Peptide Content Research Articles

Ultrasound-assisted fermentation for antioxidant peptides preparation from okara: Optimization, stability, and functional analyses

This study investigated the effects of ultrasound-assisted fermentation (UAF) on the preparation of antioxidant peptides (UAFP) from okara and examined their content, chemical structures, and antioxidant activity. After the optimal ultrasonic processing (time, 20 min; frequency, 45 KHz; power, 120 W/L), the peptide content yield reached the maximum of 12.36 ± 0.02 mg/mL, and their DPPH free radical scavenging rate was 65.15 ± 0.32 %. UAF increased the number of globular aggregates with deeper gullies, a looser structure, and higher porosity. The experiments conducted using the oxidative stress injury model of HepG2 cells showed that okara UAFP promoted cell growth and exerted a protective effect. Moreover, ultrasonic treatment remarkably improved the environmental stability (NaCl, glucose, sodium benzoate, temperature, pH, metal ions) and antioxidant activity of UAFP. Concisely, optimal ultrasonic processing can aid the fermentation of agroindustrial by-products to prepare antioxidant peptides, such as natural food antioxidant peptides from soybean waste.

Fibrous matrices facilitate pleurocidin killing of wound associated bacterial pathogens

Conventional wound infection treatments neither actively promote wound healing nor address the growing problem of antibacterial resistance. Antimicrobial peptides (AMPs) are natural defense molecules, released from host cells, which may be rapidly bactericidal, modulate host-immune responses, and/or act as endogenous mediators for wound healing. However, their routine clinical use has hitherto been hindered due to their instability in the wound environment. Here we describe an electrospun carrier system for topical application of pleurocidin, demonstrating sufficient AMP release from matrices to kill wound-associated pathogens including Acinetobacter baumannii and Pseudomonas aeruginosa. Pleurocidin can be incorporated into polyvinyl alcohol (PVA) fiber matrices, using coaxial electrospinning, without major drug loss with a peptide content of 0.7% w/w predicted sufficient to kill most wound associated species. Pleurocidin retains its activity on release from the electrospun fiber matrix and completely inhibits growth of two strains of A. baumannii (AYE; ATCC 17978) and other ESKAPE pathogens. Inhibition of P. aeruginosa strains (PAO1; NCTC 13437) is, however, matrix weight per volume dependent, with only larger/thicker matrices maintaining complete inhibition. The resulting estimation of pleurocidin release from the matrix reveals high efficiency, facilitating a greater AMP potency. Wound matrices are often applied in parallel or sequentially with the use of standard wound care with biocides, therefore the presence and effect of biocides on pleurocidin potency was tested. It was revealed that combinations displayed additive or modestly synergistic effects depending on the biocide and pathogens which should be considered during the therapy. Taken together, we show that electrospun, pleurocidin-loaded wound matrices have potential to be investigated for wound infection treatment.

Study on the anti-inflammatory activity of the porcine bone collagen peptides prepared by ultrasound-assisted enzymatic hydrolysis

In this study, the effects of ultrasound-assisted enzymatic hydrolysis on the extraction of anti-inflammatory peptides from porcine bone collagen were investigated. The results showed that ultrasound treatment increased the content of α-helix while decreased β-chain and random coil, promoted generation of small molecular peptides. Ultrasound-assisted enzymatic hydrolysis improved the peptide content, enhanced ABTS+ radical scavenging and ferrous ion chelating ability than non-ultrasound group. At the ultrasonic power of 450 W (20 min), peptides possessed significant anti-inflammatory activity, where the releasing of interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) was all suppressed in lipopolysaccharide (LPS) induced RAW264.7 cells. After the analysis with LC-MS/MS, eight peptides with potential anti-inflammatory activities were selected by the PeptideRanker and molecular docking. In general, the ultrasound-assisted enzymatic hydrolysis was an effective strategy to extract the bioactive peptides from porcine bone, and the inflammatory regulation capacity of bone collagen sourced peptides was firstly demonstrated.

Screening of probiotic Lactobacillus to reduce peanut allergy and with potential anti-allergic activity.

