Effect of fat content on the digestibility and bioaccessibility of cocoa polyphenol by an in vitro digestion model

Effect of milk addition and processing on the antioxidant capacity and phenolic bioaccessibility of coffee by using an in vitro gastrointestinal digestion model

An in vitro gastrointestinal digestion model was used to investigate the effects of milk matrix: skimmed milk (Sm), whole milk (Wm) and processing methods: pH adjustment, high pressure homogenization processing (HPHP), thermal treatment (TT) on the antioxidant capacity, phenolics bioaccessibility of coffee. Our findings showed that the antioxidant capacity of all the samples decreased or unchanged after in vitro digestion. The total phenolic bioaccessibility of coffee (C), coffee with whole milk (Cwm), and coffee with skimmed milk (Csm) decreased by 29.2%, 28.5%, 21.1% from the HPHP treatment and by 14.7%, 34.2%, and 33.8% from TT, respectively. pH adjustment had little effect on the total phenolic bioaccessibility of Cwm and Csm but significantly decreased that of C. Wm showed better protective effect on the phenolic bioaccessibility than Sm. These results may contribute to the optimization of formulations and processing methods in coffee beverage production, thereby increasing the health benefits of coffee.

Chemical Composition and In Vitro Bioaccessibility of Antioxidant Phytochemicals from Selected Edible Nuts

The ultimate health benefits of peanuts and tree nuts partially depend on the effective gastrointestinal delivery of their phytochemicals. The chemical composition and in vitro bioaccessibility of tocopherols, tocotrienols and phenolic compounds from peanuts and seven tree nuts were evaluated by analytical and chemometric methods. Total fat and dietary fiber (g 100 g-1) ranged from 34.2 (Emory oak acorn) to 72.5 (pink pine nut; PPN) and from 1.2 (PPN) to 22.5 (pistachio). Samples were rich in oleic and linoleic acids (56-87 g 100 g-1 oil). Tocopherols and tocotrienols (mg·kg-1) ranged from 48.1 (peanut) to 156.3 (almond) and 0 (almond, pecan) to 22.1 (PPN) and hydrophilic phenolics from 533 (PPN) to 12,896 (Emory oak acorn); flavonoids and condensed tannins (mg CE.100 g-1) ranged from 142 (white pine nut) to 1833 (Emory oak acorn) and 14 (PPN) to 460 (Emory oak acorn). Three principal components explained 90% of the variance associated with the diversity of antioxidant phytochemicals in samples. In vitro bioaccessibility of tocopherols, tocotrienols, hydrophilic phenolics, flavonoids, and condensed tannins ranged from 11-51%, 16-79%, 25-55%, 0-100%, and 0-94%, respectively. Multiple regression analyses revealed a potential influence of dietary fiber, fats and/or unsaturated fatty acids on phytochemical bioaccessibility, in a structure-specific manner.

DHA rich algae oil delivered by O/W or gelled emulsions: strategies to increase its bioaccessibility

BACKGROUND

The bioaccessibility of bioactive compounds for functional food deserves evaluation. An in vitro gastrointestinal digestion model was applied to provide information about the extent of lipid hydrolysis, oxidative stability and bioaccessibility of algae oil (42% of docosahexaenoic acid; DHA), comparing three lipid delivery systems: bulk oil, soy protein stabilized O/W emulsion and carrageenan gelled emulsion.

RESULTS

Lipid digestion kinetics was slightly influenced by the delivery systems. Nevertheless, at the end of intestinal digestion, lipolysis in the three samples ranged between 49% and 52%, showing a partial oil digestion. Lipid oxidation, measured by malondialdehyde, was significantly lower (P < 0.01) in both emulsified oils after intestinal digestion compared to the bulk oil. Bioaccessibility of DHA was 58%, 71% and 84% for bulk oil, O/W emulsion and gelled emulsion, respectively.

CONCLUSION

These results suggest that both emulsified delivery systems used in the present study enhanced the solubilization of free fatty acids, in particular omega-3 fatty acids, and therefore their potential intestinal absorption. © 2018 Society of Chemical Industry.

