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ACS Applied Materials & Interfaces Jun 2024Monitoring the gastric digestive function is important for the diagnosis of gastric disorders and drug development. However, there is no report on the in situ and...
Monitoring the gastric digestive function is important for the diagnosis of gastric disorders and drug development. However, there is no report on the in situ and real-time monitoring of digestive functions. Herein, we report a flexible fully organic sensor to effectively monitor protein digestion in situ in a simulated gastric environment for the first time. The sensors are made of a blend of gluten that is a protein and poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) that is a conducting polymer. During the protein digestion, the breakdown of the polypeptides increases the level of separation among the PEDOT chains, thereby increasing the resistance. The resistance variation is sensitive to various conditions, including the concentration of pepsin that is the enzyme for protein digestion, temperature, pH value, and digestive drugs. Hence, these sensors can provide real-time information about the digestion and efficacy of digestive drugs. In addition, the signals can be collected via a convenient wireless communication manner.
Topics: Humans; Polystyrenes; Digestion; Polymers; Pepsin A; Hydrogen-Ion Concentration; Temperature; Thiophenes
PubMed: 38865685
DOI: 10.1021/acsami.4c02373 -
Food Research International (Ottawa,... Jul 2024Oral delivery of larger bioactive peptides (>20 amino acids) to the small intestine remains a challenge due to their sensitivity to proteolytic degradation and chemical...
Oral delivery of larger bioactive peptides (>20 amino acids) to the small intestine remains a challenge due to their sensitivity to proteolytic degradation and chemical denaturation during gastrointestinal transit. In this study, we investigated the capacity of crosslinked alginate microcapsules (CLAMs) formed by spray drying to protect Plantaricin EF (PlnEF) (C-EF) in gastric conditions and to dissolve and release PlnEF in the small intestine. PlnEF is an unmodified, two-peptide (PlnE: 33 amino acids; PlnF: 34 amino acids) bacteriocin produced by Lactiplantibacillus plantarum with antimicrobial and gut barrier protective properties. After 2 h incubation in simulated gastric fluid (SGF) (pH 1.5), 43.39 % ± 8.27 % intact PlnEF was liberated from the CLAMs encapsulates, as determined by an antimicrobial activity assay. Transfer of the undissolved fraction to simulated intestinal fluid (SIF) (pH 7) for another 2 h incubation resulted in an additional release of 16.13 % ± 4.33 %. No active PlnEF was found during SGF or sequential SIF incubations when pepsin (2,000 U/ml) was added to the SGF. To test PlnEF release in C-EF contained in a food matrix, C-EF was mixed in peanut butter (PB) (0.15 g C-EF in 1.5 g PB). A total of 12.52 % ± 9.09 % active PlnEF was detected after incubation of PB + C-EF in SGF without pepsin, whereas no activity was found when pepsin was included. Transfer of the remaining PB + C-EF fractions to SIF yielded the recovery of 46.67 % ± 13.09 % and 39.42 % ± 11.53 % active PlnEF in the SIF following exposure to SGF and to SGF with pepsin, respectively. Upon accounting for the undissolved fraction after SIF incubation, PlnEF was fully protected in the CLAMs-PB mixture and there was not a significant reduction in active PlnEF when pepsin was present. These results show that CLAMs alone do not guard PlnEF bacteriocin peptides from gastric conditions, however, mixing them in PB protected against proteolysis and improved intestinal release.
Topics: Alginates; Bacteriocins; Capsules; Peptides; Intestine, Small; Lactobacillus plantarum; Hydrogen-Ion Concentration; Cross-Linking Reagents; Pepsin A
PubMed: 38823837
DOI: 10.1016/j.foodres.2024.114473 -
World Journal of Gastroenterology May 2024Heartburn is a common symptom shared by both gastroesophageal reflux disease (GERD) and functional heartburn (FHB), which can make it challenging to differentiate...
