Characterisation of the antioxidant peptide AEEEYPDL and its quantification in Spanish dry-cured ham

Separation, enrichment and cytoprotection of antioxidant peptides from Xuanwei ham using aqueous two-phase extraction

An ethanol/(NH4)2SO4 biphasic (aqueous two-phase) system was designed to effectively separate antioxidant peptides from Xuanwei ham, and its potential to prevent ultraviolet A-induced damage to skin cells was explored. Optimization via single factor experiments and response surface methodology revealed that under 20 % ethanol aqueous solution (w/w), 25.5 % (NH4)2SO4 aqueous solution (w/w), and pH 8.80 conditions, the optimal extraction ratio was 59.0 ± 1.73 %. In vitro antioxidant activity and cellular assays showed that the peptide purified in the upper phase exhibited strong antioxidant activity, increasing the viability of HaCat cells damaged by UVA irradiation from 56.14 ± 1.05 % to 66.3 ± 1.76 %. We used an in silico peptide screening strategy and identified 10 with potential antioxidant activity, emphasizing the important role of amino acids Pro, Gly, and Ala in antioxidant activity.

Bioactive peptides in dry-cured ham: A comprehensive review of preparation methods, metabolic stability, safety, health benefits, and regulatory frameworks

Dry-cured hams contain abundant bioactive peptides with significant potential for the development of functional foods. However, the limited bioavailability of food-derived bioactive peptides has hindered their utilization in health food development. Moreover, there is insufficient regulatory information regarding bioactive peptides and related products globally. This review summarizes diverse bioactive peptides derived from dry-cured ham and by-products originating from various countries and regions. The bioactivity, preparation techniques, bioavailability, and metabolic stability of these bioactive peptides are described, as well as the legal and regulatory frameworks in various countries. The primary objectives of this review are to dig deeper into the functionality of dry-cured ham and provide theoretical support for the commercialization of bioactive peptides from food sources, especially the dry-cured ham.

Potential of Bioactive Protein and Protein Hydrolysate from Apis mellifera Larvae as Cosmeceutical Active Ingredients for Anti-Skin Aging

This study aimed to extract bioactive proteins and protein hydrolysates from Apis mellifera larvae and assess their potential application in cosmetics as well as their irritation properties. The larvae were defatted and extracted using various mediums, including DI water, along with 0.5 M aqueous solutions of sodium hydroxide, ascorbic acid, citric acid, and hydrochloric acid. Subsequently, the crude proteins were hydrolyzed using the Alcalase® enzyme. All extracts underwent testing for antioxidant activities via the 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) and Griess assays. Anti-aging properties were evaluated in terms of anti-collagenase and anti-hyaluronidase effects. Irritation potential was assessed using the hen's egg chorioallantoic membrane (HET-CAM) test. The results revealed that the sodium hydroxide extraction showed promising outcomes in terms of yield, protein content, and effectiveness in inhibiting hyaluronidase, with the highest inhibition at 78.1 ± 1.5%, comparable to that of oleanolic acid. Conversely, crude protein extracted with ascorbic acid and its hydrolysate showed notable antioxidant and collagenase-inhibitory activities. Remarkably, their anti-collagenase effects were comparable to those of ascorbic acid and lysine. Additionally, it demonstrated safety upon testing with the CAM. In conclusion, the findings provided valuable insights into the utilization of A. mellifera larval proteins as active ingredients with a wide range of cosmeceutical applications, particularly due to their antioxidant, anti-aging, and low irritation properties, which hold significant promise for anti-skin wrinkles.

Cyperus peptide SFRWQ inhibits oxidation and inflammation in RAW264.7 cell model

Oxidative stress can induce many diseases. Antioxidant peptides from food sources have the advantages of good safety, high activity, and good absorbability. In this study, a pentapeptide (SFRWQ; SER-PHE-ARG-TRP-GLN) was identified in a protein hydrolysate of Cyperus (Cyperus esculentus L.). Enzyme-linked immunosorbent assay (ELISA), real-time quantitative (qPCR), immunofluorescence and other techniques were used to evaluate the anti-inflammatory and antioxidant effects of SFRWQ. SFRWQ was found to have 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical-scavenging ability, help increase superoxide dismutase (SOD) and catalase (CAT) levels in RAW264.7 cells, reduce reactive oxygen species (ROS) levels, and decrease tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) gene expression and secretion. The binding score of SFRWQ to recombinant Kelch-like ECH-associated protein 1 (Keap1) was greater than that of TX6. These findings suggest that SFRWQ activates the Keap1-Nrf2 cellular antioxidant signaling pathway. According to metabolomics studies, SFRWQ increased glutathione (GSH), glutathione disulfide (GSSG), and γ-glutamylcysteine levels and decreased the levels of Prostaglandin D2 (PGD2), Prostaglandin E2 (PGE2), and Prostaglandin H2 (PGH2), which are involved in arachidonic acid metabolism, to protect cells from LPS-induced damage. By elucidating the mechanism of action of SFRWQ, we provide a reference for the development of dietary antioxidant peptides.

