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AbstractBackgroundsObjectivesMaterial and methodsResultsConclusions and significanceSome studies believe that there is a correlation between larygopharyngeal reflux disease (LPRD) and allergic rhinitis (AR). Salivary pepsin concentration (SPC) test is a gradually accepted objective examination method for LPRD in recent years.To investigate the impact of coexisting LPRD on subjective severity of seasonal AR and the potential role of pepsin.Adult patients with seasonal AR were prospectively enrolled. Subjective severity of AR was assessed using the Total Nasal Symptom Score (TNSS) and visual analog scale (VAS). Potential LPRD was assessed using the Reflux Symptom Index (RSI) and SPC measurements.No significant correlation was found between the RSI value and the TNSS and VAS values (both p > .05). In contrast, the SPC value was found to be significantly associated with both of TNSS and VAS values (p < .05). Among the symptoms included in the TNSS, the SPC value was significantly and positively associated with nasal congestion and runny nose (both p < .05), but not with sneezing and nasal itching (both p > .05).Coexisting LPRD may aggravates seasonal AR symptoms. SPC could be used to examine whether AR patients have combined LPRD and to determine the necessity of anti-reflux treatment. [ABSTRACT FROM AUTHOR]

Magenstrasse (stomach road) is reported to potentially influence the absorption of orally administered drugs by facilitating a gastric emptying of ingested water under postprandial condition. We hypothesized the Magenstrasse is a consequence of the formation of protein aggregates due to the decrease in gastric pH associated with stimulated gastric acid secretion. The formation mechanism of the Magenstrasse was examined in vitro using a gastric chamber system which reproduces postprandial conditions in the stomach. Oral liquid meals containing different amounts of proteins were mixed with simulated gastric fluid containing pepsin in the gastric chamber. When a high-protein liquid meal was used, infusion of gastric acid caused protein denaturation, generating semisolid aggregates. Then, to evaluate the impact of the aggregates, fluorescein isothiocyanate-dextran 4000 (FD-4) solution was added. The presence of protein aggregates facilitated the elution of FD-4 from the gastric chamber, indicating that the semisolid aggregates suppressed mixing of FD-4 solution with meals. In addition, formation of the same type of protein aggregates was observed in vivo in rat stomach after ingesting a high-protein liquid meal. These in vitro and in vivo results support the idea that protein aggregation of liquid meals in the stomach contributes the formation of the Magenstrasse. [ABSTRACT FROM AUTHOR]

1. This study evaluated the effect of acidified drinking water on the gastrointestinal function and intestinal health of broilers.2. A total of 630 one-day-old male broilers (Arbor Acre) were randomly assigned to one of three treatment groups: drinking water treatment (CON), drinking water + 0.5 ml Selko pH®/L (Selko pH), or + 0.85 ml Forticoat®/L (Forticoat) treated groups. Performance data, gut and digesta samples were collected from the broilers at the age of 21 and 42 d.3. The results showed that acidifying drinking water had no significant effect on body weight or average daily gain (ADG). However, addition of Forticoat significantly increased (p < 0.05) feed conversion ratio (FCR) throughout the experimental period and significantly increased (p < 0.05) pepsin activity on d 21. The Selko pH supplemented drinking water significantly increased (p < 0.05) the relative length of the duodenum and jejunum on d 21. The relative length of the jejunum and caecum on d 42 compared to birds receiving CON. The addition of the Forticoat to drinking water significantly increased (p < 0.05) the relative length of the jejunum and caecum on d 42 than for samples from birds in the CON group. In the caecal chyme, abundance of Blautia, Bifidobasterium, Faecalibacterium, Limosilactobacillus and Akkermania spp. on d 21 were significantly higher (p < 0.05) in the caecum of birds receiving Selko pH than those in CON group and the number of Escherichia Shigella in Selko pH and Forticoat group were significantly lower (p < 0.05).4. Overall, adding Seiko pH and Forticoat to drinking water improved pepsin activity, reduced the number of caecal pathogens, increased the number of beneficial bacteria and improved intestinal health in broilers. [ABSTRACT FROM AUTHOR]

Objective: Using rabbit models, this study simulated the laryngopharynx's response to the synergistic effects of various acidic reflux environments and pepsin to investigate the response mechanism underlying weak acid reflux and pepsin in the mucosal barrier injury of laryngopharyngeal reflux. Methods: The rabbits were divided into six groups, and the original larynx was recorded for each group. During the study period, rabbits were sprayed with different doses of acid and pepsin solutions and monitored for hypopharyngeal mucosal transient impedance before and after modeling. After the experiment, laryngeal mucosal tissues were collected, observed using hematoxylin and eosin staining, and assessed for E-cadherin expression. The width of the intercellular space and lanthanum staining penetrating the intercellular space were also observed using electron microscopy. Results: Eight weeks post-modeling, evidence of laryngopharyngeal mucosa inflammatory responses was observed in each group. Downregulation of E-cadherin expression significantly positively correlated with acid strength (p < 0.05). The pepsin and acid intervention groups showed a significantly widened space between mucosal epithelial cells in the posterior ring area (p < 0.05). Meanwhile, in the experimental group, a large amount of stained lanthanum penetrated the intercellular spaces; however, no significant difference was observed in the mucosal impedance (MI). Conclusion: This study demonstrated that acid, weak acid, and pepsin could damage the laryngeal mucosal barrier; pepsin was an independent factor associated with tissue damage; the downregulation of hypopharyngeal cadherin was associated with acid-intensity exposure. Transient LP-MI cannot be applied directly. [ABSTRACT FROM AUTHOR]