Insight of Stability of Procyanidins in Free and Liposomal Form under an in Vitro Digestion Model: Study of Bioaccessibility, Kinetic Release Profile, Degradation, and Antioxidant Activity

Small unilamellar and multilayered liposomes loaded with polymeric (epi)catechins up to pentamers were produced. The bioaccessibility, kinetic release profile, and degradation under in vitro gastrointestinal conditions were monitored by UHPLC-DAD-QTOF-MS/MS. The results show that all of the procyanidins underwent depolymerization and epimerization into small molecular oligomers and mainly to (epi)catechin subunits. Moreover, all of the liposome formulations presented higher bioaccessibility and antioxidant activity in comparison to their respective counterparts in non-encapsulated form. Similar results were obtained with procyanidins from cocoa extract-loaded liposomes. Namely, the bioaccessibility of dimer, trimer, and tetramer fractions from cocoa-loaded liposomes were 4.5-, 2.1-, and 9.3-fold higher than those from the non-encapsulated cocoa extract. Overall, the procyanidin release profile was dependent on their chemical structure and physicochemical interaction with the lipid carrier. These results confirmed that liposomes are efficient carriers to stabilize and transport procyanidins with the aim of enhancing their bioaccessibility at a controlled release rate.

Effect of karwanda (Carissa congesta Wight) and sugar addition on physicochemical characteristics of ash gourd (Benincasa hispida) and bottle gourd (Langenaria siceraria) based beverages

There is a clear trend towards increasing consumption of juices as they can reduce imbalance of redox potential and provide necessary health benefits to consumers. Levels of karwanda (Carissa congesta Wight) and vegetable juices were varied to prepare nine different formulations of ash gourd-karwanda (AgK) and bottle gourd-karwanda blends (BgK) of higher nutritive, sensory qualities and storability. Total polyphenols (TP), antioxidant activity (AOA), total soluble solids and acidity were increased significantly (p ≤ 0.05) with addition of karwanda. AgK blend (35:35) and BgK blend (35:30) were selected based on their higher overall acceptability, TP and AOA. AgK blends had higher α-amylase (31%) while BgK blends had higher α-glucosidase (43%) inhibitory activities. Concentration of TP and anthocyanins decreased significantly (p < 0.05), AOA remained unchanged and anti-inflammatory activities decreased (33-38%) in AgK and BgK blends during accelerated storage at 50 °C for 12 days. Addition of sugar in BgK blend decreased stability of TP (11%), flavonoids (31%) and anthocyanins (8%). During in vitro gastrointestinal digestion, TP, flavonoids and anthocyanins reduction rate was significantly higher for BgK blend with sugar.

A critical review on grape polyphenols for neuroprotection: Strategies to enhance bioefficacy

The aging of populations worldwide is driving greater demands for dietary polyphenols which have been recognized as promising prophylactic and/or therapeutic agents in the context of neurodegeneration, and are ubiquitously present in plant-based diets. In particular, grape-derived products encompass a wide array of phenolic compounds purported with multiple health benefits including neuroprotective efficacy. Despite the increasing preclinical and clinical evidence demonstrating high potential of grape polyphenol (GPP)-rich botanicals in preventing and attenuating diverse neurodegenerative disorders, the limited bioavailability of GPPs, especially in the brain, generates questions as to their applications and effectiveness in neuroprotection. To address this issue, significant research efforts have been made to enhance oral bioavailability of GPPs via application of novel strategies. This review highlights some critical issues related to the bioavailability and neuroprotective efficacy of GPPs and GPP-rich botanicals. The representative bioavailability-enhancing strategies are critically reviewed to provide practical solutions for augmenting the bioefficacy of GPP-rich botanicals. Synergistic applications of encapsulation techniques (for physiochemical protection and bypassing xenobiotic metabolism) and dietary intervention strategies involving modulation of gut microbiota (for generating more bioavailable phenolic metabolites) appear promising, and may substantially enhance the bioefficacy, especially the neuroprotective efficacy, of orally consumed GPPs.

Gastrointestinal Fate of Fluid and Gelled Nutraceutical Emulsions: Impact on Proteolysis, Lipolysis, and Quercetin Bioaccessibility

Fluid and gelled nutraceutical emulsions were formulated from quercetin-loaded caseinate-stabilized emulsions by the addition of gellan gum with or without acidification with glucono-δ-lactone. Gellan gum addition increased the viscosity or gel strength of the fluid and gelled emulsions, respectively. The behavior of the nutraceutical emulsions in a simulated gastrointestinal tract depended upon their initial composition. Fluid emulsions containing different gellan gum levels (0-0.2%) had similar protein and lipid hydrolysis rates as well as similar quercetin bioaccessibility (∼51%). Conversely, proteolysis, lipolysis, and quercetin bioaccessibility decreased with an increasing gellan gum level in the gelled emulsions. In comparison to gelled emulsions, fluid emulsions were digested more rapidly and led to higher quercetin bioaccessibility. There was a good correlation between quercetin bioaccessibility and the lipolysis rate. These findings are useful for designing nutraceutical-loaded emulsions that can be used in a wide range of food products with different rheological properties.

