Search Results (531)

Chicken hemoglobin represents a source of bioactive peptides that could replace synthetic additives. This study evaluated the antibacterial and antifungal potential of chicken hemoglobin hydrolysates and the effect of their fractionation by EDUF. Hemoglobin was hydrolyzed with pepsin at pH 3 for 0.5 h and 6 h, followed by discoloration, and then fractionated by EDUF for 180 min at pH 7. Fractions were characterized using RP-UPLC-MS/MS, and antimicrobial activity was assessed. Antibacterial activity against Escherichia coli was observed only in EDUF fractions (P+180 and P−180), while crude hydrolysates showed no effect. However, MIC values of these EDUF fractions indicated weak inhibition. Antifungal activity was primarily detected in the final feed fractions against Mucor racemosus and Rhodotorula mucilaginosa (MIC: 0.04–20.00 mg/mL). Database matching of the fractions identified 22 sequences corresponding to peptides previously reported as bioactive, including ALARL, FDK, LARL, and VVYPW, which have been associated with antioxidant, ACE-inhibitory, antihypertensive, and enzyme-inhibitory properties. Nevertheless, EDUF proved to be an efficient, solvent-free, and low-energy approach for the recovery of peptide fractions from chicken hemoglobin, supporting the potential development of natural bioactive ingredients within a circular bioeconomy. Modifications of EDUF parameters, such as membrane configuration, pH, and voltage, could further enhance peptide selective recovery and the enrichment of functional fractions. Full article

Background/Objectives: Severe and recurrent infections due to multidrug-resistant (MDR) Pseudomonas aeruginosa necessitate alternative antimicrobial strategies. Fermented cacao beans represent a niche microbial ecosystem with the potential to harbor beneficial lactic acid bacteria (LAB). This study aimed to isolate and characterize LAB strains from fermented cacao beans in southern Thailand and to evaluate their probiotic potential and antimicrobial activity against MDR P. aeruginosa. Methods and Results: Five Lactiplantibacillus plantarum isolates were identified via MALDI-TOF MS and whole-genome sequencing (WGS). All strains demonstrated antimicrobial activity against 17 clinical MDR P. aeruginosa isolates and CR14 exhibited the largest inhibition zone. The isolates displayed robust probiotic traits, including survival under simulated gastrointestinal conditions. Acid tolerance (pH 2.0) reached 61.15 ± 7.75%, while resistance to pepsin, pancreatin, and bile salts exceeded 88%, 91%, and 92%, respectively. Strong adhesion was confirmed via auto-aggregation (55.02 ± 1.75%), hydrophobicity (45.58 ± 0.96%) and Caco-2 cell attachment (up to 98.11 ± 3.28%). WGS revealed multiple plantaricin-encoding clusters. Coarse-grained molecular dynamic simulations showed that two-peptide plantaricins (plnJ/K and plnNC8-αβ) self-assembled and formed stable pores in bacterial membrane models, confirming a pore-forming antimicrobial mechanism. The strains lacked acquired resistance genes and virulence factors, confirmed by in silico safety assessments. Conclusions: Thus, these L. plantarum strains are promising probiotics for managing MDR P. aeruginosa via functional foods or adjunct therapies. Full article

