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

Quality characteristics and cooking-induced changes on phenolic compounds of dried green tea noodles

Incorporating green tea powder (GTP) into wheat flour-based noodles can significantly improve nutritional value. So, this study investigated the effects of GTP (0%, 0.5%, 1%, 1.5%, and 2.0%) on the quality properties of dried green tea noodles (DGTN) and cooking-induced changes to phenolic compounds. Mixolab analysis of wheat flour with GTP showed more water absorption of dough, and the developed dough had a firmer structure. GTP markedly increased the toughness of the noodle sheet. DGTN fortified with GTP showed more stable textural properties during cooking and storage, representing higher hardness and tensile strength. The viscosity and thermal properties of DGTN showed that GTP affected the gelatinization and retrogradation behavior of starch, which were closely related to the textural properties. Overall, DGTN prepared with 1.5% GTP showed better quality properties. However, ultra-performance liquid chromatography-time (UPLC/Q-TOF-mass spectrometry [MS]/MS) analysis showed that cooking by boiling significantly decreased phenolic content in 1.5% DGTN; further analysis revealed that the thermal degradation is a key factor in the loss of polyphenols. Therefore, further studies are necessary to focus on the mechanism of cooking-induced polyphenol loss, which is of great significance for improving the nutritional value of cooked DGTN.

Phenolic Characterization of a Purple Maize (Zea mays cv. "Moragro") by HPLC-QTOF-MS and Study of Its Bioaccessibility Using a Simulated In Vitro Digestion/Caco-2 Culture Model

The present work aimed to characterize the phenolic and antioxidant content of the Argentinian purple maize "Moragro" cultivar. Additionally, the INFOGEST simulated in vitro digestion model was used to establish the effect of digestion on bioactive compounds. Finally, digestion samples were used to treat Caco-2 cells in the transwell model to better understand their bioavailability. Twenty-six phenolic compounds were found in purple maize cv. "Moragro", 15 nonanthocyanins and 11 anthocyanins. Several compounds were identified in maize for the first time, such as pyrogallol, citric acid, gallic acid, kaempferol 3-(6″-ferulylglucoside), and kaempferol 3-glucuronide. Anthocyanins accounted for 24.9% of total polyphenols, with the predominant anthocyanin being cyanidin-3-(6″ malonylglucoside). Catechin-(4,8)-cyanidin-3,5-diglucoside and catechin-(4,8)-cyanidin-3-malonylglucoside-5-glucoside were detected as characteristics of this American maize variety. Total polyphenol content (TPC; by the Folin-Ciocalteu method), HPLC-DAD/MSMS, and antioxidant activity [by DPPH and ferric-reducing antioxidant power (FRAP)] were evaluated throughout in vitro digestion. TPC, DPPH, and FRAP results were 2.71 mg gallic acid equivalents (GAE)/g, 24 μmol Trolox equiv/g, and 22 μmol Trolox eq/g, respectively. The in vitro digestion process did not cause significant differences in TPC. However, the antioxidant activity was significantly decreased. Moreover, the bioavailability of anthocyanins was studied, showing that a small fraction of polyphenols in their intact form was conserved at the end of digestion. Finally, a protective effect of digested maize polyphenols was observed in the Caco-2 cell viability. The results suggest that "Moragro" purple maize is a good source of bioavailable anthocyanins in the diet and an interesting source of this group of compounds for the food industry.

Assessment of Technological and Sensory Properties, Digestibility, and Bioactive Compounds in Polentas from Different Maize Genotypes

The sensory profile of polenta and the connections between technological attributes and varieties of maize have not been extensively studied. Thus, it is necessary to understand the possible effect of its consumption on consumers' health in terms of postprandial glucose levels and molecules associated with healthy activities. This work aims to study polenta's technological and sensory properties from different maize genotypes and evaluate their digestibility and the potential contribution of bioactive compounds on health. A commercial hybrid, two open-pollinated varieties, and three inbred lines were used. Grain physical determinations and physical-chemical semolina traits were determined. Polenta's technological quality was evaluated after simulated cooking. In vitro digestion was performed for polentas, and a sensory evaluation test was conducted. A significant correlation was found between semolina polyphenols and rapidly digestible starch (r = -0.6). Panellists characterised the genotype C6006 as having a good flavour, sandier mouthfeel, and low consistency. Also, the polenta from the hybrid exhibited sensory attributes more closely resembling commercial polenta in terms of maize odour, flavour, and consistency. The higher content of polyphenols presents in semolina affected the digestion of polenta, showing a lower proportion of rapidly digestible starch and a lower amount of bioaccessible protein fraction.

