insoluble hydroxycinnamic acid amides, derived from ferulic acid dehydrodimers (n = 47) and trimers (n = 18), were also putatively identified for the first time, suggesting that hydroxycinnamic acid amides are also linked to maize cell walls. Since hydroxycinnamic derivatives were not only identified in maize flours, but also in broas, they can contribute to the antioxidant properties and beneficial health effects of maize-based foods.

Phenolic Acid Profiles and Antioxidant Activity of Major Cereal Crops

Phenolic acids (PAs) are a dominant group of phenolic compounds in cereals, existing mostly bound to compounds of cell wall. In this study, a total of 25 cereal grain samples, including wheat, winter and spring barley, corn, and popcorn, were evaluated for bound PAs and antioxidant activity in a two-year field trial. The PA contents, determined by HPLC, were significantly affected by cereal type. The mean total PA content was highest in popcorn and corn (3298 and 2213 μg/g_dm, respectively₎, followed by winter and spring barley (991 and 908 μg/g_dm, respectively) and wheat (604 μg/g_dm). Ferulic acid was the most abundant, accounting from 62% to 83% of total PAs (in popcorn and winter and spring barley, respectively). Across cereals, p-coumaric (35-259 μg/g_dm) and p-hidroxybenzoic (45-79 μg/g_dm) were also dominant, while in corn and popcorn o-coumaric (71 and 89 μg/g_dm, respectively) also occurred in higher content. The mean total phenol content ranged from 853 μg GAE/g_dm (wheat) to 1403 μg GAE/g_dm (winter barley) with DPPH scavenging activity from 14% to 67%, respectively. A significant influence of crop years on the ferulic acid and total PA content was found, while the variability of other PAs was dependent on the cereal type. The results indicated a high health benefit potential of selected cereals.

Effects of edible plant polyphenols on gluten protein functionality and potential applications of polyphenol-gluten interactions

Expanding plant-based protein applications is increasingly popular. Polyphenol interactions with wheat gluten proteins can be exploited to create novel functional foods and food ingredients. Polyphenols are antioxidants, thus generally decrease gluten strength by reducing disulfide cross-linking. Monomeric polyphenols can be used to reduce dough mix time and improve flexibility of the gluten network, including to plasticize gluten films. However, high-molecular-weight polyphenols (tannins) cross-link gluten proteins, thereby increasing protein network density and strength. Tannin-gluten interactions can greatly increase gluten tensile strength in dough matrices, as well as batter viscosity and stability. This could be leveraged to reduce detrimental effects of healthful inclusions, like bran and fiber, to loaf breads and other wheat-based products. Further, the dual functions of tannins as an antioxidant and gluten cross-linker could help restructure gluten proteins and improve the texture of plant-based meat alternatives. Tannin-gluten interactions may also be used to reduce inflammatory effects of gluten experienced by those with gluten allergies and celiac disease. Other potential applications of tannin-gluten interactions include formation of food matrices to reduce starch digestibility; creation of novel biomaterials for edible films or medical second skin type bandages; or targeted distribution of micronutrients in the digestive tract. This review focuses on the effects of polyphenols on wheat gluten functionality and discusses emerging opportunities to employ polyphenol-gluten interactions.

Different Strategies to Obtain Corn (Zea mays L.) Germ Extracts with Enhanced Antioxidant Properties

Maize ( Zea mays L.) germs are by-products from the milling industry. The objective of this work was to compare the phenolic and lipophilic antioxidant fractions of yellow and white corn varieties, provided by Corn Valley S.r.l. (Piumbega, Mantova, Italy) and among the raw materials most processed by the company. The phenolic fraction, extracted with ultrasound-assisted extraction, alone and in combination with chemical and enzymatic hydrolyses, was analyzed with high-performance thin-layer chromatography and reversed-phase high-performance liquid chromatography-diode array detector. Among the various extraction techniques used, the combination of sonication and alkaline hydrolysis proved to be an effective method for the extraction of phenolic compounds from yellow and white germs, with the highest ferulic acid concentrations (636.54 ± 3.71 and 569.23 ± 1.69 mg FA/g dried extract, respectively), total phenolic contents (844.5 ± 64.6 and 742.8 ± 15.44 mg gallic acid equivalents/g dried extract, respectively), and the best antioxidant activity (14.33 ± 0.48 and 11.41 ± 1.1 µg/mL, respectively). The lipophilic fraction, extracted using supercritical carbon dioxide was analyzed by gas chromatography-mass spectrometry. The unsaponifiable fractions were found to be 2.41% ± 0.24% in yellow corn and 1.85% ± 0.08% in white corn; β-sitosterol, campesterol, and stigmasterol were identified as the main phytosterols characterizing both lipophilic extracts which showed the most effective antioxidant activity (1.29 ± 0.26 mg/mL and 1.33 ± 0.21 mg/mL, respectively) compared with the control. Finally, the phenolic and lipophilic extracts obtained from maize by-products may be reintroduced into the health-oriented market as extracts enriched of high-added value biomolecules with antioxidant activity both as active molecules and as additives of natural origin.