Repetitive temperature fluctuations during transportation and storage promote ice crystal formation in salmon flesh, leading to protein denaturation, lipid oxidation, and quality loss. Tuna skin, a major by-product of tuna processing, is a potential source of antifreeze peptides (AFPs) but remains underutilized. This study examined the cryoprotective effects of tuna skin-derived AFPs on salmon cubes subjected to repeated freeze–thaw cycles. Cubes treated with AFPs from three groups of protein hydrolysates prepared using trypsin, pepsin, or neutral protease were evaluated for texture, color, water holding capacity (WHC), volatile odor profiles, protein conformation, biochemical indices, and microstructure. AFP treatment improved textural properties, maintained color stability, and reduced thawing, cooking, and centrifugal losses. The neutral protease-treated group exhibited the optimal cryoprotective ability and it also limited aldehyde and sulfide accumulation, preserved the retention rate of α-helix structure at 49% which was higher than 39% in controls, and enhanced Ca²⁺-ATPase activity to 1.75 μmol Pi·mg⁻¹·h⁻¹ with a 45.8% increase compared to controls, and significantly inhibited protein and lipid oxidation. Microstructural analysis showed compact fibers and intact sarcolemma in the neutral protease-treated group samples, contrasting with severe disruption in controls. This study showed that tuna skin AFPs mitigate freeze–thaw damage in salmon cubes by stabilizing proteins and reducing oxidative deterioration, highlighting their potential as natural, healthy cryoprotectants for seafood preservation, meeting the growing demand of the food industry for clean-label, low-calorie preservation solutions, while advancing the circular economy of aquatic processing via the valorization of tuna skin by-products for high-value seafood applications. Full article

Lactoferrin (Lf) and Lf-derived peptides are multifunctional milk components with potential applications in food preservation due to their antibacterial and antioxidant properties. In this study, the antibacterial and antioxidant activities of bovine lactoferrin and Lf-derived peptides obtained by enzymatic hydrolysis with pepsin, trypsin, and chymotrypsin were evaluated. Antibacterial activity was assessed against four foodborne pathogens and spoilage microorganisms (Escherichia coli, Listeria monocytogenes, Staphylococcus epidermidis, and Latilactobacillus sakei), while antioxidant activity was determined using four complementary assays. Lf showed stronger antibacterial activity than the corresponding hydrolysates against all tested strains, while the hydrolysates notably inhibited Listeria monocytogenes and Latilactobacillus sakei. Both Lf and its peptides showed lower antioxidant capacity than Trolox, although native Lf and its peptides markedly inhibited lipid peroxidation. Lf peptides demonstrated greater antioxidant activity in the superoxide scavenging and FRAP assays. Low-molecular-weight peptides (<10 kDa) contributed most to antioxidant activity, while mass spectrometry analysis revealed peptide sequences rich in hydrophobic and electron-donating amino acid residues, providing mechanistic insight into the observed activities. Overall, these findings highlight the potential of lactoferrin and its enzymatic hydrolysates as natural antimicrobial and antioxidant agents for food preservation. Full article

The appearance of antibiotic-resistant strains of Helicobacter pylori (H. pylori) is leading to a decreased eradication rate of H. pylori infection. There is an urgent need to find new agents with antimicrobial mechanisms different from those of antibiotics, with therapeutic potential to clear colonization of H. pylori in the stomach. Some antimicrobial peptides (AMPs) possess bactericidal activity by enhancing the permeability of the outer membrane and damaging the integrity of the cell membrane. Bacteria are not susceptible to drug resistance through this antimicrobial mechanism. In this study, 28 short peptides containing 12 amino acid residues were designed based on nine amino acid fragments (KRIVQRIKD) from human cathelicidin LL-37, which is stable in gastric juice, and 3 amino acids were added at the C-terminus of the peptide. These designed peptides were not digested and degraded by pepsin at low pH values. The peptides were predicted using the online tool platform. Then, the strongest antimicrobial peptide, named SAMP-12aa (KRIVQRIKDVIR), was screened from 28 short peptides. Further studies found that SAMP-12aa retained anti-H. pylori activity after incubation in simulated gastric juice. The MIC and MBC of SAMP-12aa were 8 μg/mL and 32 μg/mL, respectively. SAMP-12aa showed good bactericidal kinetics. SAMP-12aa was found to have cell selectivity, penetrating and damaging bacterial cell membranes and exhibiting almost no toxicity to human cells at a relatively high concentration (128 μg/mL). Regulatory T (Treg) cells express CD25^High with immunosuppressive activity that induces immune tolerance in response to H. pylori. Molecular docking prediction revealed that SAMP-12aa could target the active center of Foxp3. Flow cytometry analysis revealed that SAMP-12aa can inhibit Foxp3 activity and downregulate CD25 protein expression on CD4⁺ T cells, thereby reducing the development and differentiation of CD4⁺Foxp3⁺CD25^High Treg cells with immunosuppressive effects. Further research revealed that the levels of the cytokine interferon-γ (IFN-γ), which activates CD8⁺ T-cell activity, were significantly elevated, and the levels of transforming growth factor-β (TGF-β), which inhibits CD8⁺ T-cell activity, were significantly reduced. The results of this study reveal that SAMP-12aa not only possesses antibacterial activity but also has immunomodulatory effects. Full article