Whole Flour of Purple Maize as a Functional Ingredient of Gluten-Free Bread: Effect of In Vitro Digestion on Starch and Bioaccessibility of Bioactive Compounds

The growing demand for gluten-free products requires the study of alternatives to produce nutritionally and technologically favorable foods. The aim was to evaluate the content and antioxidant capacity of gluten-free bread enriched with whole flour of purple maize (PM) and how starch and bioaccessibility of antioxidant compounds were modified during in vitro digestion. Gluten-free bread was prepared with the addition of 34%, 50%, and 70% PM, and white maize bread served as control. The content of total polyphenols, anthocyanins, and antioxidant capacity through FRAP and TEAC was measured. Specific volume, crumb texture, and starch digestibility were determined in the breads. Simultaneously, in vitro digestion and dialysis by membrane were performed to evaluate the bioaccessible and potentially bioavailable fraction. Bread with 34% PM had a similar specific volume and crumb texture to the control, but higher content of polyphenols (52.91 mg AG/100 g), anthocyanins (23.13 mg c3-GE/100 g), and antioxidant capacity (3.55 and 5.12 µmol tr/g for FRAP and TEAC, respectively). The PM breads had a higher antioxidant content and capacity and higher slowly digestible and resistant starch than the control. These parameters increased as the PM proportion rose. After digestion, anthocyanins were degraded, polyphenols and antioxidant capacity decreased, but they remained potentially bioavailable, although to a lesser extent. Bread with 34% shows acceptable technological parameters, lower starch digestibility, and contribution of bioactive compounds with antioxidant capacity. This indicates that purple maize flour represents a potential ingredient to produce gluten-free bread with an improved nutritional profile.

Modulating the glycemic response of starch-based foods using organic nanomaterials: strategies and opportunities

Traditionally, diverse natural bioactive compounds (polyphenols, proteins, fatty acids, dietary fibers) are used as inhibitors of starch digestive enzymes for lowering glycemic index (GI) and preventing type 2 diabetes mellitus (T2DM). In recent years, organic nanomaterials (ONMs) have drawn a great attention because of their ability to overcome the stability and solubility issues of bioactive. This review aimed to elucidate the implications of ONMs in lowering GI and as encapsulating agents of enzymes inhibitors. The major ONMs are presented. The mechanisms underlying the inhibition of enzymes, the stability within the gastrointestinal tract (GIT) and safety of ONMs are also provided. As a result of encapsulation of bioactive in ONMs, a more pronounced inhibition of enzymes was observed compared to un-encapsulated bioactive. More importantly, the lower the size of ONMs, the higher their inhibitory effects due to facile binding with enzymes. Additionally, in vivo studies exhibited the potentiality of ONMs for protection and sustained release of insulin for GI management. Overall, regulating the GI using ONMs could be a safe, robust and viable alternative compared to synthetic drugs (acarbose and voglibose) and un-encapsulated bioactive. Future researches should prioritize ONMs in real food products and evaluate their safety on a case-by-case basis.