Selenium Decipher: Trapping of Native Selenomethionine-Containing Peptides in Selenium-Enriched Milk and Unveiling the Deterioration after Ultrahigh-Temperature Treatment

Selenopeptide identification relies on databases to interpret the selenopeptide spectra. A common database search strategy is to set selenium as a variable modification instead of sulfur on peptides. However, this approach generally detects only a fraction of selenopeptides. An alternative approach, termed Selenium Decipher, is proposed in the present study. It involves identifying collision-induced dissociation-cleavable selenomethionine-containing peptides by iteratively matching the masses of seleno-amino acids in selenopeptide spectra. This approach uses variable-data-independent acquisition (vDIA) for peptide detection, providing a flexible and customizable window for secondary mass spectral fragmentation. The attention mechanism was used to capture global information on peptides and determine selenomethionine-containing peptide backbones. The core structure of selenium on selenomethionine-containing peptides generates a series of fragment ions, namely, C3H7Se+, C4H10NSe+, C5H7OSe+, C5H8NOSe+, and C7H11N2O2Se+, with known mass gaps during higher-energy collisional dissociation (HCD) fragmentation. De-selenium spectra are generated by removing selenium originating from selenium replacement and then reassigning the precursors to peptides. Selenium-enriched milk is obtained by feeding selenium-rich forage fed to cattle, which leads to the formation of native selenium through biotransformation. A novel antihypertensive selenopeptide Thr-Asp-Asp-Ile-SeMet-Cys-Val-Lys TDDI(Se)MCVK was identified from selenium-enriched milk. The selenopeptide (IC50 = 60.71 μM) is bound to four active residues of the angiotensin-converting enzyme (ACE) active pocket (Ala354, Tyr523, His353, and His513) and two active residues of zinc ligand (His387 and Glu411) and exerted a competitive inhibitory effect on the spatial blocking of active sites. The integration of vDIA and the iteratively matched seleno-amino acids was applied for Selenium Decipher, which provides high validity for selenomethionine-containing peptide identification.

Relationship between peptides and the change in quality characteristics of beef strip loin (M. longissimus lumborum) and tenderloin (M. psoas major)

Peptides in fresh and aged beef strip loin (M. longissimus lumborum) and tenderloin (M. psoas major) were quantified to investigate the relationship between proteolysis-induced peptides and beef quality characteristics. A total of 409 and 450 peptides were quantified from strip loin and tenderloin, respectively, and found to be significantly correlated to beef quality characteristics. Changes in redness and yellowness were significantly correlated to the peptides derived from G3P, ENOB, and KCRM in both muscles during 14 days of storage. The peptides produced from MYG, ENOB, HBA, PGK1, and TPIS were strongly associated with improved tenderness, while those derived from major myofibrillar proteins, such as MYH1, MYH2, ACTS, and DESM, were associated with changes in tenderloin color. These results improve our understanding of the association between peptides and changes in meat quality during cold storage, indicating that proteolysis-induced peptides can be indicators of the quality characteristics of fresh and aged meat.

Pork organs as a potential source of flavour-related substances

The increase in world population has generated a higher demand for quality proteins, increasing the production in meat industry but also the generation of thousands of tons of by-products, with a negative economic and environmental impact. The valorisation of slaughterhouse by-products by giving by-products a new use as food ingredient is one of the best strategies to add value while reducing environmental damage. Flavour is one of the most influential parameters in the purchasing decision of consumers, and in meat products it is mostly influenced by the content in free amino acids and nucleotides. In this study, the potential of 4 pork organs (liver, kidney, lung, and brain) as a source of flavour-related substances was investigated. Liver proved to be the organ showing the highest content of free and total amino acids related to taste, while kidney was the organ with the highest content of umami nucleotides. The results of the Taste Activity Value indicated that umami, sweet, and bittersweet amino acids are main responsible for the taste of the organs. On the other hand, the synergy between amino acids and nucleotides in relation with umami taste was determined, showing liver and kidney the best values in Equivalent Umami Content. In addition, the antioxidant activity of the organs was determined, and liver and kidney showed the highest antioxidant activity in all assays (p < 0.05). In conclusion, pork organs, especially liver and kidney, may be good candidates to be used as raw materials to produce functional flavouring ingredients.