The growing demand for sustainable protein alternatives has increased interest in underutilized plant biomasses with high nutritional potential. This study investigated the conversion efficiency of alfalfa (Medicago sativa L.) and duckweed (Lemna minor L.) proteins through multienzyme hydrolysis, with the aim of evaluating how carbohydrate–protein matrix interactions influence enzymatic accessibility and apparent protein digestibility. Three biotechnological hydrolysis schemes were applied, involving combinations of α-amylase, amyloglucosidase, protease, pepsin, pancreatin, and bile salts, including an in vitro gastrointestinal digestion simulation. The first hydrolysis scheme demonstrated that starch-rich matrices formed a viscous medium that reduced protease mobility and limited protein cleavage. Improved substrate accessibility was achieved when plant material was pre-treated with amylolytic and proteolytic enzymes, which resulted in a noticeably higher release of free amino acids. Amino acid profiling revealed that this enzymatic sequence was the most effective for disrupting carbohydrate-associated protein fractions in both species. In vitro digestion assays indicated higher apparent protein conversion for duckweed compared to alfalfa under standardized laboratory conditions. Overall, the results confirm that appropriate multienzyme strategies can enhance amino acid liberation from complex plant matrices and highlight duckweed biomass as a promising candidate for sustainable protein valorization. Full article

Fermentation with various microorganisms modifies the quality of coffee. In animal-digested coffee, enzymatic activity also affects coffee characteristics. However, limited information is available on in vitro coffee modification employing both mechanisms simultaneously in controlled conditions. In this study, robusta green beans were modified with selected bacterial species (Bacillus subtilis, Gluconobacter sp., Lactiplantibacillus plantarum) and pepsin, which was introduced at the soaking or fermentation stage. The characteristics of green and roasted coffee were analyzed, including the amount of basic aroma precursors, antioxidant activity, acrylamide concentration and volatile organic compound (VOC) content. The number of bacterial cells increased by 1.95–2.64 logCFU/mL during the modification process; pepsin addition did not affect their growth significantly. The use of acid-producing bacteria (APB) resulted in higher consumption of sucrose but also in greater retention of bioactive compounds and higher antioxidant activity. The acrylamide content in fermented and roasted beans was below 10 μg/100 g dry matter; the lowest values were reported after modification with L. plantarum. The combination of tested bacterial and enzymatic processes changed the content and composition of VOCs. Further research should focus on sensory attributes as the result of the combined modification process. Full article

To investigate the effects of dietary vitamin C (VC) supplementation at different concentrations (0, 5000, and 15,000 mg/kg) on the growth and feeding performance of sea cucumbers (Apostichopus japonicus), a 60-day feeding trial was conducted. The results demonstrated that supplementation with 5000 mg/kg VC significantly enhanced growth performance, evidenced by a higher specific growth rate and weight gain, along with a shorter feeding initiation time and increased tentacle feeding frequency. Furthermore, the activities of digestive enzymes—including amylase, lipase, and pepsin—were markedly elevated in the intestines of A. japonicus fed 5000 mg/kg VC, accompanied by increased mucus secretion in the oral tentacles. Correspondingly, intestinal 5-hydroxytryptamine (5-HT) levels and the expression of tryptophan hydroxylase (AjTPH) and 5-HT receptor (Aj5-HT4R) genes were significantly upregulated in the same group. In contrast, relatively lower growth performance was observed in the control (0 mg/kg) and high-dose (15,000 mg/kg) VC groups. Histological analysis further revealed that 5000 mg/kg VC increased villus height and width and thickened the intestinal muscle layer. Overall, dietary supplementation with 5000 mg/kg VC enhanced feeding activity, digestive function, and intestinal morphology, thereby promoting growth. However, excessive supplementation (15,000 mg/kg) failed to provide similar benefits and was associated with impaired performance. Full article