Phenolic acids, lignans, and low-molecular-weight phenolics exhibit the highest in vitro cellular bioavailability in different digested and faecal-fermented phenolics-rich plant extracts

Polyphenols are multifaceted bioactive compounds, but little is known about their real impact on human health after consumption. In this work, the phenolic profiling of quebracho, yellow maize, and violet rice extracts was comprehensively investigated, together with the impact of in vitro digestion and colonic fermentation on the bioaccessibility and bioavailability of these phytochemicals. The different matrices showed distinct profiles, potentially influencing in vitro starch digestion under cooking conditions. Furthermore, after the extracts underwent in vitro gastrointestinal digestion and faecal fermentation, phenolics exhibited a differential bioaccessibility trend at every digestion level, with matrix-dependent behaviour. The bioavailability results suggest that polyphenols are metabolised during colonic fermentation, mainly into tyrosols, phenolic acids, and lignans, which are partially absorbed by Caco-2 cells. By combining metabolomics with in vitro cellular methods, this research provides new insights into the fate of these phytochemicals in the gut, yielding comprehensive data on their consumption in food matrices.

In search of better snacks: ohmic-heating nixtamalized flour and amaranth addition increase the nutraceutical and nutritional potential of vegetable-enriched tortilla chips

BACKGROUND

Nixtamalized flour snacks such as tortilla chips are widely consumed across the world, but they are nutritionally poor and contribute to obesity and other non-communicable diseases. The production of healthy versions of such snacks, by incorporating vegetables and improving the quality of the flours used in their formulation, could help address these nutritional challenges. This study compared the fortification of baked tortilla chips with vegetable leaf powders (kale and wild amaranth at 0%, 4%, 8%, and 16% w/w) and using two types of nixtamalized flour: traditional (TNF) and with ohmic heating (OHF).

RESULTS

Overall, the use of OHF increased 1.88 times the fibre in enriched and non-enriched snacks with respect to TNF, but the latter had 1.85 times more protein. Addition of 16% of vegetable powders increased protein (kale = 1.4-fold; amaranth = 1.3-fold) and dietary fibre (kale = 1.52-fold; amaranth = 1.7-fold). Amaranth enrichment improved total phenolic content (TPC) and total flavonoid content (TFC) of chips at least 1.2 and 1.63 times, respectively. OHF chips also had higher bound TPC than TNF ones, regardless of vegetable addition. Combinations of OHF with 16% amaranth produced chips 1.74-fold higher in antioxidant capacity than non-enriched ones, due to increased content of phenolics such as ferulic acid.

CONCLUSION

This work showed that tortilla chips made using nixtamalized flour produced with assisted ohmic heating, alone or in combination with wild amaranth leaf powder, could be used in the production of healthy maize snacks to enhance their prospective antioxidant activity and nutritional value. © 2023 Society of Chemical Industry.

Dietary Polyphenols and Obesity: A Review of Polyphenol Effects on Lipid and Glucose Metabolism, Mitochondrial Homeostasis, and Starch Digestibility and Absorption

Obesity is a major global public health concern, limiting socio-economic development and human productivity. As studies focus on finding sustainable solutions to this challenge, polyphenols have shown promising results and have become a research focus. This is mainly because of associated lower risks of side effects with their use, compared to synthetic pharmaceuticals. In this study, the anti-obesity potentials of dietary polyphenols have been reviewed. Using a narrative approach, the biological activities of polyphenols and their influence on energy metabolism and mechanisms are discussed. Specifically, their roles in insulin-dependent glucose uptake, insulin sensitivity, lipid metabolism and storage in adipocytes, starch digestibility, and regulation of mitophagy and mitogenesis in muscle cells and adipocytes, were considered. After considering the major findings of many related studies, it was confirmed that polyphenols can prevent and ameliorate obesity by fighting insulin resistance (IR) induced by pro-inflammatory cytokines, scavenging reactive oxygen species (ROS) and limiting their effects, and by regulating the expression and/or activity of key enzymes along relevant pathways. More human studies are needed to reveal more about the anti-obesity effects of dietary polyphenols and their effective doses in humans.