Optimal Dietary Ferulic Acid for Suppressing the Obesity-Related Disorders in Leptin-Deficient Obese C57BL/6J -ob/ob Mice

Ferulic acid (FA) is a major polyphenolic compound and has been shown to improve the glucose and lipid homeostasis in high-fat diet-induced obese mice. Here, we found the optimal level of dietary FA to ameliorate obesity and obesity-correlated disorders, and identified the responses of gut microbiota to dietary FA in genetic leptin-deficient obese ( ob/ob) mice. The ob/ob mice exhibited persistent higher body weights, feed efficiency, white adipose tissue weights, and hepatic lipid accumulation, compared to those of the wild-type mice. However, 0.5% dietary FA suppressed these symptoms in ob/ob mice. The diversity of gut microbiota and the total abundance of obesity- and anti-obesity-related genera were not influenced after FA intervention in ob/ob mice. These data suggest that sufficient intake of FA (0.5%) could be useful for treating obesity or obesity-related diseases, and this weight-control effect is possibly not correlated with the gut-brain axis.

Influence of Agricultural Management on Phytochemicals of Colored Corn Genotypes ( Zea mays L.). Part 1: Nitrogen Fertilization

In this study, the influence of nitrogen (N) fertilization (170 versus 300 kg of N/ha) on the content of bioactive compounds of whole-meal flour of 10 different colored corn genotypes was investigated. Considerable differences in antioxidant capacity and phytochemical concentrations were observed among genotypes. Higher N fertilization rates significantly ( p < 0.05) increased the content of both total cell-wall-bound phenolics and xanthophylls (lutein and zeaxanthin). Nevertheless, the main phenolic acids (ferulic, p-coumaric, and sinapic acids) as well as the antioxidant capacity and content of β-cryptoxanthin, β-carotene, and total anthocyanins did not show significant differences as far as the N fertilization rate is concerned. For corn cultivation, the application of high N fertilization rates, generally carried out to obtain higher grain yields, could positively influence the content of some bioactives particularly in years characterized by high rainfall levels responsible for N leaching from the soil.

Influence of Agricultural Management on Phytochemicals of Colored Corn Genotypes ( Zea mays L.). Part 2: Sowing Time

Among the agronomic practices carried out in corn cultivation, the early sowing time is increasingly used by farmers of temperate regions to improve yield and reduce mycotoxin contamination of corn grains. The present study determined the influence of sowing time on the phytochemical content of grains of 10 colored genotypes of corn. There was a significant improvement of both grain yield (+26%), thousand kernel weight (+3%), and test weight (+2%) in plots sown early. The early sowing also significantly influenced the chemical composition of corn grains, with an increase in the concentration of cell-wall-bound phenolic acids (+5%) and β-cryptoxanthin (+23%) and a decrease in the concentration of lutein (-18%) and total anthocyanins (-21%). Environmental conditions that occurred during grain development significantly influenced the phytochemical content of corn grain, and early spring sowing could impart advantages in terms of both productivity and content of some antioxidants of whole-meal corn flour.

A comparative study of anthocyanin distribution in purple and blue corn coproducts from three conventional fractionation processes

The aim was to compare the distribution of ANCs in purple and blue corn coproducts from three conventional corn fractionation processes and linking ANC partitioning in different coproducts to corn kernel phenotype. Total monomeric anthocyanin (TA) from purple corn extract was 4933.1±43.4mg cyanidin-3-glucoside equivalent per kg dry corn, 10 times more than blue corn. In dry milled purple corn, maximum ANCs were present in the pericarp (45.9% of total ANCs) and in wet-milling they were concentrated in steeping water (79.1% of total ANCs). For blue corn, the highest TA was in small grits and gluten slurry in dry-milling and wet-milling coproducts, respectively. HPLC showed the highest concentration of each ANC in steeping water for purple corn coproducts. Micrographs of kernel showed pigments concentrated in pericarp layer of purple but only in aleurone of blue corn. ANCs can concentrate in certain coproducts depending upon physical distribution of pigments in kernel.