Deep-sea mollusks represent untapped resources for searching novel biologically active peptides effectual against many chronic diseases. Here we presented the identification of four novel angiotensin I-converting enzyme (ACE) inhibitory peptides from the deep-sea mollusk Gigantidas platifrons by using a combined approach of peptidomics and virtual screening. Fifteen protein hydrolysates from five deep-sea macroorganisms were prepared using three different proteases and were determined for their ACE inhibitory activities. Pepsin hydrolysate of G. platifrons protein (GPp) demonstrated the highest inhibition rate against ACE at 400 μg/mL. Then, targeted investigation was conducted on the GPp with peptidomic profiling; more than 3000 peptides were de novo identified, which were then subject to virtual screening using the docking software Smina. Subsequently, 29 peptides were selected and synthesized based on the affinity threshold and the interactions with ACE active sites. More than 58% peptides were biologically active, showing more than 50% inhibition to ACE at 400 μM. Four peptides, LAAHFAR, YAAPYR, NGAGPYGRP, and FTTFGK, exhibited low micromolar inhibition. The most potent peptide, LAAHFAR with an IC₅₀ of 6.01 ± 1.06 μM, was subject to molecular dynamics simulations for revealing atomistic interaction analysis. LAAHFAR forms comprehensively stable hydrogen bonds with the classic active site of ACE, and its N terminal arginine residue is anchored by additional hydrogen bonding to Cys370, Asp377, and Thr372. This study highlights deep-sea mollusks as an important source of novel ACE inhibitory peptides, contributing to the development of new therapeutic ingredients or functional food agents against hypertension. Full article

Natural soy protein isolate (SPI) exhibits suboptimal functional characteristics, including limited solubility, reduced foaming capacity, and diminished emulsifying ability. Conventional singular-modification techniques are unable to enhance multiple functional properties concurrently, thereby posing challenges in fulfilling the varied requirements of food processing. Therefore, this study employed ultrasonic and pepsin enzymatic modification techniques on SPI. By varying ultrasonic frequency (20 kHz, 207 kHz) and sonic energy density (295 W/L, 590 W/L), different modified protein samples were obtained. The effects of single treatment, combined treatment, and varying ultrasonic parameters on their structure and functionality were investigated. The results indicate that compared to single enzymatic hydrolysis, combination-treated SPI exhibited reduced fluorescence intensity and UV absorbance, along with significant decreases in methionine (Met) and free-sulfhydryl (SH) content (p < 0.05). Particle size decreased while distribution became more uniform, and relative molecular weight also diminished. This indicates that combined processing induces more pronounced changes in the protein’s primary to higher-order structures, thereby enhancing functional properties. Specifically, surface hydrophobicity (H₀) and emulsification stability (ESI) improved, while emulsifying capacity (EAI) significantly increased (p < 0.05). In summary, ultrasonication combined with enzymatic hydrolysis exhibits synergistic effects, optimizing protein structure and functional characteristics. This approach facilitates the development of functional foods and broadens their application scope. Full article