Phenolic Release during In Vitro Digestion of Cold and Hot Extruded Noodles Supplemented with Starch and Phenolic Extracts

Dietary phenolic compounds must be released from the food matrix in the gastrointestinal tract to play a bioactive role, the release of which is interfered with by food structure. The release of phenolics (unbound and bound) of cold and hot extruded noodles enriched with phenolics (2.0%) during simulated in vitro gastrointestinal digestion was investigated. Bound phenolic content and X-ray diffraction (XRD) analysis were utilized to characterize the intensity and manner of starch-phenolic complexation during the preparation of extruded noodles. Hot extrusion induced the formation of more complexes, especially the V-type inclusion complexes, with a higher proportion of bound phenolics than cold extrusion, contributing to a more controlled release of phenolics along with slower starch digestion. For instance, during simulated small intestinal digestion, less unbound phenolics (59.4%) were released from hot extruded phenolic-enhanced noodles than from the corresponding cold extruded noodles (68.2%). This is similar to the release behavior of bound phenolics, that cold extruded noodles released more bound phenolics (56.5%) than hot extruded noodles (41.9%). For noodles extruded with rutin, the release of unbound rutin from hot extruded noodles and cold extruded noodles was 63.6% and 79.0%, respectively, in the small intestine phase, and bound rutin was released at a much lower amount from the hot extruded noodles (55.8%) than from the cold extruded noodles (89.7%). Hot extrusion may allow more potential bioaccessible phenolics (such as rutin), further improving the development of starchy foods enriched with controlled phenolics.

Glycemic index values of traditional Kenyan foods: the missing link in the effectiveness of dietary approach in the prevention and management of diabetes mellitus in Kenya

BACKGROUND

Glycemic index (GI) measures postprandial blood sugar after consumption of carbohydrate-rich foodstuff. Kenya is yet to fully embrace this concept in prevention and management of diabetes mellitus.

OBJECTIVE

To review and tabulate GIs of locally consumed foods in order to improve dietary management of diabetes mellitus.

METHODOLOGY

A literature search was conducted using Google scholar and PubMed databases which identified 7 articles on glycemic index values of Kenyan foods published between 2002 and 2020. Two articles failed to meet the inclusion criteria and five proceeded for review. Key search words used included GI, glycemic load and glycemic response combined with Kenya. The data was reported depending on whether the testing involved healthy individuals or patients suffering from diabetes mellitus.

RESULTS

Nine individual foods and 7 mixed meals were identified. Low GI foods included beans and whole maize ugali consumed alongside cowpea leaves. High GI foods included whole maize ugali eaten with beef, boiled rice, boiled cassava and cassava-sorghum ugali eaten with silver fish.

CONCLUSION

Proper meal mixing is important in diabetes management. Cowpea leaves and beans possess GI lowering potential. This information can be used to improve guidance on food choices for diabetes patients.

Kernel characterization and starch morphology in five varieties of Peruvian Andean maize

Peruvian Andean maize (PAM) has been commonly used as an ingredient that confers color, flavor, and texture in culinary. Nevertheless, no studies are focusing on agro-industrial interest characteristics to develop new products. This study aimed to evaluate the physicochemical, nutritional, and technological characteristics of kernels and the starch granule morphology of the five main PAM varieties: Chullpi, Piscorunto, Giant Cuzco, Sacsa, and Purple. PAM's characterization was performed according to the official methods, and its morphology was observed by scanning electron microscopy (SEM). Physically, the varieties of larger kernels (Giant Cuzco and Sacsa) presented a higher 1000-kernel weight and a lower hectoliter weight than those of smaller size (Piscorunto, Purple, and Chullpi). Nutritionally, PAM had higher ether extract (5%) and ash (2%) contents than other pigmented maizes. Likewise, they presented more significant amounts of essential amino acids, as leucine (10 mg/g protein) and tryptophan (up to 2 mg/g protein); unsaturated fatty acids, oleic (30%) and linoleic (53%); and minerals, as magnesium (104 mg/100 g). SEM showed that endosperm structure and starch morphology vary according to maize types and their grain location. Starch granules of floury PAM varieties were small and polyhedral in the sub-aleurone endosperm, whereas those of the central area were bigger and spherical. In Chullpi, it was observed a portion of vitreous endosperm with a compact structure. The low protein content (8.3%) and the endosperm structure of floury varieties of PAM influenced their pasting properties. Their pasting temperature was <69 to 71 °C>, peak viscosity < 3200 to 4400 cP>, and seatback <1250 to 1706 cP>; therefore, they do not retrograde easily. The results suggest that PAM has characteristics that would help elaborate regional products with added value, such as soups, willows, beverages, and porridges.