Peanut is a significant source of nutrition and a valuable oilseed crop. It is also a serious allergy source, which poses a threat to 1.1% of the population. This study aimed to screen lactic acid bacteria (LAB) with the capacity to alleviate peanut allergenicity and exhibit anti-allergic properties. The results show that LAB can make use of substances in peanuts to reduce the pH of peanut milk from 6.603 to 3.593-4.500 by acid production and that it can utilize the protein in peanuts to reduce the allergenic content (especially Ara h 1) and improve biological activity in peanut pulp. The content of Ara h 1 peanut-sensitizing protein was reduced by 74.65% after fermentation. The protein extracted from fermented peanut pulp is more readily digestible by gastrointestinal juices. The inhibitory activity assay of hyaluronidase (an enzyme with strong correlation to allergy) increased from 46.65% to a maximum of 90.57% to reveal that LAB fermentation of peanut pulp exhibited a robust anti-allergic response. The strains identified in this study exhibited the ability to mitigate peanut allergenicity partially and to possess potential anti-allergic properties. Lactobacillus plantarum P1 and Lactobacillus salivarius C24 were identified as the most promising strains and were selected for further research. © 2023 Society of Chemical Industry.

Exploring the Release of Elastin Peptides Generated from Enzymatic Hydrolysis of Bovine Elastin via Peptide Mapping.

To enhance the understanding of enzymatic hydrolysis and to accelerate the discovery of key bioactive peptides within enzymatic products, this research focused on elastin as the substrate and investigated the variations in peptide profiles and the production of key bioactive peptides (those exceeding 5% of the total) and their impacts on the biological activity of the hydrolysates. Through the application of advanced analytical techniques, such as stop-flow two-dimensional liquid chromatography and ultra-high-performance liquid chromatography-tandem mass spectrometry, the research tracks the release and profiles of peptides within elastin hydrolysates (EHs). Despite uniform peptide compositions, significant disparities in peptide concentrations were detected across the hydrolysates, hinting at varying levels of bioactive efficacy. A comprehensive identification process pinpointed 403 peptides within the EHs, with 18 peptides surpassing 5% in theoretical maximum content, signaling their crucial role in the hydrolysate's bioactivity. Of particular interest, certain peptides containing sequences of alanine, valine, and glycine were released in higher quantities, suggesting Alcalase® 2.4L's preference for these residues. The analysis not only confirms the peptides' dose-responsive elastase inhibitory potential but also underscores the nuanced interplay between peptide content, biological function, and their collective synergy. The study sets the stage for future research aimed at refining enzymatic treatments to fully exploit the bioactive properties of elastin.

Chemical and Sensory Evaluation of Umami Taste Derived from Proteolytic Hydrolysate of Pila ampullacea

In this study, umami taste was produced and identified from bromelain and trypsin hydrolysate of Pila ampullacea (PA). The PA hydrolysates, obtained from individually bromelain and trypsin with various Enzyme-to-Substrate ratio (E/S) of 1/10, 1/20, and 1/100 (w/v) using divers proteolysis times (3, 6, 9, 12, 15 and 18 h), were evaluated their chemical properties by degree of hydrolysis (DH), total peptide content, and amino acid content. Two chosen proteolysis conditions of PA hydrolysates were concluded by sensory evaluation using hedonic test and principal component analysis (PCA). PA hydrolysate using bromelain with E/S of 1:10 (w/v) for 18 h was one of the 2 chosen proteolysis conditions, which had DH value of 56.56 ± 1.65 %, total peptide content of 10.89 ± 0.09 mg/mL, and amino acid content of 95.34 ± 0.12 ppm. On the other hand, the chosen from trypsin digestion used E/S of 1:10 (w/v) for 15 h, which had DH value of 49.71 ± 0.22 %, total peptide content of 6.44 ± 0.28 mg/mL, and amino acid content of 81.43 ± 1.29 ppm. PA hydrolysates were subjected to explain the released peptides using liquid chromatography-tandem mass spectrometry (LC-MS/MS) and database-assisted identification. There were many identified peptides contained in PA hydrolysates that contributed to umami taste. Their sequences from bromelain digestion were GPEGPQGPPGPRG, GIMLGAA, GLPGLPGLKGDPGEPGLP, GKDGEAG, GLVMDSCAGH, and EEKITEDDDAVGDDAENR. Several peptide fragments from trypsin digestion were GQTVIGL, GLPGLPGLSGPKG, DTGPAGPAGPAGPQGPR and QTLEKALSHVIQEFETEKQLITVNAR. HIGHLIGHTS Umami taste derived from proteolytic hydrolysate of Pila ampullacea was firstly reported The findings revealed that Pila ampullacea hydrolysates using bromelain with the Enzyme-to-Substrate ratio (E/S) 1:10 (w/v) for 18 h and trypsin with E/S of 1:10 (w/v) for 15 h had exhibited as the proficient treatment for hydrolysis conditions and selected based on sensory properties This new method will be of considerable advantage to the best practice of umami taste establishment as flavor enhancer in the food manufacture GRAPHICAL ABSTRACT