Effects of In Vitro Digestion on the Content and Biological Activity of Polyphenols from Acacia mearnsii Bark

The stability and bioaccessibility of polyphenol from Acacia mearnsii bark were measured at various stages during in vitro simulated digestion. Subsequently, the changes in the total polyphenol content (TPC) and biological activity were studied. The results showed that the phenolic compounds from A. mearnsii remained stable, and TPC underwent few changes during gastric digestion. Nonetheless, intestinal digestion led to the degradation of proanthocyanidins (PAs) and a significant decrease in TPC (26%). Degradation was determined by normal-phase HPLC and gel permeation chromatography. Only monomers, dimers, and trimers of flavan-3-ols were identified in the serum-accessible fraction for characterization of their bioaccessibility. The results also indicated the obvious antioxidant capacity of PAs from A. mearnsii bark, and ~53% of the α-glucosidase⁻inhibitory effect was preserved. All these findings show that PAs from A. mearnsii bark as a native plant source may be particularly beneficial for human health as a natural nutritional supplement.

In vitro bioaccessibility of individual carotenoids from persimmon (Diospyros kaki, cv. Rojo Brillante) used as an ingredient in a model dairy food

BACKGROUND

Addition of persimmon fruit, which is highly rich in carotenoids, to dairy products represents an alternative to obtain functional foods. However, carotenoid bioaccessibility is strongly influenced by fat content and food composition. That is why in vitro bioaccessibility of individual carotenoids was evaluated in persimmon-based dairy products formulated with whole (3.6% fat) or skimmed milk (0.25% fat) and different freeze-dried persimmon tissues.

RESULTS

Unambiguous identification of seven xanthophylls (neoxanthin, violaxanthin, antheraxanthin, lutein, zeaxanthin, lutein epoxide and β-cryptoxanthin) and three hydrocarbon carotenes (α-carotene, β-carotene and lycopene) was achieved using high-performance liquid chromatography with a reverse-phase C-30 column. Total carotenoid content declined up 71% through the digestion process. In vitro bioaccessibility of carotenoids was significantly higher in dairy products formulated with whole milk than those with skimmed milk, representing a difference of more than 21% (in the formulation using persimmon whole fruit as ingredient). Furthermore, addition of whole milk to any type of persimmon tissue significantly improved the bioaccessibility of total provitamin A carotenoids, reaching the highest values (38%) with whole fruit and whole milk.

CONCLUSION

The higher fat content in whole milk exerted a significant influence on carotenoid bioaccessibility, especially when using freeze-dried persimmon whole fruit. © 2017 Society of Chemical Industry.

Simulated Gastrointestinal Digestion, Bioaccessibility and Antioxidant Capacity of Polyphenols from Red Chiltepin (Capsicum annuum L. Var. glabriusculum) Grown in Northwest Mexico

Chiltepin, a wild chili mostly used in different traditional foods and traditional medicine in Northwest Mexico, represents a source of polyphenols. However, studies about the bioaccessibility of polyphenols as a parameter to measure the nutritional quality and bioefficacy of them in the fruit after consumption are scarce. Chiltepin showed phenolic acids and flavonoids contents between 387 and 65 μg/g, respectively. Nevertheless, these values decreased after the digestion process. Before digestion, gallic acid, 4-hydroxibenzoinc acid, chlorogenic acid, caffeic acid, p-coumaric acid, quercetin and luteolin were the main polyphenols found in chiltepin by HPLC-DAD and confirmed by FIA-ESI-IT-MS/MS. Gallic and chlorogenic acids were non-detected in the gastric phase, while only p-coumaric acid (5.35 ± 3.89 μg/g), quercetin (5.91 ± 0.92 μg/g) and luteolin (2.86 ± 0.62 μg/g) were found in the intestinal phase. The bioaccessibility of phenolic acids, flavonoids, and total polyphenols after the intestinal phase was around 24, 17 and 23%, respectively. Overall, results indicated that release of polyphenols from chiltepin fruit might be affected by the food matrix and gastrointestinal conditions due to the low bioaccessibility values observed.