Polyphenolic inhibition of enterocytic starch digestion enzymes and glucose transporters for managing type 2 diabetes may be reduced in food systems

With the current global surge in diabetes cases, there is a growing interest in slowing and managing diabetes and its effects. While there are medications that can be used, they have adverse side effects such as hypoglycemia and weight gain. To overcome these problems, bioactive compounds commonly found in fruits, vegetables and cereal grains are used to slow starch digestion and transport of simple sugars across the intestinal epithelia thereby reducing plasma blood glucose spike. These effects are achieved through inhibition of amylases, glucosidases and glucose transporters present in the gastrointestinal tract and brush boarder membrane. The extent of inhibition by polyphenols is dependent on molecular structure, doses and food matrix. Glycemic lowering effect of polyphenols have been demonstrated both in in vivo and in vitro studies. However, when these compounds are incorporated in food systems, they can interact with other polymers in the food matrix leading to lesser inhibition of digestion and/or glucose transporters compared to isolated or pure compounds as often witnessed in most in vitro studies.

Colored Corn: An Up-Date on Metabolites Extraction, Health Implication, and Potential Use

Colored (orange, pink, red, purple, and blue) corn strongly attracted attention on its healthy properties mainly due to its anthocyanin and carotenoid composition which is also responsible for its pigmentation. The present review summarized the recent updates on the extraction and chemical characterization of the main plant secondary metabolites present in colored seeds, kernel, cob, husk, and silk. The main approaches used to stabilize the extracts have been discussed as well as their food and non-food uses. Both in vitro and in vivo (animal models) studies on the different effects (antibacterial, antimutagenic, antioxidant, and anti-inflammatory activities, effects on metabolic syndrome, diabetes, glucose and lipidic metabolism, and neuroprotection) of pigmented extracts on animal and human health have been summarized.

Evaluation of vitamin D bioaccessibility and mineral solubility from test meals containing meat and/or cereals and/or pulses using in vitro digestion

In this study, we evaluated vitamin D and mineral (iron, zinc, magnesium) transfer to the bolus aqueous phase during the digestion of meals with/without pulses. We performed in vitro digestions using test meals made either of i) beef and/or semolina and/or chickpeas, or of ii) potatoes supplemented or not with fibers, phytates, tannins and saponins. Chickpea presence led to a decrease in vitamin D bioaccessibility (-56%, p ≤ 0.05) and mineral solubility (-28% for iron, p ≤ 0.05) compared with meals with beef and/or semolina only. This effect was largely compensated for vitamin D by the fact that this vitamin was more stable during digestion of meals based on plant foods only than of meals with beef. Tannins were the most deleterious compounds for iron solubility, while phytates and tannins decreased vitamin D bioaccessibility. Agronomical or technical solutions to selectively decrease the amount in pulses of compounds that affect micronutrient bioavailability should be further explored.

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.

Mining maize diversity and improving its nutritional aspects within agro-food systems

Agro-food systems are undergoing rapid innovation in the world and the system's continuum is promoted at different scales with one of the main outcomes to improve nutrition of consumers. Consumer knowledge through educational outreach is important to food and nutrition security and consumer demands guide breeding efforts. Maize is an important part of food systems. It is a staple food and together with rice and wheat, they provide 60% of the world's caloric intake. In addition to being a major contributor to global food and nutrition security, maize forms an important part of the culinary culture in many areas of Africa, the Americas, and Asia. Maize genetics are being exploited to improve human nutrition with the ultimate outcome of improving overall health. By impacting the health of maize consumers, market opportunities will be opened for maize producers with unique genotypes. Although maize is a great source of macronutrients, it is also a source of many micronutrients and phytochemicals purported to confer health benefits. The process of biofortification through traditional plant breeding has increased the protein, provitamin A carotenoid, and zinc contents of maize. The objective of this paper is to review the innovations developed and promoted to improve the nutritional profiles of maize and outcomes of the maize agro-food system.