Impact of Wooden Breast myopathy on in vitro protein digestibility, metabolomic profile, and cell cytotoxicity of cooked chicken breast meat

This study investigated the impacts of Wooden Breast (WB) abnormality on in vitro protein digestibility and cytotoxicity of cooked chicken breast meat. Chicken breasts without (non-WB, n = 6) or with severe WB condition (WB, n = 6) were cooked and subjected to static in vitro protein digestion. The results showed no significant differences in free-NH2, degree of hydrolysis and distribution of peptide molecular weight between non-WB and WB samples at late intestinal digestion (P5), suggesting no adverse effects of WB on protein digestibility. Based on peptidomic analysis, P5 fraction of WB showed greater content of peptides with oxidative modification than that of non-WB. Untargeted metabolomics did not find any metabolites with potential toxicity either in non-WB and WB. Hydrolyzed non-WB and WB (1.56 to 100 µg/mL) did not affect viability of Caco-2 and Vero cells but addition of WB samples reduced Caco-2 cell viability compared with non-WB.

Increased Expression Levels of Thermophilic Serine Protease TTHA0724 through Signal Peptide Screening in Bacillus subtilis and Applications of the Enzyme.

The thermostable protease TTHA0724 derived from Thermus thermophilus HB8 is an ideal industrial washing enzyme due to its thermophilic characteristics; although it can be expressed in Escherichia coli via pET-22b, high yields are difficult to achieve, leading to frequent autolysis of the host. This paper details the development of a signal peptide library in the expression system of B. subtilis and the optimization of signal peptides for enhanced extracellular expression of TTHA0724. When B. subtilis was used as the host and the optimized signal peptide was used, the expression level of TTHA0724 was 16.7 times higher compared with E. coli. B. subtilis as an expression host does not change the characteristics of TTHA0724. The potential application fields of TTHA0724 are studied. TTHA0724 can be used as a detergent additive at 60 °C, which can sterilize and eliminate mites while thoroughly cleaning protein stains. Soybean meal enzymatic hydrolysis with TTHA0724 at a high temperature produced a higher content of antioxidant peptides. These results indicate that TTHA0724 has great potential for industrial applications.

Aging mechanism for improving the tenderness and taste characteristics of meat.

Tenderness and taste characteristics of meat are the key determinants of the meat choices of consumers. This review summarizes the contemporary research on the molecular mechanisms by which postmortem aging of meat improves the tenderness and taste characteristics. The fundamental mechanism by which postmortem aging improves the tenderness of meat involves the operation of the calpain system due to apoptosis, resulting in proteolytic enzyme-induced degradation of cytoskeletal myofibrillar proteins. The improvement of taste characteristics by postmortem aging is mainly explained by the increase in the content of taste-related peptides, free amino acids, and nucleotides produced by increased hydrolysis activity. This review improves our understanding of the published research on tenderness and taste characteristics of meat and provides insights to improve these attributes of meat through postmortem aging.