BACKGROUND: Protein‐derived peptide fractions can play a key role in the physiological and metabolic regulation and modulation of the body, which suggests that they could be used as functional ingredients to improve health and to reduce the risk of disease. This work aimed to evaluate the in vitro antithrombotic and anticariogenic bioactivity of hydrolysates and protein fractions obtained from cowpea (Vigna unguiculata) by biocatalysis. RESULTS: Cowpea protein concentrate was hydrolyzed by sequential action with two enzyme systems, Pepsin‐Pancreatin or Alcalase‐Flavourzyme. There was extensive enzymatic hydrolysis, with degrees of hydrolysis of 34.94% and 81.43% for Pepsin‐Pancreatin and Alcalase‐Flavourzyme, respectively. The degree of hydrolysis for the control treatments, without the addition of the enzymes Pepsin‐Pancreatin and Alcalase‐Flavourzyme was 1.1% and 1.2%, respectively. The hydrolysates were subjected to fractionation by ultrafiltration, with five cut‐off points according to molecular weight (<1, 1–3, 3–5, 5–10 and >10 kDa). The Alcalase‐Flavourzyme hydrolysate led to 100% inhibition of platelet aggregation, while the Pepsin‐Pancreatin hydrolysate showed 77.41% inhibition, but this was approximately 100% in the ultrafiltered fractions. The highest anticariogenic activity was obtained with the Pepsin‐Pancreatin system, with 61.55% and 56.07% for calcium and phosphorus demineralization, respectively. CONCLUSION: Hydrolysates and their peptide fractions from Vigna unguiculata exhibited inhibition of platelet aggregation and protection of tooth enamel and have the potential for use in the development of functional products with beneficial health effects. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

AbstractThe nutritive value of a protein is determined not only by its amino acid composition, but also by its digestibility in the gastrointestinal tract. The interaction between proteins and pepsin in the gastric stage is the first step and plays an important role in protein hydrolysis. Moreover, it affects the amino acid release rates and the allergenicity of the proteins. The interaction between pepsin and proteins from different food sources is highly dependent on the protein species, composition, processing treatment, and the presence of other food components. Coagulation of milk proteins under gastric conditions to form a coagulum is a unique behavior that affects gastric emptying and further hydrolysis of proteins. The processing treatment of proteins, either from milk or other sources, may change their structure, interactions with pepsin, and allergenicity. For example, the heat treatment of milk proteins results in the formation of a looser curd in the gastric phase and facilitates protein digestion by pepsin. Heated meat proteins undergo denaturation and conformational changes that enhance the rate of pepsin digestion. This review provides new ideas for the design of food products containing high protein concentrations that optimize nutrition while facilitating low allergenicity for consumers. [ABSTRACT FROM AUTHOR]

This study optimized the process of extracting protein from black garlic using an alkaline dissolution and acid precipitation method through response surface methodology. The optimal extraction conditions were determined as a solid-to-liquid ratio of 1:50, an extraction time of 100 min, an extraction temperature of 30 °C, and an alkaline extraction pH of 9.0. Under these optimized conditions, the actual black garlic protein (BGP) extraction yield was 12.10% ± 0.21%, and the isoelectric point of the obtained BGP was 3.1. Subsequently, this study extracted black garlic protein under optimal conditions and subjected it to enzymatic hydrolysis using different enzymes (trypsin, pepsin, and their mixed enzymes). The functional characteristics, antioxidant activity, and hypoglycemic activity of black garlic protein before and after enzymatic hydrolysis were compared. Among the hydrolysates, the pepsin hydrolysate (BGPH-P) had the smallest particle size (188.57 ± 1.93 nm) and the highest Zeta potential (−29.93 ± 0.42 mV). Scanning electron microscopy showed that BGPH-P had the smallest and most dispersed particles. Fourier-transform infrared (FTIR) spectroscopy revealed that the dual enzymatic hydrolysis hydrolysate (BGPH-PT) exhibited the most stable structure. Compared to BGP, the hydrolysates demonstrated significantly improved solubility, water-holding capacity, and foaming ability (p < 0.05), while their emulsifying activity, emulsion stability, DPPH radical scavenging capacity, and hypoglycemic activity decreased. In summary, the BGP extracted using the optimized process demonstrated good antioxidant and hypoglycemic activities, while its enzymatic hydrolysate BGPH-P exhibited excellent solubility, water-holding capacity, and emulsifying properties, providing valuable insights for the further development of black garlic protein and its hydrolysates. [ABSTRACT FROM AUTHOR]

In this investigation, collagen was successfully extracted from the skin and fins of the orange-spotted grouper, Epinephelus coioides, with recovery rates of 4.45% and 23.65% (dry weight basis), respectively. UV–Vis spectrophotometric analysis demonstrated distinct absorbance peaks at 222 nm and 217 nm for collagen isolated from the skin and fins, correspondingly. Both collagen sources were confirmed to be type I, characterized by the presence of two α-chains (α1 and α2), with glycine as the predominant amino acid, an absence of tryptophan, and a notable content of proline and hydroxyproline. The enzymatic hydrolysis of fin-derived collagen using pepsin yielded low-molecular-weight peptides (PHC), which were subsequently incorporated into the diet of 1.5-year-old zebrafish, either alone or in combination with glucosamine (GC), to assess their biological effects. After eight weeks of dietary supplementation, zebrafish fed PHC or the combined PHC + GC diets exhibited a significant upregulation of sox9a (jef) expression in spinal tissues, accompanied by a marked downregulation of runx2. Although the differences in swimming performance among the groups were not statistically significant, zebrafish that received PHC or the combined supplements demonstrated enhanced endurance compared to the control group. These results suggest that collagen sourced from grouper may have advantageous effects in supporting cartilage health in aged zebrafish. Furthermore, utilizing fish by-products for collagen extraction enhances resource efficiency and aligns with circular economy principles. [ABSTRACT FROM AUTHOR]

Background: Enteral feeding intolerance, a common type of gastrointestinal dysfunction leading to underfeeding, is associated with increased mortality. Tracheal pepsin A, an indicator of microaspiration, was found in 39% of patients within 24 hours of enteral feeding. Tracheal pepsin A is a potential biomarker of enteral feeding intolerance. Objective: To identify predictors of microaspiration (tracheal or oral pepsin A). It was hypothesized that variables predicting the presence of tracheal pepsin A might be similar to predictors of enteral feeding intolerance. Methods: In this secondary analysis, machine learning models were fit for 283 adults receiving mechanical ventilation who had tracheal and oral aspirates obtained every 12 hours for up to 14 days. Pepsin A levels were measured using the proteolytic enzyme assay method, and values of 6.25 ng/mL or higher were classified as indicating microaspiration. Demographics, comorbidities, and variables associated with enteral feeding were analyzed with 3 machine learning models—random forest, XGBoost, and support vector machines with recursive feature elimination—using 5-fold cross-validation tuning. Results: Random forest for tracheal pepsin A was the best-performing model (area under the curve, 0.844 [95% CI, 0.792-0.897]; accuracy, 87.55%). The top 20 predictors of tracheal pepsin A were identified. Conclusion: Four predictor variables for tracheal pepsin A (microaspiration) are also reported predictors of enteral feeding intolerance, supporting the exploration of tracheal pepsin A as a potential biomarker of enteral feeding intolerance. Identification of predictor variables using machine learning models may facilitate treatment of patients at risk for enteral feeding intolerance. [ABSTRACT FROM AUTHOR]