Polyphenols and Sesquiterpene Lactones from Artichoke Heads: Modulation of Starch Digestion, Gut Bioaccessibility, and Bioavailability following In Vitro Digestion and Large Intestine Fermentation

Artichoke is a relevant source of health-promoting compounds such as polyphenols and sesquiterpene lactones. In this study, the bioaccessibility and gut bioavailability of artichoke constituents were evaluated by combining in vitro digestion and large intestine fermentation, metabolomics, and Caco-2 human intestinal cells model. Moreover, the ability of artichoke polyphenols to modulate the in vitro starch digestibility was also explored. An untargeted metabolomic approach based on liquid chromatography quadrupole-time-of-flight (UHPLC/QTOF) mass spectrometry coupled with multivariate statistics was used to comprehensively screen the phytochemical composition of raw, digested, and fermented artichoke. Overall, a large abundance of phenolic acids and sesquiterpene lactones was detected, being 13.77 and 11.99 mg·g-1, respectively. After 20 h of in vitro large intestine fermentation, a decrease in polyphenols and sesquiterpene lactones content was observed. The most abundant compounds characterizing the raw material (i.e., chlorogenic acid and cynaropicrin equivalents) showed an average % bioaccessibility of 1.6%. The highest % bioaccessibility values were recorded for flavonoids such as anthocyanin and flavone equivalents (on average, 13.6%). However, the relatively high bioavailability values recorded for flavonols, phenolic acids, and sesquiterpene lactones (from 71.6% up to 82.4%) demonstrated that these compounds are able to be transported through the Caco-2 monolayer. The phenolic compounds having the highest permeation rates through the Caco-2 model included low molecular weight phenolics such as tyrosol and 4-ethylcatechol; the isoflavonoids 3'-O-methylviolanone, equol 4'-O-glucuronide, and hydroxyisoflavone; together with the methyl and acetyl derivatives of glycosylated anthocyanins. Therefore, although human in vivo confirmatory trials are deemed possible, current findings provide insights into the mechanistic effects underlying artichoke polyphenols and sesquiterpenoids bioavailability following gastrointestinal and large intestine processes.

Phytochemical Profile and Biological Properties of Colchicum triphyllum (Meadow Saffron)

In this work, the phytochemical profile and the biological properties of Colchicum triphyllum (an unexplored Turkish cultivar belonging to Colchicaceae) have been comprehensively investigated for the first time. Herein, we focused on the evaluation of the in vitro antioxidant and enzyme inhibitory effects of flower, tuber, and leaf extracts, obtained using different extraction methods, namely maceration (both aqueous and methanolic), infusion, and Soxhlet. Besides, the complete phenolic and alkaloid untargeted metabolomic profiling of the different extracts was investigated. In this regard, ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS) allowed us to putatively annotate 285 compounds when considering the different matrix extracts, including mainly alkaloids, flavonoids, lignans, phenolic acids, and tyrosol equivalents. The most abundant polyphenols were flavonoids (119 compounds), while colchicine, demecolcine, and lumicolchicine isomers were some of the most widespread alkaloids in each extract analyzed. In addition, our findings showed that C. triphyllum tuber extracts were a superior source of both total alkaloids and total polyphenols, being on average 2.89 and 10.41 mg/g, respectively. Multivariate statistics following metabolomics allowed for the detection of those compounds most affected by the different extraction methods. Overall, C. triphyllum leaf extracts showed a strong in vitro antioxidant capacity, in terms of cupric reducing antioxidant power (CUPRAC; on average 96.45 mg Trolox Equivalents (TE)/g) and ferric reducing antioxidant power (FRAP) reducing power (on average 66.86 mg TE/g). Interestingly, each C. triphyllum methanolic extract analyzed (i.e., from tuber, leaf, and flower) was active against the tyrosinase in terms of inhibition, recording the higher values for methanolic macerated leaves (i.e., 125.78 mg kojic acid equivalent (KAE)/g). On the other hand, moderate inhibitory activities were observed against AChE and α-amylase. Strong correlations (p < 0.01) were also observed between the phytochemical profiles and the biological activities determined. Therefore, our findings highlighted, for the first time, the potential of C. triphhyllum extracts in food and pharmaceutical applications.