Isolation, Identification, Activity Evaluation, and Mechanism of Action of Neuroprotective Peptides from Walnuts: A Review

As human life expectancy increases, the incidence of neurodegenerative diseases in older adults has increased in parallel. Walnuts contain bioactive peptides with demonstrated neuroprotective effects, making them a valuable addition to the diet. We here present a comprehensive review of the various methods used to prepare, isolate, purify, and identify the neuroprotective peptides found in walnuts. We further summarise the different approaches currently used to evaluate the activity of these peptides in experimental settings, highlighting their potential to reduce oxidative stress, neuroinflammation, and promote autophagy, as well as to regulate the gut microflora and balance the cholinergic system. Finally, we offer suggestions for future research concerning bioavailability and improving or masking the bitter taste and sensory properties of final products containing the identified walnut neuroprotective peptides to ensure successful adoption of these peptides as functional food ingredients for neurohealth promotion.

Strategic Approaches to Improvise Peptide Drugs as Next Generation Therapeutics

In recent years, the occurrence of a wide variety of drug-resistant diseases has led to an increase in interest in alternate therapies. Peptide-based drugs as an alternate therapy hold researchers' attention in various therapeutic fields such as neurology, dermatology, oncology, metabolic diseases, etc. Previously, they had been overlooked by pharmaceutical companies due to certain limitations such as proteolytic degradation, poor membrane permeability, low oral bioavailability, shorter half-life, and poor target specificity. Over the last two decades, these limitations have been countered by introducing various modification strategies such as backbone and side-chain modifications, amino acid substitution, etc. which improve their functionality. This has led to a substantial interest of researchers and pharmaceutical companies, moving the next generation of these therapeutics from fundamental research to the market. Various chemical and computational approaches are aiding the production of more stable and long-lasting peptides guiding the formulation of novel and advanced therapeutic agents. However, there is not a single article that talks about various peptide design approaches i.e., in-silico and in-vitro along with their applications and strategies to improve their efficacy. In this review, we try to bring different aspects of peptide-based therapeutics under one article with a clear focus to cover the missing links in the literature. This review draws emphasis on various in-silico approaches and modification-based peptide design strategies. It also highlights the recent progress made in peptide delivery methods important for their enhanced clinical efficacy. The article would provide a bird's-eye view to researchers aiming to develop peptides with therapeutic applications.

Graphical Abstract

Production of Food-Derived Bioactive Peptides with Potential Application in the Management of Diabetes and Obesity: A Review

The prevalence of diabetes mellitus and obesity is increasing worldwide. Bioactive peptides are naturally present in foods or in food-derived proteins. Recent research has shown that these bioactive peptides have an array of possible health benefits in the management of diabetes and obesity. First, this review will summarize the top-down and bottom-up production methods of the bioactive peptides from different protein sources. Second, the digestibility, bioavailability, and metabolic fate of the bioactive peptides are discussed. Last, the present review will discuss and explore the mechanisms by which these bioactive peptides help against obesity and diabetes based on in vitro and in vivo studies. Although several clinical studies have demonstrated that bioactive peptides are beneficial in alleviating diabetes and obesity, more double-blind randomized controlled trials are needed in the future. This review has provided novel insights into the potential of food-derived bioactive peptides as functional foods or nutraceuticals to manage obesity and diabetes.

The moisture adsorption, caking, and flowability of silkworm pupae peptide powders: The impacts of anticaking agents

This study aimed to explore the impacts of different anticaking agents on the moisture adsorption, caking, and flowability of silkworm pupae peptide powders (SPPP). The characteristics of water distributions in SPPP with anticaking agents were investigated by LF NMR. The morphological observation of powders was analyzed by scanning electron microscope. Moisture sorption curves and moisture sorption isotherm curves indicated that calcium stearate, silicon dioxide and calcium silicate of 20 % reduced hygroscopicity and increased critical relative humidity. The angle of repose analysis revealed that anticaking agents could also increase flowability (45°-49°). LF NMR analysis indicated that anticaking agents reduced the moisture adsorption ability of SPPP. Scanning electron microscope observations demonstrated different shapes and surface morphology of SPPP using different anticaking agents. Notably, silicon dioxide served as the most effective anticaking agent by forming a physical barrier. Overall, anticaking agents can effectively delay moisture adsorption and deliquescence of SPPP by different anticaking fashions.

