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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]

Snakebites envenoming are a global public health problem that largely affects economically vulnerable populations. The primary recognized treatment involves hyperimmune serum, consisting of sterile and heterologous immunoglobulin solutions targeting specific antigens. One established production method in Vital Brazil Institute involves antibody digestion by pepsin, fractionation with ammonium sulfate salt, and thermocoagulation, yielding 30-40% and requiring a 5-day duration. This study aims to assess a novel production method centered on recovering the (Fab')2 fraction using caprylic acid, intending to implement a more efficient technological process. A new methodology was developed, defining digestion conditions (37 °C, pH 3.2; 2.5 g L-1 of pepsin over 120 minutes at 150 rpm) and fractionation parameters (37 °C, pH 5.8; 2% caprylic acid over 60 minutes at 250 rpm). These conditions were established through the application of Quality by Design, supported by a critical risk analysis. This method reduced the usage of raw materials, process time, and labor cost per hour while maintaining yield with greater purity. These modifications were promising, resulting in higher purity and lower manufacturing costs, thereby expanding the prospect of achieving a more robust production process with a safer, optimized product. This allows meeting production goals and exploring new opportunities in foreign markets. [ABSTRACT FROM AUTHOR]

In this study, we evaluated the clinical utility of tracheal aspirates α-amylase (AM), pepsin, and lipid-laden macrophage index (LLMI) in the early diagnosis of ventilator-associated pneumonia (VAP) in elderly patients on mechanical ventilation. Within 96 hours of tracheal intubation, tracheal aspirate specimens were collected from elderly patients on mechanical ventilation; AM, pepsin, and LLMI were detected, and we analyzed the potential of each index individually and in combination in diagnosing VAP. Patients with VAP had significantly higher levels of AM, pepsin, and LLMI compared to those without VAP (P < 0.001), and there was a positive correlation between the number of pre-intubation risk factors of aspiration and the detection value of each index in patients with VAP (P < 0.001). The area under a receiver operating characteristic (ROC) curve (AUC) of AM, pepsin, and LLMI in diagnosis of VAP were 0.821 (95% CI:0.713–0.904), 0.802 (95% CI:0.693–0.892), and 0.621 (95% CI:0.583–0.824), the sensitivities were 0.8815, 0.7632, and 0.6973, the specificities were 0.8495, 0.8602, and 0.6291, and the cutoff values were 4,321.5 U/L, 126.61 ng/ml, and 173.5, respectively. The AUC for the combination of indexes in diagnosing VAP was 0.905 (95% CI:0.812–0.934), and the sensitivity and specificity were 0.9211 and 0.9332, respectively. In the tracheal aspirate specimens, the detection rate of AM ≥ cutoff was the highest, while it was the lowest for LLMI (P < 0.001). The detection rates of AM ≥ cutoff and pepsin ≥ cutoff were higher within 48 hours after intubation than within 48–96 hours after intubation (P < 0.001). In contrast, the detection rate of LLMI ≥ cutoff was higher within 48–96 hours after intubation than within 48 hours after intubation (P < 0.001). The risk factors for VAP identified using logistic multivariate analysis included pre-intubation aspiration risk factors (≥3), MDR bacteria growth in tracheal aspirates, and tracheal aspirate AM ≥ 4,321.5 U/L, pepsin ≥ 126.61 ng/ml, and LLMI ≥ 173.5. The detection of AM, pepsin, and LLMI in tracheal aspirates has promising clinical utility as an early warning biomarker of VAP in elderly patients undergoing mechanical ventilation. [ABSTRACT FROM AUTHOR]

Laryngopharyngeal reflux (LPR) is a common worldwide disease. LPR symptoms may involve distant organs and tissues including the ocular surface with manifestations of a Dry Eye-like disease. We evaluated the concomitant involvement of the ocular surface in patients with LPR. We also defined the clinical signs and the roles of chemical and neuro-inflammatory mediators in the tears of LPR patients. Seventy-seven patients with LPR (mean age 65.8 ± 16.8 SD) and 25 healthy controls (mean age 56.5 ± 16.3 SD) were recruited from the otorhinolaryngology unit. Each subject was evaluated for the presence of concomitant ocular surface disease through clinical examination, including the measurement of tear break-up time (TBUT) and the Ocular Surface Disease Index (OSDI) questionnaire. Tears and conjunctival imprints were collected. The presence of pepsin in tears was detected by ELISA. HLA-DR in conjunctival imprints were imaged by immunofluorescence microscopy. RT-PCR quantified conjunctival mRNA transcripts of HLA-DR, IL-8, MUC5AC, NADPH, VIP, and NPY. Patients with LPR had significantly increased OSDI and reduced TBUT scores compared to control subjects (p < 0.05 each). Pepsin was detected in 51% of patient tears while it was not measurable in the controls (p < 0.01). Immunoreactivity for HLA-DR in the conjunctival impressions was greater than for the controls with an increased mRNA expression (p < 0.05). mRNA transcripts for IL-8, NADPH, and VIP were significantly increased in LPR patients (p < 0.05 each), but neither MUC5AC nor NPY was different from controls. LPR can adversely affect the ocular surface, leading to moderate signs and symptoms of dry eye. This study provides evidence that the presence of pepsin, HLA-DR immunoreactivity, and increased mRNA expression of neuro-inflammatory markers in the tears and conjunctival imprints of LPR patients suggests a potential link between LPR inflammation and ocular surface disease. [ABSTRACT FROM AUTHOR]

Non-acid reflux is the most common form of laryngopharyngeal reflux (LPR). However, the damage caused by non-acid reflux to the laryngeal mucosa is weaker than that caused by acid reflux. To evaluate whether pepsin immunohistochemical (IHC) staining of laryngeal lesions can accurately diagnose acidic and non-acidic LPR. Hypopharyngeal-esophageal multichannel intraluminal impedance-pH monitoring was performed, and the patients were divided into acid reflux and non-acid reflux groups. Pathological sections of laryngeal lesions were examined using pepsin IHC staining, which was positive when pepsin was detected in the cytoplasm. The study included 136 patients, with 58 in the acid reflux group, 43 in the non-acid reflux group, and 35 in the without reflux group. There were no significant differences in the positive rate of pepsin IHC staining between the non-acid and acid reflux groups (p =.421). The sensitivity of pepsin IHC staining for the diagnosis of acid and non-acid reflux was 94.8% and 90.7%, respectively. The sensitivity of pepsin IHC staining for laryngeal lesions in the diagnosis of non-acidic LPR is satisfactory. Pepsin IHC staining is suitable for LPR screening of patients with laryngeal lesions as it is economical, non-invasive, and highly sensitive. [ABSTRACT FROM AUTHOR]

