Bioaccessible and dialysable polyphenols in selected apple varieties following in vitro digestion vs. their native patterns

Characterization, Bioaccesibility and Antioxidant Activities of Phenolic Compounds Recovered from Yellow pea (Pisum sativum) Flour and Protein Isolate

This study focused on studying the bioaccesible phenolic compounds (PCs) from yellow pea flour (F) and protein isolate (I). Total phenolic contents (TPC), PCs composition and antioxidant activities were analysed in ethanol 60% extracts obtained by applying ultrasound assisted extraction (UAE, 15 min/40% amplitude). The preparation of I under alkaline conditions and the elimination of some soluble components at lower pH produced a change of PCs profile and antioxidant activity. After simulated gastrointestinal digestion (SGID) of both ingredients to obtain the digests FD and ID, notable changes in the PCs concentration and profiles could be demonstrated. FD presented a higher ORAC activity than ID (IC50 = 0.022 and 0.039 mg GAE/g dm, respectively), but lower ABTS•+ activity (IC50 = 0.8 and 0.3 mg GAE/g dm, respectively). After treatment with cholestyramine of extracts from FD and ID in order to eliminate bile salts and obtain the bioaccesible fractions FDb and IDb, ROS scavenging in H2O2-induced Caco2-TC7 cells was evaluated, registering a greater activity for ID respect to FD (IC50 = 0.042 and 0.017 mg GAE/mL, respectively). These activities could be attributed to the major bioaccesible PCs: OH-tyrosol, polydatin, trans-resveratrol, rutin, (-)-epicatechin and (-)-gallocatechin gallate for FD; syringic (the most concentrated) and ellagic acids, trans-resveratrol, and (-)-gallocatechin gallate for ID, but probably other compounds such as peptides or amino acids can also contribute.

Partitioning and in vitro bioaccessibility of apple polyphenols during mechanical and physiological extraction: A hierarchical clustering analysis with LC-ESI-QTOF-MS/MS

Polyphenol partitioning during mechanical (cold-pressing) and physiological (digestion) extraction at the individual polyphenol and subclass level was investigated. UHPLC-ESI-QTOF-MS/MS analysis yielded a comprehensive identification of 45 polyphenols whose semi-quantification revealed a hierarchical clustering strongly determined by polyphenol structure and their location within the apple tissue. For instance, pomace retained most flavonols and flavanols (degree of polymerization DP 5-7), which were highly hydrophobic, hydroxylated, or large (>434 Da), and more abundant in peel. In vitro digestion UHPLC-ESI-QTOF-MS/MS analysis of whole apple (and its corresponding matrix-free extract) clustered polyphenols into five main groups according to their interaction with plant cell walls (PCWs) during each digestion phase. This grouping was not reproduced in pomace, which exhibited a greater matrix effect than whole apple during oral and gastric digestion. Nevertheless, the interaction between most polyphenol groups, including dihydrochalcones, flavanols (DP 1-4) and hydroxycinnamic acid derivatives, and pomace PCWs was lost during intestinal digestion.

A comparative study of electrical and conventional pre-treatments for quality assessment of hot air dried green bell pepper

In this study, the effect of pretreatments (hot water blanching, microwave blanching and ohmic heating) on drying kinetics and quality characteristics of green bell pepper dried at 60, 70 and 80 °C was investigated. Four mathematical models were fitted to experimental data and Logarithmic model was found to be the best for all the samples. Rehydration ability of only ohmic heating pretreated peppers was higher than untreated ones. Total polyphenol (TP) content and antioxidant capacity (AC) of dried peppers varied between 3.21-5.08 mg gallic acid equivalent (GAE)/g dry matter (DM) and 1037.57-2407.40 mmol AAE/100 g DM, respectively. The content of ascorbic acid (AA) in dried samples was in the range of 187.25-722.55 µg/g DM. The bioaccessibility of TP after in-vitro digestion varied from 79.44 to 97.73%. Losses of chlorophyll a and b were very high in all samples compared to fresh ones but the most in control samples.

The Behavior of Phenolic Compounds from Apples during Simulated Gastrointestinal Digestion with Focus on Chlorogenic Acid

The fate of phenolic compounds during digestion is important for their bioactive effects in the digestive tract. The aim was to study the various phenolic compounds occurring in the peel and flesh of apples in in vitro simulated gastrointestinal digestion, focusing on the behavior of chlorogenic acids. Additionally, the behavior of individual chlorogenic acids (chlorogenic, neochlorogenic, and cryptochlorogenic) was studied in models of simulated salivary, gastric, and intestinal fluid electrolyte solutions (SSF, SGF, SIF). At the end of the intestinal phase of the digestion of peel and flesh, the amount of recovered dihydrochalcones and flavonols increased or was similar to the amount in the gastric phase, which showed their stability. Anthocyanins and flavan-3-ols decreased, which suggests their biotransformation. Chlorogenic acid isomerized into neochlorogenic and cryptochlorogenic acid: chlorogenic acid from the peel into 22% and 41% of the isomers in the salivary and intestinal phases, respectively; chlorogenic acid from the flesh into 12% of the isomers in the intestinal phase. Similarly, chlorogenic acid isomerized in model solutions (20% and 26% of the isomers in SSF and SIF, respectively). Neochlorogenic and cryptochlorogenic acid isomerized in SSF and SIF into other two forms. They were all stable in SGF. For bioactive effects in the digestive tract, the biotransformation of chlorogenic acids should be considered.

Autochthonous Fermentation as a Means to Improve the Bioaccessibility and Antioxidant Activity of Proteins and Phenolic Compounds of Yellow Pea Flour

This study focused on evaluating the potential of the natural fermentation of pea flour to improve the release of antioxidant compounds. Preliminary fermentations of 36.4% w/w flour dispersions were performed in tubes under different conditions (24 and 48 h, 30 and 37 °C). Finally, fermented flours (FFs) were obtained in a bioreactor under two conditions: 1: 36.4% w/w, 24 h, 30 °C (FF1); 2: 14.3% w/w, 24 h, 37 °C (FF2). The pH values decreased to 4.4-4.7, with a predominance of lactic acid bacteria. As in the fermentations in tubes, an increment in the proteolysis degree (TNBS method) (greater for FF2), polypeptide aggregation and a decrease in their solubility, an increase in <2 kDa peptides, and an increase in the Oxygen Radical Absorption Capacity (ORAC) potency of PBS-soluble fractions after fermentation were demonstrated. Also, fermentation increased the proteolysis degree after simulated gastrointestinal digestion (SGID, COST-INFOGEST) with respect to the non-fermented flour digests, with some differences in the molecular composition of the different digests. ORAC and Hydroxyl Radical Averting Capacity (HORAC) potencies increased in all cases. The digest of FF2 (FF2D) presented the greater ORAC value, with higher activities for >4 kDa, as well as for some fractions in the ranges 2-0.3 kDa and <0.10 kDa. Fermentation also increased the 60%-ethanol-extracted phenolic compounds, mainly flavonoids, and the ORAC activity. After SGID, the flavan-3-ols disappeared, but some phenolic acids increased with respect to the flour. Fermentation in condition 2 was considered the most appropriate to obtain a functional antioxidant ingredient.