During fermentation, bacterial and fungal species synthesize substrate-specific enzymes to obtain nutrients. During this process, potential allergenic products, including immunologically important gluten peptides, can be created. Current protocols for assessing the levels of these peptides often overlook the specific gluten source. In this study, wheat sources provided by commercial enzyme suppliers underwent gluten extraction before being pooled into a Complete Gluten Mix, which then underwent variations of hydrolysis utilizing the digestive enzymes, pepsin and trypsin complexes. The resulting gluten peptide profiles were examined using the Wes automated Western blot system to confirm the presence of small, immunologically relevant gluten peptides. These hydrolysates were further tested for suitability as a relevant calibrant against commercially available ELISA standards. The PT3 calibrant, a hydrolyzed version of the Complete Gluten Mix, was found to be the most suitable, as it contained <50 kDa gluten peptides and gave similar absorbance readings to the majority of ELISA kit standards tested, and overlaid the GlutenTox® Competitive G12 antibody calibration curve, which was designed against the 33-mer immunogenic peptide from wheat. Additionally, no gluten bands were observed on the Wes for the enzymes of interest, which was confirmed through ELISA analysis. [ABSTRACT FROM AUTHOR]

Abstract The aim of the present work was to immobilize L-arginine deiminase on suitable supports such as chitosan, alginate, and silica gel to study its stability. Additionally, the study aims to investigate the anticancer effects of the free purified enzyme on hepatocellular carcinoma (Hep-G2) and breast cancer (MCF-7) cell lines. L-arginine deiminase (ADI: EC 3.5.3.6) was immobilized on chitosan, Ca-alginate, and silica gel, with immobilization efficiencies of 89.0%, 72.8%, and 66.5%, respectively. The optimal immobilization time for the highest efficiency was 4 h. Increasing the concentration of glutaraldehyde improved the immobilization efficiency of ADI on chitosan. The chitosan-immobilized ADI retained about 45% of its activity after 8 cycles. The optimal pH values were 6 for the free purified ADI and 7 for the chitosan-immobilized ADI. The optimal temperature increased from 40 °C for the free enzyme to 45 °C after immobilization. The activation energies for the free and chitosan-immobilized enzymes were 71.335 kJ/mol and 64.011 kJ/mol, respectively. The Km values for the free and chitosan-immobilized ADI were 0.76 mM and 0.77 mM, respectively, while the Vmax values were 80.0 U/mg protein for the free ADI and 71.4 U/mg protein for the chitosan-immobilized ADI. After 30 days of storage at 4 °C, the residual activities were 40% for the free purified ADI and 84% for the chitosan-immobilized ADI. At 25 °C, the residual activities were 10% for the free ADI and 75% for the chitosan-immobilized ADI. The chitosan-immobilized ADI exhibited significantly higher stability against proteases such as pepsin and trypsin compared to the free enzyme. The purified ADI also demonstrated enhanced potential anticancer effects and significant cytotoxicity against the Hep-G2 and MCF-7 tumor cell lines compared to doxorubicin. These findings suggest that purified ADI has potential as an anticancer agent, though further in-depth studies are required.

Marine collagen is gaining more attraction than terrestrial collagen because it is free of zoonotic disease and religious constrain. In this study, we aimed to investigate and compare the physicochemical properties and functional characteristics of acid‐soluble collagen (ASC‐MF) and pepsin‐soluble collagen (PSC‐MF) extracted from scales of Megalonibea fusca. ASC‐MF and PSC‐MF were evaluated in terms of yield, collagen type, amino acid composition, thermal stability, microstructure, cytotoxicity, and other physicochemical parameters. ASC‐MF and PSC‐MF depicted 1.72 ± 0.2% and 11.72 ± 0.3% of dry weight yields, respectively, and were identified as type I collagen with an intact triple‐helical structure by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS‐PAGE), spectroscopic analysis, and electron microscopy. Additionally, compared with many temperate and tropical species, ASC‐MF and PSC‐MF showed higher thermal stability, with the maximum transition temperature (Tmax) of 53.50°C (ASC‐MF) and 43.16°C (PSC‐MF). CCK‐8 assay showed that ASC‐MF and PSC‐MF have no cytotoxicity in vitro. The determination of blood clotting index values showed that both ASC‐MF and PSC‐MF had good hemostatic ability. In summary, these findings show that PSC‐MF isolated from the scales of M. fusca may be a feasible alternative to terrestrial collagen sources in food and biomedical applications. [ABSTRACT FROM AUTHOR]