The aim of the study was to evaluate the whey protein hydrolysate with bio-functional attributes viz. antioxidative, anti-inflammatory and ACE inhibition efficacy and release of bioactive peptides with antioxidative and ACE-inhibitory activity by employing Pepsin. The antioxidant, Anti-inflammatory, ACE inhibitory and proteolytic activities of the whey protein hydrolysates were studied followed by SDS-PAGE analysis and IEF. Anti-inflammatory activity of whey protein hydrolysate was also studied on RAW 264.7 cell line. The separation of the bioactive peptides from whey protein hydrolysate was achieved by RP-HPLC. The purified bioactive peptides were identified and characterized using RPLC/MS. WPC (Whey protein concentrate) hydrolysate with pepsin showed proteolytic activity ranging between 14.46 and 18.87 mg/ml. Using the ABTS assay, the highest antioxidative activity was observed in 10 kDa retentate (84.50%) and 3 kDa retentate (85.96%), followed by the highest proteolytic activity (13.83 mg/ml) and ACE inhibitory activity (58.37%) in a 5% WPC solution at 65 °C after 8 h of pepsin hydrolysis. When the protein hydrolysate concentration was low, the production of proinflammatory cytokines by lipopolysaccharide-treated murine macrophages (RAW 264.7) was reduced. SDS-PAGE results exhibited very little protein bands when comparing with WPC hydrolysates to insoluble WPC. There were no protein spots on 2 D gel electrophoresis and "in-solution trypsin digestion" technique have been utilized to digest protein samples directly from WPC hydrolysates. Novel antioxidative peptides and ACE inhibitory peptides were also observed by comparing two databases, i.e., BIOPEP and AHTPDB respectively. The peptide sequences used in this study were found to have excellent potential to be used as inhibitors of hACE as all of them were able to show substantial interactions against the enzyme's active site. The antihypertensive and antioxidative peptides from whey protein hydrolysates may be beneficial for the future development of physiologically active functional foods. Further, in vivo investigations are required to establish the health claim for each individual bioactive peptide from whey protein hydrolysate. Supplemental data for this article is available online at [ABSTRACT FROM AUTHOR]

The objective of this study was to perform prediction in silico of bioactivity, toxicity, allergenicity, and cell penetration potentials and evaluate, in vitro, the biological activities of swine plasma hydrolysates obtained using pepsin. The size of the peptides was determined through SDS-PAGE electrophoresis and the presence of functional groups through Fourier transform infrared spectroscopy (FTIR). Proteins and peptides were separated by online nanoscale capillary liquid chromatography and analyzed by tandem mass spectrometry with nanoelectrospray (nanoESI MS/MS). In silico potentials were obtained using digital platforms. Antioxidant activity, inhibition of α-amylase and α-glucosidase digestive enzymes, and inhibition of angiotensin-I converting enzyme were determined in vitro. The maximum degree of hydrolysis (28.44%) was obtained at 42 °C, pH 2, and 125 rpm. Peptides with sizes inferior to 10 kDa were obtained, and the FTIR spectra showed the efficiency of the enzyme. A total of 129 proteins and 376 peptides were identified, of which 72 presented bioactive potential. No bioactive peptide presented toxicity potential. However, 79.17% are possible allergens. Six bioactive peptides are cellular penetrants. The need for further in vitro evaluation is evident. The antioxidant activity values were considered satisfactory, with DPPH radical scavenging and iron-reducing power, more than 80%. All hydrolysates tested inhibited α-amylase and α-glucosidase, however, a low inhibition. The maximum inhibition of the angiotensin-converting enzyme was 15.41%. For these enzymes, the values of inhibition can be increased with the purification of peptides that have bioactivity, identified in the in silico study. Swine plasma can be a protein source with the potential to provide compounds with biological activities for functional/nutraceutical application. [ABSTRACT FROM AUTHOR]

Several scientific studies to evaluate the process of digestion and fractionation of immunoglobulins have been carried out in order to improve the production of hyperimmune sera. Today, quality, safety, and production efficiency, along with the development of optimized, robust, and cost-effective processes are priorities. Thus, this work analyzed previous studies of enzymatic digestion of heterologous immunoglobulin G, as well as studies of protein fractionation with caprylic acid, to verify the experimental conditions and their impacts on production processes. The establishment of possible variables; such as concentration, pH, time, and temperature; may allow optimization of the production of hyperimmune sera. Most of the digestive processes evaluated took place at 37° C, pH 3.2, with times longer than 90 minutes, and pepsin inactivation between pH 7.0 and 7.2, while fractionation with caprylic acid used a concentration of 5%, 37° C, and pH 5.0–5.8, for 60 minutes. This work aimed to establish, the ideal conditions to be applied in the production of hyperimmune sera. [ABSTRACT FROM AUTHOR]

The biofilm lifestyle plays a major role in the resistance and virulence of Pseudomonas aeruginosa and Enterococcus faecalis. In this study, two microencapsulated proteases (pepsin ME-PEP and trypsin ME-TRYP) were evaluated for their biofilm dispersal activity and their synergistic effect with microencapsulated carvacrol (ME-CARV). Spray-drying was used to protect enzymes and essential oil and enhance their activities. Cell count analysis proved the synergistic activity of enzymes and carvacrol treatment as biofilms were further reduced after combined treatment in comparison to ME-CARV or enzymes alone. Furthermore, results showed that sequential treatment in the order ME-TRYP - ME-PEP - ME-CARV resulted in more efficient biofilm removal with a maximum reduction of 5 log CFU mL−1 for P. aeruginosa and 4 log CFU mL−1 for E. faecalis. This study proposes that the combination of microencapsulated proteases with ME-CARV could be useful for the effective control of P. aeruginosa and E. faecalis biofilms. [ABSTRACT FROM AUTHOR]

Owing to their central roles in cellular signaling, construction, and biochemistry, collagen-collagen interactions, and collagen self-assembly have become a major focus of molecular design and synthetic biology. The well-ordered assembly of collagen molecules on mica has attracted extensive attention for its essential applications and studies on the self-assembly process as a model system. Although collagen assembly mediated by various ions on mica has been reported over these years, specific effects of transition metal ions in this field have never been deeply surveyed and discussed till now. In this work, type I collagen extracted from rat tail tendon by pepsin solubilization method was selected to explore the kinetic process and self-assembly characteristics. In the presence of Cu2+ and Zn2+ sulfates, the turbidity method was used to directly measure the kinetic process of collagen self-assembly and atomic force microscopy (AFM) was applied to observe the patterns of collagen self-assembly on mica. The results showed that the favorable properties of transition metal coordination (bonding strength, directionality, and reversibility) were helpful for increasing the collagen fibrillogenesis rate, and at different ion concentrations, Cu2+ and Zn2+ ions affected the interactions between collagen molecules and mica surface by destroying the hydration membranes on the surface of collagen molecules and the hydrogen bonds between the amino acid residues of collagen molecules. Circular dichroism (CD) analysis demonstrated that collagen had complete triple-strand conformation in the presence of Cu2+ and Zn2+. These results and analysis would be helpful for directing the patterns of collagen self-assembly on a solid surface and provide theoretical guidance for creating collagen-based high-performance materials and/or adding functionality in materials for various applications. [ABSTRACT FROM AUTHOR]

