Gluten-free cereal-based food products: the potential of metabolomics to investigate changes in phenolics profile and their in vitro bioaccessibility

Tracking the changes and bioaccessibility of phenolic compounds of sorghum grains (Sorghum bicolor (L.) Moench) upon germination and seedling growth by UHPLC-QTOF-MS/MS

In this study, phenolic profile/content was analyzed by high-resolution untargeted metabolomics after short germination (72 h) and seedling growth (144 h), using three sorghum genotypes varying in tannin content (IS 29569, Macia and IS 30400). In vitro antioxidant capacity and phenolic bioaccessibility were determined by microplate-based and INFOGEST methods, respectively. A total of 58 % annotated compounds were found in all genotypes; and phenolic acids and flavonoids represent more than 80 % of sorghum total abundance. PCA analysis showed higher phenolic variability in germination times (72 %) than genotypes (51 %). Germination reduced total ion abundance (-7 %) and free:bound phenolic compounds ratio (2.4-1.1), but antioxidant capacity remained constant. These results indicate the cell matrix-phenolic decomplexation, with the free compounds were quickly consumed after radicle emergence. Germination increased phenolic bioaccessibility (mainly in oral phase) but reduces flavonoids contents in gastric/intestinal digestion steps. This work can stimulate seed germination as a viable option for sorghum-based foods development, with improved nutritional and bioactive properties.

Plant-Based Antioxidants in Gluten-Free Bread Production: Sources, Technological and Sensory Aspects, Enhancing Strategies and Constraints

The recognized contribution of antioxidant compounds to overall health maintenance and spotted deficiencies in celiac patients' diets has driven more intensive research regarding antioxidant compounds' inclusion in gluten-free bread (GFB) production during the last decade. The presented review gathered information that provided insights into plant-based antioxidant sources which are applicable in GFB production through the resulting changes in the technological, sensory, and nutritional quality of the resulting antioxidant-enriched GFB. The influence of the bread-making process on the antioxidant compounds' content alteration and applied methods for their quantification in GFB matrices were also discussed, together with strategies for enhancing the antioxidant compounds' content, their bioaccessibility, and their bioavailability, highlighting the existing contradictions and constraints. The addition of plant-based antioxidant compounds generally improved the antioxidant content and activity of GFB, without a profound detrimental effect on its technological quality and sensory acceptability, and with the extent of the improvement being dependent on the source richness and the amount added. The determination of a pertinent amount and source of plant-based antioxidant material that will result in the production of GFB with desirable nutritional, sensory, and technological quality, as well as biological activity, remains a challenge to be combated by elucidation of the potential mechanism of action and by the standardization of quantification methods for antioxidant compounds.

Simulated Gastrointestinal Digestion of Bioprocessed Spelt Seeds: Bioaccessibility and Bioactivity of Phenolics

The goal of this research was to evaluate the impact of different bioprocessing techniques on improved bioaccessibility of phenolics from spelt seeds. Despite the negative influence of gastrointestinal digestion, fermentation of germinated seeds significantly increased the bioaccessibility of total phenolics and their antioxidant activity compared to digested raw seeds. Enzymatic treated fermented seeds showed the highest relative bioaccessibility of p-coumaric and trans-ferulic acids, while their absolute contents were significantly higher in “germinated + fermented” seeds. Our research suggests that pretreatment of spelt seeds with hydrolytic enzymes improves access of fermenting microorganisms to structural elements, resulting in an increased content of extractable and bound trans-ferulic acid. Significantly higher biostability of phenolics was observed in raw seeds. Some major quality changes in the composition of extracts were observed under simulated in vitro digestion, since antioxidants of the same extract showed a different relative decrease in DPPH• and ABTS•+ scavenging activities compared to the raw seeds or their corresponding undigested counterparts. It is therefore important to increase the content of extractable antioxidants in seeds by bioprocessing, since they are strongly diminished during digestion.