Effect of encapsulation on stability of anthocyanins and chlorogenic acid isomers in aronia during in vitro digestion and their transformation in a model system

Aronia extract was encapsulated with maltodextrin (MD) or MD plus carboxymethyl cellulose, gum Arabic, or xanthan gum and digested under simulated conditions. The retention of anthocyanins was higher (75 %) in encapsulated aronia as compared to non-encapsulated one (58 %). Cryptochlorogenic acid significantly increased after in vitro digestion, whereas neochlorogenic acid and chlorogenic acid decreased. The increase of cryptochlorogenic acid was about two-fold higher in non-encapsulated aronia than encapsulated aronia. In a model system, cyanidin 3-galactoside and chlorogenic acid were separately digested under simulated conditions. Cyanidin 3-galactoside-C7H12O6 adduct (m/z 640) was firstly observed in the digested cyanidin 3-galactoside solution, suggesting that degradation products of anthocyanins bind to intact anthocyanins. In a separate study, cryptochlorogenic acid increased as much as chlorogenic acid decreased, indicating that chlorogenic acid can be transformed into cryptochlorogenic acid during digestion. The results show that encapsulation lowered molecular transformations of anthocyanins and chlorogenic acid during in vitro digestion.

In Vitro Assessment of Cortisol Release Inhibition, Bioaccessibility and Bioavailability of a Chemically Characterized Scutellaria lateriflora L. Hydroethanolic Extract

Excess cortisol release is associated with numerous health concerns, including psychiatric issues (i.e., anxiety, insomnia, and depression) and nonpsychiatric issues (i.e., osteoporosis). The aim of this study was to assess the in vitro inhibition of cortisol release, bioaccessibility, and bioavailability exerted by a chemically characterized Scutellaria lateriflora L. extract (SLE). The treatment of H295R cells with SLE at increasing, noncytotoxic, concentrations (5-30 ng/mL) showed significant inhibition of cortisol release ranging from 58 to 91%. The in vitro simulated gastric, duodenal, and gastroduodenal digestions, induced statistically significant reductions (p < 0.0001) in the bioactive polyphenolic compounds that most represented SLE. Bioavailability studies on duodenal digested SLE, using Caco-2 cells grown on transwell inserts and a parallel artificial membrane permeability assay, indicated oroxylin A glucuronide and oroxylin A were the only bioactive compounds able to cross the Caco-2 cell membrane and the artificial lipid membrane, respectively. The results suggest possible applications of SLE as a food supplement ingredient against cortisol-mediated stress response and the use of gastroresistant oral dosage forms to partially prevent the degradation of SLE bioactive compounds. In vivo studies and clinical trials remain necessary to draw a conclusion on the efficacy and tolerability of this plant extract.

Phenolic Compounds from Apples: From Natural Fruits to the Beneficial Effects in the Digestive System

Conditions in the gastrointestinal tract and microbial metabolism lead to biotransformation of parent, native phenolic compounds from apples into different chemical forms. The aim of this work was to review current knowledge about the forms of phenolic compounds from apples in the gastrointestinal tract and to connect it to their potential beneficial effects, including the mitigation of health problems of the digestive tract. Phenolic compounds from apples are found in the gastrointestinal tract in a variety of forms: native (flavan-3-ols, phenolic acids, flavonols, dihydrochalcones, and anthocyanins), degradation products, various metabolites, and catabolites. Native forms can show beneficial effects in the stomach and small intestine and during the beginning phase of digestion in the colon. Different products of degradation and phase II metabolites can be found in the small intestine and colon, while catabolites might be important for bioactivities in the colon. Most studies connect beneficial effects for different described health problems to the whole apple or to the amount of all phenolic compounds from apples. This expresses the influence of all native polyphenols from apples on beneficial effects. However, further studies of the peculiar compounds resulting from native phenols and their effects on the various parts of the digestive tract could provide a better understanding of the specific derivatives with bioactivity in humans.

Polyphenolic profile, processing impact, and bioaccessibility of apple fermented products

Health-promoting foods have become increasingly popular due to intensified consumer interest and awareness of illnesses. There is a global market for apple fruits, which are affordable, nutritious, tasty, and produced in large quantities for direct consumption as well as food processing to make derived products. The food matrix of apples is suitable for fermentation, besides containing a high amount of phenolics and polyphenols. Fermentation of apples is one of the most common methods of preserving apple fruit and its byproducts. With different fermentation techniques, apple fruit can be used to make a wide range of products, such as fermented apple juice, cider, liqueurs, apple cider, apple vinegar and fermented apple solids, because it is not only a low-cost and simple method of processing the fruit, but it can also sometimes increase the bioavailability of nutrients and the levels of components that can improve health and sensory quality. To understand the health benefits of food products and how the fermentation process impacts polyphenols, it is also crucial to observe the effects of digestion on polyphenol bioaccessibility. Polyphenolic profile changes can be observed via both in vitro and in vivo digestion methods; however, in vitro digestion methods have the advantage of observing every step of gastrointestinal track effects and have less cost as well. In this review, the polyphenolic profile, processing impact, and bioaccessibility of apple-fermented products is assessed, with most available studies showing polyphenol profiles and bioaccessibility in apple varieties and fermented apple products.