Heartburn is a common symptom shared by both gastroesophageal reflux disease (GERD) and functional heartburn (FHB), which can make it challenging to differentiate between the two conditions. However, examining oral manifestations of GERD can be a cost-effective and readily available method to aid in this differentiation process. It may serve as a valuable tool in distinguishing GERD from FHB.
Topics: Humans; Gastroesophageal Reflux; Saliva; Heartburn; Pepsin A; Diagnosis, Differential; Biomarkers
PubMed: 38817654
DOI: 10.3748/wjg.v30.i19.2612 -
Spectrochimica Acta. Part A, Molecular... Oct 2024The effects of common migration substances in milk packaging on digestive protease were studied. We choose the common migrants found in eight types of multi-layer...
The effects of common migration substances in milk packaging on digestive protease were studied. We choose the common migrants found in eight types of multi-layer composite milk packaging. Enzyme activity experiments revealed that pepsin activity decreased by approximately 18 % at 500 μg/mL of stearic acid and stearamide treatment, while trypsin activity decreased by approximately 18 % only by stearic acid treatment (500 μg/mL). Subsequently, fluorescence spectroscopy, circular dichroism spectroscopy, and molecular docking technology were employed to investigate the inhibition mechanism of protease activity by migrating substances in three systems: stearic acid-trypsin, stearic acid-pepsin, and stearamide-pepsin. Results showed that the inhibitory effect of stearic acid on trypsin is a reversible mixed inhibition, whereas the inhibitory effects of stearic acid and stearamide on pepsin are non-competitive. In all three systems, ΔH < 0, ΔS < 0, and ΔG < 0, indicating the binding process between the migrant and the protease is a spontaneous exothermic process primarily driven by hydrogen bonding and van der Waals forces. In addition, their binding constants are all around 10 L/moL, indicating that there are moderate binding affinities exist between migrants and proteases. The binding process results in the quenching of the protease's endogenous fluorescence and induces alterations in the enzyme's secondary structure. Synchronized fluorescence spectroscopy showed that stearic acid enhanced the hydrophobicity near the Tyr residue of trypsin. The molecular docking results indicated that the binding affinity of stearic acid-trypsin, stearic acid-pepsin, and stearamide-pepsin was -22.51 kJ/mol, -12.35 kJ/mol, -19.28 kJ/mol respectively, which consistent with the trend in the enzyme activity results. This study can provide references for the selection of milk packaging materials and the use of processing additives, ensuring food health and safety.
Topics: Molecular Docking Simulation; Animals; Milk; Spectrometry, Fluorescence; Trypsin; Food Packaging; Stearic Acids; Pepsin A; Circular Dichroism; Peptide Hydrolases; Thermodynamics
PubMed: 38801790
DOI: 10.1016/j.saa.2024.124517 -
International Journal of Biological... Jun 2024Ovomucin-Complex extracted from egg white is expected to have a barrier function similar to gastric mucin. In this study, the dynamic changes in structure, rheological...
Ovomucin-Complex extracted from egg white is expected to have a barrier function similar to gastric mucin. In this study, the dynamic changes in structure, rheological properties and binding ability of Ovomucin-Complex during in vitro simulated gastric digestion were investigated. The results from HPLC and CLSM showed that extremely acidic pH (pH = 2.0) promoted Ovomucin-Complex to form aggregation. Acid-induced aggregation may hinder its binding to pepsin, thus rendering Ovomucin-Complex resistant to pepsin. Consequently, most of the polymer structure and weak gel properties of Ovomucin-Complex retained after simulated gastric digestion as verified by HPLC, CLSM and rheological measurement, although there was a small breakdown of the glycosidic bond as confirmed by the increased content of reducing sugar. The significantly reduced hydrophobic interactions of Ovomucin-Complex were observed under extremely acidic conditions and simulated gastric digestion compared with the native. Noticeably, the undigested Ovomucin-Complex after simulated gastric digestion showed a higher affinity (K = 5.0 ± 3.2 nm) for urease - the key surface antigen of Helicobacter pylori. The interaction mechanism between Ovomucin-Complex and urease during gastric digestion deserves further studies. This finding provides a new insight to develop an artificial physical mucus barrier to reduce Helicobacter pylori infection.