Bound Polyphenols from Red Quinoa Prevailed over Free Polyphenols in Reducing Postprandial Blood Glucose Rises by Inhibiting α-Glucosidase Activity and Starch Digestion

Inhibiting α-glucosidase activity is important in controlling postprandial hyperglycemia and, thus, helping to manage type-2 diabetes mellitus (T2DM). In the present study, free polyphenols (FPE) and bound polyphenols (BPE) were extracted from red quinoa and their inhibitory effects on α-glucosidase and postprandial glucose, as well as related mechanisms, were investigated. HPLC-MS analysis showed that the components of FPE and BPE were different. FPE was mainly composed of hydroxybenzoic acid and its derivatives, while BPE was mainly composed of ferulic acid and its derivatives. BPE exhibited stronger DPPH and ABTS antioxidant activities, and had a lower IC50 (10.295 mg/mL) value in inhibiting α-glucosidase activity. The inhibition kinetic mode analysis revealed that FPE and BPE inhibited α-glucosidase in a non-competitive mode and an uncompetitive mode, respectively. Furthermore, compared to FPE, BPE delayed starch digestion more effectively. BPE at 50 mg/kg reduced postprandial glucose increases comparably to acarbose at 20 mg/kg in ICR mice. These results could provide perspectives on the potential of BPE from red quinoa, as a functional food, to inhibit α-glucosidase activity, delay postprandial glucose increases and manage T2DM.

Technological, Sensory, and Hypoglycemic Effects of Quinoa Flour Incorporation into Biscuits

Background. Biscuits are consumed by all of society in the world. Incorporation of different ratios of quinoa flour into wheat flour for the production of biscuits is needed for the production of functional foods. Objective. This study aimed to evaluate the incorporation of 12.5% or 25% quinoa flour into biscuit production, evaluate rheological and sensory characteristics, and investigate the effect of the consumption of 20% cooked biscuits on diabetic rats. Design. The gross chemical composition, total carotenoids, phenolic and flavonoids of wheat flour and quinoa flour, and the rheological properties of the control, 12.5% quinoa, and 25% quinoa biscuit dough were determined. The effects of consumption of 12.5% quinoa and 25% quinoa biscuits on diabetic rats were investigated. Results. Quinoa flour had significantly higher levels of the gross chemical composition except for carbohydrate and increased phenolic compound and flavonoids content than those in wheat flour. Increasing the amount of quinoa flour in the biscuits could increase the farinograph and extensograph values of the dough. Biological results showed that the highest improvement in nutritional values appeared in the diabetic rat group, which consumed 25% quinoa biscuit for 60 days. The consumption of 12.5% quinoa biscuit and 25% quinoa biscuit showed a decline in blood glycosylated hemoglobin and glucose and an elevation in insulin levels compared with the positive control diabetic rat group. Discussion and Conclusion. It is encouraging to replace wheat flour with quinoa flour in biscuit manufacturing owing to positive effects on both the technological properties and sensory evaluation of biscuits. The increase of quinoa flour up to 25% had favorable nutritional values and hypoglycemic effects.

Effect of extrusion and turmeric addition on phenolic compounds and kafirin properties in tannin and tannin-free sorghum

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-MS^E 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.

Metabolomics: An analytical technique for food processing evaluation

This review aimed to retrieve the most recent research with strong impact concerning the application of metabolomics analysis in food processing. The literature reveals the high capacity of this methodology to evaluate chemical and organoleptic transformations that occur during food production. Current and potential applications of metabolomics analysis will be addressed, focusing on process-composition-function relationships. The use of the metabolomics approach to evaluate transformations in foods submitted to minimal processes, heat or cold treatments, drying, fermentation, chemical and enzymatic treatments and processes using innovative technologies will be discussed. Moreover, the main strategies and advantages of metabolomics-based approaches are reviewed, as well as the most used analytical platforms. Overall, metabolomics can be seen as an important tool to support academia and industry on pursuing knowledge about the transformation of raw animal or plant materials into ready-to-eat products.