The Use of Fruit and Vegetable by-Products as Enhancers of Health Status of Piglets after Weaning: The Role of Bioactive Compounds from Apple and Carrot Industrial Wastes

At weaning, piglets are exposed to a large variety of stressors, from environmental/behavioral factors to nutritional stress. Weaning transition affects the gastrointestinal tract especially, resulting in specific disturbances at the level of intestinal morphology, barrier function and integrity, mucosal immunity and gut microbiota. All these alterations are associated with intestinal inflammation, oxidative stress and perturbation of intracellular signaling pathways. The nutritional management of the weaning period aims to achieve the reinforcement of intestinal integrity and functioning to positively modulate the intestinal immunity and that of the gut microbiota and to enhance the health status of piglets. That is why the current research is focused on the raw materials rich in phytochemicals which could positively modulate animal health. The composition analysis of fruit, vegetable and their by-products showed that identified phytochemicals could act as bioactive compounds, which can be used as modulators of weaning-induced disturbances in piglets. This review describes nutritional studies which investigated the effects of bioactive compounds derived from fruit (apple) and vegetables (carrot) or their by-products on the intestinal architecture and function, inflammatory processes and oxidative stress at the intestinal level. Data on the associated signaling pathways and on the microbiota modulation by bioactive compounds from these by-products are also presented.

Physicochemical properties, phenolic content and in vitro digestion profile of Chinese black rice (Oryza sativa L.)

Yangxian black rice, as one of the ancient Chinese black rice varieties, is widely planted in the Yangxian area of China. This study investigated the physicochemical properties, phenolic content and in vitro digestion profile of Chinese black rice under gradient milling treatment. The chemical composition, color, pasting and thermal properties of black rice with different milling degrees were comprehensively compared. In vitro digestion analysis indicated that cooked rice flour had higher rapidly digestible starch (RDS) and lower resistant starch (RS) contents compared with the uncooked one. Besides, all cooked black rice samples exhibited high predicted glycemic index (pGI) value and whole black rice showed a lower pGI than refined rice. The microstructure and the abundance of phenolic compounds in the solid matrix during different treatments or digestion stages were observed by CLSM. Furthermore, a total of 102 phenolic constituents were absolutely quantified by targeted metabolomics techniques. Methanol extraction and moderate cooking treatment contributed to the release of phenolic compounds from the solid matrix of whole black rice. Besides, compared to the gastric digestion stage, the transition in the intestinal environment caused a decrease in the majority of the analyzed polyphenols. Identifying the phenolic constituents was favorable for a better elucidation of the chemical basis of the function and nutritional value of Chinese black rice.

Characterization of Fruit Vinegars via Bioactive and Organic Acid Profile Using Chemometrics

Vinegar has been known as a traditional remedy since ancient times. In addition to being used as a flavoring and aroma enhancer in world cuisines, it has attracted more and more attention due to its bioactive potential and health properties. Although the most common use is apple cider vinegar together with grape vinegar, vinegar produced from red fruits has come to the fore due to their health purposes. Rosehip, pomegranate, fig, guelder-rose, blackberry, raspberry, and blueberry vinegars were evaluated regarding the organic acid content, phenolic compound content, and bioactive potential to assess their health potential and associated contents. Acetic acid, citric acid, succinic acid, and malic acid were determined as prominent organic acids in the vinegar samples. In contrast, gallic acid, vanillic acid, protocatechuic acid, and ferulic acid were dominant regarding phenolic compounds. Raspberry, guelder-rose, and pomegranate vinegars came forth regarding their bioactive content and potential. The discriminative parameters of the vinegar samples were pH, total acidity, dL-isocitric acid, gallic acid, and hydroxybenzoic acid. Fruit vinegars were determined to have a notable bioactive content compared to apple and grape vinegars. The use of these vulnerable bioactive materials in vinegar fermentation could provide an effective way for nutrition and raw material resourcing.

Plant Polyphenols and Their Potential Benefits on Cardiovascular Health: A Review

Fruits, vegetables, and other food items contain phytochemicals or secondary metabolites which may be considered non-essential nutrients but have medicinal importance. These dietary phytochemicals exhibit chemopreventive and therapeutic effects against numerous diseases. Polyphenols are secondary metabolites found in vegetables, fruits, and grains. These compounds exhibit several health benefits such as immune modulators, vasodilators, and antioxidants. This review focuses on recent studies on using dietary polyphenols to treat cardiovascular disorders, atherosclerosis, and vascular endothelium deficits. We focus on exploring the safety of highly effective polyphenols to ensure their maximum impact on cardiac abnormalities and discuss recent epidemiological evidence and intervention trials related to these properties. Kaempferol, quercetin, and resveratrol prevent oxidative stress by regulating proteins that induce oxidation in heart tissues. In addition, polyphenols modulate the tone of the endothelium of vessels by releasing nitric oxide (NO) and reducing low-density lipoprotein (LDL) oxidation to prevent atherosclerosis. In cardiomyocytes, polyphenols suppress the expression of inflammatory markers and inhibit the production of inflammation markers to exert an anti-inflammatory response. Consequently, heart diseases such as strokes, hypertension, heart failure, and ischemic heart disease could be prevented by dietary polyphenols.

Plants from Northwestern Anatolia Display Selective Cytotoxicity and Induce Mitotic Catastrophe: A Study on Anticancer and Genotoxic Activities

Anatolia is rich in floristic diversity with a high rate of endemism. Eight plant species from northwestern Anatolia were evaluated for their anti-growth properties in two malignant (MCF-7 and MDA-MB-231) and a non-malignant (MCF-10A) breast cell lines. The two most active extracts, Achillea multifida (AME) and Astragalus sibthorpianus (ASE), induced apoptotic cell death in all cell lines. The major phenolic compounds in AME were identified as chlorogenic acid, and catechins in ASE. ASE displayed selective cytotoxicity against breast cancer cells, with DNA damage repair in non-malignant cells contributing to its selectivity. Conversely, AME induced DNA damage in a time-dependent manner and displayed a dual dose-dependent biological activity, resulting in mitotic catastrophe and apoptosis at different doses. Most plant species exhibited moderate to strong cytotoxicity, highlighting their medicinal and economic potential and the need for their protection.