Influence of Pig Genetic Line and Salt Reduction on Peptide Production and Bioactivity of Dry-Cured Hams

Ham (Jamón) is a product of great value in Spanish gastronomy, although experts have recommended reducing its consumption due to its high salt content and its relationship with cardio-vascular diseases due to the increase in blood pressure it may cause. Therefore, the objective of this study was to evaluate how the reduction of salt content and the pig genetic line influence bioactivity in boneless hams. For this purpose, 54 hams were studied, 18 boneless Iberian hams (RIB), 18 boneless white hams from commercial cross-bred pigs (RWC), and 18 salted and traditionally processed Iberian hams (TIB) to check if the pig genetic line (RIB vs. RWC) or the processing (RIB vs. TIB) affect the peptide production and bioactivity of the hams. The pig genetic line significantly affected the activity of ACE-I and DPPH, with RWC having the highest ACE-I activity and RIB having the highest antioxidative activity. This coincides with the results obtained in the identification of the peptides and the bioactivity analysis performed. Salt reduction positively affected the different hams, influencing their proteolysis and increasing their bioactivity in traditionally cured hams.

Mechanism investigation of fermented egg-milk peptides on colonic inflammatory diseases: based on in vivo and in silico research

Fermented egg-milk peptides (FEMPs) could alleviate the symptoms of inflammatory diseases but the underlying regulating mechanism of effective ingredients is unclear now. Our research was designed to confirm the protective function of FEMP, then analyze the potential targets and pathways that could be regulated by digested FEMP (dFEMP). The results showed that FEMP could ease the inflammatory symptoms in the colon, repair the damage of inflammation, and decrease the level of pro-inflammatory cytokines (decreased by 31.81% TNF-α, 60.20% IL-1β, 85.65% IL-6). The results of in silico experiments revealed that dFEMP could influence many inflammation-related targets. Most targets affected the inflammation-related function and participated in the inflammatory signaling pathways, such as the T cell receptor (TCR) signaling pathway. Besides, molecular docking results revealed that hydrogen-bonding and salt bridges played vital roles in the dFEMP-target interactions. Combining in vivo experiments with in silico experiments, this study can prove a new theory for research between the bioactive peptides and inflammation.

Food Protein-Derived Antioxidant Peptides: Molecular Mechanism, Stability and Bioavailability

The antioxidant activity of protein-derived peptides was one of the first to be revealed among the more than 50 known peptide bioactivities to date. The exploitation value associated with food-derived antioxidant peptides is mainly attributed to their natural properties and effectiveness as food preservatives and in disease prevention, management, and treatment. An increasing number of antioxidant active peptides have been identified from a variety of renewable sources, including terrestrial and aquatic organisms and their processing by-products. This has important implications for alleviating population pressure, avoiding environmental problems, and promoting a sustainable shift in consumption. To identify such opportunities, we conducted a systematic literature review of recent research advances in food-derived antioxidant peptides, with particular reference to their biological effects, mechanisms, digestive stability, and bioaccessibility. In this review, 515 potentially relevant papers were identified from a preliminary search of the academic databases PubMed, Google Scholar, and Scopus. After removing non-thematic articles, articles without full text, and other quality-related factors, 52 review articles and 122 full research papers remained for analysis and reference. The findings highlighted chemical and biological evidence for a wide range of edible species as a source of precursor proteins for antioxidant-active peptides. Food-derived antioxidant peptides reduce the production of reactive oxygen species, besides activating endogenous antioxidant defense systems in cellular and animal models. The intestinal absorption and metabolism of such peptides were elucidated by using cellular models. Protein hydrolysates (peptides) are promising ingredients with enhanced nutritional, functional, and organoleptic properties of foods, not only as a natural alternative to synthetic antioxidants.