Gastrointestinal interactions, absorption, splanchnic metabolism and pharmacokinetics of orally ingested phenolic compounds

The positive health effects of phenolic compounds (PCs) have been extensively reported in the literature. An understanding of their bioaccessibility and bioavailability is essential for the elucidation of their health benefits. Before reaching circulation and exerting bioactions in target tissues, numerous interactions take place before and during digestion with either the plant or host's macromolecules that directly impact the organism and modulate their own bioaccessibility and bioavailability. The present work is focused on the gastrointestinal (GI) interactions that are relevant to the absorption and metabolism of PCs and how these interactions impact their pharmacokinetic profiles. Non-digestible cell wall components (fiber) interact intimately with PCs and delay their absorption in the small intestine, instead carrying them to the large intestine. PCs not bound to fiber interact with digestible nutrients in the bolus where they interfere with the digestion and absorption of proteins, carbohydrates, lipids, cholesterol, bile salts and micronutrients through the inhibition of digestive enzymes and enterocyte transporters and the disruption of micelle formation. PCs internalized by enterocytes may reach circulation (through transcellular or paracellular transport), be effluxed back into the lumen (P-glycoprotein, P-gp) or be metabolized by phase I and phase II enzymes. Some PCs can inhibit P-gp or phase I/II enzymes, which can potentially lead to drug-nutrient interactions. The absorption and pharmacokinetic parameters are modified by all of the interactions within the digestive tract and by the presence of other PCs. Undesirable interactions have promoted the development of nanotechnological approaches to promote the bioaccessibility, bioavailability, and bioefficacy of PCs.

Coencapsulation of (-)-Epigallocatechin-3-gallate and Quercetin in Particle-Stabilized W/O/W Emulsion Gels: Controlled Release and Bioaccessibility

Particle-stabilized W₁/O/W₂ emulsion gels were fabricated using a two-step procedure: ( i) a W₁/O emulsion was formed containing saccharose (for osmotic stress balance) and gelatin (as a gelling agent) in the aqueous phase and polyglycerol polyricinoleate (a lipophilic surfactant) in the oil phase; ( ii) this W₁/O emulsion was then homogenized with another water phase (W₂) containing wheat gliadin nanoparticles (hydrophilic emulsifier). The gliadin nanoparticles in the external aqueous phase aggregated at pH 5.5, which led to the formation of particle-stabilized W₁/O/W₂ emulsion gels with good stability to phase separation. These emulsion gels were then used to coencapsulate a hydrophilic bioactive (epigallocatechin-3-gallate, EGCG) in the internal aqueous phase (encapsulation efficiency = 65.5%) and a hydrophobic bioactive (quercetin) in the oil phase (encapsulation efficiency = 97.2%). The emulsion gels improved EGCG chemical stability and quercetin solubility under simulated gastrointestinal conditions, which led to a 2- and 4-fold increase in their effective bioaccessibility, respectively.

Bioaccessibility of Phenolic Compounds and Antioxidant Capacity of Chia (Salvia hispanica L.) Seeds

The aim of this work was to evaluate (i) the phenol and flavonoid recovery and bioaccessibility indexes and (ii) the antioxidant activity of both types of non-defatted and defatted chia seeds during the in vitro gastrointestinal digestion. The ground samples were subjected to in vitro simulated gastrointestinal digestion, and the resultant fractions were extracted and subjected to spectrophotometric assays. The results pointed to increasing concentrations of polyphenolic compounds during digestion, although only a low-medium percentage of phenols and a low percentage of flavonoids were available for absorption in the intestinal tract. In addition, the high level of fats seemed to have a negative effect on the bioaccessibility of flavonoids. Further studies should be undertaken to better understand the stabilization of the bioactive compounds of chia and to improve their bioaccessibility. Meanwhile, the present study represents a solid base for studying the bioavailability of bioactive compounds of chia seeds.

In vitro digestion models suitable for foods: Opportunities for new fields of application and challenges

In vitro digestion assays simulate the physiological conditions of digestion in vivo and are useful tools for studying and understanding changes, interactions, as well as the bioaccessibility of nutrients, drugs and non-nutritive compounds. The technique is widely used in fields such as nutrition, pharmacology and food chemistry. Over the last 40 years, more than 2500 research articles have been published using in vitro digestion assays (85% of which have been published in the last two decades) to elucidate multiple aspects such as protein digestibility, nutrient interactions or the viability of encapsulated microorganisms. The most recent trend in the use of this technique involves the determination of the antioxidant activity of bioactive compounds after digestion. However, the inability to reproduce certain in vivo digestion events, as well as the multiple models of in vitro digestion, point to a need to optimize and validate the method with in vivo assays to determine its limitations and uses. The purpose of this paper is to provide an overview of the current state of the art of in vitro digestion models through an analysis of how they have evolved in terms of the development of digestion models (parameters, protocols, guidance) and taking into consideration the boom in new fields of application.