In Vitro Bioaccessibility Assessment of Phenolic Compounds from Encapsulated Grape Pomace Extract by Ionic Gelation

Grape pomace is a by-product of winemaking characterized by a rich chemical composition from which phenolics stand out. Phenolics are health-promoting agents, and their beneficial effects depend on their bioaccessibility, which is influenced by gastrointestinal digestion. The effect of encapsulating phenol-rich grape pomace extract (PRE) with sodium alginate (SA), a mixture of SA with gelatin (SA-GEL), and SA with chitosan (SA-CHIT) on the bioaccessibility index (BI) of phenolics during simulated digestion in vitro was studied. A total of 27 individual phenolic compounds (IPCs) were quantified by UHPLC. The addition of a second coating to SA improved the encapsulation efficiency (EE), and the highest EE was obtained for SA-CHIT microbeads (56.25%). Encapsulation affected the physicochemical properties (size, shape and texture, morphology, crystallinity) of the produced microbeads, which influenced the delivery of phenolics to the intestine and their BI. Thus, SA-GEL microbeads had the largest size parameters, as confirmed by scanning electron microscopy (SEM), and the highest BI for total phenolic compounds and IPCs (gallic acid, 3,4-dihydroxybenzoic acid and o-coumaric acid, epicatechin, and gallocatechin gallate) ranged from 96.20 to 1011.3%. The results suggest that encapsulated PRE has great potential to be used as a functional ingredient in products for oral administration.

Bile Acids and Short-Chain Fatty Acids Are Modulated after Onion and Apple Consumption in Obese Zucker Rats

Gut microorganisms are involved in the development and severity of different cardiovascular diseases, and increasing evidence has indicated that dietary fibre and polyphenols can interact with the intestinal microbiota. The study objective was to investigate the effect of onion and apple intake on the major types of microbial-derived molecules, such as short-chain fatty acids (SCFAs) and bile acids (BAs). Obese Zucker rats were randomly assigned (n = eight rats/group) to a standard diet (OC), a standard diet/10% onion (OO), or a standard diet/10% apple (OA). Lean Zucker rats fed a standard diet served as a lean control (LC) group. Faecal samples were collected at baseline, and 8 weeks later, the composition of the microbial community was measured, and BA and SCFA levels were determined using high-performance liquid chromatography-mass spectrometry (HPLC-MS) and gas chromatography-mass spectrometry (GC-MS), respectively. Rats fed onion- and apple-enriched diets had increased abundance of beneficial bacteria, such as Bifidobacterium spp. and Lactobacillus spp., enhanced SCFAs (acetic, propionic, isobutyric, and valeric acids), decreased excretion of some BAs, mainly of the primary (CA, α-MCA, and β-MCA) and secondary type (ω-MCA, HDCA, NCA, DCA, and LCA), and increased amount of taurine- and glycine-conjugated BAs compared to the OC group. The contribution of specific bioactive compounds and their metabolites in the regulation of the microbiome and the pathways linked to SCFA and BA formation and their relationship with some diseases needs further research.

Phenolic characterization of fermented jujube puree by HPLC-MS/MS and their release during in vitro dynamic digestion

Health benefits of fruit products fermented with probiotics are partially attributed to their increased contents of phenolic compounds. In this study, the effect of in vitro dynamic gastrointestinal digestion on the release of phenolic compounds and changes in the antioxidant activity of jujube puree fermented with Streptococcus thermophilus was investigated. Thirteen target phenolic compounds were characterized by high-performance liquid chromatography-tandem mass spectrometry. The recovery of this developed method ranged from 87.41% to 111.03%, and the limits of detection and quantification were low. Fermentation with Streptococcus thermophilus significantly increased the contents of most phenolic compounds in jujube puree. Fermentation reduced the decrease in the contents of most phenolic compounds in jujube puree during gastrointestinal digestion and, as a consequence improved the antioxidant capacity of digested fractions. These findings indicated that fermentation could increase the bioaccessibility of specific phenolics in jujube, as well as the antioxidant activity of this fruit.

Beneficial effects of phenolic compounds: native phenolic compounds vs metabolites and catabolites

In the human body, the positive effects of phenolic compounds are increasingly observed through their presence in tissues and organs in their native form or in the form of metabolites or catabolites formed during digestion, microbial metabolism, and host biotransformation. The full extent of these effects is still unclear. The aim of this paper is to review the current knowledge of beneficial effects of native phenolic compounds or their metabolites and catabolites focusing on their role in the health of the digestive system, including disorders of the gastrointestinal and urinary tracts and liver. Studies are mostly connecting beneficial effects in the gastrointestinal and urinary tract to the whole food rich in phenolics, or to the amount of phenolic compounds/antioxidants in food. Indeed, the bioactivity of parent phenolic compounds should not be ignored due to their presence in the digestive tract, and the impact on the gut microbiota. However, the influence of their metabolites and catabolites might be more important for the liver and urinary tract. Distinguishing between the effects of parent phenolics vs metabolites and catabolites at the site of action are important for novel areas of food industry, nutrition and medicine.

Structural, in vitro digestion, and fermentation characteristics of lotus leaf flavonoids

Bioaccessibility and bioactivity of flavonoids in lotus leaves are related to their characteristics in gastrointestinal digestion and colonic fermentation. The aim of this study is to investigate the stability of lotus leaf flavonoids (LLF) in simulated gastrointestinal digestion, and its modulation on gut microbiota in vitro fermentation. Results showed that LLF mainly consisted of quercetin-3-O-galactoside, quercetin-3-O-glucuronide, quercetin-3-O-glucoside, and kaempferol-3-O-glucoside. These flavonoids kept stability with only a small fraction degraded in simulated gastric and intestinal fluids. In vitro fermentation, LLF stimulated the growth of Actinobacteria and Firmicutes, inhibited the growth of Proteobacteria, and induced the production of fermentation gases and short-chain fatty acids. Interestingly, supplementation of soluble starch significantly improved the utilization of LLF by the intestinal flora. These results revealed that LLF shaped a unique biological web with Lactobacillus and Bifidobacterium spp. as the core of the biological network, which would be more beneficial to gut health.

Investigation of some bioactive compounds, in vitro bioaccessibility, and sensory acceptability of couscous produced by pre-gelatinized rice flour

BACKGROUND

The purpose of this study was to investigate the sensory properties, antioxidant capacities, total phenolic content, and their bioaccessibility in gluten-free rice couscous that is produced without additives. Since rice does not contain gluten, pre-gelatinized rice flour (GRF) was added instead of gum and enzymes in order to provide the desired structure in the couscous samples.