Amaranth is a protein-rich seed, highly consumed in Mexico and reported as a potential source of bio-peptides with physiological function. Therefore, the objective of this study was to evaluate and identify bioactive peptide sequences from amaranth protein fractions released by pepsin and pancreatin in vitro digestion. Multifunctional bioactivities of peptides were measured through antihypertensive, antithrombotic and antioxidant assays. Peptide sequences were identified by analysis with a Nano-LC-ESI-MS/MS. With these results, it was demonstrated that the in vitro enzymatic digestion mechanism allows the release of multifunctional bioactive peptide fractions from amaranth proteins. [ABSTRACT FROM AUTHOR]

In recent years, there has been a lot of interest in the modern organic synthesis using enzymes as biocatalysts. A multicomponent reaction of 4-formylphenyl benzoates, malononitrile, and pyrazolones utilizing pepsin as a biocatalyst was investigated in different reaction conditions. The best yields of pyrano[2,3-c]pyrazoles were obtained by grinding the respective reactants in a mortar in the presence of pepsin for 1.5–2 h at room temperature. Instead of pyrazolones, 1,3-cyclic diketones and 4-arylazo-5-aminopyrazoles were used to prepare new series of 4H-chromenes, and pyrazolo[1,5-a]pyrimidines in good to excellent yields after grinding the respective reactants for 0.5–3 h. The new target molecules showed a wide range of antibacterial activity against four different ATCC bacterial strains. The pyrazolo[1,5-a]pyrimidines 14a and 14f displayed moderate antibacterial activity against the K. pneumoniae and S. aureus strains with inhabitation zones of 29.6–30.3 mm and MIC values of 125–250 μg/mL. [ABSTRACT FROM AUTHOR]

The aim of this study was preparation of a soybean protein hydrolyzate with thrombin inhibitory activity and isolation, identification, and characterization of the active peptides from the hydrolyzate. In this study, a soybean protein hydrolyzate with the thrombin inhibiting IC50 value of 2.78 mg/mL was prepared under the improved pepsin hydrolysis condition, which exhibited the highest thrombin inhibitory activity in these soybean protein-derived hydrolyzates. A novel nonapeptide FFPDIPKIK with the IC50 value of 2.36 mM was screened from the hydrolyzate by in silico methods. The kinetic studies and molecular docking showed that the nonapeptide adopted a mixed-type mode to inhibit thrombin and bound with thrombin with several hydrogen bonds and hydrophobic interactions. The nonapeptide was partially digested using the in vitro digestion model, and its truncated peptides had comparable thrombin inhibitory activity. The results suggested that soybean protein hydrolyzate could be exploited as a functional food ingredient against coagulation. [ABSTRACT FROM AUTHOR]

Portulacca oleracea L. has been used for treatment of different ailments. The aim of this study was to investigate the effectiveness and possible mechanism of action involved in the anti gastric ulcerogenic effect of Portulacca oleracea. Methanolic extract & subsequent fractions (100, 200 and 400 mg/kg) of Portulacca oleracea (P. oleracea) were administered orally to experimental rabbits one hour before oral administration of HCl/ethanol (40:60). Anti gastric ulcerogenic potential of P. oleracea was evaluated by assessment of gastric pH, pepsin, free acidity, ulcer index, mucus content and total acidity. For the investigation of possible mechanism of action malondialdehyde (MDA), histamine, and H + K + ATPase content were determined in the stomach homogenate. Histopathological study of stomach tissue was carried out by H&E dye. Ethyl acetate fraction (EAF) of P. oleracea was the most potent fraction among all fractions that exhibited efficient protection against acidified ethanol mediated gastric-ulcer. The ethyl acetate fraction (EAF) significantly increased the pH of gastric juice, while pepsin and histamine was observed to decrease significantly in comparison to acidified ethanol group (***p ≤ 0.001). The EAF showed moderately H + K + ATPase inhibitory activity. Moreover, it was also observed that EAF decreased the malondialdehyde (MDA) level in the stomach tissue homogenate showing antioxidant effect. Histopathological studies showed that among the tested fractions, EAF significantly prevented acidified ethanol induced gastric mucosal damage. These results showed that mechanism of anti gastric ulcerogenic potential of P. oleracea could be associated with the reduction in histamine level, H + K + ATPase inhibition and reduced MDA level. [ABSTRACT FROM AUTHOR]

Laryngopharyngeal reflux (LPR) is a prevalent disease in the ENT outpatient department. Methods of LPR diagnosis differ much. Narrow-band imaging (NBI) and Salivary pepsin-level measurements have been considered as totally new ways for the diagnosis of LPR in recent years. We aimed to identify the specific manifestation of LPR and assess the correlation between NBI views and pepsin levels in LPR diagnosing. 130 Patients enrolled in our study were divided into LPR group and non-LPR group according to the scores of RSI and RFS. All individuals received endoscopic NBI tests and salivary pepsin measurements. NBI views of the larynx were divided into four grades based on the existing descriptive guidelines and our clinical observations, and the correlation between NBI grading and salivary pepsin levels was calculated. NBI grading and pepsin levels are significantly correlated with RFS/RSI scores. The diagnostic concentration of salivary pepsin was 33 ng/ml. There was a significant correlation between NBI grading and salivary levels. NBI grading system was proved to provide a better diagnostic value in the diagnosis of LPR. There was a possibility that a combination of these two methods might increase the diagnostic accuracy of this disease. [ABSTRACT FROM AUTHOR]

Bacteria infection and laryngopharyngeal reflux (LPR) were believed the important pathogenesis of chronic otitis media with effusion (COME). But no study researched the relationship between them on COME. To confirm bacterial could arrive middle ear through LPR and produced acid metabolites to activate the pepsinogen of LPR causing COME. Children (65) diagnosed COME with 122 middle ear effusions were included in COME group. Children (22) with congenital/acquired profound deafness with 22 middle ear lavage were included in CI group. Pepsin A concentration in the effusion and lavage fluid were measured. The DNA of the bacteria, IL-8 and TNF-α in the effusion were detected. The average concentration of pepsin A in the effusions and lavage were 176.65 ± 242.09 and 19 ng/ml. Bacterial infection rates were 75.76% and 24.24% in the pepsin A(+) and pepsin A(−) patients. In the bacterial (+), the patients of pepsin A(+) was 4.33 times higher than those of pepsin A(−). TNF-α in pepsin A(+) was higher than that in pepsin A(−). TNF-α and IL-8 were higher in bacteria(+) than those of bacteria(−). Bacterial infection and LPR might act in synergy in the pathogenesis of COME. First time to propose LPR and bacterial infection might work synergistically to cause COME [ABSTRACT FROM AUTHOR]

Gastroesophageal reflux disease (GERD) is a prevalent gastrointestinal disorder with substantial morbidity. However, the reliable, non-invasive, and specific diagnosis of GERD remains a challenge due to the lack of specific symptoms and imaging features. Herein, we report a supramolecular tandem assay through using a reporter pair of sulfonatocalix[4]arene and lucigenin for the sensitive and real-time detection of saliva pepsin, an ideal biomarker for GERD. Moreover, we achieve the detection of pepsin in commercial artificial saliva, demonstrating the potential of this supramolecular approach for point-of-care testing of GERD. [ABSTRACT FROM AUTHOR]