This study presents the first characterization of the globulin fraction from a newly registered chickpea cultivar, which represents the first desi-type cultivar (GB Cappuccino) released in Brazil. Although desi chickpeas are widely consumed in other countries, they have not been part of the Brazilian dietary pattern, and this introduction may represent an opportunity for changing this scenario. Characterizing its proteins is essential, given that legumes are recognized as important protein sources. In this study, globulins were confirmed as the predominant protein fraction, with the legumin-like fraction accounting for more than 80% of the total globulins. Its electrophoretic and amino acid profiles were highly distinctive and strongly influenced by this major fraction. In addition to the expected solubilization in saline solution, under in vitro pepsin–pancreatin digestion conditions designed to assess maximum hydrolysis potential, the globulin fraction was partially hydrolyzed, indicating a degree of protein digestibility while simultaneously releasing peptides that exhibited antioxidant activity and angiotensin-converting enzyme (ACE) inhibitory potential. Overall, these results highlight the nutritional relevance of this new cultivar and, based on the preliminary bioactivity screening performed, suggest that its globulin-rich protein composition may represent a promising source of bioactive peptides. Full article

The pistachio nut (Pistacia vera L.) is a rich and high-quality source of protein, as is its waste. This study investigated the potentials of pistachio nut waste proteins to obtain bioactive peptides exhibiting antioxidative and antibacterial activities, and their amino acid profile. Enzymatic hydrolysis with pepsin, trypsin, chymotrypsin, and savinase was applied to the pistachio protein isolate (PPI) obtained from pistachio waste. In addition, solid-state fermentation (SSF) was applied to defatted pistachio with Bacillus subtilis, and peptides were produced. The highest degree of hydrolysis was obtained at 28.2% by using pepsin (p < 0.05). The highest ABTS radical scavenging activity was found as 232 µmol TE/g defatted pistachio (d.b.) for trypsin hydrolysate (p < 0.05). The maximum DPPH radical scavenging activity was found as 70.2 µmol TE/g defatted pistachio (d.b.) by hydrolysis with savinase. After gel filtration, the highest ABTS radical scavenging activity was found to be 0.1166 mg TE/mL in the T7 sample (p < 0.05), while the highest DPPH scavenging activity was found to be 0.0573 mg TE/mL in the S8 sample (p < 0.05). The sample showing the highest antibacterial activity was chymotrypsin hydrolysate with MIC = 0.378 mg/mL against Staphylococcus aureus. The total amino acid contents (TAA) of PPI, hydrolysate samples, and the SSF sample ranged from 63.136 to 76.665 g/100 g protein. It was also seen that proteins and peptides obtained from pistachio waste have a rich amino acid profile, especially Asp and Tyr, and good antioxidant activity. Full article

Macroalgae plays a significant role in the formulation of innovative and environmentally sustainable approaches to address food challenges. Specifically, green macroalgae serve as dietary supplements aimed at improving the health, growth, and feeding efficiency of various species of marine and freshwater fishes, as well as mollusks. The effects of Chaetomorpha linum extract (CLE) on growth performance, physiological responses, and disease resistance are studied in Bellamya bengalensis against Aeromonas hydrophila. In this experiment, adult B. bengalensis (4412 ± 165.25 mg) were randomly divided into 15 rectangular glass aquariums (35 snail/aquaria; 45 L capacity) and their basal diet was supplemented with different levels of CLE, including 0 (CLE0), 1 (CLE1), 2 (CLE2), 3 (CLE3), and 4 (CLE4) g/kg for 60 days. The growth performance in the CLE3 dietary group was significantly higher that of the CLE0 group, exhibiting both linear and quadratic trends in relation to dietary CLE levels (p < 0.05). The activities of pepsin, amylase, and lipase were found to be highest in CLE3 and lowest in CLE0. Both linear and quadratic responses to dietary CLE levels in digestive enzymes were observed (p < 0.05). The activities of superoxide dismutase and catalase in the hepatopancreas were found to be elevated in snails due to the synergistic effect of the supplemented CLE diet. Among different levels of diet given, CLE2-supplemented snails showed an increase in their enzyme activity (p < 0.05). Interestingly, all the CLE-treated snails expressed elevated levels of mucus lysozyme and mucus protein when compared to control (p < 0.05). Additionally, hepatopancreatic acid phosphatase and alkaline phosphatase activity were elevated in snails consuming CLE3 (p < 0.05). The transcription levels of immune-related genes, including mucin-5ac and cytochrome, were significantly elevated in snails that were fed a diet supplemented with 2–4 g of CLE/kg. Furthermore, the transcription level of the acid phosphatase-like 7 protein gene also increased in snails receiving CLE-supplemented diets. After a 14-day period of infection, snails that consumed a diet supplemented with 3–4 g/kg of CLE exhibited a notable increase in survival rates against virulent A. hydrophila. Based on the above findings, it is suggested that a diet supplemented with 3 g/kg of CLE may enhance growth, antioxidant and immune defense, and disease resistance in the freshwater snail B. bengalensis. Full article