Production of branched-chain flavor compounds from hydrolysis of pork myofibrillar protein by optimizing the inoculation of Limosilactobacillus fermentum YZU-06 and Staphylococcus saprophyticus CGMCC 3475

This study aimed to develop a mixed starter of Limosilactobacillus fermentum YZU-06 and Staphylococcus saprophyticus CGMCC 3475 isolated from Jinhua ham for enhancing the production of branched-chain flavor compounds from pork myofibrillar protein. Different ratios of mixed strains (3:1, 2:1, 1:2, and 1:3) and single strains were employed to incubate with myofibrillar protein extract to detect viable counts, pH, proteolysis, and branched-chain volatiles at 24, 48 and 72 h of incubation. The result showed that the inoculated strains had acid-producing characteristics and bacterial suitability. The mixed starter of 2:1, 1:2, and 1:3 treatments exhibited a higher degree of protein degradation, as indicated by a 90% similarity through cluster analysis of myofibrillar protein in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Compared to the other treatment groups, 2:1 group showed a significantly higher peptide content of 123.58 μg/mL and a greater concentration of free amino acids (236.67 mg/L). Furthermore, 2:1 group obtained the highest levels of 3-methylbutanal (56.06 μmol/L), 2-methylpropanal (1.76 μmol/L), and 2-methylbutanal (0.48 μmol/L). Our findings emphasize the importance of appropriate proportions of L. fermentum YZU-06 and S. saprophyticus CGMCC 3475 for the starter to produce branched-chain flavor compounds of meat products.

Physicochemical properties, biological activities, and peptidome profile of grass carp swim bladder collagen hydrolysates

This study investigated the physicochemical properties and biological activities of hydrolysates derived from grass carp swim bladder collagen through enzymatic hydrolysis using Papain, Alcalase, Flavourzyme, and Neutrase. The results indicated that the select of protease significantly influences the degree of hydrolysis (DH), molecular weight distribution (MW), trichloroacetic acid-nitrogen solubility index (TCA-NSI), structure, and bioactivities of the hydrolysates. The hydrolysate of Alcalase (HA) exhibited the highest DH, TCA-NSI, Fe2+ chelating activity, 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity, and angiotensin-converting enzyme (ACE) inhibitory activity. Pearson's correlation and principal component analysis (PCA) revealed strong interrelationships among the DH, TCA-NSI, β-sheet content, Fe2+ chelating activity, ACE inhibitory activity, and short peptide content within the hydrolysates (|r| > 0.80, P < 0.05). A total of 524 peptides were identified from HA, and 20 novel peptides with no toxicity, no allergenicity, and potential bioactivity were discovered by in silico strategy. Molecular docking analysis revealed that hydrophobic interactions and hydrogen bonds were the primary interaction forces between the peptides with free radicals and ACE. These findings provide a foundation for the high-value utilization of grass carp swim bladder hydrolysates as bioactive peptides in the food industry, enabling the sustainable utilization of freshwater swim bladder by-products.

Total peptide content and amino acid profile of fermented shrimp (Litopenaeus vannamei) sausage

Hypertension can be prevented by bioactive containing food such as shrimp. Food value can be increased through fermentation. During the process of fermentation, microbes and enzymes will break down proteins into peptides and amino acids, making the foods easier to digest in the body. This study aimed to determine the fermentation effect on shrimp sausage's peptide and amino acid content. An experimental study with a completely randomized design, involving the treatment of 4 levels of fermentation duration as control, was carried out three times. Fermentation was conducted spontaneously with a salt concentration of 1.2%, smoking at 50oC for 3 hrs, and a fermentation temperature of 35oC. The parameters measured were peptide content and amino acid profile using the Ophtaldehyde (OPA) and HPLC methods. The peptide content data statistical analysis used the One Way ANOVA and continued with the post hoc test. Amino acid profile data are further presented descriptively. There is an influence between the fermentation duration and the peptide content in the product (p≤0.05), and 15 types of amino acids were obtained in fermented shrimp sausage. According to this study, the third day of fermentation is the most efficient time for generating peptides and amino acids in shrimp sausage, with glutamate being the highest amount of amino acid produced throughout fermentation. Fermentation process and duration had effect on shrimp sausage's peptide and amino acid content.

