Simulated Digestive Conditions Research Articles

Extraction optimization, antidiabetic and antiglycation potentials of aqueous glycerol extract from rice (Oryza sativa L.) bran

The purpose of this investigation was to explore aqueous glycerol as food grade solvent for rice bran polyphenolic antioxidants extraction and investigate the antidiabetic and antiglycation potential of the extract and its major polyphenols. Response surface methodology (Box-Behnken design) was implemented to optimize experimental conditions for rice bran polyphenols and antioxidants extraction. The optimum conditions provided a very satisfactory outcome in total polyphenols (549.6 ± 8.05 mg gallic acid equivalent per 100 g dry weight) and DPPH scavenging activity (57.83 ± 1.8%). The chromatographic separation of the extract showed higher concentrations of ferulic acid, ρ-coumaric acid and chlorogenic acid followed by caffeic acid, syringic acid and rutin. Moreover, the extract inhibited α-amylase, α-glucosidase, and lipase activity as 34.2 ± 3.2%, 29.9 ± 1.0%, and 12.4 ± 2.3%, respectively. Furthermore, fructose readily forms Advanced Glycation End Products (AGEs) fluorescence with basic amino acids in low concentration in simulated intestinal digestion conditions. The extract inhibited AGEs formation by 52.6% at 20 μL/mL. Our study indicated that the antidiabetic and antiglycation potential of rice bran extract was mainly driven by the extract polyphenols. Rice bran glycerol extract could be employed as a natural antidiabetic and antiglycation remedy, and as economically and eco-friendly source of potent bioactive compounds with satisfactory outcome.

English

Bioavailability of oxalate is highly influenced by the presence of metal cations in the gastrointestinal tract as a result of the different solubility of oxalate salts. Bioavailability is further influenced by pH effects on oxalate solubility at various stages of digestion, particularly at gastric pH at which insoluble oxalate has been found to solubilize. The aim of the present study was to assess the effect of gastrointestinal pH and different metal ions on the relative solubility of oxalate after treatment with relevant gastric and intestinal enzymes in simulated gastrointestinal digestion conditions. Whole bran cereals and beans were used as test samples. Oxalate solubility increased along with reproducible recovery such as 97±4 at gastric pH-2 compared to higher pH. High amount of soluble oxalate (32±1.2) was found in wheat bran after simulated in vitro digestion under gastric conditions as compared to intestinal conditions i.e. 11±0.5. The availability of calcium for absorption was found to be very low compared to that of magnesium and potassium i.e., 15±0.3, 13±0.5 to 10±0.42 and 4±1 in wheat bran sample at gastric and intestinal conditions simultaneously. The formation of a complex between calcium and oxalate reduced solubility and hence made calcium less available for absorption. Presence of metals and oxalate not only reduces oxalate availability, but it also reduces availability of metal cations.

In vitro Simulated Digestion and Microstructure of Peppermint Oil Nanoemulsion.

The variations in average particle size, zeta potential, free fatty acids (FFA) release rate, and the bioavailability of menthol under in vitro simulated digestion conditions of peppermint oil nanoemulsion were investigated. 3D confocal laser scanning microscopy and Cryo-scanning electron microscopy were used to observe the microstructure characteristics of peppermint oil nanoemulsion, which indicated that soybean protein was completely adsorbed at the oil-water interface of the nanoemulsion and presented a core shell structure. And the results indicated that FFA release rate and menthol bioavailability of peppermint oil nanoemulsion prepared by using high-pressure homogenization were much higher. In the simulated gastric digestion phase, the average particle size and the zeta potential of the nanoemulsion increased, and droplet polymerization appeared. After the simulated intestinal, the interfacial protein of nanoemulsion was hydrolyzed, and the oil droplets were digested, which resulted in the decreased particle size and increased absolute value of zeta potential.

Two Novel Multi-Functional Peptides from Meat and Visceral Mass of Marine Snail Neptunea arthritica cumingii and Their Activities In Vitro and In Vivo.