This investigation focused on the sustainable valorization of red-bellied pacu (RBP) skin towards finding an alternative to bovine and porcine collagen. Acid-soluble collagen (ASC, 45.8 ± 0.7%) and pepsin soluble collagen (PSC, 57.8 ± 1.9%) were successfully extracted from RBP skin and comparatively elucidated their characteristics and in-vitro fibril-forming potential. The extracted collagens were characterized as type I collagen and confirmed the well-preserved triple-helical configuration by sodium dodecyl sulphate polyacrylamide gel electrophoresis and Fourier transform-infrared spectroscopy analysis. Both ASC and PSC exhibited relatively better thermo-stability, and the denaturation temperatures were found to be 35.5–35.29 °C by differential scanning calorimetry analysis. Both collagens displayed higher (p ≤ 0.05) solubility at low NaCl concentrations. The extracted ASC and PSC showed the same degree of fibril-forming capacities and confirmed well-defined fibril morphologies. Overall, the results showed the possibilities of effectively exploring RBP skin as a potential alternative source for realistic and safe collagen for food, nutrition, pharmaceutical, and other applications. [ABSTRACT FROM AUTHOR]

Backgound: Pepsin immunohistochemical (IHC) staining is a promising diagnostic approach of laryngopharyngeal reflux (LPR). The interarytenoid mucosa has been proved to be an effective biopsy area. Objectives: To investigate whether positive result of pepsin IHC staining in laryngeal lesions can predict LPR. Methods: The study included 136 patients with laryngeal cancer or vocal cord leukoplakia. 24 h multichannel intraluminal impedance-pH (MII-pH) was performed before operation, and pepsin IHC staining was performed on pathological sections after operation. The results of the two methods were compared. Results: Among the 136 patients, 101 with at least one LPR event were regarded as MII-pH positive group, and another 35 were negative. The positive rate of pepsin IHC staining was 93.1% in MII-pH positive group and 54.1% in MII-pH negative group (p <.05). If the MII-pH results were used as a reference, the sensitivity and specificity of pepsin IHC staining in the diagnosis of LPR were 93.1 and 45.7%, respectively. The consistency of pepsin IHC and MII-pH was moderate (Kappa value = 0.452). Conclusions: The sensitivity of pepsin IHC staining in laryngeal lesions for diagnosing LPR is satisfactory. The existence of false negative of MII-pH may be the main reason for the low specificity. [ABSTRACT FROM AUTHOR]

Peptic hydrolysates were prepared by digesting the cutlassfish muscle protein using pepsin for 1, 3, and 6 h, and their inhibitory activity against angiotensin-I converting enzyme (ACE) was studied. The ACE-inhibitory effect of the peptic hydrolysate of cutlassfish muscle generated at the 3 h time point exhibited the strongest activity. After identifying the optimal hydrolysate, the active peptide was isolated by ultrafiltration, gel permeation, and high performance liquid chromatography (HPLC). The resulting purified peptide was characterized using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF/TOF MS/MS) and was identified to be a 496.44 Da pentapeptide (Phe-Ser-Gly-Gly-Glu). The ACE-inhibitory activity of the active peptide exhibited an IC50 value of 0.033 ± 0.003 mg/ml. A molecular docking program was used to simulate the interaction between the peptide and ACE, which revealed that the inhibitory effect was mainly due to the hydrogen bonds between ACE and the peptide. Based on the ACE-inhibitory properties and the molecular docking study of the resulting active peptide, we demonstrated an increase in nitric oxide (NO) production in a dose-dependent manner. In conclusion, cutlassfish protein hydrolysate and the resulting active peptide could be used as active ingredients in functional food as anti-hypertensive agents. [ABSTRACT FROM AUTHOR]

Protein hydrolysates usually possess higher nutritive value than an equivalent mixture of free amino acids. This study was aimed at determining the antioxidant activities of protein hydrolysates of Treculia africana seeds. Soluble protein was isolated from Treculia africana seed flour by alkaline solubilization and acid precipitation, and further hydrolyzed with three proteases (trypsin, pancreatin and pepsin) individually and in a sequential two- and three-protease systems. Antioxidant activities (DPPH, FRAP and lipid peroxidation) of the hydrolysates were investigated. Hydrolysates from Treculia africana seed protein showed varying degree of hydrolysis, pancreatin hydrolysates had the highest (94.92%) and pancreatin-pepsin hydrolysates had the least (6.59%). Pancreatin proved to be the most efficient protease for hydrolyzing Treculia africana protein with a high protein recovery of 156.06 mg/ml. Its hydrolysates exhibited the highest DPPH scavenging activity (71.02%) and had a high radical-mediated peroxidation of oleic acid. Likewise, pancreatin hydrolysates as well as trypsin-pancreatin hydrolysates showed the highest FRAP activity (37.17 and 38.52 µg/ml BHA, respectively). Pancreatin hydrolysates showed significant higher (p < 0.05) antioxidant potentials than other hydrolysates of T. africana seed protein. These findings showed the potential use of Treculia africana hydrolysates as antioxidants in reducing food spoilage and management of oxidative stress-related metabolic disorders. [ABSTRACT FROM AUTHOR]

The usage of porcine pepsin or other porcine derivatives in food products is a common practice in European, American and certain Asian countries although it creates issues in religious and personnel health concerns. In this study, porcine pepsin was detected using indirect ELISA that involved the anti-pep80510 polyclonal antibody raised against a specific peptide of porcine pepsin, pep80510. The sensitivity of the assay for standard porcine pepsin was 0.008 µg/g. The immunoassay did not cross-react to other animal rennet and milk proteins except for microbial coagulant from Mucor miehie. The recovery of porcine pepsin in spiked cheese curd within the range of CV < 20% while for porcine pepsin in spiked cheese whey the recovery is also within the range of CV% < 20%. [ABSTRACT FROM AUTHOR]

One member of the polychlorinated biphenyls that is linked to a number of human diseases is 3,3′,4,4′,5-pentachlorobiphenyl. Here, density functional theory calculation, molecular simulations and multi-spectroscopic techniques were utilized to evaluate the interaction mechanism of 3,3′,4,4′,5-pentachlorobiphenyl with the pepsin, the digestive enzyme. The results of density functional theory and molecular simulations demonstrated that 3,3′,4,4′,5-pentachlorobiphenyl could be a good candidate for its availability toward pepsin with a frontier orbital gap of 0.18109 eV, and bound to the hydrophobic cavity of pepsin. The steady-state fluorescence and time-resolved fluorescence revealed that the quenching was initiated by complexation of pepsin and 3,3′,4,4′,5-pentachlorobiphenyl with the binding constant of 105 order. The UV-absorption, synchronous fluorescence spectroscopy, Fourier transform infrared spectroscopy, circular dichroism spectroscopy, and three-dimensional fluorescence data further confirmed that the changes in the secondary structure of pepsin were induced on the presence of 3,3′,4,4′,5-pentachlorobiphenyl, and a quantitative analysis of the secondary structure elements in pepsin was obtained. [ABSTRACT FROM AUTHOR]