The present investigation deals with comparisons drawn among three types of different mustard seed coat colors, namely, Black (Brassica nigra), Brown (Brassica juncea), and White (Sinapis alba), with respect to protein's bio-availability through pepsin digestibility, with and without the involvement of major anti-nutritional factors (glucosinolate type AITC, Allylisothiothiocyanate) and relative food functions. These are validated by means of crude protein determination, precipitated protein isolate preparation for evaluating the fat absorption capacity (FAC), emulsifying activity (EA), emulsion stability (ES), whippability, foam stability (FS), the nitrogen solubility index (NSI), and the protein dispersibility index (PDI). The results indicate that the partial removal of glucosinolates from brown mustard (0.91 to 0.31%), black mustard (0.74 to 0.31%), and white mustard (0.58 to 0.30%) improved protein's digestibility, as analyzed through a pepsin assay, with values of 12.84, 12.60, and 4.53% in brown, black, and white mustard, respectively. Among functional properties, the highest FAC, whippability, foam stability, and NSI values were noted in the brown mustard seed meal, derived from precipitated protein isolates, while EA and PDI were the highest in white mustard seeds, and black seeds possessed the highest ES value. Interestingly, these mustard seed meals are limited in their consumption, albeit by virtue of the different phytochemical and food functional parameters that are being elucidated here. The present research shows the relevance of different food functional properties and the presence of anti-nutritional factors, and uses protein-digestibility tests, which are important deciding parameters for enhanced food consumption in animal diets. Additionally, targeted molecular and protein–protein docking results revealed how and why the mustard seed meals are limited in their consumption by virtue of various metabolite interactions. This thereby opens the gateways to many required in vivo and in silico future research insights among AITC–pepsin, AITC–myrosinase, pepsin–myrosinase, and cruciferin–myrosinase complexes. Consequently, the metabolic pathways governing AITC involved in the glucosinolate–myrosinase system need to be studied in depth for a better understanding of in vivo AITC metabolism. This knowledge can guide future studies in improving the health benefits of mustard seeds and seed meals while addressing their consumption limitations. [ABSTRACT FROM AUTHOR]

α-amylase can effectively inhibit the activity of digestive enzymes and alter nutrient absorption. The impact of ovum hydrolysates of sea cucumbers on α-amylase activity was investigated in this study. The protein hydrolysates generated using different proteases (pepsin, trypsin, and neutral protease) and molecular weights (less than 3000 and more than 3000) were investigated. The results showed that all three different hydrolysates demonstrated calcium-chelating activity and induced a fluorescence-quenching effect on α-amylase. The sea cucumber ovum hydrolysate with a molecular weight of less than 3000 Da, isolated using trypsin, showed the most effective inhibitory effect on α-amylase, with an inhibition rate of 53.9%, and the inhibition type was identified as mixed forms of inhibition. In conclusion, the generation and utilization of protein hydrolysates from sea cucumber ovum as a functional food ingredient could be a potential approach to add value to low-cost seafood by-products. [ABSTRACT FROM AUTHOR]

Methyl thiophanate (MT) is a widely used fungicide in agriculture; however, it presents substantial health risks to humans. Exposure to MT can damage the human nervous and reproductive systems and inhibit pepsin, a crucial enzyme for digestion and metabolism. This research aimed to investigate the interaction between MT and pepsin using different spectroscopic techniques and dynamic simulations. The UV-Vis results further validated the Trp delocalization findings through molecular docking. At various temperature levels, the effective quenching constants (k q) were found to be 8.28×103, 5.36×103 and 2.43×103 L mol−1, respectively, indicating static quenching with a k q greater than 2 × 1010. Thermodynamic analysis revealed Δ H 0 = −56.56 kJ mol − 1 and ∆ S 0 = −102 J mol − 1 K − 1 , highlighting the significance of hydrogen bonds and Van der Waals interactions in the complex, consistent with docking analyses. By studying the interaction between pepsin and MT, valuable insights can be gained into its impact on digestive system enzymes, leading to a better understanding of MT's toxicological and inhibitory effects on digestion. This interaction disrupts protein digestion, which has broader implications for nutrient absorption and overall digestive health. [Display omitted] • Pesticides are essential agricultural chemicals to kill harmful organisms. • The conformational of pepsin alter after binding to Methyl Thiophanate. • Structural changes lead to changes in pepsin function. • The results obtained in this in vitro and in silico confirm another. [ABSTRACT FROM AUTHOR]

Purpose: The inhibition of thrombin has proven to be an efficacious therapeutic approach for managing cardiovascular disease (CVD), with widespread implementation in clinical settings. Oral ingestion of peptides and protein drugs is influenced by gastrointestinal digestive enzymes. We aimed to evaluate the thrombin inhibitory properties of hirudo hydrolysates (HHS) produced by pepsin and propose a comprehensive approach to screen and evaluate thrombin inhibitors. Methods: We evaluated the in vitro inhibitory properties of the hirudo extract, both before and after hydrolysis with pepsin, toward thrombin. We screened for the most potent thrombin inhibitory peptide (TIP) using nano liquid chromatography-tandem mass spectrometry (Nano LC-MS/MS) coupled with in silico analysis. Next, we employed the thrombin inhibition activity IC50 to investigate the interaction between TIP and thrombin, and conducted in vitro evaluations of its anticoagulant effects (APTT, TT, PT), as well as its ability to inhibit platelet aggregation. Furthermore, we utilized UV-Vis spectroscopy to explore structural changes in thrombin upon binding with TIP and employed molecular dynamics simulations to delve deeper into the potential atomic-level interaction modes between thrombin and TIP. Results: The retention rate of thrombin inhibition for HHS was found to be between 60% and 75%. A total of 90 peptides from the HHS were identified using LC-MS/MS combined with de novo sequencing. Asn-Asp-Leu-Trp-Asp-Gln-Gly-Leu-Val-Ser-Gln-Asp-Leu (NDLWDQGLVSQDL, P1) was identified as the most potent thrombin inhibitory peptide after in silico screening (molecular docking and ADMET). Then, the in vitro study revealed that P1 had a high inhibitory effect on thrombin (IC50: 2,425.5 ± 109.7 μM). P1 exhibited a dose-dependent prolongation of the thrombin time (TT) and a reduction in platelet aggregation rate. Both UV-Vis spectroscopy and molecular dynamics simulations demonstrated that P1 binds effectively to thrombin. Conclusion: Overall, the results suggested that HHS provides new insights for searching and evaluating potential antithrombotic compounds. The obtained P1 can be structurally optimized for in-depth evaluation in animal and cellular experiments. [ABSTRACT FROM AUTHOR]