Neptunea arthritica cumingii (Nac) is a marine snail with high nutritional and commercial value; however, little is known about its active peptides. In this study, two multi-functional peptides, YSQLENEFDR (Tyr-Ser-Gln-Leu-Glu-Asn-Glu-Phe-Asp-Arg) and YIAEDAER (Tyr-Ile-Ala-Glu-Asp-Ala-Glu-Arg), were isolated and purified from meat and visceral mass extracts of Nac using a multi-bioassay-guided method and were characterized by using liquid chromatography-tandem mass spectrometry. Both peptides showed high antioxidant, angiotensin-converting enzyme (ACE)-inhibitory, and anti-diabetic activities, with half-maximal effective concentrations values less than 1 mM. Antioxidant and ACE-inhibitory activities were significantly higher for YSQLENEFDR than for YIAEDAER. In a zebrafish model, the two peptides exhibited strong scavenging ability for reactive oxygen species and effectively protected skin cells against oxidative damage without toxicity. Molecular docking simulation further predicted the interactions of the two peptides and ACE. Stability analysis study indicated that the two synthetic peptides maintained their activities under thermal stress and simulated gastrointestinal digestion conditions. The low molecular weight, high proportion of hydrophobic and negatively-charged amino acids, and specific C-terminal and N-terminal amino acids may contribute to the observed bio-activities of these two peptides with potential application for the prevention of chronic noncommunicable diseases.

Simulated digestion and fermentation in vitro with human gut microbiota of polysaccharides from Coralline pilulifera

Crude polysaccharides from Coralline pilulifera (CPPS) were purified by DEAE Sepharose Fast Flow to afford four purified fractions of CPPS-1, CPPS-2, CPPS-3 and CPPS-4. The physicochemical property and digestion under simulated saliva, gastric, small intestinal conditions and fermentation of CPPS-3 were investigated in vitro. CPPS-3 was composed of glucose and galactose, its molecular weight was 716 kDa, the contents of carbohydrate, protein, uronic acid and sulfuric radical were 67.84%, 1.00%, 0.38% and 9.07%, respectively. There was no significant difference on the molecular weight and content of reducing sugars, and no monosaccharides were released after saliva, gastric and small intestine digestion, indicating that CPPS-3 could not be digested under the simulated digestion conditions. After fermentation for 24 h in vitro, the carbohydrate content was decreased to 30.76%, suggesting that CPPS-3 could be broken down and utilized by gut microbiota. Some health-promoting gut microbiota such as Bacteroides, Megamonas and Veillonella were significantly enhanced, suggesting that CPPS-3 could regulate the composition of gut microbiota. What's more, CPPS-3 could promote the productions of short-chain fatty acids (22.17 and 16.17 mmol/L at 24 h for CPPS-3 and control, respectively), which could contribute to host health. Therefore, CPPS-3 is expected to be developed as functional foods.

Immense Insulin Intestinal Uptake and Lymphatic Transport Using Bile Acid Conjugated Partially Uncapped Liposome.

We provide immense insulin absorption from the gastrointestinal tract, combining apical sodium-dependent bile acid transporter-mediated intestinal uptake and the lymphatic transport pathway. This strategy has proven to employ chondroitin sulfate- g-taurocholic acid coated, insulin-loaded partially uncapped liposome (IPUL-CST) for type 1 diabetes mellitus (T1DM) treatment. The loading efficiency of insulin in IPUL-CST increased significantly from 33% to 75% via the partially uncapped liposome preparation method. Moreover, the IPUL-CST revealed an improved insulin protection efficacy in GIT simulated pH and digestive enzyme conditions. The high dose of IPUL-CST in the small intestine was detected 4 h post-oral administration using ex vivo optical imaging and fluorescence intensity. The IPUL-CST exhibited significantly enhanced intestinal absorption (oral bioavailability, 34%; Tmax, 9 h) and reduced blood glucose levels for 16 h in T1DM. The results demonstrated that the new investigated IPUL-CST is a promising carrier for oral insulin delivery.