RESULTS

According to the results, the total phenolic content of couscous samples was increased with GRF addition. The highest extractable and hydrolyzable antioxidant capacity values were observed in the couscous samples supplemented with 30% GRF using the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation, cupric-reducing antioxidant capacity, and ferric reducing antioxidant capacity methods. The bioaccessibility of antioxidant capacity was found to be significantly higher (P < 0.05) than the control sample in all methods except the 1,1-diphenyl-2-picrylhydrazyl free radical method in the couscous samples.

CONCLUSION

According to the data obtained, it has been determined that couscous, which has a very small round shape, can be produced with GRF without additives. In this context, gluten-free rice couscous could be used as an alternative valuable food in terms of nutrition and can be an alternative traditional food for celiac diseases as well as for individuals preferring the consumption of gluten-free products. © 2022 Society of Chemical Industry.

Assessment of the Bioaccessibility of Elaeagnus angustifolia L. Flour and Its Use in Cracker Formulation

In this study, in vitro digestion of polyphenols of oleaster (Elaeagnus angustifolia L.) flour (OF) and the potential use of OF in cracker production were studied. The results showed that 21.90 mg gallic acid equivalent (GAE)/g dry matter (DM) of total polyphenol (TP), 28.15 mg rutin equivalent (RE)/g DM of total flavonoid (TF) and 7709.13 mmol ascorbic acid equivalent (AAE)/100 g DM of antioxidant capacity (AC) were found in OF. The bioaccessibility and content of the OF polyphenols and their AC during in vitro digestion varied depending on the digestion stage. The stability of the OF polyphenols was higher in gastric stage (41.92%) than intestinal one (34.01%). OF was used to replace flour in the cracker formulation at the levels of 5, 10 and 15% (w/w) and increased the TP contents and AC of the crackers compared to the sample without OF (control). The addition of OF to the cracker dough increased the bioaccessibility of the cracker polyphenols. After digestion, bioaccessibilities of enriched crackers (107.90-126.81%) were found higher than that of control sample (93.73%). However, as the level of OF in cracker increased, bioaccessibility of polyphenols decreased. The results generally indicated that oleaster has a good potential for the enrichment of foods.

Identification of Phenolics Profile in Freeze-Dried Apple Peel and Their Bioactivities during In Vitro Digestion and Colonic Fermentation

Freeze-dried apple peel powder (Fd-APP) was subjected to in vitro digestion and colonic fermentation to evaluate the variations in its phenolic composition, bioactivities (antioxidant activity, α-amylase, and α-glucosidase inhibition), and fecal metabolic outputs. A total of 88 phenolics were tentatively identified, of which 51 phenolic compounds were quantitated in Fd-APP sample extracts before digestion, and 34 were released during subsequent phases of digestion. Among these, phenolic acids showed the highest bio accessibility index (BI) of 68%, followed by flavonoids (63%) and anthocyanins (52%). The inhibitory functions of Fd-APP extract against α-amylase and α-glucosidase pre- and post-digestion were moderate and ranged from 41.88 to 44.08% and 35.23 to 41.13%, respectively. Additionally, the antioxidant activities revealed a significant (p ≤ 0.05) decline during the in vitro digestion. However, the colonic fermentation stage presented different products where the intact parent phenolic compounds present in Fd-APP were utilized by gut microbes and produced various phenolic metabolites such as 3- hydroxyphenyl acetic acid (3-HPAA), ferulic acid (FA), 3-(4-hydroxyphenyl) propionic acid (3,4 HPPA) and 4- hydroxybenzoic acid (4-HBA). Furthermore, colonic fermentation of Fd-APP accelerated the production of short-chain fatty acids (SCFAs), with acetic acid being the most prevalent (97.53 ± 9.09 mM). The decrease in pH of fermentation media to 4.3 significantly (p ≤ 0.05) enhanced counts of Bifidobacterium (10.27 log CFU/mL), which demonstrated the potential prebiotic effects of Fd-APP. These findings indicated that the consumption of apple peel as a constituent of novel functional foods may support and protect the intestinal microbiota and consequently promote human health.

Bioavailability of Phenolic Compounds in Californian-Style Table Olives with Tunisian Aqueous Olive Leaf Extracts

Recent advances in biotechnology have ensured that one of the main olive tree by-products is olive leaf extract (OLE), a rich source in bioactive compounds. The aim of this work was to study the phenolic composition in different OLEs of three Tunisian varieties, namely, 'Sayali', 'Tkobri', and 'Neb Jmel'. The in vitro biodigestibility effect after 'Sayali' OLE addition to Californian-style 'Hojiblanca' table olives was also studied. This OLE contained bioactive molecules such as hydroxytyrosol, tyrosol, oleropeine, Procianidine B1 (PB1), and p-cumaric acid. These compounds were also found in fresh olives after OLE was added. Furthermore, from fresh extract to oral digestion, the detected amount of bioavailable phenol was higher; however, its content decreased according to each phase of gastric and intestinal digestion. In the final digestion phase, the number of phenols found was lower than that of fresh olives. In addition, the phenolic content of Californian-style 'Hojiblanca' table olives decreased during the in vitro digestion process. The antioxidant activity of this variety decreased by 64% and 88% after gastrointestinal digestion, being the highest antioxidant capacity found in both simulated gastric and intestinal fluid, respectively. The results show us that the 'Sayali' variety is rich in phenolic compounds that are bioavailable after digestion, which could be used at an industrial level due to the related health benefits.

In Vitro Bioaccessibility and Health Risk Assessment of Arsenic and Zinc Contaminated Soil Stabilized by Ferrous Sulfate: Effect of Different Dietary Components

Iron-based materials have good stability in reducing the mobility and toxicity of heavy metals, but the behavior and human health risks of heavy metals could be affected by dietary components. This study investigated the effect of typical diets (lettuce, cooked rice and apples) on the bioaccessibility and morphological changes of arsenic (As) and zinc (Zn) in contaminated site after stabilization by ferrous sulfate (FeSO4). The results showed that the bioaccessibility of As and Zn were increased in a co-digestion system of food. The augmented effect on As bioaccessibility mainly occurred in the gastric phase: apple > lettuce > cooked rice (p < 0.05), while the augmented effect on Zn bioaccessibility mainly occurred in the intestinal phase: lettuce > apple > cooked rice (p < 0.05). FeSO4 weakened the dissolution effect of dietary components on As bioaccessibility, and reduced As bioaccessibility in the gastric and intestinal phases by 34.0% and 37.9% (p < 0.05), respectively. Dietary components and Fe fractions influenced the speciation and distribution of As and Zn. FeSO4 reduced the hazard quotient (HQ) and carcinogenic risk (CR) values of the contaminated soil by 33.97% and 33.59%, respectively. This study provides a reference for a better understanding of more realistic strategies to modulate exposure risks of heavy metal-contaminated sites.