A study evaluated porcine in vitro digestion and non-starch polysaccharide (NSP) solubilization of corn and wheat without or with xylanase alone or xylanase plus feruloyl esterase (FE). The enzymes supplied 4000 U of xylanase and 35 U of FE per kilogram of sample. Samples were digested with pepsin at a pH of 2.0 and then with pancreatin at a pH of 6.8. The digested samples were filtered to obtain unhydrolyzed residue, which was then washed using alcohol and acetone. The cereal grains (CGs) before in vitro digestion and the washed unhydrolyzed residues were analyzed for dry matter and NSP. Xylanase improved (P < 0.05) in vitro digestibility of dry matter (IVDDM) for wheat (85% vs. 89%), but not for corn (78% vs. 79%). Addition of FE to the xylanase-supplemented CGs increased (P < 0.05) IVDDM for both CGs, and reduced (P < 0.05) the arabinoxylans in the unhydrolyzed residue for corn, but not for wheat. In conclusion, xylanase product used in the current study is more effective in improving the digestibility of nutrients in wheat than in corn. The FE product used in the current study can improve the efficacy of xylanase in improving the nutrient digestibility of wheat and corn. [ABSTRACT FROM AUTHOR]

The use of animal by-products to produce bioactive peptides is a promising and sustainable approach in the food and nutrition industry. Meat by-products can be used as a key raw material for the production of high-value-added components, such as bioactive peptides, to ensure sustainability. Porcine livers and hearts classified as category three by-products were selected for the study, together with those intended for human consumption, in which no changes were observed after veterinary post-mortem examination. Hydrolysis was performed at three different times 3 h, 6 h, and 24 h, using pepsin and papain. The influence of different hydrolysis times and enzymes on the degree of hydrolysis (DH) value was determined. The highest value of DH was found in porcine hearts after 24 h following hydrolysis with pepsin enzymes (33.56 ± 0.31). The antiradical activity was assessed by measuring the absorbance of DPPH• and ABTS•+ in hydrolysates obtained from porcine meat by-products. Porcine livers hydrolysates treated with papain for 24 h showed the highest radical scavenging abilities ABTS•+ (97.2 ± 1.79%) and DPPH• (92.07 ± 2.23%). The identification and quantification of peptides from porcine livers and hearts were conducted using SWATH-MS technology. The most abundant peptides that showed a relationship with antioxidant capacity were WGKVNVDEVGGEALGRL, WGKVNVDEVGGEAL, and GLWGKVNVDEVGGEALGRL from beta hemoglobin. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the effects of retrograded resistant starch (RS3) (0, 2%, 4% and 6%; w/v) on the emulsion gel properties stabilized by myofibrillar proteins (MPs) and in vitro protein digestibility of the gels. The RS3 was prepared from corn or potato starch using the gelatinization–ultrasound–retrogradation method. The results showed that the addition of RS3 decreased the surface hydrophobicity (p < 0.05) and increased the fluorescence intensity of MPs, indicating enhanced protein–protein interactions. More stable emulsions stabilized by MP/RS3 mixtures were formed, along with higher electronegativity, a smaller droplet size and reduced creaming index. These changes promoted the formation of better gel networks with the oil droplets evenly dispersed, thus improving gel strength, water holding capacity (WHC) and texture, especially at the concentration of 6% RS3 added. The gel force results indicated that the addition of RS3 enhanced the hydrophobic interaction and disulfide bonds between MPs. LF-NMR and MRI data further confirmed that RS3 addition facilitated the migration of free water to immobilized water. Furthermore, the incorporation of RS3 caused a relatively lower pepsin digestibility but did not change the overall in vitro protein digestibility of the gels. This paper provides a method to produce high-quality low-GI meat products without degrading protein digestibility. [ABSTRACT FROM AUTHOR]

Intracellular alcohol oxidase (AOX) was isolated from the basidiomycetous white rot fungus Cerrena unicolor FCL139. The enzyme was semi-purified (13-fold) using two-step chromatography with 30% activity recovery. The identity of the protein was confirmed by LC-MS/MS analysis, and its MW (72 kDa) and pI (6.18) were also determined. The kinetics parameters of the AOX reaction towards various substrates were analysed, which proved that, in addition to methanol (4.36 ± 0.27% of the oxidised substrate), AOX most potently oxidises aromatic alcohols, such as 4-hydroxybenzyl alcohol (14.0 ± 0.8%), benzyl alcohol (4.2 ± 0.3%), anisyl alcohol (7.6 ± 0.4%), and veratryl alcohol (5.0 ± 0.3%). Moreover, the influence of selected commercially available proteases on the biocatalytic properties of AOX from C. unicolor was studied. It was proved that the digested enzyme lost its catalytic potential properties except when incubated with pepsin, which significantly boosted its activity up to 123%. [ABSTRACT FROM AUTHOR]

Poly succinimide (PSI) was synthesized from L-poly aspartic acid by thermal polycondensation reactio n・ The crosslinking agent acryloxyethylamine poly succinimide (AEA-PSI) was obtained by the reaction of PSI with ethanol and acrylylation PSI reacted with ethanol・ The P (NIPAm-co-AA) hydrogel was synthesized w 让h N-isopropylacrylamide(NIPAm) and acrylic acid (A A) as monomers and AEA-PSI as crosslinkers・ The drug sustained release and biodegradation properties of P(NIPAm-cAA) hydrogel were studied・ The results showed that when the NIPAm/AA molar ratio of P (NIPAm-co-AA) hydrogel was 92/8, the dosage of AEA-PSI was 4%, and the temperature was 37 °C, the sustained release effect of P(NIPAm-co-AA) hydrogel was the best, and the sustained release rate reached 60% w让hin 24 h・ The addition of pepsin had no significant effect on the sustained release rate of the drug・ The degradation rate of P(NIPAm-co-AA) hydrogel in simulated gastric fluid was higher than that in simulated intestinal fluid, and the degradation rate of P(NIPAm-co-AA) hydrogel in simulated gastric fluid reached more than 15% w:ithin 24 h・ [ABSTRACT FROM AUTHOR]