Immunomodulatory effect of earthworm protein autolysates on Cyclophosphamide(CTX)-Induced immunosuppressed mice

Earthworms are rich in protein and are considered a good source of edible insect protein. However, there has been limited research on the bioactivity of earthworm protein hydrolysates. The present study investigated the immunological impact of earthworm protein autolysate (EPA) on Cyclophosphamide (CTX)-induced immunosuppressed mice model. The results revealed that the Degree of Hydrolysis (DH) and percentage of soluble peptide content of the EPA were 22.38% and 77.92%, respectively. EPA was efficient in treating CTX-dropped mice's immunosuppression as well as intestinal inflammation. The peptide sequences of the EPA digestion products were identified, and ten top-scoring peptides were obtained using the PeptideRanker and HPepDOCK assessment, whose activity was validated in the macrophage model, with WNWLLPLMLG having the best immunomodulatory activity. Therefore, EPA may be a potential resource for immunomodulatory peptides, and autolysis can be a reliable technique for preparing peptides.

Characterization of the physicochemical Properties, bacterial community and non-volatile profiles of fermented Yu jiangsuan by Weissella cibaria and Lactobacillus plantarum

Yu jiangsuan (YJS) is a unique traditional fermented condiment in China. Physicochemical, bacterial communities, and non-volatile properties were examined in inoculation Autochthonous Weissella cibaria and Lactobacillus plantarum. The results indicated that inoculation samples did well in shortening fermentation time; amino acid nitrogen (AN) and TCA-soluble peptide contents of fermented YJS were 10.8% and 17.4% higher than those of naturally fermented YJS, respectively. However, its total volatile base nitrogen (TVB-N), thiobarbituric acid (TBARS), and nitrite were only 74.3%, 87.2% and 83.6% of those of naturally fermented YJS. In addition, the dominant bacterial genera were Lactobacillus, Weissella and Pectobacterium, whose contributions were 41.2%, 20.3% and 5.5%, respectively. Moreover, 26 significantly differential metabolites were identified, and involved in 10 metabolic pathways. The decomposition of substrates and the formation of differential metabolites in YJS were primarily centered on the TCA cycle and the metabolism of carbohydrates. Therefore, this study is conducive to discovering the bacterial community structure and metabolite composition of probiotic inoculated YJS fermentation, as well as the potential value of core functional bacteria genera in controlling YJS production in industry.

Surimi Production from Tropical Mackerel: A Simple Washing Strategy for Better Utilization of Dark-Fleshed Fish Resources

Mackerel (Auxis thazard), a tropical dark-fleshed fish, is currently a viable resource for the manufacture of surimi, but the optimal washing procedure for more efficient use of this particular species is required right away. Washing is the most critical stage in surimi production to ensure optimal gelation with odorless and colorless surimi. The goal of this study was to set a simple washing medium to the test for making mackerel surimi. Washing was performed three times with different media. T1 was washed with three cycles of cold carbonated water (CW). T2, T3, and T4 were washed once with cold CW containing 0.3%, 0.6%, or 0.9% NaCl, followed by two cycles of cold water. T5, T6, and T7 were produced for three cycles with CW containing 0.3%, 0.6%, or 0.9% NaCl. For comparison, unwashed mince (U) and conventional surimi washed three times in cold tap water (C) were employed. The maximum yield (62.27%) was obtained by washing with T1. When varying quantities of NaCl were mixed into the first washing medium (T2–T4), the yield decreased with increasing NaCl content (27.24–54.77%). When washing with NaCl for three cycles (T5–T7), the yield was greatly decreased (16.69–35.23%). Conventional surimi washing (C) produced a yield of roughly 40%, which was comparable to T3. Based on the results, treatments that produced lower yields than C were eliminated in order to maximize the use of fish resources and for commercial reasons. The maximum NaCl content in CW can be set at 0.6% only during the first washing cycle (T3). Because of the onset of optimal unfolding as reported by specific biochemical characteristics such as Ca2+-ATPase activity (0.2 μmol inorganic phosphate/mg protein/min), reactive sulfhydryl group (3.61 mol/108 g protein), and hydrophobicity (64.02 µg of bromophenol blue bound), T3 washing resulted in surimi with the greatest gel strength (965 g.mm) and water holding capacity (~65%), with fine network structure visualized by scanning electron microscope. It also efficiently removed lipid (~80% reduction), myoglobin (~65% reduction), non-heme iron (~94% reduction), and trichloroacetic acid-soluble peptide (~52% reduction) contents, which improves whiteness (~45% improvement), reduces lipid oxidation (TBARS value &lt; 0.5 mg malondialdehyde equivalent/kg), and decreases the intensity of the gel’s fishy odor (~30% reduction). As a result, washing mackerel surimi (A. thazard) with CW containing 0.6% (w/v) NaCl in the first cycle, followed by two cycles of cold water washing (T3), can be a simple method for increasing gel-forming capability and oxidative stability. The mackerel surimi produced using this washing approach has a higher quality than that produced with regular washing. This straightforward method will enable the sustainable use of dark-fleshed fish for the production of surimi.