Topics: Urease; Ovomucin; Hydrogen-Ion Concentration; Digestion; Protein Binding; Pepsin A; Polymerization; Helicobacter pylori; Rheology; Humans
PubMed: 38735615
DOI: 10.1016/j.ijbiomac.2024.132295 -
Food Research International (Ottawa,... Jun 2024In this article, the synthesis of antioxidant peptides in the enzymatic hydrolysis of caprine casein was analyzed at three different time points (60 min, 90 min, and...
In this article, the synthesis of antioxidant peptides in the enzymatic hydrolysis of caprine casein was analyzed at three different time points (60 min, 90 min, and 120 min) using immobilized pepsin on activated and modified carbon (AC, ACF, ACG 50, ACG 100). The immobilization assays revealed a reduction in the biocatalysts' activity compared to the free enzyme. Among the modified ones, ACG 50 exhibited greater activity and better efficiency for reuse cycles, with superior values after 60 min and 90 min. Peptide synthesis was observed under all studied conditions. Analyses (DPPH, β-carotene/linoleic acid, FRAP) confirmed the antioxidant potential of the peptides generated by the immobilized enzyme. However, the immobilized enzyme in ACG 50 and ACG 100, combined with longer hydrolysis times, allowed the formation of peptides with an antioxidant capacity greater than or equivalent to those generated by the free enzyme, despite reduced enzymatic activity.
Topics: Antioxidants; Enzymes, Immobilized; Goats; Caseins; Animals; Pepsin A; Glutaral; Peptides; Iridoids; Hydrolysis; Charcoal
PubMed: 38729685
DOI: 10.1016/j.foodres.2024.114161 -
Journal of Medicinal Food May 2024The principal mechanisms surrounding gastrointestinal (GI) side effects due to chemotherapy are unclear, whereas the information regarding symptom management of patients...
The principal mechanisms surrounding gastrointestinal (GI) side effects due to chemotherapy are unclear, whereas the information regarding symptom management of patients with esophageal cancer post-esophagectomy is lacking. Esophagectomy patients are left with significant anatomical changes to the GI tract, including the cutting of the vagus nerve, which regulates gastric secretions, gastric acid pH, and motility. A 76-year-old male patient self-referred himself to the clinical dietitian for nutritional management of chronic nausea, fatigue, weight loss, and dumping syndrome 9 months post-esophagectomy, which was not responsive to medications. A physical functional nutritional assessment with evaluation of diet history and elimination suggested gastric hypochlorhydria. Gastric acid is needed for the active absorption of iron, zinc, B complex vitamins, especially B12, and digestion of consumed proteins. A digestive supplement, betaine hydrochloric acid with pepsin (BHClP), was introduced, and the patient ingested 1 capsule containing 500 mg betaine hydrochloride and 23.5 mg pepsin prior to protein-containing meals and reported a substantial decrease in GI symptoms while eating a regular diet with no limitations. He gained necessary weight and energy for daily activities. After a few months, the patient discontinued BHClP, and GI symptoms and dumping syndrome returned, leading to a loss of 7.5% of his body weight. The patient reinitiated the supplement and GI symptoms dissipated, and weight was restored. BHClP provided metabolic therapeutic benefit to optimize the patient's oral intake, preventing further complications and malnutrition. The success with BHClP for this patient case suggests that more research is needed to fully realize the mechanisms and clinical usage.
Topics: Humans; Male; Aged; Esophageal Neoplasms; Betaine; Pepsin A; Dumping Syndrome; Dietary Supplements; Esophagectomy
PubMed: 38695854
DOI: 10.1089/jmf.2023.0174 -
International Journal of Biological... May 2024In the current study, how pectin retards the digestibility of wheat gluten was investigated using a static in vitro gastric-duodenal model. The degree of protein...