Chemical Composition, In Vitro Bioaccessibility and Antioxidant Activity of Polyphenolic Compounds from Nutraceutical Fennel Waste Extract

Fennel (Foeniculum vulgare Mill.) waste contains a broad range of bioactive molecules, including polyphenols, which have poor bioaccessibility during gastrointestinal digestion. This work aimed to investigate the bioaccessibility of total phenolic compounds and the antioxidant capacity during simulated gastrointestinal digestion using two nutraceutical formulations based on non-acid-resistant (NAR) and acid-resistant (AR) capsules containing aqueous-based extracts from fennel waste. Moreover, to obtain a comprehensive investigation of the polyphenolic constituents of the fennel waste extract, a high-resolution mass spectrometry (Q-Orbitrap) analysis was performed. Notably, chlorogenic acids, such as 4-caffeoylquinic acid and 3,4-dicaffeoylquinic acid, were the most detected compounds found in assayed samples (1.949 and 0.490 mg/g, respectively). After in vitro gastrointestinal digestion, the extract contained in AR capsules displayed higher bioaccessibility in both the duodenal and colonic stages (1.96 and 5.19 mg GAE/g, respectively) than NAR capsules (1.72 and 3.50 mg GAE/g, respectively), suggesting that the acidic gastric conditions negatively affected the polyphenol compounds released from the NAR capsules. Therefore, the aqueous extract of fennel waste could be proposed as an innovative and easily available source of dietary polyphenols. Furthermore, the use of an AR capsule could improve the polyphenol bioaccessibility and can be proposed as a nutraceutical formulation.

Impact of Grape Pomace Powder on the Phenolic Bioaccessibility and on In Vitro Starch Digestibility of Wheat Based Bread

Breads were prepared by substituting common wheat flour with 0 (GP0), 5 (GP5) and 10 (GP10) g/100 g (w/w) of grape pomace powder (GPP) and were analyzed for the phenolic profile bioaccessibility as well as the in vitro starch digestion during simulated digestion. The free and bound phenolic composition of native GPP and resulting breads were profiled using ultra-high-performance chromatography-quadrupole-time-of-flight (UHPLC-QTOF). The raw GPP was characterized by 190 polyphenols with the anthocyanins representing the most abundant class, accounting for 11.60 mg/g of cyanidin equivalents. Regarding the fortified bread, the greatest (p < 0.05) content in phenolic compounds was recorded for the GP10 sample (considering both bound and free fractions) being 127.76 mg/100 g dry matter (DM), followed by the GP5 (106.96 mg/100 g DM), and GP0 (63.76 mg/100 g DM). The use of GPP determined an increase of anthocyanins (considered the markers of the GPP inclusion), recording 20.98 mg/100 g DM in GP5 and 35.82 mg/100 g DM in GP10. The bioaccessibility of anthocyanins increased in both GP5 and GP10 breads when moving from the gastric to the small intestine in vitro digestion phase with an average value of 24%. Both the starch hydrolysis and the predicted glycemic index decreased with the progressive inclusion of GPP in bread. Present findings showed that GPP in bread could promote an antioxidant environment in the digestive tract and influence the in vitro starch digestion.

Moringa oleifera L. leaf powder as ingredient in gluten-free biscuits: nutritional and physicochemical characteristics

Dried powder from Moringa oleifera L. leaves (MOLP) could be considered a promising naturally gluten-free (GF) ingredient to be added in the formulation of GF food products aiming to improve the overall nutritional characteristics. In this work, GF biscuits were formulated by replacing a commercial GF flour mix with 0, 5, 10, and 15 g/100 g of MOLP. Chemical composition, physical and textural characteristics, starch pasting properties, and the in vitro starch digestibility were considered. Adding MOLP increased the amount of protein and total dietary fibre. Even at the lowest MOLP-substitution level, the biscuits had a total dietary fibre content > 6 g/100 g dry matter. Differences in the chemical composition might account for differences in starch properties in terms of pasting behaviour and in vitro digestibility. Using MOLP decreased the in vitro starch hydrolysis index of biscuits, the lowest value (69.3) obtained at the greatest MOLP inclusion level. In addition, an increase in the resistant starch content was reported, passing from 1.1 to 2.7 g/100 g dry matter for GF biscuits containing 0 to 15 g/100 g of MOLP. Colour, spread ratio, and hardness were affected by MOLP inclusion. Biscuits containing 15 g/100 g of MOLP were characterized by the highest hardness value (41.9 N). Substitution level of 10 g/100 g should be considered the threshold level for obtaining a product with similar spread ratio than the control.