Polyphenols and Their Interactions With Other Dietary Compounds: Implications for Human Health

Regular and optimal intake of polyphenols associates with numerous health-promoting effects. Bioavailability and activity of polyphenols depend on foods' structure and interactions with other food constituents, especially proteins, lipids, and carbohydrates. Polyphenols-proteins interactions can result in various biological effects, such as sense of astringency. So far, polyphenols interactions with food lipids have not been of special importance, except in case of plant oils. Polyphenols-carbohydrates interactions can influence the organoleptic properties, while interactions with dietary fibers are particularly significant. Polyphenols can decrease the synthesis of fats and fatty acids in the liver, or delay their absorption in intestines. Also, polyphenols can slow down digestion of carbohydrates, through the inhibition of digestive enzymes or modulation of glucose uptake. Both animal and plant proteins have low impact on the bioavailability of polyphenols, but some in vitro studies reported that milk proteins could enhance intestinal absorption of polyphenols from tea. Dietary fats may alter the passage of polyphenols through gastrointestinal tract and impact absorption of more hydrophobic polyphenols in particular. While some studies reported that associations with carbohydrates could decrease bioavailability of polyphenols, the others showed the opposite effects. Macronutrients can be used for encapsulation of polyphenols, which can increase their bioavailability and ensure controlled and targeted release. Polyphenols' interactions in the body include their incorporation in cell membranes which causes changes in fatty acid profile and impacts membrane-bound transporters and enzymes. Finally, gut microbiota plays essential role in metabolism of both polyphenols and macronutrients and thus can have great impact on their interactions.

Effect of Glycosylation Degree of Quercetin on Its In Vitro Bioaccessibility in Food Grade Organogels

Bioavailability of lipophilic bioactive represents a main concern in food industries. Several methods have been used to enhance it. Organogels is an alternative to improve lipophilic substances delivery. The objective of the present work was to evaluate the effect of organogel structures on digestibility of quercetin. Commercial monoacylglycerides (Myverol) was used as gelator. Three different vegetable oils were used (canola, corn, and soy). Samples were subject to rheological test, polarized light microscopy, and quercetin bioaccessibility. Results indicated that organogels prepared with canola oil showed higher elastic modulus, crystalline level, most ordered needled-shaped network, and higher bioaccessibility of quercetin. Quercetin glycosylation degree influences its behavior; better results in mechanical tests were observed for quercetin with lower degree of glycosylation. Higher bioaccessibility was obtained at higher glycosylation levels. Thus, a more resistant structure enhances compound release, but this is dependent on the oil type and the degree of glycosylation of quercetin.

Effect of in vitro simulated gastrointestinal digestion on polyphenol and polysaccharide content and their biological activities among 22 fruit juices

Polyphenols and polysaccharides, as natural bioactive compounds from common fresh fruits, are concerned in reducing risk of developing obesity and diabetes for human in recent years. The content of polyphenol and polysaccharide, their bioactivities among 22 fruit juices were investigated before and after in vitro gastrointestinal digestion in present study. After digestion, contents of polyphenol, polysaccharide and their antioxidant activity, the inhibitory activity of α-amylase and α-glucosidase significantly increased. Punica granatum Linn and Actinidia globosa C. F. Liang displayed maximal increment up to 2, 0.25 and 1.6 fold in contents of polyphenols and polysaccharides, and the inhibitory activity of α-amylase, respectively. The correlation coefficient between contents and inhibitory activity of α-amylase increased in range of 0.002 to 0.485. Lycopersicon esculentum Mill and Pyrus bretschneideri Rehd exhibited maximum increase in the inhibitory activity of α-glucosidase with lowest contents of polyphenols and polysaccharides. The results indicated that polyphenols and polysaccharides digested synergistically contributing to the inhibitory α-amylase activity, and other responsibly bioactive ingredients for inhibitory α-glucosidase activity would be worthy discussed future. The findings above highlighted some potential application of common fruit juices in controlling hyperglycemia and obesity.

Modeling of the Nanoparticles Absorption Under a Gastrointestinal Simulated Ambient Condition