Metabolomic Study to Evaluate the Transformations of Extra-Virgin Olive Oil's Antioxidant Phytochemicals During In Vitro Gastrointestinal Digestion

In this work, different commercial extra-virgin olive oils (EVOO) were subjected to in vitro gastrointestinal digestion and the changes in bioactive compounds were evaluated by ultra-high-pressure liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry, using untargeted metabolomics. As expected, raw EVOO samples were abundant in total sterols (on average: 3007.4 mg equivalents/kg) and tyrosol equivalents (on average: 334.1 mg equivalents/kg). However, the UHPLC-QTOF screening allowed us to annotate 310 compounds, with a large abundance of sterols (219 compounds), followed by polyphenols (67 compounds) and terpenoids. The in vitro gastrointestinal digestion was found to affect the phytochemical composition of the different EVOO samples. In particular, both unsupervised and supervised statistics depicted the modifications of the bioactive profile following gastric and pancreatic phases. Overall, the compounds which resulted as the most affected by the in vitro digestion were flavonoids (cyanidin and luteolin equivalents), whilst relatively high % bioaccessibility values were recorded for tyrosol equivalents during the pancreatic phase (on average, 66%). In this regard, oleuropein-aglycone (i.e., the major phenolic compound in EVOO) was converted to hydroxytyrosol, moving from an average value of 1.3 (prior to the in vitro digestion) up to 9.7 mg equivalents/kg during the pancreatic step. As proposed in the literature, the increase in hydroxytyrosol might be the result of the combined effect of lipase(s) activity and acidic conditions. Taken together, the present findings corroborate the suitability of untargeted metabolomics coupled to in vitro digestion methods to investigate the bioaccessibility of phenolic compounds. In this regard, a significant impact of in vitro gastrointestinal digestion on polyphenolic profiles has been detected, thus suggesting the need to account for actual bioaccessibility values rather than just considering the amounts in the raw commodity.

Water Cooking Stability of Dried Noodles Enriched with Different Particle Size and Concentration Green Tea Powders

Incorporating green tea powder (GTP) into dried noodles enriched the functional characteristics of noodles. To achieve the maximum benefits from GTP, the water cooking stability of dried green tea noodles (DGTN) should be investigated. Indeed, antioxidant activities and phenolic compounds of DGTN after water cooking markedly decreased. The results showed that large GTP particles caused the increased cooking loss of DGTN, but the phenolic compound loss of DGTN prepared with them was low after cooking. Analysis of texture properties and microstructure showed that DGTN with a 2% concentration of large GTP particles formed some holes in the noodles’ network, and its breaking strength decreased. However, we observed that many GTP particles adhered to the surface of DGTN prepared with small GTP particles, and they were easier to lose after water cooking. Comprehensive analysis concluded that cooking loss, functional compounds retention and textural properties of DGTN were related to GTP particle size and concentration via the microstructure.

Cinnamon Shows Antidiabetic Properties that Are Species-Specific: Effects on Enzyme Activity Inhibition and Starch Digestion

Despite considerable research the evidence around the antidiabetic properties of cinnamon remains equivocal, and this may be due to varietal differences which is an aspect that is understudied. This study systematically compared the anti-hyperglycaemic properties of the four major commercial cinnamon types used around the world (Chinese; Cinnamomum cassia [CC], Indonesian; C. burmanii [IC], Vietnamese; C. loureirii [VC], and Ceylon; C. zeylanicum [SC]). LC-MS analysis showed distinct diffrences in the phytochemical profiles of cinnamon with SC showing the lowest coumarin concentration. CC and IC had the highest polyphenol levels and antioxidant potential, and all four types differed significantly in their content (P < 0.001). All cinnamon types showed potent species-specific effects on starch digestion enzyme activity inhibition (P < 0.001), CC was most effective against α-amylase and all four strongly inhibited α-glucosidase compared to acarbose. Cinnamon significantly reduced starch breakdown during oral (P = 0.006) and gastric (P = 0.029) phases of gastro-intestinal digestion with IC and SC showing consistent effects. No effects of cinnamon were seen in the intestinal phase. IC, VC and SC showed the greatest potential to inhibit formation of advanced glycation endproducts (AGEs) during digestion. In conclusion, cinnamon demonstrates anti-hyperglycaemic properties, however effects are species-specific with best overall properties seen for Ceylon cinnamon.