In Vitro Evaluation of Enriched Brewers' Spent Grains Using Bacillus subtilis WX-17 as Potential Functional Food Ingredients

Brewers' spent grains (BSGs) are nutritious food processing by-products generated in the brewing industry. In this study, in vitro digestion-fermentation was employed to examine fermented BSG using Bacillus subtilis WX-17 as functional food ingredients. Insoluble fibers in BSG were converted into soluble fibers after fermentation, giving an increase from 6.13 ± 0.42 to 9.37 ± 0.53 mg/100 g BSG. After in vitro digestion of unfermented and fermented BSG, various nutritional components were found to be higher in fermented BSG. Components such as amino acids and fatty acids gave a concentration of 1.635 ± 0.236 mg/mL and 6.35 ± 0.65 mg/mL, respectively. Additionally, vitamin K₂ MK7 was detected in fermented BSG with a concentration of 0.00012 ± 0.000005 mg/mL. Probiotics Bacillus subtilis WX-17 was observed to withstand the in vitro digestion. After in vitro fermentation, various short-chain fatty acids namely acetic acid, propanoic acid, and butyric acid were produced at higher amounts for fermented BSG. The concentrations obtained were 124.11 ± 18.72 mM, 13.18 ± 1.38 mM, and 46.25 ± 7.57 mM respectively. As for gut microbiota profile, differential genera such as Bacteroides and Ruminococcus were detected, showing different effects on the intestinal microbiota. This study demonstrates the potential of using microbial fermentation of underutilized BSG to serve as potential functional food ingredients.

Red beet (Beta vulgaris) and amaranth (Amaranthus sp.) microgreens: Effect of storage and in vitro gastrointestinal digestion on the untargeted metabolomic profile

This study aimed to investigate the combined effect of storage at 4 °C (10-days) and in vitro gastrointestinal digestion on the phytochemical profile of red beet (Beta vulgaris) and amaranth (Amaranthus sp.) microgreens. The untargeted profiling based on UHPLC-QTOF metabolomics allowed annotating 316 compounds, comprising mainly polyphenols and lipids. An impact of storage on the total phenolic content (TPC) was observed, with a maximum increase at 10-days of storage for both red beet (+1.3-fold) and amaranth (+1.1-fold). On the other hand, in vitro digestion of both red beet and amaranth microgreens produced a significant increase in TPC (36-88%), CUPRAC (27-40%), DPPH (6-43%), and BC (41-57%) to reach the maximum at 10 days of storage. Tyrosinase inhibitory potential also decreased following digestion. The combination of biochemical changes occurring in microgreen immature plants (likely in response to the harvest stress) with changes during digestion, determined the actual functional value of microgreens.

Effect of Moringa oleifera L. Leaf Powder Addition on the Phenolic Bioaccessibility and on In Vitro Starch Digestibility of Durum Wheat Fresh Pasta

Fresh pasta was formulated by replacing wheat semolina with 0, 5, 10, and 15 g/100 g (w/w) of Moringa oleifera L. leaf powder (MOLP). The samples (i.e., M0, M5, M10, and M15 as a function of the substitution level) were cooked by boiling. The changes in the phenolic bioaccessibility and the in vitro starch digestibility were considered. On the cooked-to-optimum samples, by means of ultra-high-performance liquid chromatography-quadrupole time-of-flight (UHPLC-QTOF) mass spectrometry, 152 polyphenols were putatively annotated with the greatest content recorded for M15 pasta, being 2.19 mg/g dry matter (p < 0.05). Multivariate statistics showed that stigmastanol ferulate (VIP score = 1.22) followed by isomeric forms of kaempferol (VIP scores = 1.19) and other phenolic acids (i.e., schottenol/sitosterol ferulate and 24-methylcholestanol ferulate) were the most affected compounds through the in vitro static digestion process. The inclusion of different levels of MOLP in the recipe increased the slowly digestible starch fractions and decreased the rapidly digestible starch fractions and the starch hydrolysis index of the cooked-to-optimum samples. The present results showed that MOLP could be considered a promising ingredient in fresh pasta formulation.