Laryngopharyngeal reflux (LPR) manifests as a variety of nonspecific upper aerodigestive tract symptoms. Rather than a single disorder, LPR may be conceived of as a spectrum of subtypes with varying clinical presentations. LPR signs and symptoms arise from the direct and/or indirect effects of refluxate, physical and molecular injury of the mucosa, and neurologic responses to esophageal events. Specific constituents of refluxate exert distinct mucosal responses and immediate or delayed effects resulting in transient or persistent symptoms and/or laryngeal hypersensitivity. While the complex etiology of LPR presents challenges to its diagnosis and management, tools that aid the identification of LPR subtypes can provide insight into treatment decision‐making. Hypopharyngeal‐esophageal multichannel intraluminal impedance‐pH monitoring provides detailed analysis of reflux events, enabling the development of individualized treatment plans, yet cost and availability limit its widespread use. Alginates offer temporary symptom relief and antireflux surgery may provide benefit when symptoms are recalcitrant to other approaches. Pepsin inhibitors hold promise as a medical therapy when surgery is not an option. Laryngeal hypersensitivity should be considered as part of a comprehensive therapeutic approach. Promising medical and scientific research continues to yield new insights into the complex etiology of LPR and novel strategies for its diagnosis and management. [ABSTRACT FROM AUTHOR]

Background and Purpose: The definitive diagnosis of gastroesophageal reflux disease (GERD) often requires invasive investigations like upper gastrointestinal endoscopy or reflux monitoring. We aimed to explore the relationship between salivary pepsin and GERD and its value as a non‐invasive diagnostic tool. Methods: Databases (PubMed, Web of Science, Cochran Library, and EMBASE) were searched from their inception to January 22, 2024 to explore the correlation of salivary pepsin with GERD. The meta‐analysis data retrieved were summarized, including the salivary pepsin concentration, sensitivity of diagnosis (SEN), specificity of diagnosis (SPE), negative likelihood ratio, positive likelihood ratio, diagnostic odds ratio, and receiver operating characteristic (ROC) curve. Results: The meta‐analysis comparing salivary pepsin concentration in two groups (proven GERD and non‐GERD) with 18 studies revealed that the proven GERD group had higher salivary pepsin concentration than the non‐GERD group (SMD = 1.74 [95% CI 1.14–2.34]). The meta‐analysis of salivary pepsin diagnostic value for proven GERD incorporated 23 studies. The results showed pooled SEN (0.73 [95% CI 0.66–0.80]), SPE (0.72 [95% CI 0.65–0.78]), positive likelihood ratio (2.61 [95% CI 2.02–3.39]), negative likelihood ratio (0.37 [95% CI 0.28–0.50]), diagnostic odds ratio (7.03 [95% CI 4.24–11.66]) and area under the SROC curve (0.79 [95% CI 0.75–0.82]). Conclusion: GERD patients presented a higher salivary pepsin concentration. Salivary pepsin is both sensitive and specific in identifying GERD, making it a promising non‐invasive marker for diagnosis. [ABSTRACT FROM AUTHOR]

To investigate the predictive capability of pepsin level in the laryngeal mucosa to the therapeutic effect of proton-pump inhibitors in patients with suspected laryngopharyngeal reflux (LPR), so as to verify whether it can be referred to as a biomarker of LPR. Prospective case study. Sixty patients with clinical empiric LPR were enrolled, with an reflux symptom index (RSI) ≥ 13 and an reflux finding score (RFS) > 7 as screening criteria. Biopsy specimens from the interarytenoid mucosa were obtained under topical anesthesia for pepsin immunohistochemical staining. Two parameters were observed in these patients with different pepsin levels after the administration of esomeprazole for 12 weeks: the RSI and the RFS. Among the 60 cases, 35 cases were negative or weakly positive for pepsin (Pepsin(-) group), and 25 cases were moderately positive or strongly positive for pepsin (Pepsin(+) group). After therapy, the RSI significantly decreased from 17.00 (15.00, 19.00) to 6.00 (5.00, 11.00) in the Pepsin(+) group (Z = -4.38, P < 0.01), but no difference was found in the RFS (T = 1.48, P > 0.05). No significant difference was observed in the RSI (T = 2.01, P > 0.05) or the RFS (T = 2.01, P > 0.05) in the Pepsin(-) group either before or after therapy. An improvement in the RSI ≥ 50% was taken as the standard of effective therapy. The effective rate in the Pepsin(+) group was 72.0% (18/25), while it was 14.3% (5/35) in the Pepsin(-) group. There was a significant difference in the effective rate between the two groups (χ2 = 20.55, P < 0.01). Proton-pump inhibitors exhibited better effects in patients with higher pepsin levels in the laryngeal mucosa. Laryngeal mucosa pepsin may serve as an ideal indicator to screen patients suitable for proton-pump inhibitor therapy and a reliable biomarker to identify patients with LPR. [ABSTRACT FROM AUTHOR]

Objective: The pathogenic mechanism underlying the effects of acidic pepsin in laryngeal cancer remains unclear. This study investigated whether acidic pepsin influences Glut‐1 expression and glycolytic activity in laryngeal carcinoma cells and whether it plays a role in the growth and migration of these cells through glycolysis. Study Design: In vitro study. Setting: A university‐affiliated hospital. Methods: Laryngeal carcinoma TU 212 and TU 686 cells were treated with acidic pepsin and 2‐deoxy‐d‐glucose (2‐DG), then transfected with Glut‐1 small interfering RNA (siRNA). Glucose uptake was detected by a radioimmunoassay counter, lactate secretion was detected by a lactic acid kit, and Glut‐1 expression was detected by western blotting. Cell viability, migration and invasion, and clonal formation were assessed using the Cell Counting Kit‐8, Transwell chamber, and clonal formation assays, respectively. Results: Acidic pepsin significantly increased Glut‐1 expression in laryngeal carcinoma cells compared with the control group (P <.01). It also significantly enhanced 18F‐fluorodeoxyglucose (Cin/Cout) uptake, lactate secretion, cell viability, migration, invasion, and clonal formation in laryngeal carcinoma cells compared with the control group (P <.01). The glycolytic inhibitor 2‐DG and Glut‐1 siRNA significantly reversed the effects of acidic pepsin on laryngeal carcinoma cells (P <.01). Conclusion: Acidic pepsin enhances the growth and migration of laryngeal carcinoma cells by upregulating Glut‐1, thus promoting glycolysis. [ABSTRACT FROM AUTHOR]