Bioavailability Assessment of Yarrow Phenolic Compounds Using an In Vitro Digestion/Caco-2 Cell Model: Anti-Inflammatory Activity of Basolateral Fraction

In this study, a combined in vitro digestion/Caco-2 model was performed with the aim to determine the phenolic compounds bioavailability of two yarrow extracts. HPLC-PAD characterisation indicated that the main components in both extracts were 3,5-dicaffeoylquinic acid (DCQA) and luteolin-7-O-glucoside. Analyses after the simulated digestion process revealed that phenolic composition was not affected during the oral phase, whereas gastric and intestinal phases represented critical steps for some individual phenolics, especially intestinal step. The transition from gastric medium to intestinal environment caused an important degradation of 3,5-DCQA (63-67% loss), whereas 3,4-DCQA and 4,5-DCQA increased significantly, suggesting an isomeric transformation within these caffeic acid derivatives. However, an approx. 90% of luteolin-7-O-glucoside was recovered after intestinal step. At the end of Caco-2 absorption experiments, casticin, diosmetin and centaureidin represented the most abundant compounds in the basolateral fraction. Moreover, this fraction presented anti-inflammatory activity since was able to inhibit the secretion of IL-1β and IL-6 pro-inflammatory cytokines. Thus, the presence in the basolateral fraction of flavonoid-aglycones from yarrow, could be related with the observed anti-inflammatory activity from yarrow extract.

Phenolic composition of grape pomace and its metabolism

Grape pomace is the most important residual after wine making, and it is considered to be a very abundant source for the extraction of a wide range of polyphenols. These polyphenols exhibit a variety of bioactivities, such as antioxidant, anti-inflammatory, and anti-cancer. They are also beneficial in alleviating metabolic syndrome and regulating intestinal flora, etc. These health effects are most likely contributed by polyphenol metabolite, which are formed by the grape pomace phenolics after a complex metabolic process in vivo. Therefore, understanding the phenolic composition of grape pomace and its metabolism is the basis for an in-depth study of the biological activity of grape pomace polyphenols. In this paper, we first summarize the composition of phenolics in grape pomace, then review the recent studies on the metabolism of grape pomace phenolics, including changes in phenolics in the gastrointestinal tract, their pharmacokinetics in the systemic circulation, the tissue distribution of phenolic metabolites, and the beneficial effects of metabolites on intestinal health, and finally summarize the effects of human health status and dietary fiber on the metabolism of grape polyphenols. It is expected to provide help for the in-depth research on the metabolism and biological activity of grape pomace polyphenol extracts, and to provide theoretical support for the development and utilization of grape pomace.

Influence of Green Tea Added to Cherry Wine on Phenolic Content, Antioxidant Activity and Alpha-Glucosidase Inhibition during an In Vitro Gastrointestinal Digestion

Cherries are a good source of bioactive compounds, with high antioxidant activity as well as nutritional and therapeutic importance. In this study, cherry wines enriched with green tea infusion (mild and concentrated) were produced, and their biological properties were evaluated. During winemaking, the main vinification parameters (alcohol, reducing sugars, acidity, total polyphenol content) as well biological activity (antioxidant activity, alpha-glucosidase inhibition potential) were determined. An in vitro digestion process was also performed to evaluate the impact of the gastrointestinal environment on the biological stability of the wines, and to analyze the interactions of wine-intestinal microflora. The addition of green tea to the cherry wine significantly increased the total polyphenol content (up to 2.73 g GAE/L) and antioxidant activity (up to 22.07 mM TE/L), compared with the control wine. However, after in vitro digestion, a reduction in total polyphenols (53–64%) and antioxidant activity (38–45%) were noted. Wines fortified with green tea expressed a stronger inhibition effect on intestinal microflora growth, of which E. coli were the most sensitive microorganisms. The tea-derived bioactive compounds significantly increased the potential of alpha-glucosidase inhibition. The proposed wines could be a good alternative type of wine, with an increased polyphenol content and the potential to control the insulin response supporting therapy for diabetes.

Simulated Gastric and Intestinal Fluid Electrolyte Solutions as an Environment for the Adsorption of Apple Polyphenols onto β-Glucan

Interactions with dietary fibers in the gastrointestinal tract might affect the potential bioactivities of phenolic compounds. In this study, the interactions between apple phenolic compounds and β-glucan (a dietary fiber) were studied by studying the adsorption process in simulated gastric and intestinal fluid electrolyte solutions. Phenolic compounds were extracted from apples, adsorbed onto β-glucan (2 h, 37 °C, in gastric or intestinal fluid electrolyte solutions), and determined using high performance liquid chromatography. Phenolic compounds (flavan-3-ols, flavonols, phenolic acids, and dihydrochalcone) were stable in the gastric fluid (pH 3). In the intestinal fluid (pH 7), flavan-3-ols were not found and chlorogenic acid isomerized. Polyphenols from the apple peel (up to 182 and 897 mg g⁻¹) and flesh (up to 28 and 7 mg g⁻¹) were adsorbed onto β-glucan in the gastric and intestinal fluids, respectively. The adsorption was affected by the initial concentration of the polyphenols and β-glucan and by the environment (either gastric or intestinal fluid electrolyte solution). By increasing the initial polyphenol amount, the quantity of adsorbed polyphenols increased. Increasing the amount of β-glucan decreased the amount adsorbed. The results can be helpful in explaining the fate of phenolic compounds in the gastrointestinal tract.

Bioaccessibility of Phenolic Acids and Flavonoids from Buckwheat Biscuits Prepared from Flours Fermented by Lactic Acid Bacteria

The literature reports that the consumption of common buckwheat (Fagopyrum esculentum Moench), exactly the polyphenols it contains, is associated with a wide spectrum of health benefits. Therefore, the determination of the bioaccessibility of phenolic acids and flavonoids from buckwheat biscuits formulated from liquid-state fermented flours (BB_F) by selected lactic acid bacteria (LAB) after gastrointestinal digestion was addressed in this study. Bioaccessibility could be defined as the fraction of a compound that is released from the food matrix in the gastrointestinal lumen and used for intestinal absorption. The bioaccessibility of eight phenolic acids (protocatechuic, vanillic, syringic ferulic, caffeic, sinapic, p-coumaric, and t-cinnamic) and six flavonoids (epicatechin, vitexin, orientin, apigenin, kaempferol, and luteolin) were provided for BB_F and BB_C (buckwheat biscuits prepared from fermented and unfermented flours, respectively). The bioaccessibility indexes (BI) indicated the high bioaccessibility of phenolic acids and improved bioaccessibility of flavonoids from BB_F. Moreover, the data provide evidence for the suitability of selected LAB strains to be used as natural sour agents for further bakery product development rich in phenolic acids and flavonoids with LAB-dependent bioaccessibility.