Proanthocyanidins (PAs) have several bioactivities, but they are unstable in the digestive tract and possess low bioavailability. Nanoencapsulation stabilizes these compounds for oral administration. The intestinal absorption of grape seed and skin extracts, and the poly-lactic acid (PLA) nanoparticles loaded with such extracts was modeled, taking into consideration physicochemical process parameters, evaluating the PAs concentration profile in the human small intestine. Density (ρ), solubility, viscosity (μ), diffusion coefficient (D), and the global mass transfer coefficient (K) for both substrates were estimated, simulating their passing from the intestine into the blood at 37°C. For the seed and skin extracts encapsulated in PLA the physicochemical parameters were: D = 1.81 × 10^^-5 and D = 5.72 × 10^^-5 cm²/s; K = 3.4 × 10^^-3 and K = 2.47 × 10^^-4 cm/s, respectively. Lower resistance was offered by the seed extract than by skin extracts (nanoencapsulated), which was explained by differences in structural composition, and average molecular weight of the two kinds of extracts, which should be more favorable to the mass transfer in comparison to the raw extracts. The concentration profile of grape extracts in the small intestine was modeled through a pure convection model, and the encapsulated extract on PLA nanoparticles using a mixed regime model, which described the process of dissolution and absorption of the grape extracts from the intestine to the blood stream. The absorbed fraction predicted by the model was 42.7 and 24.2% for seed and skin extracts, respectively. Those values increased to 100% for both extracts after the simulation with the nanoencapsulated extracts. Consequently, extract encapsulation should produce a significant increase in intestinal absorption.

Food processing strategies to enhance phenolic compounds bioaccessibility and bioavailability in plant-based foods

Phenolic compounds are important constituents of plant-based foods, as their presence is related to protective effects on health. To exert their biological activity, phenolic compounds must be released from the matrix during digestion in an absorbable form (bioaccessible) and finally absorbed and transferred to the bloodstream (bioavailable). Chemical structure and matrix interactions are some food-related factors that hamper phenolic compounds bioaccessibility and bioavailability, and that can be counteracted by food processing. It has been shown that food processing can induce chemical or physical modifications in food that enhance phenolic compounds bioaccessibility and bioavailability. These changes include: (i) chemical modifications into more bioaccessible and bioavailable forms; (ii) cleavage of covalent or hydrogen bonds or hydrophobic forces that attach phenolic compounds to matrix macromolecules; (iii) damaging microstructural barriers such as cell walls that impede the release from the matrix; and (iv) create microstructures that protect phenolic compounds until they are absorbed. Indeed, food processing can produce degradation of phenolic compounds, however, it is possible to counteract it by modulating the operating conditions in favor of increased bioaccessibility and bioavailability. This review compiles the current knowledge on the effects of processing on phenolic compounds bioaccessibility or bioavailability, while suggesting new guidelines in the search of optimal processing conditions as a step forward towards the design of healthier foods.

Effect of olive cultivar on bioaccessibility and antioxidant activity of phenolic fraction of virgin olive oil

AIM

This study aims to characterize the phenolic profile and antioxidant capacity of seven monovarietal virgin olive oils (VOOs) and evaluate their in vitro gastrointestinal stability.

METHODS

'Picual', 'Blanqueta', 'Sevillana', 'Habichuelero', and 'Chetoui' olive cultivars were selected for VOO extraction. The oils were subjected to in vitro digestion. The recovery index (RI) of phenolic compounds after each digestion step and the bioaccessibility index (BI) were evaluated. In addition, the antioxidant activity of the bioaccessible fraction (BF) of VOOs was determined by DPPH, ABTS, and ORAC assays, as well as by studying the intracellular reactive oxygen species in Caco-2 cells.

RESULTS

Differences were found in the composition of phenolic compounds in VOOs depending on cultivars. During the digestive process, important losses of phenolic compounds were observed between the buccal and duodenal steps, unlike HTy and Ty, which presented increased recovery due to the hydrolysis of secoiridoid derivatives. Differences in the bioaccessibility of phenolic compounds were found between varieties of VOOs. 'Sevillana' VOO had the highest total bioaccessibility (36%), followed by the 'Picual' (19%), 'Chetoui' (17%), 'Habichuelero' (10%), and 'Blanqueta' (8%) varieties. The BF of all the varieties of VOO showed similar radical ABTS scavenging capacity, 'Chetoui', and 'Blanqueta'-BF having the highest radical DPPH scavenging capacity, and 'Habichuelero' and 'Picual'-BF showing protective effects against the peroxyl radical measured by ORAC_FL assay. All VOO-BFs presented decreases in ROS levels in Caco-2 cells.

CONCLUSIONS

Our results suggest differences in the bioaccessibility of phenolics from diverse VOO varieties, which could lead to different biological properties. Therefore, this study represents a first step toward the development of novel dietary strategies focusing on the phenolic supplementation of different VOOs to preserve human health.