Kaempferia parviflora, a medicinal herb, treats hypertension and promotes longevity with good health and well-being. Its bioactive component is poorly soluble in water, resulting in poor absorption. This study aimed to enhance the bioavailability of K. parviflora dichloromethane (KPD) extract using a self-nanoemulsifying drug delivery system (SNEDDS). KPD was dissolved in diethylene glycol monoethyl, polyoxyl-35 castor oil and caprylic/capric glyceride, and clear yellow SNEDDS solution was obtained. The methoxyflavone markers were used for content and dissolution analysis. Solid SNEDDS was prepared by stepwise mixing of KPD using a mortar and pestle (1:1 ratio) with five solid carriers: Aerosil® 200, Florite® RE, Neusilin® US2 (NEUS), Fujicalin®, and Neusilin® UFL2. The USP apparatus II with simulated gastric fluid USP (SGF without pepsin, pH 1.2) was used in order to perform the in vitro dissolution. The methoxyflavones dissolution at 60 min from KPD, SEDDS, and SNEDDS/NEUS were approximately 16, 92, and 73%, respectively. The pharmacokinetic profiles of methoxyflavones for oral administration were studied using Wistar rats; the areas under the curve of SNEDDS/NEUS (1.77-fold) and SNEDDS (5.38-fold) were significantly higher than that of KPD. The developed formulations showed good stability after storage for 6 months under accelerated and normal conditions. [ABSTRACT FROM AUTHOR]

Pepsin enzyme from skipjack tuna was extracted for the production of kawakawa (Euthynnus affinis) fish protein hydrolysate. Using ultra-fractionation, Kawakawa protein hydrolysates were separated into four different fractions, including fractioned protein hydrolysate I (FPH I) (< 1 kDa), FPH-II (1–3 kDa), FPH-III (3–10 kDa), and FPH-IV (> 10 kDa). The antioxidant activity was assessed by 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity, inhibition of linoleic acid oxidation, reducing power tests, and chelating activity of metal ions. Results indicated that FPH II fraction peptides had higher antioxidant activity in comparison with the other fractions, followed by FPH I. Further, the fractions were evaluated for angiotensin converting enzyme (ACE) inhibition, and IC50 value ranged from 0.45 to 1.86 mg/ml with higher activity in FPH I (IC50 0.45). Finally, the amino acid profile of different fractions was analyzed. The fractions exhibited significant amounts of hydrophobic amino acids, which could perform as hydrogen donors, frustrate the free radicals, and inhibit the ACE. The recovered pepsin from the viscera was used to produce hydrolysates with good biological activities. Peptides lower than 3 KDa had antioxidant activity as positive controls and significant ACE activity. These are very important findings that could be used to conduct further research in a preclinical study of these peptides. [ABSTRACT FROM AUTHOR]

In order to study the interaction mechanism between meloxicam and pepsin, the interaction between meloxicam and pepsin was studied by fluorescence spectroscopy, UV-visible absorption spectroscopy, circular dichroism spectroscopy and molecular docking under physiological conditions (pH = 2.20). The results of spectral experiments showed that meloxicam quenched the intrinsic fluorescence of pepsin by static quenching, formed a stable complex at 1:1, and changed the conformation of pepsin. The thermodynamic results showed that the main force type of meloxicam and pepsin system was hydrophobic interaction. Molecular docking showed that there was a hydrogen bond in addition to hydrophobic interaction, and the best binding site between meloxicam and pepsin was near the catalytic active center of pepsin. The results showed that the combination of the meloxicam and pepsin changed the microenvironment of amino acid residues at the catalytic active center of pepsin. Under the experimental conditions, the protein binding rate of meloxicam to pepsin W(B) was 2.97–48.3%, indicating that the binding of meloxicam to pepsin had an effect on the number of free pepsin. The drug binding rate of the system W(Q) was 2.97–1.39%, indicating that the binding effect of meloxicam and pepsin on the number of free drug molecules was weak, so the binding effect would not have a significant effect on the efficacy of meloxicam. [ABSTRACT FROM AUTHOR]

Casein is an excellent carrier for curcumin, but it is susceptible to hydrolysis in gastrointestinal digestion. This study intended to design a tailored nano-carrier composed of camel casein/bovine whey protein to protect casein and curcumin during digestion. After loading curcumin to the casein, whey protein was added to solution followed by heating at 80°C for 10 min in order to form casein/whey protein aggregations. Binding of curcumin to the solution was assayed by fluorescence. The results showed that in the existence of aggregated whey proteins, stability of curcumin against gastrointestinal condition significantly improved. These results attributed to the protective effect of the aggregated whey proteins during the gastric digestion and denaturation in the accessibility of pepsin to the casein. It was demonstrated that this method might be a good design to combat susceptibility of casein without the use of any synthetic material. [ABSTRACT FROM AUTHOR]

Ara h 1 is one of the major allergens existed in peanut, peptides formed in the digestion process of Ara h 1 could induce allergic symptoms and cause local inflammatory. The mechanism of intestine epithelial immune has not been clarified yet. Here we explored the effect of digestion on the immunoreactivity and proinflammatory properties of recombinant Ara h 1 (rAra h 1). rAra h 1 was treated (or untreated) with heat, digested by pepsin. According to the results, in the early period of digestion, both native and heated rAra h 1 were degraded. Q-PCR and Western-blot results revealed that the NF-κB pathway was involved in the cytokine secretion. The proinflammatory effect were less pronounced in the samples treated with heat, demonstrating that digestion, instead of thermal process, could modify the proteins and peptides, which could then play a significant role in the activation of Caco-2 cells via the NF-κB pathway. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the effect of right lateral positioning in comparison with supine positioning on tracheal aspirate pepsin levels as a marker of aspiration of gastric contents in ventilated preterm neonates. Study design: This randomized controlled trial was conducted on 60 ventilated preterm neonates <35 weeks; 30 neonates were nursed in right lateral position for 6 hours while the other 30 neonates were nursed in supine position for 6 hours. Tracheal aspirate sample was obtained from each neonate in both the groups just after the end of 6 hours and pepsin level was measured. Results: Neonates in right lateral position group had significantly lower tracheal pepsin level than neonates in supine position group (6 ng/ml) interquartile range [IQR] (3–20) versus 15 ng/ml [IQR] (5.5–90) (p =.024). There is positive correlation between tracheal aspirate pepsin level and fraction of inspired oxygen (FiO2) needed during the intervention (r = 0.383, p =.040). There is no correlation between tracheal pepsin level and gestational age, birth weight, or duration of mechanical ventilation and other ventilatory settings. Conclusion: Nursing ventilated premature infants in right lateral position is associated with decreased aspiration of gastric contents. [ABSTRACT FROM AUTHOR]