In vitro digestion for assessing micronutrient bioavailability: the importance of digestion duration

Static digestion in vitro is a commonly used technique for investigating micronutrient availability which allows the nutrients or foods of interest to be exposed to conditions that simulate those found within the stomach and small intestine. The activity of these digestive enzymes throughout their respective simulated digestion phases has been reported to decline due to the autolytic activity of the proteases and therefore incomplete digestion may result. The degree of protease inactivation under commonly simulated digestion conditions requires further quantification. Pepsin and pancreatic protease activities were assessed throughout a simulated digestion protocol in vitro over multiple time points using stop-rate spectroscopy. The protease activity of both pepsin and pancreatin decreased significantly during their respective digestion phases. Results suggest that gastric and intestinal proteases are destroyed or inactivated during their respective digestive phase. For this reason, prolonged digestion protocols may require protease supplementation throughout digestion to correctly simulate physiological conditions.

Anti-infectious properties of the probiotic Saccharomyces cerevisiae CNCM I-3856 on enterotoxigenic E. coli (ETEC) strain H10407.

Enterotoxigenic Escherichia coli (ETEC) are major food-borne pathogens responsible for traveler's diarrhea. The production of adhesins and the secretion of enterotoxins constitute the major virulence traits of the bacteria. Treatments are mainly symptomatic and can involve antibiotherapy. However, given the rise of antibiotic resistance worldwide, there is an urgent need for the development of new preventive strategies for the control of ETEC infections. Among them, a promising approach is the use of probiotics. The aim of this study was to investigate, using complementary in vitro and in vivo approaches, the inhibitory potential of the yeast Saccharomyces cerevisiae CNCM I-3856 against the human ETEC reference strain H10407. In conventional culture media, S. cerevisiae significantly reduced ETEC growth and toxin production. The yeast also inhibited bacterial adhesion to mucin-agar and intestinal Caco-2/TC7 cells in a dose-dependent manner. Lastly, pre-treatment with S. cerevisiae inhibited interleukin-8 production by ETEC-infected intestinal cells. In streptomycin-treated mice, the probiotic yeast decreased bacterial colonization, mainly in the ileum, the main site of ETEC pathogenesis. For the first time, this study shows that the probiotic yeast S. cerevisiae CNCM I-3856 can exert an anti-infectious activity against a human ETEC strain through a multi-targeted approach, including inhibition of bacterial growth and toxin production, reduction of bacterial adhesion to mucins and intestinal epithelial cells, and suppression of ETEC-induced inflammation. Interestingly, the highest activity was obtained with a prophylactic treatment. Further studies will aim to assess the effect of the yeast on ETEC survival and virulence under human simulated digestive conditions.

Improving in vivo conversion of oleuropein into hydroxytyrosol by oral granules containing probiotic Lactobacillus plantarum 299v and an Olea europaea standardized extract

This study reports novel food-grade granules for co-delivery of L. plantarum 299v and a standardized extract of Olea europaea leaves (Phenolea®) as oral carrier of probiotics and hydroxytyrosol. Different granule formulations containing either L. plantarum 299v (Lac), or the olive leave extract (Phe) or their combination (Lac-Phe) have been successfully produced through wet granulation employing excipients generally regarded as safe as granulating/binding agents. L. plantarum cells withstood the manufacturing process and were stable upon storage at 4 °C for more than 6 months. In vitro dissolution studies in simulated gastro-intestinal fluids showed the capability of the granules to rapidly dissolve and deliver both olive leave phenols and living L. plantarum cells. In simulated digestion conditions, Lac and Lac-Phe granules protected L. plantarum against the harsh environment of the gastro–intestinal tract. Co-administration of Lac and Phe oral granules to healthy mice provided for higher amounts of hydroxytyrosol in urines as compared to Phe granules alone, suggesting that L. plantarum 299v boosted in vivo conversion of oleuropein to hydroxytyrosol. On the other hand, PCR-assisted profiling of the Lactobacillus population in faeces obtained from mice treated with Lac or Lac plus Phe confirmed that the probiotic arrived alive to colon and was there able to exert a sort of perturbing effect on the climax colonic microflora. Overall, these results pave the way towards the development of a nutraceutical useful for combined delivery of bioactive hydroxytyrosol and probiotics to colon site.

Stability of Anthocyanins and Their Degradation Products from Cabernet Sauvignon Red Wine under Gastrointestinal pH and Temperature Conditions.