In this study, we introduce a novel cleavage reaction lateral flow assay (LFA) based on pepsin activity against a pepsin-susceptible peptide (PSP) substrate to detect salivary pepsin. Two types of cleavage reaction LFAs, the within-tube and on-strip cleavage reactions, were prepared based on the PSP and pepsin reaction location. In the within-tube cleavage reaction LFA, samples were treated in the microtube within a heating block for 30 min separately and subsequently developed with running buffer in the LFA. For the on-strip cleavage reaction, samples were treated on the reaction zone of the strip within the heating zone of the multifunctional strip cassette for 10 min. After developing the running buffer in the LFA, the assay image was obtained using a universal mobile reader with a multifunctional strip cassette. The within-tube cleavage reaction LFA showed high sensitivity (limit of detection [LOD] 1.9 ng/mL), good specificity, and high reproducibility. This assay exhibited better linearity in the log concentration range of pepsin (4–500 ng/mL) than a commercially available dipstick assay. The on-strip cleavage reaction LFA showed a similar sensitivity (LOD 1.4 ng/mL) to that of the within-tube reaction assay. Therefore, we expect these cleavage reaction LFAs using PSP to be utilized as simple and effective tools to detect salivary pepsin. [ABSTRACT FROM AUTHOR]

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Objective: To investigate the consistency between the reflux symptom score (RSS) and the multitemporal salivary pepsin test in screening for laryngopharyngeal reflux (LPR) and the screening value of the RSS for LPR by simultaneously administering daytime multitemporal salivary pepsin test and RSS to patients. Methods: This was a single-center prospective observational study. All included patients underwent simultaneous daytime multitemporal salivary pepsin testing and RSS. A participant was considered to have LPR when one or more positive salivary pepsin test results or RSS score > 13 were obtained. The consistency between the multitemporal salivary pepsin test and the RSS was compared by the weighted Cohen's kappa statistic. The screening value of the RSS for LPR was investigated by receiver operating characteristic (ROC) analysis. Results: A total of 67 patients were included. The positivity rate of LPR was 71.64% according to the results of the multitemporal salivary pepsin test. According to RSS, the positive rate of LPR was 70.15%. The weighted Kappa value between the multitemporal salivary pepsin test and the RSS was 0.675 (p < 0.001). The area under curve of RSS screening for LPR was 0.843 (p < 0.01), and the sensitivity, specificity, positive predictive value, and negative predictive value of RSS screening for LPR were 89.58%, 78.95%, 91.49%, and 75%, respectively. Conclusion: There is a good consistency between the RSS and the multitemporal salivary pepsin test, and the RSS has a good screening value for LPR, which can be applied to screen for LPR in otolaryngologic patients. [ABSTRACT FROM AUTHOR]

Breakthrough symptoms are thought to occur in roughly half of all gastroesophageal reflux disease (GERD) patients despite maximal acid suppression (proton pump inhibitor, PPI) therapy. Topical alginates have recently been shown to enhance mucosal defense against acid-pepsin insult during GERD. We aimed to examine potential alginate protection of transcriptomic changes in a cell culture model of PPI-recalcitrant GERD. Immortalized normal-derived human esophageal epithelial cells underwent pretreatment with commercial alginate-based anti-reflux medications (Gaviscon Advance or Gaviscon Double Action), a matched-viscosity placebo control, or pH 7.4 buffer (sham) alone for 1 min, followed by exposure to pH 6.0 + pepsin or buffer alone for 3 min. RNA sequencing was conducted, and Ingenuity Pathway Analysis was performed with a false discovery rate of ≤0.01 and absolute fold-change of ≥1.3. Pepsin-acid exposure disrupted gene expressions associated with epithelial barrier function, chromatin structure, carcinogenesis, and inflammation. Alginate formulations demonstrated protection by mitigating these changes and promoting extracellular matrix repair, downregulating proto-oncogenes, and enhancing tumor suppressor expression. These data suggest molecular mechanisms by which alginates provide topical protection against injury during weakly acidic reflux and support a potential role for alginates in the prevention of GERD-related carcinogenesis. [ABSTRACT FROM AUTHOR]

The production of bioactive peptides (BPs) usually involves the enzymatic hydrolysis stage during which one or more proteases are used to break down the parental protein into shorter fragments. In this review, efforts were made to focus on using pepsin as a unique protease capable of generating BPs. We started with the description of BPs and proteases prior to the unraveling of pepsin's properties and immobilization for the production of BPs. The peptic hydrolysis of food-derived proteins to generate BPs with biological functions, e.g. antioxidative, ACE-inhibitory, metal-binding, antidiabetic, anti-inflammatory, and antimicrobial activities from vegetable, fish, seafood, whey, casein, blood plasma, and egg proteins, among other unconventional protein sources were discussed. The review concluded with BPs used in developing food products for their techno-functional properties such as emulsifying, water, and fat-holding capacities. [ABSTRACT FROM AUTHOR]

Animal bones, particularly from cattle after slaughter, are commonly discarded, posing environmental challenges and highlighting the need for sustainable valorization. This study investigated the effect of enzyme and organic acid treatment on physicochemical properties, particle size, microstructure and safety of meat-bone paste (MBP). Two samples were prepared: a control (MBP-C) without enzyme treatment and an experimental sample (MBP-E) treated with pepsin and ascorbic acid. Results showed that the enzyme reaction rate increased from 0.004 mmol/min at 60 min to 0.014 mmol/min at 120–180 min before declining to 0.006 mmol/min at 480 min, suggesting substrate depletion or product inhibition. Temperature greatly influenced reaction rates, peaking at 0.0129 mmol/min at 30 °C, with significant declines at higher temperatures due to enzyme denaturation. The enzyme's kinetic performance was proportional to the pepsin concentration, demonstrating enhanced catalytic efficiency at higher enzyme concentrations. Particle size analysis revealed that enzyme treatment significantly reduced bone particle size, with 86.33% of particles measuring between 0.05 and 0.2 mm, compared to 86.4% between 0.25 and 0.75 mm in the untreated sample. Microscopy confirmed these findings, showing an average particle size reduction from 0.21 mm to 0.052 mm after enzyme treatment. Physicochemical analysis revealed no significant differences in chemical composition between the two samples. However, enzyme-treated MBP-E exhibited a lower pH (5.9) compared to MBP-C (7.02), attributed to the addition of ascorbic acid. Water-binding capacity significantly increased in MBP-E (82.54% vs. 77.28%), indicating enhanced hydration and collagen loosening during enzymatic action. Enzyme treatment significantly reduced the total viable count and eliminated pathogenic bacteria (E. coli, Listeria, Salmonella), improving MBP safety. These findings highlight the potential of this approach for valorizing animal bones as a valuable food ingredient while promoting sustainable waste management practices. [ABSTRACT FROM AUTHOR]