The role of metabolism (and the microbiome) in defining the clinical efficacy of dietary flavonoids

At a population level, there is growing evidence of the beneficial effects of dietary flavonoids on health. However, there is extensive heterogeneity in the response to increased intake, which is likely mediated via wide interindividual variability in flavonoid absorption and metabolism. Flavonoids are extensively metabolized by phase I and phase II metabolism (which occur predominantly in the gastrointestinal tract and liver) and colonic microbial metabolism. A number of factors, including age, sex, and genotype, may affect these metabolic processes. In addition, food composition and flavonoid source are likely to affect bioavailability, and emerging data suggest a critical role for the microbiome. This review will focus on the current knowledge for the main subclasses of flavonoids, including anthocyanins, flavonols, flavan-3-ols, and flavanones, for which there is growing evidence from prospective studies of beneficial effects on health. The identification of key factors that govern metabolism and an understanding of how the differential capacity to metabolize these bioactive compounds affect health outcomes will help establish how to optimize intakes of flavonoids for health benefits and in specific subgroups. We identify research areas that need to be addressed to further understand important determinants of flavonoid bioavailability and metabolism and to advance the knowledge base that is required to move toward the development of dietary guidelines and recommendations for flavonoids and flavonoid-rich foods.

Food Matrix Effects of Polyphenol Bioaccessibility from Almond Skin during Simulated Human Digestion

The goal of the present study was to quantify the rate and extent of polyphenols released in the gastrointestinal tract (GIT) from natural (NS) and blanched (BS) almond skins. A dynamic gastric model of digestion which provides a realistic simulation of the human stomach was used. In order to establish the effect of a food matrix on polyphenols bioaccessibility, NS and BS were either digested in water (WT) or incorporated into home-made biscuits (HB), crisp-bread (CB) and full-fat milk (FM). Phenolic acids were the most bioaccessible class (68.5% release from NS and 64.7% from BS). WT increased the release of flavan-3-ols (p < 0.05) and flavonols (p < 0.05) from NS after gastric plus duodenal digestion, whereas CB and HB were better vehicles for BS. FM lowered the % recovery of polyphenols, the free total phenols and the antioxidant status in the digestion medium, indicating that phenolic compounds could bind protein present in the food matrix. The release of bioactives from almond skins could explain the beneficial effects associated with almond consumption.

Data in support of antioxidant activities of the non-extractable fraction of dried persimmon (Diospyros kaki Thunb.)

This data article is related to the research article entitled, “Antioxidant potential in non-extractable fraction of dried persimmon (Diospyros kaki Thunb.)” (Matsumura et al., 2016) [1]. We investigated antioxidant activities of the non-extractable fraction of dried persimmon fruits in vitro and in vivo. We evaluated both extracted fraction and non-extractable fraction, and reported that non-extractable fraction may possess significantly antioxidant potential in vivo on the basis of the oxygen radical absorbance capacity (ORAC). We showed our experimental raw data about antioxidant capacity of dried persimmon, plasma triglycerides (TG) and HDL-cholesterol (HDL-C), and this data article might contribute to evaluate real antioxidant capacity of other fruits and vegetables.

Potential of Excipient Emulsions for Improving Quercetin Bioaccessibility and Antioxidant Activity: An in Vitro Study

The potential for excipient emulsions to enhance the bioaccessibility and antioxidant activity of quercetin was determined in this study. Oil-in-water excipient emulsions containing two levels (4 or 10%) of small lipid droplets (d < 250 nm) were prepared from a long-chain triglyceride (corn oil). The solubilization of quercetin by the excipient emulsions was faster than by bulk corn oil or bulk water, and the solubilization rate was higher at 100 °C than at 30 °C. The bioaccessibility of quercetin samples was determined using an in vitro gastrointestinal model, and the bioactivity of quercetin was determined using a rat feeding study. The excipient emulsions were more effective at enhancing quercetin bioaccessibility and rat plasma antioxidant activity than either bulk oil or bulk water. This effect was attributed to the rapid digestion of the long chain triglycerides when they were in an emulsified form, which led to the rapid production of mixed micelles capable of solubilizing, protecting, and transporting quercetin.

The content of polyphenolic compounds in cocoa beans (Theobroma cacao L.), depending on variety, growing region, and processing operations: a review

Polyphenols form the largest group of compounds among natural antioxidants, which largely affect the overall antioxidant and anti-free radical activity of cocoa beans. The qualitative and quantitative composition of individual fractions of polyphenolic compounds, even within one species, is very diverse and depends on many factors, mainly on the area of cocoa trees cultivation, bean maturity, climatic conditions during growth, and the harvest season and storage time after harvest. Thermal processing of cocoa beans and cocoa derivative products at relatively high temperatures may in addition to favorable physicochemical, microbiological, and organoleptic changes result in a decrease of polyphenols concentration. Technological processing of cocoa beans negatively affects the content of polyphenolic compounds.