This study investigated the stability of wine anthocyanins under simulated gastrointestinal pH and temperature conditions, and further studied the evolution of anthocyanin degradation products through simulated digestive conditions. The aim of this study was to investigate the relation between anthocyanins’ structure and their digestive stability. Results showed that a total of 22 anthocyanins were identified in wine and most of these anthocyanins remained stable under simulated gastric digestion process. However, a dramatic concentration decrease happened to these anthocyanins during simulated intestinal digestion. The stability of anthocyanins in digestive process appeared to be related to their structure. The methoxy group in the B-ring enhanced the stability of anthocyanins, whereas hydroxyl group resulted in a reduction of their stability. Acylation decreased the stability of malvidin 3-O-glucoside. Pyruvic acid conjugation enhanced the structural stability of pyranoanthocyanins, whereas acetaldehyde attachment weakened their stability. A commercial malvidin 3-O-glucoside standard was used to investigate anthocyanin degradation products under simulated digestion process, and syringic acid, protocatechuic acid and vanillic acid were confirmed to be the degradation products via anthocyanin chalcone conversion path. Gallic acid, protocatechuic acid, vanillic acid, syringic acid, and p-coumaric acid in wine experienced a significant concentration decrease during digestion process. However, wine model solution revealed that phenolic acids remained stable under gastrointestinal conditions, except gallic acid.

Digestibility of fucosylated glycosaminoglycan from sea cucumber and its effects on digestive enzymes under simulated salivary and gastrointestinal conditions

The digestibility of fucosylated glycosaminoglycan (FG) and its effects on digestive enzymes were investigated using an in vitro digestion model. Results showed that the molecular weight and the reducing sugar content of FG were not significantly changed, and no free monosaccharides released from FG were detected after the salivary, gastric and intestinal digestion, indicating that both the backbone and the sulfated fucose branches of FG are resistant to be cleaved in the saliva and gastrointestinal tract environments. Furthermore, FG can dose-dependently inhibit digestive enzymes such as α-amylase, pepsin and pancreatic lipase in different degrees under the simulated digestion conditions due to the sulfate and carboxyl groups. These physiological effects of FG may help control the postprandial glucose concentration and have the potential in the prevention or treatment of reflux disease and obesity. The findings may provide information on the digestibility and beneficial physiological effects of FG as a potential natural product to promote human health.

In vitro digestion by saliva, simulated gastric and small intestinal juices and fermentation by human fecal microbiota of sulfated polysaccharides from Gracilaria rubra

In the present study, the changes of polysaccharides from Gracilaria rubra (GRPS) under simulated oral, gastric and small intestine digestion conditions were firstly investigated. The results indicated that GRPS was not digested under such conditions. Then, the prebiotic property of GRPS was investigated via in vitro fermentation by human gut microbiota in mixed cultures. The results showed that GRPS was gradually degraded and utilized by gut microbiota. With the proceeding of fermentation, pH kept a downward trend and the concentration of short-chain fatty acids increased, especially acetic, propionic and isobutyric acids. Furthermore, GRPS exhibited a modulatory effect on microbial structure by lowering the ratio of Firmicutes/Bacteroidetes and increasing the relative abundances of bacteria that could degrade GRPS to satisfy the growth of gut microbiota. The results suggested that GRPS had the potential to be developed as prebiotics.