Incorporation of Blue Honeysuckle Juice into Fermented Goat Milk: Physicochemical, Sensory and Antioxidant Characteristics and In Vitro Gastrointestinal Digestion

The addition of fruit juice may improve the physicochemical and functional characteristics of dairy products. The study evaluated the effect of 1−6% (v/v) blue honeysuckle juice (BHJ) on the physicochemical, sensory and antioxidant characteristics of fermented goat milk (FGM) during 21 days of refrigerated storage and in vitro gastrointestinal digestion. The incorporation of BHJ significantly increased (p < 0.05) the water-holding capacity, viscosity, redness (a*) value, total phenolic content (TPC) and ferric ion-reducing antioxidant power during storage. Additionally, BHJ affected the microstructure and sensory score of the samples. FGM treated with 4% (v/v) BHJ exhibited the highest overall acceptability. The supplementation of BHJ diminished the goaty flavor and promoted in vitro protein digestion. Furthermore, the TPC was enhanced in addition to the antioxidant activity of FGM containing BHJ throughout the in vitro digestion. Therefore, FGM supplemented with BHJ serves as a novel and attractive goat dairy product.

Bioaccessibility and antioxidant capacity of phenolic compounds during shelf life of a new functional vegetable mix

Fresh-cut vegetables are minimally processed healthy products that have gained the preference of consumers in accordance to the current lifestyle. Fresh-cut industry is continuously evolving and pursuing new varieties of raw material to develop innovative vegetable products, which fulfil consumer expectations. The current study evaluated the phenolic compounds in an innovative vegetable mix (red cabbage, rocket, parsley and beet greens) as well as their antioxidant capacity and bioaccessibility during their shelf life under refrigerated storage. The initial total phenolic compound and flavonoids content in the salad mixture were 163.3 ± 5.77 mg GAE/100 g FW and 280.96 ± 25.14 mg QE/100 g FW, respectively. The initial antioxidant capacity in the salad mixture was 85.4 ± 7.9 mg TE/100 g FW for DPPH and 318.1 ± 26.5 mg TE/100 g FW for ABTS assays. After digestion, total phenolic compound and TEAC capacity at initial times showed percentage of recovery values close to the chemical extraction and suffered a decrease towards day 10 of storage. Flavonoids and DPPH capacity showed recovery percentages less than 50%, at all storage times. Regarding sensory quality, the shelf-life of the salad mixture was limited by the presence of unacceptable off-odors at day 7 but since at microbiological evaluation, the shelf-life of the product is no longer than 5 days.

The effect of in vitro gastrointestinal digestion on the phenolic profiles, bioactivities and bioaccessibility of Rhodiola

Changes in the phenolic profiles and antioxidant and antiproliferative activities of Rhodiola after simulated in vitro digestion were first assessed in this study. Furthermore, permeability and uptake assays as well as RT-qPCR and western blot analyses were performed in order to explore the bioaccessibility of the digesta and its underlying mechanism. The results reveal that in vitro gastrointestinal digestion significantly reduced the total phenolics and total flavonoids as well as the extracellular, cellular antioxidant and antiproliferative activities of Rhodiola, in which the colon digesta had the largest reduction. However, in vitro digestion augmented the cellular uptake rates of Rhodiola phenolics with higher permeability coefficients. The colon digesta (GA-Dig) exhibited the highest uptake of gallic acid (GA, the main compound) instead of GA in its pure form, indicating the synergistic effects of GA and other phenolics in Rhodiola. In-depth mechanistic studies suggest that the fabulous uptake rates and permeability coefficients of the colon digesta were triggered by the down-regulation of the expression levels of ABCF2 mRNA and protein. These findings indicate that simulated gastrointestinal digestion could promote the bioaccessibility and bioactivities of phenolics in Rhodiola.

Antioxidant activity, stability, in vitro digestion and cytotoxicity of two dietary polyphenols co-loaded by β-lactoglobulin

The combination of multiple dietary polyphenols may have synergistic beneficial effects. And the beneficial effects can be further improved by the encapsulation of proteins. The interactions of procyanidin B2 (PB2) and/or dihydromyricetin (DMY) with β-lactoglobulin (β-LG) were investigated using multi-spectroscopic techniques and molecular docking. The structural change of β-LG in the presence of PB2 and/or DMY was demonstrated by dynamic light scattering, Fourier transform infrared spectroscopy and circular dichroism spectroscopy. Response surface analysis was used to optimize the synergistic antioxidant activity between PB2 and DMY. Besides, the antioxidant activity, stability, in vitro digestion and cytotoxicity of PB2 and DMY in the binary and ternary systems were investigated. These studies will elucidate the interaction mechanism of PB2 and/or DMY with β-LG. The research results can provide theoretical support for the development of functional foods and beverages with synergistic activity, improved stability and bioaccessibility, thereby promoting human health and preventing diseases.

A combined analytical-chemometric approach for the in vitro determination of polyphenol bioaccessibility by simulated gastrointestinal digestion

In this study, an integrated characterisation through polyphenol and caffeine content and antioxidant activity was combined with chemometric analysis to assess the effects of simulated in vitro gastrointestinal digestion on the bioaccessibility of these bioactive compounds from nine different tea infusions. Tea infusions were characterised based on total flavonoids, total polyphenols and antioxidant activity, together with the determination of individual polyphenol content. Fourteen phenolic compounds, including phenolic acids, stilbenes and flavonoids, were selected based on their reported bioactivity and high accessibility, attributed to their low molecular weight. Both polyphenols and caffeine were initially monitored in raw tea infusions and through the different digestion stages (salivary, gastric and duodenal) by capillary high performance liquid chromatography coupled to diode array detection (cHPLC-DAD) and/or HPLC coupled to a triple quadrupole mass analyser (HPLC–MS/MS). Multivariate analysis of the studied bioactives, using principal component analysis and cluster analysis, revealed that the decaffeination process seems to increase the stability and concentration of the compounds evaluated during digestion. The greatest transformations occurred mainly in the gastric and duodenal stages, where low bioactivity indices (IVBA) were shown for resveratrol and caffeic acid (IVBA = 0%). In contrast, the polyphenols gallic acid, chlorogenic acid and quercetin gave rise to their availability in white, green and oolong infusion teas (IVBA > 90%). Furthermore, highly fermented black and pu-erh varieties could be designated as less bioaccessible environments in the duodenum with respect to the tested compounds.