Long-term frozen storage is widely used for pork preservation, yet its impact on protein digestibility remains inadequately explored. This study investigated the effect of frozen storage duration (0, 3, and 12 months) on the changes in digestive properties and protein structure of minced pork during in vitro digestion. With extended freezing, the hardness, chewiness, and shear force of pork significantly increased, while protein digestibility decreased. A confocal laser scanning microscope showed an increase in the particle size of digesta. After 12 months of frozen storage, the digestibility of the pork samples decreased. The extent of reduction reached 11.31% under pepsin digestion and 11.33% under pepsin–trypsin digestion, compared to the fresh samples. Structural analysis indicated that prolonged freezing led to protein denaturation and aggregation, as confirmed by a decrease in α-helix contents, an increase in the β-sheet and random coil structures, and the formation of high-molecular-weight aggregates. These structural alterations hindered protease accessibility, resulting in reduced digestibility. The detrimental effects on protein structure and digestibility became more pronounced with longer frozen storage. Full article

Seven amidrazones containing a characteristic NH₂–N=C(Ar¹)–NHAr² moiety, where Ar¹, Ar² are phenyl, 4-methylphenyl, 4-nitrophenyl, 2-pyridyl, and 4-pyridyl substituents, denoted as 2a–2g, were synthesized by the reactions between thioamides and hydrazine. Their molecular structures were confirmed by ¹H, ¹³C, ¹H-¹³C HMQC, ¹H-¹³C HMBC, and ¹H-¹⁵N HMBC NMR spectroscopy, with complete assignment of the detected signals, as well as by high-resolution mass spectra. The biological activity of all compounds was studied, exhibiting antioxidant properties determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) methods, inhibitory potential against digestive tract enzymes (α-amylase, lipase, pepsin), cytotoxicity (hemolysis), and antimicrobial activities (against Gram-positive and Gram-negative bacteria, and a fungus). The antioxidant activity of the studied amidrazones varied from 83.34% to 93.27% and 1.01–5.79 mM FeSO₄ for the DPPH and FRAP methods, respectively. Moreover, these derivatives revealed inhibition potential against α-amylase (28.6–86.8%), lipase (28.0–60.0%), and pepsin (34.1–76.6%), which increased when increasing their concentrations from 0.2 to 1 mg/mL. Among them, compound 2d (possessing 2-pyridyl and 4-nitrophenyl substituents) stood out in particular, as a potent antioxidant (DPPH = 90.43%, FRAP = 4.73 Mm FeSO₄) with the highest activity against Gram-positive bacteria: S. aureus (MIC = 64 μg/mL), G. rubripertincta (MIC = 64 μg/mL), and fungus: C. albicans (MIC = 32 μg/mL); high α-amylase (86.8%) inhibition at the highest concentration (1 mg/mL); and lipase (38.0%) and pepsin (43.8%) inhibition at the lowest concentration (0.2 mg/mL). The obtained results were analyzed by unsupervised multivariate techniques to confirm significant differences in the biological activity of amidrazones depending on the Ar¹ and Ar² substituents. Full article