Pectin-iron capsules: Novel system to stabilise and deliver lactic acid bacteria

The delivery of probiotics has been a challenge because microorganisms must overcome harmful environments both at a technological and at a physiological level. Encapsulation is one of the strategies to protect microorganisms against both problems. This work aimed at encapsulating probiotic Lactobacillus plantarum CIDCA 83114 in pectin-iron beads obtained by ionotropic gelation, enabling bacteria safe delivery and providing a source of iron and fibre.Microorganisms in the stationary phase were suspended in a 4% w/v pectin solution at pH 5, and the suspension, dripped into a 150 mM FeSO4 solution. The beads were freeze-dried and stored for 60 days at 4 °C. The morphology of the beads was observed by scanning electron microscopy. Bacterial culturability was determined after freeze-drying, and after the exposure to simulated saliva, gastric and intestinal conditions. The iron and pectin releases were also investigated in the same digestive conditions.Microorganisms were fully entrapped in smooth and spherical pectin-iron beads of ca. 1–2 mm diameter. Bacterial culturability did not decrease during storage. Encapsulation protected microorganisms against simulated digestive conditions, also enabling the complete release of iron and pectins in the gut.The results obtained support the safe delivery of both probiotic bacteria and iron to the gut. As iron deficiency still continuous to be a worldwide problem, using iron-pectin beads could be an adequate strategy to functionalise food products, contributing to attain the recommended iron intake.

Fermented pomegranate wastes as sustainable source of ellagic acid: Antioxidant properties, anti-inflammatory action, and controlled release under simulated digestion conditions

Wastes deriving from production of wines by yeast fermentation of Punica granatum (fermented pomegranate wastes, FPW) showed a marked antioxidant activity in a series of conventional chemical tests. HPLC/MS analysis of the methanol extract showed the presence of ellagic acid (EA) as the main phenolic component at levels up to 40% on a w/w basis. Experiments using murine macrophages showed that FPW extract is able to reduce the LPS-induced expression of pro-inflammatory genes IL-1β, TNF-α and iNOS. A remarkable increase in the antioxidant properties and extractable EA content was observed following acid hydrolytic treatment of FPW. Under simulated gastrointestinal conditions, EA was slowly released from FPW up to 80% of the overall content over 2 h incubation at the slightly alkaline pHs simulating the small intestine environment, suggesting a potential of the material in nutraceuticals and other applications.

Correlation of lithium bioaccessibility from tea (Camellia sinensis L.) with tea type and consumption habits

In this study, the total contents, leachability into tea infusions, and bioaccessibility of lithium from black, Earl Grey, and green teas were evaluated by inductively coupled plasma mass spectrometry. Leachabilities were evaluated after infusion for 2, 5, or 10min. Bioaccessibility was determined in vitro under simulated stomach and intestinal digestion conditions. Addition of lemon juice, sugar, or milk for consumption, and calcium, tannic acid, and citric acid as additives were evaluated to determine if they affected bioaccessibility of lithium from black tea. The bioaccessible lithium contributed to 0.01%, 0.02%, and 0.03% of the recommended dietary allowances of lithium for black, Earl Grey, and green tea samples, respectively. These contributions may increase up to 4.4 times or decrease up to seven times with certain additives.

Digestibility of Quinoa (Chenopodium quinoa Willd.) Protein Concentrate and Its Potential to Inhibit Lipid Peroxidation in the Zebrafish Larvae Model.

Quinoa protein concentrate (QPC) was extracted and digested under in vitro gastrointestinal conditions. The protein content of QPC was in the range between 52.40 and 65.01% depending on the assay used. Quinoa proteins were almost completely hydrolyzed by pepsin at pH of 1.2, 2.0, and 3.2. At high pH, only partial hydrolysis was observed. During the duodenal phase, no intact proteins were visible, indicating their susceptibility to the in vitro simulated digestive conditions. Zebrafish larvae model was used to evaluate the in vivo ability of gastrointestinal digests to inhibit lipid peroxidation. Gastric digestion at pH1.2 showed the highest lipid peroxidation inhibition percentage (75.15%). The lipid peroxidation activity increased after the duodenal phase. The digest obtained at the end of the digestive process showed an inhibition percentage of 82.10%, comparable to that showed when using BHT as positive control (87.13%).

In vitro digestion of rice bran proteins produces peptides with potent inhibitory effects on α-glucosidase and angiotensin I converting enzyme.