Phenolics and Mineral Elements Composition in Underutilized Apple Varieties

(1) Background: The aim of this research is to study the importance of improving knowledge of old variety apples in terms of phytochemicals, antioxidant capacity and mineral elements. (2) Methods: Fifteen phenolic compounds (UHPLC-MS/MS techniques), eight mineral elements (Ca, K, Cu, Mn, Fe, Zn, Na and Mg), antioxidant capacity (DPPH%) and vitamin C content in four ancient apple varieties of Tuscany (‘Mora’, ‘Nesta’, ‘Panaia’ and ‘Ruggina’), with the ‘Golden Delicious’ cultivar as reference, were analyzed. (3) Results: Ancient cultivars exhibited a superior antioxidant capacity compared to commercial cultivars. ECTC and CGA were the polyphenols that mostly characterized the ancient apples. The contents of the elements of concern, Zn and Mn, were higher in the ancient cultivars ‘Panaia’ and ‘Ruggina’, while Na showed significant low concentration in ‘Nesta’, ‘Panaia’ and ‘Ruggina’ compared to ‘Golden Delicious’. The vitamin C content also indicated that ‘Mora’, ‘Panaia’ and ‘Ruggina’ old variety had an AsA content around 10 times higher than the ‘Golden Delicious’ apple. (4) Conclusions: Underutilized varieties could be an excellent source of bioactive phenolic phytochemicals, mineral nutrients and vitamins that may offer special nutraceutical benefits compared to other fruits.

Antioxidants Bioaccessibility and Lactobacillus salivarius (CECT 4063) Survival Following the In Vitro Digestion of Vacuum Impregnated Apple Slices: Effect of the Drying Technique, the Addition of Trehalose, and High-Pressure Homogenization

To benefit the health of consumers, bioactive compounds must reach an adequate concentration at the end of the digestive process. This involves both an effective release from the food matrix where they are contained and a high resistance to exposure to gastrointestinal conditions. Accordingly, this study evaluates the impact of trehalose addition (10% w/w) and homogenization (100 MPa), together with the structural changes induced in vacuum impregnated apple slices (VI) by air-drying (AD) and freeze-drying (FD), on Lactobacillus salivarius spp. salivarius (CECT 4063) survival and the bioaccessibility of antioxidants during in vitro digestion. Vacuum impregnated apple slices conferred maximum protection to the lactobacillus strain during its passage through the gastrointestinal tract, whereas drying with air reduced the final content of the living cells to values below 10 cfu/g. The bioaccessibility of antioxidants also reached the highest values in the VI samples, in which the release of both the total phenols and total flavonoids to the liquid phase increased with in vitro digestion. The addition of trehalose and homogenization at 100 MPa increased the total bioaccessibility of antioxidants in FD and AD apples and the total bioaccessibility of flavonoids in the VI samples. Homogenizing at 100 MPa also increased the survival of L. salivarius during in vitro digestion in FD samples.

Advances in static in vitro digestion models after the COST action Infogest consensus protocol

In vitro digestion models are essential to predictively evaluate the bioaccessibility and bioactivity of food molecules or natural products. Dynamic models better simulate the gastrointestinal conditions as they reproduce similar physiological environments. Despite this, static methods, also known as biochemical methods, represent a simple and useful approach for the study of different types of molecules, with a broad applicability in the nutritional, pharmaceutical, and toxicological fields. In addition, static models can be validated, avoiding the disadvantage of a difficult reproducibility of dynamic in vitro systems and inter-individual variations of in vivo experiments. A crucial point in the standardization of static models was the COST Action Infogest in 2014, which elaborated an international consensus static digestion method to harmonize experimental conditions and has general guidelines, thus allowing the comparison of studies and data. The aim of our review is to underline the impact of the Infogest consensus method and the development and evolution of in vitro static methods in the following years, with a focus on food applications.

Effects of combined application of high-pressure processing and active coatings on phenolic compounds and microbiological and physicochemical quality of apple cubes

BACKGROUND

In recent years the use of high-pressure processing (HPP) of fruit products has steadily increased due to its antimicrobial effectiveness and the retention of nutritional and quality attributes compared to conventional thermal technologies. Edible coatings are already being used to enhance the quality of minimally processed fruits. Thus, apple cubes (AC) and alginate-vanillin-coated apple cubes (AVAC) were subjected to HPP (400 MPa/5 min/35 °C). The microbiological and physicochemical parameters were evaluated and the bioactive compounds were monitored before and after HPP of apple cubes. Also, an in vitro gastrointestinal digestion (GID) was conducted.

RESULTS

HPP left L. monocytogenes counts below the detection limit (2 log UFC g^-1 ), regardless of the presence of coating. For E. coli, HPP + active coating showed a synergism affording the greatest reduction (>5 log) for AVAC-HPP. Firmness was maintained in AVAC-HPP samples, while AC-HPP samples suffered reductions of 35%. Colour attributes were also better retained in AVAC-HPP samples. In general, HPP led to a decrease in phenolic compounds. Regarding the effects of GID, vanillin-based active coating exerted a protective effect on some phenolics. Thus, p-coumaroylquinic acid concentration was maintained for AVAC and AVAC-HPP during GID. Epigallocatechin, the compound with the highest concentration in apple cubes, increased for AVAC (106%) and AVAC-HPP (57%). Also, phloridzin concentration increased for AVAC-HPP (17%). At the end of GID, procyanidin B1 and epigallocatechin were the main phenolic compounds for all samples, AVAC showing the highest concentration.

CONCLUSIONS

This work demonstrates that the combined application of HPP and active coatings on apple cubes could be used to obtain a safe and good-quality product. © 2021 Society of Chemical Industry.