High Fischer ratio oligo-peptides hydrolysate (DAHFP) from minced meat of Skipjack (Katsuwonus pelamis) were prepared by hydrolysis of pepsin and flavourzyme, then adsorpte on activated carbon. DAHFP was separated by Sephadex G-25 to obtain two fractions with molecular weight of 600 and 1300 kDa, which had the Fischer ratios of 37.52 and 32.08, respectively. The activity of the active component of DAHFP (AC- DAHFP) from combining two fractions was evaluated. Results showed that the maximum extension rate of the loss time of righting reflex was 33.68% and the maximum shortening rate of sober-up time was 29.98%. The difference in content of hepatic glycogen (HG) and blood urea nitrogen (BUN) was significant (P <.05) among the high, moderate dose groups and the blank group. All results indicated that AC- DAHFP could be used in anti-drunken, sobering-up and anti-fatigue. Additionally, peptides were isolated from two fractions using C18 reversed phase high-performance liquid chromatography (RP-HPLC). Five of the peptide sequences were detected as Leu-Leu-Tyr-Ala-Ala-Gly-Ala; Leu-Leu-Asp-Val-Tyr; Leu-Leu-Phe-Thr-Thr-Gln; Leu-Leu-Tyr-Val-Tyr-Gln; Tyr-Val-Ser-Trp-Lys-Leu. [ABSTRACT FROM AUTHOR]

Pepsin-soluble collagen (PSC) was extracted and purified from wasted skin and bone of the golden pompano by acetic acid-pepsin method. The result showed that the PSCs extraction yields of skin and bone were 21.81% and 1.25% (wet weight), 62.21% and 1.78% (on the basis of lyophilized dry weight), respectively. Golden pompano skin and bone PSCs contained the typical chain of α and β dimers, and they were preliminarily judged to belong to type I collagen. The skin PSC had similar amino acid composition to bone PSC, which is rich in glycine, alanine, proline, and hydroxyproline. After addressing the pepsin, three helical structure of PSCs were intact, and their natural structures largely remained. The denaturation temperatures of skin and bone PSCs were 37.04°C and 38.23°C, respectively. Solubility results showed that the skin and bone PSCs solubility was the largest at pH = 3. The solubility of skin and bone PSCs was stable at NaCl concentrations lower than 3%. In addition, two PSCs in acid and low salt conditions had good solubility. This study demonstrated that golden pompano skin and bone could be used as good materials to extract PSC, representing an economic benefit and added value. Abbreviations: SDS-PAGE: Sodium dodecyl sulfate polyacrylamide gel electrophoresis; FTIR: Fourier transform infrared; DSC: Differential scanning calorimetry; XRD: X-ray diffraction [ABSTRACT FROM AUTHOR]

The mechanism of interaction between cefonicid sodium and pepsin was investigated by various spectroscopic methods and molecular docking. Cefoncid sodium quenched the intrinsic fluorescence of pepsin at pH of 2.0 to form a new complex in a 1:1 binding mode driven by Van der Waals and hydrogen bonds. The mechanism of quenching was static. The results of molecular docking indicated that the cefonicid sodium-binding site was located in the active site of pepsin. The protein binding rates of cefonicid sodium in gastric juice was calculated and the binding model was established. It is concluded that cefonicid sodium is not suitable for oral administration. [ABSTRACT FROM AUTHOR]

Collagen is a major component of the extracellular matrix and is used as a material in tissue engineering. We demonstrated the extraction of atelocollagen from porcine auricular and characterized its unique physical and biochemical properties. Extracted type I collagens of auricular collagen using acetic acid and pepsin (PAC) showed superior fibrillogenesis and viscoelasticity compared to type I collagen from porcine skin. The observation of PAC fibrils by transmission electron microscopy and Atomic Force Microscope under physiological conditions revealed long fibrils with pronounced 3D structures, while type I collagen from porcine skin revealed a flat structure. Furthermore, a PAC-coated plate promoted higher cell proliferation than when grown on a skin type I collagen-coated plate. Porcine auricular type I collagen has superior biophysical and biological properties in terms of viscoelasticity, fibrillogenesis, and cell proliferation, and can be used in further studies toward novel potential applications in the field of medical materials. [ABSTRACT FROM AUTHOR]

The typical intervention for iron-deficiency anaemia is through oral supplementation with iron salts, which have unpleasant side effects. Therefore, there is a need for the development of supplements which will be absorbed more effectively and may have fewer side effects. This study investigated the effects of partially hydrolysed pork proteins on the bioavailability of non-haem iron. The peptides were derived using either pepsin or a combination of bacterial and fungal proteases, and their ability to deliver iron was evaluated in a rat intestine epithelial tissue model. The greatest iron absorption was achieved with peptides hydrolysed by pepsin of low molecular weight (<6-8 kDa). The peptides hydrolysed with bacterial and fungal enzymes may have bound to the iron too strongly, affecting bioavailability. Finally, hydrolysing proteins using pepsin in the presence of iron produces a complex that resulted in more ferritin expression than mixing the peptides with iron after hydrolysis. [ABSTRACT FROM AUTHOR]

The present study aimed to evaluate structure and digestibility of dry-cured ham in relation to different cooking temperatures (70, 100 and 120°C), and further assess the relationship between structure and digestibility. The secondary structure analysis showed that the content of α-helix decreased from 55.03% to 20.61%, accompanied by an increase in the content of β-sheet and random coil from the raw to 120°C. The digestibility showed that proteolysis rate of myofibrillar proteins by pepsin and trypsin & α-chymotrypsin (digestive enzymes) significantly increased to 0.62 and 0.51 at 100°C, compared with the raw. Odour and taste were susceptible to cooking temperature, and 100°C enhanced odour and taste attributes of ham. The changes of protein conformation were closely related to the digestibility. Correlation analysis further demonstrated that activities of digestive enzymes for proteins were negatively correlated with α-helical and β-sheet, and positively correlated with β-turn and random coil. [ABSTRACT FROM AUTHOR]

Recent evidence provides that seafood has a lot of health benefits due to its unique bioactive compounds. Sea squirt is widely cultured and consumed as a foodstuff in Korea; however, seldom reports with reference to bioactivities are available until now. In this study, edible part of sea squirt was hydrolyzed by pepsin and its hydrolysates was evaluated for anticancer effect on human colon cancer HT-29 cells. Sea squirt hydrolysates (SSQ) reduced HT-29 cell viability. Treatment with SSQ resulted in the increase in reactive oxygen species (ROS) generation followed by disruption of mitochondrial membrane potential (MMP). Flow cytometry analysis revealed that SSQ induced G2/M phase arrest and apoptosis evidenced by Hoechst 33342 staining. Levels of mRNA expression by real-time polymerase chain reaction (PCR) showed that treatment with SSQ in HT-29 cells upregulated expression of p53, bax, and caspase-3 genes and downregulated expression of bcl-2 gene. Protein level of cytochrome c into cytosol and caspase-3 by Western blotting were also increased by treatment with SSQ in HT-29 cells. These results suggest that SSQ may be useful for functional food ingredients and/or nutraceuticals. [ABSTRACT FROM AUTHOR]