The bioactivities of peptides released from the digestion of rice bran protein under in vitro simulated human digestive conditions were investigated. Four protein fractions extracted from rice bran were digested and the hydrolysates were fractionated by ultrafiltration and anion exchange chromatography. α-Glucosidase and angiotensin converting enzyme (ACE) inhibitory activities of the crude hydrolysates and their fractions were determined. Peptides with molecular weight (MW) < 3 kDa gave markedly higher α-glucosidase inhibitory activities than the crude digests, while the ACE inhibitory activities of the MW < 3 kDa fractions were similar to those of the crude extracts. Peptides from albumin and glutelin exhibited the greatest inhibitory effects on α-glucosidase and ACE at 52.43 ± 2 mg acarbose equivalent and 170.13 ± 2.2 nmol captopril equivalent g-1 peptide respectively. Liquid chromatography/tandem mass spectrometry (LC/MS/MS) analysis identified 39 peptides in the most active fraction of the hydrolysates, and 37 of these contained peptide sequences that are known to exhibit antidiabetic or antihypertensive activities. Consumption of rice bran proteins can potentially lead to generation of bioactive peptides in the digestive tract with substantial health benefits. ACE and α-glucosidase inhibitory activities of the digests of rice bran proteins, and albumin and glutelin in particular, were especially strong, comparable to that of the standard drugs. © 2017 Society of Chemical Industry.

Probiotic potential of indigenous yeasts isolated during the fermentation of table olives from Northeast of Portugal

Abstract The aim of this study was to evaluate the probiotic potential of 16 yeast strains previously isolated during the natural fermentation of table olives Negrinha de Freixo cultivar, in relation to enzymatic activities; ability to grow at 37 °C; antimicrobial activity; autoaggregation capacity; antioxidant activity and survival in gastrointestinal tract conditions. The highest antioxidant activity was observed for Saccharomyces cerevisiae, similar to the reference strain S. boulardii. Candida norvegica 7A and Galactomyces reessii 34A showed antifungal ability to the pathogenic microorganism Cryptococcus neoformans. Regarding the autoaggregation capacity, S. cerevisiae 15A, C. tropicalis 1A and C. norvegica 7A showed > 80% after 24 h. Pichia guilliermondii 25A and C. norvegica 7A were the most resistant to the simulated digestive conditions, similar to the reference strain (S. boulardii). Thus, these results suggest that some yeast strains involved in the fermentation of table olives have probiotic potential. Industrial relevance In this study, we highlight the probiotic potential of yeast microbiota usually found in green table olives. These yeast strains could be used as culture starters for the development of new functional products.

Influence of mandarin fiber addition on physico-chemical properties of nanoemulsions containing β-carotene under simulated gastrointestinal digestion conditions

There is a lack of knowledge about how soluble fiber used as stabilizer may influence physicochemical properties of nanoemulsions during the lipid digestion process. In this study, different concentrations of mandarin fiber (0.5, 1.0, 1.5, 2.0 g/100 g) were added to nanoemulsions containing oil enriched with β-carotene (4 g/100 g emulsion) and tween 20 (1.5 g/100 g emulsion). As nanoemulsions were subjected to the different phases of an in vitro simulated gastrointestinal tract (GIT), its particle size was gradually increased. Furthermore, the higher the mandarin fiber content in the nanoemulsion, the greater the particle size. Nanoemulsions containing concentrations of mandarin fiber over 1.5 g/100 g showed the lowest ζ-potential, meaning that the droplets may become unstable and were likely to aggregate. Besides, adding until 1 g of mandarin fiber/100 g was effective to enhance bioaccessibility of the β-carotene incorporated in nanoemulsions. The present study provides valuable information on the phenomenology of incorporating mandarin fiber within β-carotene enriched nanoemulsions.

Evaluation of in Vitro Reducing Effect of Several Vegetable Extracts on the Digestive Bioavailability of Heavy Metals

The study aimed at assessing the in vitro digestive bioavailability of heavy metals in the presence of plant extracts under simulated digestive system conditions. The complexing ability of aqueous herbal extracts of Crataegus sp., Tilia spp., Rosa canina, Vaccinium myrtillus, Geranium robertianum, Mentha piperita, Cynara cardunculus subsp. Scolymus, Plantago sp., and Coriandrum sativum was researched on Cu+2, Cd+2, Ni+2, Pb+2 and Hg+2 cations. The quantitative determination of the fraction of free metal left, available for absorption, was achieved by atomic absorption spectroscopy (AAS) or potentiometry using an ion-selective electrode (ISE).