The Reciprocal Interactions between Polyphenols and Gut Microbiota and Effects on Bioaccessibility

As of late, polyphenols have increasingly interested the scientific community due to their proposed health benefits. Much of this attention has focused on their bioavailability. Polyphenol-gut microbiota interactions should be considered to understand their biological functions. The dichotomy between the biotransformation of polyphenols into their metabolites by gut microbiota and the modulation of gut microbiota composition by polyphenols contributes to positive health outcomes. Although there are many studies on the in vivo bioavailability of polyphenols, the mutual relationship between polyphenols and gut microbiota is not fully understood. This review focuses on the biotransformation of polyphenols by gut microbiota, modulation of gut microbiota by polyphenols, and the effects of these two-way mutual interactions on polyphenol bioavailability, and ultimately, human health.

Antioxidant potential in non-extractable fractions of dried persimmon (Diospyros kaki Thunb.)

Dried fruits of persimmon (Diospyros kaki Thunb.) are a traditional food in Japan and contain large quantities of tannins. In this study, we investigated the in vitro and in vivo antioxidant potentials of non-extractable fractions from dried persimmons. Hydrolysed non-extractable fractions showed the highest antioxidant activities in vitro. In subsequent experiments, the plasma oxygen radical absorbance capacity (ORAC) values in rats supplemented with a 5% non-extractable fraction were approximately 1.5times higher than those in control rats after 1week in vivo. Furthermore, using an in vitro model of the gastrointestinal tract, the ORAC values of the non-extractable fraction were significantly increased with colonic fermentation in the large bowel stage. These data indicate that non-extractable fractions may possess significant antioxidant potential in vitro and in vivo.

Mechanisms by which cocoa flavanols improve metabolic syndrome and related disorders

Dietary administration of cocoa flavanols may be an effective complementary strategy for alleviation or prevention of metabolic syndrome, particularly glucose intolerance. The complex flavanol composition of cocoa provides the ability to interact with a variety of molecules, thus allowing numerous opportunities to ameliorate metabolic diseases. These interactions likely occur primarily in the gastrointestinal tract, where native cocoa flavanol concentration is high. Flavanols may antagonize digestive enzymes and glucose transporters, causing a reduction in glucose excursion, which helps patients with metabolic disorders maintain glucose homeostasis. Unabsorbed flavanols, and ones that undergo enterohepatic recycling, will proceed to the colon where they can exert prebiotic effects on the gut microbiota. Interactions with the gut microbiota may improve gut barrier function, resulting in attenuated endotoxin absorption. Cocoa may also positively influence insulin signaling, possibly by relieving insulin-signaling pathways from oxidative stress and inflammation and/or via a heightened incretin response. The purpose of this review is to explore the mechanisms that underlie these outcomes, critically review the current body of literature related to those mechanisms, explore the implications of these mechanisms for therapeutic utility, and identify emerging or needed areas of research that could advance our understanding of the mechanisms of action and therapeutic potential of cocoa flavanols.

Phenolic recovery and bioaccessibility from milled and finished whole grain oat products

Phenolics naturally present in whole grain oats are recovered well through traditional grain processing, milling and food processing.

Wild Raspberry Subjected to Simulated Gastrointestinal Digestion Improves the Protective Capacity against Ethyl Carbamate-Induced Oxidative Damage in Caco-2 Cells

Ethyl carbamate (EC), a probable human carcinogen, occurs widely in many fermented foods. Previous studies indicated that EC-induced cytotoxicity was associated with oxidative stress. Wild raspberries are rich in polyphenolic compounds, which possess potent antioxidant activity. This study was conducted to investigate the protective effect of wild raspberry extracts produced before (RE) and after in vitro simulated gastrointestinal digestion (RD) on EC-induced oxidative damage in Caco-2 cells. Our primary data showed that ethyl carbamate could result in cytotoxicity and genotoxicity in Caco-2 cells and raspberry extract after digestion (RD) may be more effective than that before digestion (RE) in attenuating toxicity caused by ethyl carbamate. Further investigation by fluorescence microscope revealed that RD may significantly ameliorate EC-induced oxidative damage by scavenging the overproduction of intracellular reactive oxygen species (ROS), maintaining mitochondrial function and preventing glutathione (GSH) depletion. In addition, HPLC-ESI-MS results showed that the contents of identified polyphenolic compounds (esculin, kaempferol O-hexoside, and pelargonidin O-hexoside) were remarkably increased after digestion, which might be related to the better protective effect of RD. Overall, our results demonstrated that raspberry extract undergoing simulated gastrointestinal digestion may improve the protective effect against EC-induced oxidative damage in Caco-2 cells.