Production of value-added peptides from soybean meal during natural solid-state fermentation: Metabolites and bacterial communities

This study is aimed at producing value-added peptide products from soybean meal (SBM) through natural solid-state fermentation (NSSF) using the indigenous microorganisms present in SBM. The variation of metabolites and the succession of bacterial communities in SBM fermentation were explored. Results revealed that during NSSF, the pH, microbial counts, the contents of soluble protein, peptide, and free amino acids (FAAs), and protease activity increased (p < 0.05), whereas the trypsin inhibitor (TI) activity decreased significantly (p < 0.05) under optimal NSSF conditions (ambient temperature of 45 °C and moisture content of 55%). Molecular weight (MW) distribution showed that macromolecular proteins in the SBM were degraded into small peptide fragments with MW < 3000 Da after NSSF. Bacillus and Bacillus subtilis were the predominant bacterial genera and species, respectively, in the NSSF process, which was highly associated with the accumulation of metabolites, including soluble protein, peptide, and protease, and the degradation of TI. NSSF could be regarded as an effective way to enhance the nutritional value and produce value-added peptides from the SBM.

Fully automated radiolabeling of [68Ga]Ga-EMP100 targeting c-MET for PET-CT clinical imaging

Backgroundc-MET is a transmembrane receptor involved in many biological processes and contributes to cell proliferation and migration during cancer invasion process. Its expression is measured by immunehistochemistry on tissue biopsy in clinic, although this technique has its limitations. PET-CT could allow in vivo mapping of lesions expressing c-MET, providing whole-body detection. A number of radiopharmaceuticals are under development for this purpose but are not yet in routine clinical use. EMP100 is a cyclic oligopeptide bound to a DOTA chelator, with nanomolar affinity for c-MET. The aim of this project was to develop an automated method for radiolabelling the radiopharmaceutical [68Ga]Ga-EMP100.ResultsThe main results showed an optimal pH range between 3.25 and 3.75 for the complexation reaction and a stabilisation of the temperature at 90 °C, resulting in an almost complete incorporation of gallium-68 after 10 min of heating. In these experiments, 90 µg of EMP-100 peptide were initially used and then lower amounts (30, 50, 75 µg) were explored to determine the minimum required for sufficient synthesis yield. Radiolysis impurities were identified by radio-HPLC and ascorbic acid and ethanol were used to improve the purity of the compound. Three batches of [68Ga]Ga-EMP100 were then prepared according to the optimised parameters and all met the established specifications. Finally, the stability of [68Ga]Ga-EMP100 was assessed at room temperature over 3 h with satisfactory results in terms of appearance, pH, radiochemical purity and sterility.ConclusionsFor the automated synthesis of [68Ga]Ga-EMP100, the parameters of pH, temperature, precursor peptide content and the use of adjuvants for impurity management were efficiently optimised, resulting in the production of three compliant and stable batches according to the principles of good manufacturing practice. [68Ga]Ga-EMP100 was successfully synthesised and is now available for clinical development in PET-CT imaging.