In the current study, how pectin retards the digestibility of wheat gluten was investigated using a static in vitro gastric-duodenal model. The degree of protein hydrolysis was estimated using the o-phthaldialdehyde method, while the in vitro digestograms were mathematically fitted using a single first-order kinetics model. Peptides' profile, free amino acids compositions, gluten-pectin interactions and their effects on enzymatic activities of proteolytic enzymes as well as on the gluten secondary structures under digestive conditions were studied using combined techniques. Results showed that pectin could retard gluten digestibility through 1). preferential absorption to insoluble gluten aggregates by electrostatic interactions; 2). increasing the helix and reducing the β-sheet content of the solubilized gluten protein fractions in terms of their secondary molecular structures; 3). reducing pepsin activity by forming negatively charged pectin-gluten mixtures which then interacted with the positively charged pepsin molecules. The deeper insight into gluten-pectin interactions and their influences on gluten digestibility under gastrointestinal conditions provides important clues for developing effective forms of dietary fiber to improve the nutritional benefits of plant protein in individuals.
Topics: Pectins; Glutens; Digestion; Hydrolysis; Pepsin A; Duodenum; Triticum; Proteolysis; Amino Acids; Kinetics
PubMed: 38688790
DOI: 10.1016/j.ijbiomac.2024.131690 -
Journal of Nutritional Science and... 2024The Ussing chamber is a tool for analyzing drug absorption. We investigated whether the Ussing chamber can be used to analyze the process from digestion to absorption of...
The Ussing chamber is a tool for analyzing drug absorption. We investigated whether the Ussing chamber can be used to analyze the process from digestion to absorption of protein in the gastrointestinal tract. Mixtures containing infant formula, whole cow's milk, processed soy milk, enteral nutrition, or human breast milk, were placed in the apical membrane side equipped with Caco-2 cells. After the addition of first pepsin then pancreatin, samples from the apical and basal membranes were collected. Infant formula showed the highest digestibility and absorption rate. This may be attributed to the presence of whey protein, which is rapidly digested and absorbed. The digestion and absorption of human breast milk showed different results in each donor, suggesting that digestion and absorption may vary among individuals. We concluded that the Ussing chamber can continuously analyze the process from digestion to absorption of proteins in the gastrointestinal tract.
Topics: Digestion; Humans; Caco-2 Cells; Gastrointestinal Tract; Milk, Human; Infant Formula; Animals; Intestinal Absorption; Whey Proteins; Milk Proteins; Milk; Dietary Proteins; Enteral Nutrition; Soy Milk; Infant; Pepsin A
PubMed: 38684386
DOI: 10.3177/jnsv.70.158 -
Food Research International (Ottawa,... Jun 2024In this paper, the effect of monosodium glutamate (MSG) on coconut protein (CP) solubility, surface hydrophobicity, emulsification activity, ultraviolet spectroscopy and...
In this paper, the effect of monosodium glutamate (MSG) on coconut protein (CP) solubility, surface hydrophobicity, emulsification activity, ultraviolet spectroscopy and fluorescence spectroscopy was investigated. Meanwhile, the changes in the in vitro digestive properties of coconut milk were also further analyzed. MSG treatment altered the solubility and surface hydrophobicity of CP, thereby improving protein digestibility. Molecular docking showed that CP bound to pepsin and trypsin mainly through hydrogen bonds and salt bridges. And MSG increased the cleavable sites of pepsin and trypsin on CP, thus further improving the protein digestibility. In addition, MSG increased the Na concentration in coconut milk, promoted flocculation and aggregation between coconut milk droplets, which prevented the binding of lipase and oil droplets and inhibited lipid digestion. These findings may provide new ideas and insights to improve the digestive properties of plant-based milk.
Topics: Sodium Glutamate; Digestion; Cocos; Hydrophobic and Hydrophilic Interactions; Solubility; Molecular Docking Simulation; Plant Proteins; Trypsin; Pepsin A
PubMed: 38658074
DOI: 10.1016/j.foodres.2024.114288