Untargeted screening of the bound / free phenolic composition in tomato cultivars for industrial transformation

BACKGROUND

Tomato is one of the most important agricultural crops and it is characterized by a wide bioactive compound profile. However, little information is reported on its comprehensive polyphenol profile. In this work, 13 commercial tomato cultivars for industrial transformation were screened by ultra-high-pressure liquid chromatography coupled to quadrupole-time-of-flight mass spectrometry (UHPLC-QTOF-MS) for both free and bound phenolic profiles. Thereafter, the in vitro antioxidant activity of each cultivar was assessed by ferric reducing antioxidant power (FRAP) and oxygen radical absorbance activity (ORAC) assays. Multivariate statistics, i.e. orthogonal projection to latent structures discriminant analysis (OPLS-DA), were then used to model samples according to their distinct phenolic signatures, thus providing compounds that better discriminated between the distributions of the cultivars that were considered.

RESULTS

More than 350 phenolic compounds could be identified across the samples that were considered: flavonoids (such as flavones and flavanols), hydroxycinnamic acids, lignans, and lower-molecular-weight phenolics were the most frequently observed classes of phenolics in tomato berries. Anthocyanins were the most abundant class among bound phenolics (being highest in the Leader F1 and Defender F1 cultivars), followed by tyrosols (mainly in Heinz cultivars). However, flavones and hydroxybenzoic acids were the most represented discriminant phenolics in the bound fraction.

CONCLUSIONS

Untargeted metabolomics allowed significant differences in phenolic composition to be outlined across the tomato cultivars that were analyzed. Such differences were particularly evident regarding the free-to-bound phenolic ratio, hence allowing differences in the bioaccessibility of phenolics to be postulated. © 2019 Society of Chemical Industry.

Transformation of polyphenols found in pigmented gluten-free flours during in vitro large intestinal fermentation

In this work, 18 gluten-free flours (prepared from cereals, pseudocereals and legumes), differing in pigmentation, were screened for their phenolic profiles, cooked and, then, subjected to digestion and large intestinal fermentation in vitro. A combined targeted/untargeted metabolomic approach was used to elucidate the microbial biotransformation processes of polyphenols following digestion. This preliminary work demonstrated an increase in 3,5-dihydroxybenzoic acid (on average from 0.67 up to 1.30 μmol/g dry matter) throughout large intestinal fermentation of pseudocereals (esp. quinoa), due to their high alkylresorcinol contents. Isoflavones were converted into equol- or O-desmethylangolensin- derivatives, whereas anthocyanins were degraded into lower-molecular-weight phenolics (i.e., protocatechuic aldehyde and 4-hydroxybenzoic acid, with the latter exhibiting the highest increase over time). A decreasing trend was observed for antioxidant activities (i.e., FRAP and ORAC values) moving from digested to faecal fermented samples. These findings highlight that gluten-free flours are able to deliver bioaccessible polyphenols to the colon.

Edible nuts deliver polyphenols and their transformation products to the large intestine: An in vitro fermentation model combining targeted/untargeted metabolomics

The fate of polyphenols from edible tree nuts was investigated using a simulated in vitro intestinal fermentation system. The digested food matrix was fermented for 48 h and the changes in the phenolic profiles were evaluated by both untargeted UHPLC-QTOF and targeted UHPLC-Orbitrap mass spectrometry. The untargeted metabolomics approach allowed us to monitor the comprehensive changes in phenolic profiles from 0 up to 48 h of in vitro fermentation. Multivariate statistics (i.e., orthogonal projection to latent structures discriminant analysis) applied to this untargeted data allowed us to identify the most discriminating phenolic metabolites and to further understand the colonic transformation pathways involved. In particular, 13 putatively identified compounds derived from flavonoids, lignans and phenolic acids were found to have the highest discrimination potential. Six phenolic metabolites were then quantified by means of targeted metabolomics (using a UHPLC-Orbitrap). These metabolites included 3,4-dihydroxyphenylacetic acid, 4-hydroxybenzoic acid, hippuric acid, caffeic acid, protocatechuic acid and protocatechuic aldehyde. Using the targeted data, a clear matrix effect was observed over time, with an increase of some phenolic metabolites moving from 8 to 48 h of in vitro fermentation. Based on these data, catabolic pathways for colonic microbial degradation of flavonoids, hydroxycinnamic acids, tyrosols and lignans are proposed. Our findings show that edible tree nuts deliver polyphenols to the colon, where several microbial transformations occur that lead to smaller phenolic metabolites being observed. Furthermore, we found that the combined use of targeted and untargeted metabolomics can be particularly effective for investigating the fate of polyphenols in the large intestine.