Enhancing bioavailability of soy protein isolate (SPI) nanoparticles through limited enzymatic hydrolysis: Modulating structural properties for improved digestion and absorption

The bioavailability of nanoparticles during the digestive process is intricately linked to their structural integrity and interactions with bile salts. In this study, enzymatically hydrolyzed protein nanoparticles encapsulating β-carotene (BC) were prepared using three proteases with different cleavage specificity. In vitro digestion and cellular uptake models are employed to investigate the structural changes of BC during the digestion process and their bioavailability. It was found that Flavorzyme exhibited lower hydrolysis degree as compared to Neutrase and Alcalase, selectively hydrolyzing the 7S subunit of SPI while retaining a higher content of acidic peptides within the 11S subunit, resulting in higher surface hydrophobicity. Therefore, partially hydrolyzed protein nanoparticles (SPIH@NPs) prepared with Flavorzyme (SPIH–F@NP) demonstrated the strongest resistance to digestion. Compared to SPI nanoparticles, the release rate of β-carotene in SPIH-F@NP was reduced from 25.99% to 13.13%, leading to a higher retention of β-carotene in the aqueous phase and a 2.66-fold increase in its bioaccessibility. Moreover, SPIH-F@NP demonstrated the highest affinity for bile salts, resulting in a 1.48-fold improvement in the absorption efficiency of β-carotene compared to SPI nanoparticles. These findings establish a theoretical basis for further enhancing the application potential of protein-based nanoparticles in terms of bioavailability.

Preparation of high content collagen peptides and study of their biological activities

Collagen peptides play an important role in the increasing use of collagen peptides as dietary supplements in food and beverages and as bioactive ingredients in cosmetics, healthcare, and pharmaceuticals. Collagenase enzymatically cleaves gelatin to produce collagen polypeptides. However, the enzymatic activity of collagenase is very low (25900 U) and does not allow for adequate enzymatic digestion. Therefore, proteases are used to assist in enzymatic digestion. Porcine gelatin, bovine gelatin, and fish protein gum were enzymatically digested, and the content of collagen peptides in the enzymatically digested lyophilized powder was identified by high-performance liquid chromatography and mass spectrometry, and then the content of the desired collagen peptides was increased by isolation and purification, and the result of the determination was that the content of collagen peptides was the highest after enzymatic digestion and isolation and purification with the use of porcine gelatin as the raw material, and the content of the collagen peptides was about 45.47%. β-nicotinamide mononucleotide (NMN) was mixed with the prepared samples to determine its antioxidant properties and ability to promote the growth of human dermal fibroblasts. The results showed that the antioxidant capacity was enhanced with the increase of collagen polypeptide content, and NMN could promote the scavenging of DPPH• and •OH free radicals by collagen polypeptides. The ability to promote the growth of human dermal fibroblasts was enhanced with the increase of collagen polypeptide content. This paper aimed to prepare a high content of collagen polypeptides from three raw materials, porcine gelatin, bovine gelatin, and fish protein gum, and further to determine the biological activities.

Mechanism of the Allergenicity Reduction of Ovalbumin by Microwave Pretreatment-Assisted Enzymolysis through Biological Mass Spectrometry.

Ovalbumin (OVA) is a major allergen in hen eggs. Enzymolysis has been demonstrated as an efficient method for reducing OVA allergenicity. This study demonstrates that microwave pretreatment (MP) at 400 W for 20 s assisting bromelain enzymolysis further decreases the allergenicity of OVA, which was attributed to the increase in the degree of hydrolysis and promoted the destruction of IgE-binding epitopes. The results showed that MP could promote OVA unfolding, expose hydrophobic domains, and disrupt tightly packed α-helical structures and disulfide bonds, which increased the degree of hydrolysis by 7.28% and the contents of peptides below 1 kDa from 43.55 to 85.06% in hydrolysates compared with that for untreated OVA. Biological mass spectrometry demonstrated that the number of intact IgE-binding epitope peptides in MP-assisted OVA hydrolysates decreased by 533 compared to that in hydrolysis without MP; consequently, their IgG/IgE binding rates decreased more significantly. Therefore, MP-assisted enzymolysis may provide an alternative method for decreasing the OVA allergenicity.