Untargeted Metabolomic Profiling, Multivariate Analysis and Biological Evaluation of the True Mangrove (Rhizophora mucronata Lam.)

Currently, there is a renewed interest towards the development of plant-based pharmacophores. In this work, 16 extracts prepared from the leaves, twigs, roots and fruits of a hydro-halophyte, Rhizophora mucronata Lam. (Family: Rhizophoraceae), were studied for possible antioxidant activity and the phenolic profiles established. Thereafter, enzymatic inhibitory activities (α-amylase, α-glucosidase, tyrosinase, acetyl- (AChE), butyrylcholinesterase (BChE), lipase, and elastase) were assessed. The total phenolic, flavonoid, phenolic acid, tannin, flavanol and triterpenoid content were estimated using standard assays. An untargeted metabolomics-based approach, based on ultra-high-pressure liquid chromatography coupled to quadrupole-time-of-flight mass spectrometry (UHPLC-QTOF-MS) followed by multivariate statistics, was then used to comprehensively profile and describe the phenolics present. UHPLC-QTOF-MS allowed for putatively annotating 104 phenolic acids, 103 flavonols, 94 flavones, 71 anthocyanins, 66 tyrosols, 29 lignans, 15 alkylphenols and 10 stilbenes in the extracts. Nine strains (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Methicillin-resistant Staphylococcus aureus (MRSA), Salmonella enteritidis, Sarcina lutea, Proteus mirabilis, Bacillus cereus and Candida albicans) were then used to investigate the antimicrobial properties. The methanolic twig extract exhibited significant reducing potential towards Cu (II)/Cu (I) and Fe (III)/Fe (II) (1336.88 ± 15.70 and 710.18 ± 21.04 mg TE/g, respectively) and was the most potent DPPH radical scavenger (807.07 ± 6.83 mg TE/g). Additionally, the methanolic twig extract showed significant inhibition against most targeted enzymes. Anti-microbial results showed that all extracts were active against MRSA. Multivariate analysis demonstrated that the phenolic profile of ethyl acetate extracts and leaves were the two most discriminative parameters in terms of solvents and organs, respectively. The present findings indicated that R. mucronata may be further explored for the management/prevention of oxidative stress, neurodegenerative complications and hyperpigmentation.

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.

Banana flour phenolics inhibit trans-epithelial glucose transport from wheat cakes in a coupledin vitrodigestion/Caco-2 cell intestinal model

A 10% replacement of wheat flour with banana flour subjected to different processing conditions resulted in from 45.0 to 54.5% higher glucose transport inhibition.

Phenolic Profile and Susceptibility to Fusarium Infection of Pigmented Maize Cultivars

Maize is a staple food source in the world, whose ancient varieties or landraces are receiving a growing attention. In this work, two Italian maize cultivars with pigmented kernels and one inbred line were investigated for untargeted phenolic profile, in vitro antioxidant capacity and resistance to Fusariumverticillioides infection. "Rostrato Rosso" was the richest in anthocyanins whilst phenolic acids were the second class in abundance, with comparable values detected between cultivars. Tyrosol equivalents were also the highest in "Rostrato Rosso" (822.4 mg kg-1). Coherently, "Rostrato Rosso" was highly resistant to fungal penetration and diffusion. These preliminary findings might help in breeding programs, aiming to develop maize lines more resistant to infections and with improved nutraceutical value.

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.