Dietary corn fractions reduce atherogenesis in low-density lipoprotein receptor knockout mice

Accumulating evidence has suggested that intake of whole grains is a protective factor against pathogenesis of coronary artery disease. The exact mechanisms, however, are still not clearly understood. In this study, we hypothesized that adequate intake of corn fractions (aleurone, endosperm and germ) can modify lipid profiles in relation to atherosclerotic lesion development in low-density lipoprotein receptor knockout (LDLr-KO) mice. The purpose of the present study was to investigate the potential cardiovascular benefits of corn fractions in LDLr-KO mice through a number of biomarkers including lipid profile, and morphologic and morphometrical analysis of atherosclerotic lesions in aortic root. Four groups of male LDLr-KO mice were fed with the experimental diets supplemented with (3 treated) or without (control) 5% (wt/wt) of each of corn fractions for 10 weeks. All diets were supplemented with 0.06% (wt/wt) cholesterol. Compared with mice in the control group, atherosclerotic lesions in the aortic roots were significantly reduced (P=.003) in the mice that were fed diet supplemented with aleurone and germ fractions. This effect was associated with significant reductions in plasma total (P=.02) and LDL (P=.03) cholesterol levels, and an increase in fecal cholesterol excretion (P=.04). Furthermore, abdominal fat mass was significantly reduced by consumption of aleurone (P=.03). In summary, the consumption of aleurone and germ may help attenuate atherosclerosis by reducing plasma total and LDL cholesterol levels.

Antioxidant Secondary Metabolites in Cereals: Potential Involvement in Resistance to Fusarium and Mycotoxin Accumulation

Gibberella and Fusarium Ear Rot and Fusarium Head Blight are major diseases affecting European cereals. These diseases are mainly caused by fungi of the Fusarium genus, primarily Fusarium graminearum and Fusarium verticillioides. These Fusarium species pose a serious threat to food safety because of their ability to produce a wide range of mycotoxins, including type B trichothecenes and fumonisins. Many factors such as environmental, agronomic or genetic ones may contribute to high levels of accumulation of mycotoxins in the grain and there is an urgent need to implement efficient and sustainable management strategies to reduce mycotoxin contamination. Actually, fungicides are not fully efficient to control the mycotoxin risk. In addition, because of harmful effects on human health and environment, their use should be seriously restricted in the near future. To durably solve the problem of mycotoxin accumulation, the breeding of tolerant genotypes is one of the most promising strategies for cereals. A deeper understanding of the molecular mechanisms of plant resistance to both Fusarium and mycotoxin contamination will shed light on plant-pathogen interactions and provide relevant information for improving breeding programs. Resistance to Fusarium depends on the plant ability in preventing initial infection and containing the development of the toxigenic fungi while resistance to mycotoxin contamination is also related to the capacity of plant tissues in reducing mycotoxin accumulation. This capacity can result from two mechanisms: metabolic transformation of the toxin into less toxic compounds and inhibition of toxin biosynthesis. This last mechanism involves host metabolites able to interfere with mycotoxin biosynthesis. This review aims at gathering the latest scientific advances that support the contribution of grain antioxidant secondary metabolites to the mechanisms of plant resistance to Fusarium and mycotoxin accumulation.

Inhibition of Intestinal α-Glucosidase and Glucose Absorption by Feruloylated Arabinoxylan Mono- and Oligosaccharides from Corn Bran and Wheat Aleurone

The effect of feruloylated arabinoxylan mono- and oligosaccharides (FAXmo) on mammalian α-glucosidase and glucose transporters was investigated using human Caco-2 cells, rat intestinal acetone powder, and Xenopus laevis oocytes. The isolated FAXmo from wheat aleurone and corn bran were identified to have degree of polymerization (DP) of 4 and 1, respectively, by HPLC-MS. Both FAXmo extracts were effective inhibitors of sucrase and maltase functions of the α-glucosidase. The IC50 for FAXmo extracts on Caco-2 cells and rat intestinal α-glucosidase was 1.03–1.65 mg/mL and 2.6–6.5 mg/mL, respectively. Similarly, glucose uptake in Caco-2 cells was inhibited up to 40%. The inhibitory effect of FAXmo was dependent on their ferulic acid (FA) content (R = 0.95). Sodium independent glucose transporter 2 (GLUT2) activity was completely inhibited by FAXmo in oocytes injected to express GLUT2. Our results suggest that ferulic acid and feruloylated arabinoxylan mono-/oligosaccharides have potential for use in diabetes management.

Does Whole Grain Consumption Alter Gut Microbiota and Satiety?

This review summarizes recent studies examining whole grain consumption and its effect on gut microbiota and satiety in healthy humans. Studies comparing whole grains to their refined grain counterparts were considered, as were studies comparing different grain types. Possible mechanisms linking microbial metabolism and satiety are described. Clinical trials show that whole grain wheat, maize, and barley alter the human gut microbiota, but these findings are based on a few studies that do not include satiety components, so no functional claims between microbiota and satiety can be made. Ten satiety trials were evaluated and provide evidence that whole oats, barley, and rye can increase satiety, whereas the evidence for whole wheat and maize is not compelling. There are many gaps in the literature; no one clinical trial has examined the effects of whole grains on satiety and gut microbiota together. Once understanding the impact of whole grains on satiety and microbiota is more developed, then particular grains might be used for better appetite control. With this information at hand, healthcare professionals could make individual dietary recommendations that promote satiety and contribute to weight control.