The objectives of the present work were first to evaluate the sensitivity to cow raw milk of the population of Fez, and then to study the effect of heating and pepsin hydrolysis on the allergenicity of casein. A cross-sectional study was carried out in Fez Hospitals, in which 1000 patients were recruited to establish a sera bank used to evaluate specific IgE to cow milk and to casein. Then, we evaluated the reaction of human IgE to heated and pepsin-hydrolysed casein. The results showed that 11.5% of the population studied self-reported reactions to foods. From them, 3.6% reported allergy to milk. Evaluation of specific IgE to cow raw milk showed that 11.9% of patients presented higher specific IgE levels. The treatments of casein indicated that both heating and pepsin hydrolysis totally decreased its binding on the human IgE. [ABSTRACT FROM AUTHOR]

The major objective of this study was to investigate the pepsin digests of cutlassfish muscle for their antioxidant activity. The peptide isolated after 3 h of pepsin hydrolysis demonstrated the highest scavenging activity for both 1,1-Diphenyl-2-picrylhydrazyl (DPPH) and alkyl radicals. It also had the highest yield of the isolates with the highest protein content, which was likely related to its higher degree of hydrolysis than the other hydrolysates. The antioxidant peptide purified from the 3 h pepsin hydrolysate indicated the amino acid sequence, Phe-Ser-Gly-Gly-Glu. This study suggests that cutlassfish muscle is an excellent antioxidant source and could be effectively used as a food ingredient and in pharmaceuticals. [ABSTRACT FROM AUTHOR]

The interaction between trelagliptin and pepsin was probed through spectroscopy methods and molecular dynamics simulation. Results of fluorescence lifetime and fluorescence spectroscopy analysis showed that trelagliptin can spontaneously interact with pepsin through a static quenching. This interaction was mainly driven by hydrogen bonding and van der Waals, as evident from thermodynamic parameters and molecular dynamics simulation. The microenvironment of tyrosine residues and the secondary structure of pepsin were slightly influenced by trelagliptin based on synchronous fluorescence, three-dimensional fluorescence, and circular dichroism spectra. In addition, the activity of pepsin was hardly affected by the insertion of trelagliptin. Molecular dynamics simulations were used to further analyze the pepsin-trelagliptin complex. This study provides useful information for binding mechanisms of trelagliptin on pepsin. [ABSTRACT FROM AUTHOR]

This study aimed to investigate in vitro and in vivo the probiotic characteristics of lactic acid bacteria (LAB) isolated from Korean traditional fermented foods. Caenorhabditis elegans  (C. elegans) was used for analytical assays of fertility, chemotaxis, life-span, worm-killing and bacterial colonization in the intestinal lumen of the worm. All 35 strains of LAB reduced fertility and slowed development in the worms. The worm-killing assay showed that LAB significantly increased the lifespan (P < 0.05) and reduced the susceptibility to virulent PA14; however, the heat-killed LAB did not. The bacterial colonization assay revealed that LAB proliferated and protected the gut of the worm against infection by Pseudomonas aeruginosa PA14. In addition, specific LAB Pediococcus acidilactici(P. acidilactici DM-9), Pediococcus brevis (L. brevis SDL1411), and Pediococcus pentosaceus (P. pentosaceus SDL1409) strains showed acid resistance (66-91%), resistance to pepsin (64-67%) and viability in simulated intestinal fluid (67-73%) based on in vitro probiotic analyses. Taken together, these results suggest that C. elegans may be a tractable model for screening efficient probiotics. [ABSTRACT FROM AUTHOR]

Collagen is the major connective tissue (CT) protein and one of the main constituents of the jumbo squid (Dosidicus gigas). Therefore, physicochemical changes of pepsin-solubilized collagen (PSC) and insoluble collagen (IC) were studied after cooking (100°C/30 min) of muscle (mantle, fins, and arms). Different pyridinoline (Pyr) contents (the major cross-linking molecule in collagen fibers) were found in the fresh muscle of the three anatomical regions. After the cooking process, a decrease from 10 to 30% in the thermal resistance of collagen was observed, depending on the anatomical region and fraction evaluated. Furthermore, the electrophoretic profile, Fourier transform infrared (FTIR) spectroscopy, and the amino-acid profile revealed that structural changes occurred in the two different collagen fractions caused by the thermal process, and the changes were greater in the mantle. Under the conditions applied in this study, collagen fractions from the squid arms showed more stability during the cooking process due to the high cross-linking degree of their fibers. [ABSTRACT FROM AUTHOR]

Acid-solubilized collagen (ASC) and pepsin-solubilized collagen (PSC) from golden pompano skins were extracted and characterized. The molecular weight of ASC was about 130 kDa for α1and 115 kDa for α2, which were slightly higher than those of PSC. Similar amino acid composition and Fourier transform infrared (FTIR) spectra were observed in both collagens, but slight differences were found in the peptide maps of collagen digested by V8 protease and trypsin. The denaturation temperatures (Tds) of ASC and PSC calculated from the reduced viscosity were 31.8 and 30.0°C, while the transition temperature (Tm) of ASC and PSC analyzed by DSC were 33.0 and 32.0°C, respectively. ASC has a lag phase, a growth phase, and a plateau phase in the turbidity–time curve, while PSC does not have similar phenomenon. It was found that the fibril gel of ASC could be formed at 25°C, leading to improved thermal stability. [ABSTRACT FROM PUBLISHER]

Objectives: We investigated the relationship between laryngopharyngeal reflux (LPR) and chronic rhinosinusitis (CRS), and explored the effects of pepsin A on the level of heat shock protein 70 (HSP70) in CRS. Methods: We included 23 CRS patients with nasal polyps (CRSwNP), 26 CRS patients without nasal polyps (CRSsNP) and nine normal controls to measure pepsin A levels in nasal secretions, blood plasma and nasal tissues, to measure HSP70 levels in nasal tissues, and to detect pepsinogen A, HSPA5, cyclooxygenase- 2 (COX-2), and carbonic anhydrase III (CAIII) mRNA expression levels in nasal tissues. Results: Pepsin A levels in nasal secretions were significantly higher in CRSwNP/CRSsNP patients than in controls. HSP70 levels were significantly increased in pepsin A-positive turbinate mucosa compared to controls (p<.001). Similarly, HSP70 levels were significantly increased in pepsin A-positive polyp tissues than in pepsin A-negative polyp tissues (p=.016). Furthermore, no association was found between the presence of pepsin A and HSPA5, COX-2, and CAIII mRNA expression levels. Conclusions: These results suggest that LPR may play a role in the development of CRS through pepsin A reflux, and increased HSP70 expression may be associated with the pathogenic mechanism of mucosal injury in CRS. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the IgE sensitivity to sardine parvalbumin (SP) in a Moroccan population from Fez region, and then to study the effect of temperature and enzymatic digestion on the allergenicity of SP. This work was conducted with a questionnaire completed by a sera-bank, obtained from 1008 patients recruited from Fez Hospitals. Their sera were analyzed for specific IgE against SP. From the questionnaire, 8.1% reported adverse reactions to fish and shellfish, where sardine was the most common species causing adverse reactions in patients. Evaluation of specific IgE showed that 7.8% of patients present higher values. Further indirect ELISA and dot-blot results indicated that SP, a major fish allergen, showed a reduction in the human IgE binding under heating and pepsin hydrolysis. These results demonstrate that this population was sensitive to SP and the sensitivity could be reduced by heating and more where it was digested by pepsin. [ABSTRACT FROM AUTHOR]

