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International audience; Phenolic compounds (PC) strongly contribute to the beneficial health effects of wheat, but their interactions can affect the quality of end-use wheat products. Free and bound PC were comprehensively characterized in 14 wheat flours (Triticum aestivum) from different Brazilian genotypes and technological qualities by using a metabolomics approach (UPLC-ESI-QTOF-MSE) combined with classical characterizations: colorimetry, ash, protein, starch and total phenolic content (TPC). Globally, 43 PC were identified: 33 (bound, 28 (free) and 15 in all flours, regardless of extract. Ferulic acid isomers were the most abundant PC, representing 25–50% of ion abundance depending on genotype. Campeiro, Sossego and Topázio genotypes showed a distinguished profile, with the highest total relative abundance of PC. TPC was significantly higher in flours with higher gluten strength (66.5–58.0 mg GAE/100 g flour). The ratio free-to-bound of PC averaged 1.15 between the flours of different technological qualities. Although PCA highlighted specific PC related to technological qualities, the genotype effect was very pronounced. This study correlates the phenolic profile and technological quality of wheat flours and provides the most recent data on the secondary metabolites profile, especially PC in refined flour, attesting to its significant nutritional importance due to its large consumption in refined forms.

Untargeted metabolomics analysis was applied to evaluate the phenolic profile of whole wheat bread with yerba mate (YM) during the bread-making process (flour, dough and bread). The free, bound and total phenolic contents of the samples evaluated by the Folin-Ciocalteu method showed the highest values for the flour, dough and bread samples prepared with 4.5% YM in fine and medium particle sizes (flour 181.48 - 175.26 mg GAE/g; dough 149.62 - 141.40 mg GAE/g; and bread 148.32 - 147.00 mg GAE/g). Globally, 104 phenolic compounds were tentatively identified, belonging to the five subclasses: flavonoids (35), phenolic acids (32), other polyphenols (10), stilbenes (2) and lignan (1). Of these compounds, 24 had the same m/z but showed different fragmentation profiles. A higher number of polyphenols was identified in the bound extracts (77%) than in the free extracts (59%). The addition of 4.5% of YM promoted an improved and more abundant profile of phenolic compounds in the dough and bread. The major compounds found in the samples containing YM were 5-caffeoylquinic acid and caffeic acid. The baking process did not adversely affect the abundance of phenolic compounds. The bread-making process positively affected the phenolic profile due to the release of bound phenolic compounds. At the same time, the addition of YM as a natural ingredient promoted an increase in the polyphenols in the bread.

International audience; Sorghum is a potential substitute for corn/wheat in cereal-based extruded products. Despite agronomic advantages and its rich diversity of phenolic compounds, sorghum kafirins group together and form complex with tannins, leading to a low digestibility. Phenolic content/profile by UPLC-ESI-QTOF-MSE and kafirins polymerization by SE-HPLC were evaluated in wholemeal sorghum extrudates; tannin-rich (#SC319) and tannin-free (#BRS330) genotypes with/without turmeric powder. Total phenolic, proantocyanidin and flavonoid contents were strongly correlated with antioxidant capacity (r > 0.9, p < 0.05). Extrusion increased free (+60%) and decreased bound phenolics (−40%) in #SC319, but reduced both (−40%; −90%, respectively) in #BRS330, which presented lower abundance after extrusion. Turmeric addition did not significantly impact antioxidant activity, phenolic content and profile and kafirins profile. Tannins presence/absence impacted phenolic profiles and polymerization of kafirins which appears related to the thermoplastic process. The extrusion improved proteins solubility and can positively enhance their digestibility (phenolic compounds-proteins interactions), making more accessible to proteolysis in sorghum extrudates.

A two-step extraction of soluble (AG) and gluten (GLU) proteins was performed on nine common wheat flours of different technological qualities, low (LW), medium (MD), and superior (SP). The immunogenic and allergenic peptides were identified and relatively quantified by a non-targeted multiplexed MS-MS method that used a Triticum aestivum database (UniProt) and ProPepper™. Collectively, 3603 and 91,609 peptides were identified, and, after clustering and filtering for this study, approximately 450 and 1708 peptides from GLU and AG fractions, respectively, were obtained from all samples. Approximately 19% of the identified peptides showed immunogenic action associated with prolamins. For the most part, 60% of the peptides belonged to high-molecular-weight glutenins. The immunogenic peptides were more expressed in LW than in SP and MD flours. Low quality flours also contained the highest number of epitopes (28) associated with CD and wheat allergies. The major proteins from AG associated with respiratory allergies were α-amylase inhibitors and serpins. Two serpins were found more expressed in LW flours. This paper offers the most comprehensive immunogenic profile of wheat proteins based on proteomics to date. These results indicate that low quality wheat flours are a more conceivable cause of immunological reactions.

UPLC-QTOF-MSE phenolic profile of kombuchas produced from the fermentation of green tea or black tea at 25 °C for 10 days was investigated along with the determination of their antioxidant capacities, antibacterial and antiproliferative activities. Overall, 127 phenolic compounds (70.2% flavonoids, 18.3% phenolic acids, 8.4% other polyphenols, 2.3% lignans and 0.8% stilbenes) were identified, with 103 phenolic compounds reported for the first time in kombuchas. A greater diversity and abundance of phenolic compounds was detected in black tea kombucha, which resulted in a higher antioxidant capacity. However, the green tea kombucha was the only one that presented antibacterial activity against all the bacteria tested and an increased antiproliferative activity against the cancer cell lines, which was attributed to the presence of catechins among the most abundant phenolic compounds and verbascoside as an exclusive compound. Thus, the type of tea used in the kombucha production interferes in its bioactive composition and properties.

Brewers' spent grain (BSG) is the major by-product of the brewing industry and presents a rich chemical composition as substrate for fermentation, besides a valuable source of bioactive compounds. Solid-state fermentation (SSF) was applied using five strains of filamentous fungi in different types of BSG to evaluate the release of phenolic compounds (PC) characterized by UPLC-ESI-QTOF-MSE. Aspergillus oryzae after 3 days of fermentation was the most effective in the release of antioxidant compounds based on Folin-Ciocalteu and DPPH results. Globally, a total of 102 compounds were tentatively identified. Ferulic, p-coumaric and caffeic acids were the most abundant PC in BSG. Metabolomic approach was essential to reveal distinct PC when SSF was applied to BSG, the ratio bound to free PC was strongly reduced, probably due to the release of compounds from the lignocellulosic matrix by the fungi β-glucosidase. The malt types also significantly impacted the fermentation behavior, resulting in different phenolic profiles. Unlike the number of identifications, the total abundance was 50% reduced after fermentation, probably due to the biotransformation/degradation of hydroxycinnamic acids into their derivatives. SSF effectively increased the release of bound PC leading to a more complex and distinguished profile according to type of malt.