Gastroesophageal reflux disease (GERD) is a common gastrointestinal disorder that significantly affects populations in both developing and developed countries. Due to both intrinsic pathology and extrinsic risk factors, the incidence of GERD has risen substantially in recent decades. This disorder results from an imbalance between the esophagus’s defensive mechanisms and the harmful effects of the refluxate. The pepsin, an enzyme secreted exclusively by the stomach, plays a critical role in the pathogenesis of GERD due to its invasiveness effects in acidic environments. By thoroughly understanding the pathogenesis of pepsin-induced GERD, we could better address its diagnostic and therapeutic potential in clinical practice. Although current diagnostic tools are widely used, they have several limitations. As a result, researchers have increasingly focused on the salivary pepsin test, a novel diagnostic method that utilizes the specific pathological mechanisms of pepsin. To overcome the drawbacks of the currently used salivary pepsin test, fluorescence response detection has been integrated with other technologies. Beyond its diagnostic significance, pepsin in saliva may also serve as a target for GERD management in innovative clinical trials. In this review, we summarize the latest advancements in the diagnosis and management of GERD to improve patient outcomes.

BackgroundLaryngopharyngeal reflux (LPR) is defined as an extraesophageal reflux of gastroduodenal contents to the laryngopharynx, affecting the upper aerodigestive tract. There is currently no standardized treatment protocol for LPR. The use of proton pump inhibitors (PPIs) is widely established in common practice and derives from the standard approach of using PPIs to treat patients with gastroesophageal reflux disease (GERD). However, as PPIs may not be effective on all types of reflux, the aim of our study was to evaluate the effectiveness of dietary changes and mucosal protectants, alone or in combination, in LPR treatment.MethodsThis multicenter randomized controlled trial included 48 patients divided into three groups: dietary modifications only, mucosal protectors only, and a combination of both. The patients’ responses were assessed over 1 month using the Reflux Symptom Index (RSI) and Reflux Finding Score (RFS), along with measurements of salivary and nasal pepsin concentration and rhinomanometry.ResultsSignificant improvements were observed in RSI and RFS scores across all groups. The group receiving combined dietary modifications and mucosal protectors showed the most substantial benefits. Additionally, a notable reduction in salivary and nasal pepsin concentrations and nasal resistances was observed, particularly in patients combining dietary modifications and mucosal protectors.ConclusionThe study showed that combined dietary modifications and mucosal protects strategies effectively manage LPR symptoms, offering a potential therapeutic approach.

Abstract Background Reflux symptom index(RSI) and reflux finding score (RFS) are widely used scoring systems used to diagnose laryngopharyngeal reflux disease(LPRD). However many patients do visit the outpatient department with minimal symptoms not sufficient to fit the criteria described by Belafsky et al. for diagnosing LPRD. Most of these patients are provisionally diagnosed and treated for LPRD. Reflux symptom index(RSI) and reflux finding score (RFS) are widely used scoring systems used to diagnose(LPRD) (Belafsky PC et al., J Voice 16(2):274–7, 2002, Belafsky PC et al, Laryngoscope 111(8):1313–7, 2001). RSI has nine questions that the patient must grade from 0 to 5. An abnormal score is greater than 13. Laryngopharyngeal reflux (LPR) may or may not be diagnosed using the RSI and RFS especially when patients present with minimum symptoms not sufficient to score more than 13 and 7 respectively. These patients may miss the diagnosis and have to be treated empirically. Pepsin’s presence in the saliva is indicative of reflux as pepsin is a gastric enzyme (NICE advice on Peptest for diagnosing gastro-oesophageal reflux, 2015, Wood JM et al., J Laryngol Otol 125(12):1218–24, 2011). Patients with minimum symptoms may be missed if diagnosis relies only on RSI AND RFS. The present study aims to see the correlation of pepsin-proven LPRD and RSI and RFS. Methods This is a prospective study, 49 patients with symptoms suggestive of LPRD who tested positive for the pepsin test were further analysed for RSI and RFS. A cut-off value of > 25 ng/mL was considered diagnostic of LPRD (Dhillon VK et al., Curr Gastroenterol Rep 18(8):44, 2016). Result The average RSI and RFS were respectively 10 and 4. The mean age of the patients in the study was 39 years and the mean weight was 60 kg. The association between RSI and PEPSIN detection is considered to be not statistically significant. Chi-squared equals 0.086 with 1 degree of freedom. The two-tailed P value equals 0.7698. Chi-squared equals 0.233 with 1 degree of freedom. The two-tailed P value equals 0.6295. The association between RFS and PEPSIN detection is considered to be not statistically significant. In terms of correlation analysis, neither the RSI nor the RFS had Pearson’s correlation coefficient that was statistically significant. Conclusion Since salivary pepsin detection and the RSI do not have any significant correlation, the RSI is not a valid diagnostic method for LPR and should not be used exclusively. Level of evidence 4.

The study of the extraesophageal reflux effect on the middle ear structures in adults is of considerable interest. The mechanism of formation of gastroesophageal reflux disease associated otitis media is closely related to such concepts as nasopharyngeal reflux and laryngopharyngeal reflux. The article presents an analysis of the medical literature focusing on the mechanisms of development of inflammation mechanisms in the middle ear cavity affected by the gastric contents. The article uses publications in such scientific databases as PubMed, eLIBRARY, Science Direct, Research Gate, dated from 1990 to 2024. A detailed understanding of pathophysiological mechanisms affecting formation of the middle ear cavity inflammation under the influence of extraesophageal reflux has been obtained. Major scientific studies confirm that gastroesophageal reflux disease acts as a risk factor for the middle ear cavity inflammation formation.