Electron transport layer (ETL) in perovskite-based solar cells (PSCs) is attractive from the perspective of photon-to-electron conversion efficiency. TiO2thin film is preferred in situations where microstructure, stability and charge transport characteristics are important. In this regard, we illustrate an approach that involves the synthesis of TiO2–pepsin thin film that can be used either as a mesoporous or compact layer depending on the device architecture of PSC devices. It was observed that pepsin acts as organic glue to TiO2nanoparticles and facilitates in controlling morphology of the thin film. The addition of pepsin did not have any adverse effect on TiO2anatase phase. Thickness and roughness of mesoporous and compact TiO2thin film suggested that controlled agglomeration can be achieved by tuning the concentration of pepsin in the precursor colloidal solution. The spin-coated thin films indicated high bulk mobility (205 cm2V−1 s−1) and good thermal stability over a wide range temperature (25–700°C). Furthermore, in the presence of pepsin group in TiO2thin film, the inherent optical properties were retained, as confirmed by UV–vis analysis. [ABSTRACT FROM PUBLISHER]

Sea cucumberAcaudina leucoproctais a potential alternative collagen source. However, the high levels of heavy metals contained in the body wall restricts its utilization. In this work, an efficient method was established to remove the heavy metals accumulated in the body wall ofA.leucoproctaby demineralizing with 0.2 M ethylenediaminetetraacetic acid (EDTA). The resulting body wall ofA.leucoproctawas then used for extracting pepsin-soluble collagen (PSC) with pepsin proteolysis. The PSC from the body wall ofA.leucoproctawas obtained with a yield of 43.99 ± 0.65% (dry weight) and high purity. Maximum and minimum solubility for the isolated PSC in 0.5 M acetic acid was observed at pH 2.66 and 4.43, respectively. The solubility was remarkably decreased in the presence of NaCl. The denaturation temperature of PSC rehydrated in 0.5 M acetic acid was measured as 25.4°C. The PSC was characterized as type I collagen, which consists of three α1chains without α2chain. Interestingly, α1chain in PSC showed two isoforms with the pI values of 4.02 and 4.29. The heavy metals existing in PSC were all below the contaminant limit of edible gelatin. The PSC isolated from the body wall could be an alternative to mammalian collagens. [ABSTRACT FROM AUTHOR]

The gastrointestinal (GI) stability of three flavonoids, dihydromyricetin (DMY), myricetin (MYR), and myricitrin (MYT), was examined in simulated physiological fluids. Several factors that may influence the degradation rate of theses flavonoids were evaluated, including pH and the presence of pepsin and pancreatin enzymes. We found that GI stability followed the order of MYT > DMY > MYR. These flavonoids were stable in simulated gastric fluids and buffer solutions (pH 1.2), but encountered a pseudo-first-order kinetic degradation in simulated intestinal fluids and buffer solutions (pH 6.8). We conclude that it is the pH, rather than the presence of pepsin or pancreatin, which most strongly influences the stability of these three flavonoids. Further study of the stability of the compounds using a pH range (1.0–8.0) indicated potential instability in the duodenum, small intestine, and colon. Therefore, we conclude that the low bioavailability of these flavonoids may be due to their poor stability in the GI tract. [ABSTRACT FROM PUBLISHER]

Nori, the dried sheets ofPorphyra, is a popular edible seaweed and a potential source of high quality protein, vitamins, and minerals. In the present study, the antioxidant potential of Nori has been investigated. For this purpose, an aqueous extract was obtained by soaking powdered Nori in KCl-HCl buffer and hydrolyzing it with pepsin. The antioxidant activity of aqueous extract of crude as well as pepsin hydrolyzate was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, reducing power, total antioxidant capacity and lipid peroxidation by thiobarbituric acid reactive substances (TBARS) and compared with L-ascorbic acid. After hydrolysis, the scavenging ability and inhibition of lipid per oxide was doubled, and a sevenfold increase in reducing power activity was observed. The small molecular weight fractions (F-II) of hydrolyzate obtained after gel filtration showed further increase in the activity. These results demonstrate that hydrolysis produces better antioxidants that could be used as an alternative to synthetic antioxidants. [ABSTRACT FROM AUTHOR]

The aim of the present study was to develop a newin vitromethod for evaluating the digestibility of commercial diets for dogs. First, in order to develop thein vitromethod, the digestibility of four commercial diets for dogs was evaluated through severalin vitrotrials and results were compared with those that were retrieved from the literature. Thein vitromethod that was developed consists of two incubation phases, a first lasting 2h and taking place in the presence of pepsin, gastric lipase and HCl (gastric phase) and a second 4h one with pancreatin and bile salts (intestinal phase). Later, digestibility of 16 extruded diets for dogs was evaluated bothin vivowith adult dogs andin vitro. There was a close linear relationship betweenin vivototal tract andin vitrodry matter digestibility (r2 = .81), whereas accuracy of crude protein digestibility using thein vitromethod was lower (r2 = .51). Linear regression accuracy for ether extract and starch digestibility was low, but the digestibility results obtained with thein vitromethod (95.3 and 98.7% for ether extract and starch, respectively) were very close to those from thein vivotrial (average digestibility of ether extract and starch was 94.8 and 99.1%, respectively). The presentin vitromethod has proved to be a relatively simple, quick procedure for predicting the digestibility of commercial diets for dogs. The utilisation of such a method may significantly reduce the need forin vivodigestion trials with dogs. [ABSTRACT FROM PUBLISHER]

Recently, our study found that naked nucleic acids (NAs) can be digested by pepsin. To better understand the fate of dietary DNA in the digestive tract, in this study we investigated the effects of several food compositions on its digestion. The results showed that protein inhibited the digestion of DNA when the protein:DNA ratio was higher than 80:1 (m/m). DNA found in nucleoprotein (NA), which more closely resembles the state of DNA in food, was as efficiently digested as naked DNA. When the carbohydrate:DNA ratio was 50:1–140:1 (m/m), mono-, di- and polysaccharides did not inhibit DNA digestion. NaCl exhibited an inhibitory effect at 300 mM, whereas divalent cations (Ca2+ and Mg2+) exerted a much stronger inhibitory effect even at 50 mM. The polycation compounds (e.g. chitosan and spermine) showed a significant inhibitory effect at N/P (NH3+/PO4−) = 10:1. The close relationship between food composition and DNA digestion suggests that dietary habits and food complexes are important for understanding thein vivofate of the ingested DNA in the digestive tract. [ABSTRACT FROM PUBLISHER]