Nontargeted Metabolomics for Phenolic and Polyhydroxy Compounds Profile of Pepper (Piper nigrum L.) Products Based on LC-MS/MS Analysis

In the present study, nontargeted metabolomics was used to screen the phenolic and polyhydroxy compounds in pepper products. A total of 186 phenolic and polyhydroxy compounds, including anthocyanins, proanthocyanidins, catechin derivatives, flavanones, flavones, flavonols, isoflavones and 3-O-p-coumaroyl quinic acid O-hexoside, quinic acid (polyhydroxy compounds), etc. For the selected 50 types of phenolic compound, except malvidin 3,5-diglucoside (malvin), l-epicatechin and 4'-hydroxy-5,7-dimethoxyflavanone, other compound contents were present in high contents in freeze-dried pepper berries, and pinocembrin was relatively abundant in two kinds of pepper products. The score plots of principal component analysis indicated that the pepper samples can be classified into four groups on the basis of the type pepper processing. This study provided a comprehensive profile of the phenolic and polyhydroxy compounds of different pepper products and partly clarified the factors responsible for different metabolite profiles in ongoing studies and the changes of phenolic compounds for the browning mechanism of black pepper.

Gluten-free flours from cereals, pseudocereals and legumes: Phenolic fingerprints and in vitro antioxidant properties

The interest in gluten-free (GF) products increases together with the increase in gluten-sensitive people. However, GF foods might have decreased nutritional quality as compared to the gluten containing counterparts. In this work, an investigation of the phenolic and antioxidant profile in 18 GF flours belonging to legumes, cereals and pseudocereals was achieved. Significant differences could be observed across samples. Total phenolic content was highest in violet rice flours, whereas total anthocyanins were highest in violet, nerone, and black rice flours. FRAP and ORAC antioxidant activities were correlated to phenolic contents and found to be higher in violet rice flours. Metabolomics highlighted a wide diversity in phenolics, with flavonoids (197 compounds ascribable to anthocyanins, flavones, flavanones, isoflavonoids, flavonols, and flavanols), phenolic acids (74 compounds belonging to hydroxycinnamics, hydroxybenzoics, and hydroxyphenylacetics), and tyrosol derivatives the most represented. Finally, OPLS-DA multivariate statistics outlined flavonoids, furofurans and phenolic acids as the most discriminant phenolics.

Effect of dietary polyphenols on the in vitro starch digestibility of pigmented maize varieties under cooking conditions

Interest in using polyphenols as modulators of the activity of starch digestive enzymes is increasing. The main purpose of this study was to investigate the role of phenolic compounds characterising pigmented maize flours in the modulation of in vitro starch digestibility. Flours from three different pigmented maize varieties were evaluated under cooking conditions and compared to common yellow maize (YM). The untargeted metabolomics-based approach comprehensively annotated around 300 phenolic compounds, with a high distribution of anthocyanins and phenolic acids (in free and bound fractions of maize samples) and significant differences across genotypes. Following in vitro starch digestion, the cooked pigmented maize flours showed higher resistant starch content (from 5.1 to 6.9 g /100 g dry matter), as well as lower starch hydrolysis index (HI) when compared to YM flour, with the "Rostrato Rosso" maize having the lowest HI (i.e., 61). Coherently, multivariate statistics following metabolomics showed the discrimination potential of anthocyanins' profile after cooking, characterising the "Rostrato Rosso" during in vitro digestion. These findings might be related to the modulation of enzyme activity by phenolic compounds during in vitro digestion. Therefore, the use of pigmented maize flours might help in the formulation of gluten-free foods with slowly digestible starches by exploiting the wide phenolic composition of these matrices.