In Vitro Antioxidant and Antiaging Activities of Collagen and Its Hydrolysate from Mackerel Scad Skin (Decapterus macarellus)

The skin of mackerel scad fish (Decapterus macarellus) is a new source for pepsin-soluble collagen and its hydrolysate, both of which have never been explored. This study aims to characterize and determine the in vitro antioxidant, antiglycation, and antityrosinase activity of pepsin-soluble collagen (PSC) and hydrolyzed collagen (HC) from mackerel scad skin. PSC was extracted using 0.5 M acetic acid containing 0.1% pepsin for 48 h at 4 °C. The obtained PSC was then hydrolyzed with collagenase type II (6250 U/g) to produce HC. The PSC yield obtained was 6.39 ± 0.97%, with a pH of 6.76 ± 0.18, while the HC yield was 96% from PSC. SDS-PAGE and Fourier Transform Infrared (FTIR) analysis showed the typical features of type I collagen. HC demonstrated high solubility (66.75–100%) throughout the entire pH range (1–10). The PSC and HC from mackerel scad skin showed antioxidant activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH), with IC50 values of 148.55 ± 3.14 ppm and 34.966 ± 0.518 ppm, respectively. In the antiglycation test, PSC had an IC50 value of 239.29 ± 15.67 ppm, while HC had an IC50 of 68.43 ± 0.44 ppm. PSC also exhibited antityrosinase activity, with IC50 values of 234.66 ± 0.185 ppm (on the L-DOPA substrate), while HC had an IC50 value of 79.35 ± 0.5 ppm. Taken together, these results suggest that the skin of mackerel scad fish has potential antiaging properties and can be further developed for pharmaceutical and cosmetic purposes.

Structure-Activity Relationship of Pine Nut-Derived Peptides and Their Protective Effect on Nerve-Cell Mitochondria

This study aimed to investigate the structure-activity relationship of the pine nut antioxidant peptide WYPGK and its derivative peptides, and to evaluate the protective effect of the latter on oxidative damage to mitochondrial structure and function in PC12 cells. Molecular docking revealed the derivative peptides WYFGK and WYSGK to have higher affinity to the active region of sirtuin 3 (SIRT3) (−6.08 kcal/mol and −5.87 kcal/mol, respectively), hence indicating that they are promising SIRT3 inducers and antioxidant factors. The derivative peptide WYSGK presented the highest ORAC value (5457.70 µmol TE/g), ABTS scavenging activity (70.05%), and Fe2+-chelating activity (81.70%), followed by WYPGK and WYFGK. Circular dichroism and nuclear magnetic resonance data suggested that the presence of 3-Ser in WYSGK increased its β-sheet content, and that the active hydrogen atoms produced chemical shifts. In H2O2-induced PC12 cells, WYSGK substantially reduced ROS and MDA levels, and increased ATP levels. Transmission electron microscopy and Seahorse Analyze assay proved the peptide WYSGK to significantly alleviate mitochondrial damage and respiratory dysfunction (p < 0.05), thereby implying that a study of structure-activity relationships of the peptides can possibly be an effective approach for the development of functional factors.

Peptidomics as a useful tool in the follow-up of food bioactive peptides

There is an intense research activity on bioactive peptides derived from food proteins in view of their health benefits for consumers. However, their identification is quite challenging as a consequence of their small size and low abundance in complex matrices such as foods or hydrolyzates. Recent advances in peptidomics and bioinformatics are getting improved sensitivity and accuracy and therefore such tools are contributing to the development of sophisticated methodologies for the identification and quantification of peptides. These developments are very useful for the follow-up of peptides released through proteolysis either in the food itself through the action of endogenous peptidases during processing stages like fermentation, drying or ripening, or from food proteins hydrolyzed by commercial peptidases or microorganisms with proteolytic activity. This chapter is presenting the latest advances in peptidomics and its use for the identification and quantification of peptides, and as a useful tool for controlling the proteolysis phenomena in foods and protein hydrolyzates.

Production, bioactivities and bioavailability of bioactive peptides derived from walnut origin by-products: a review

Walnut-origin by-products obtained from walnut oil extraction industry are high in proteins with various physiological functions and pharmacological properties and an extensive potential for usage in producing bioactive peptides. This review presents the current research status of bioactive peptides derived from walnut by-products, including preparation, separation, purification, identification, bioactivities, and bioavailability. A plethora of walnut peptides with multiple biological activities, including antioxidative, antihypertensive, neuroprotective, antidiabetic, anticancer, and antihyperuricemia activities, were obtained from walnut-origin by-products by enzymatic hydrolysis, fermentation, and synthesis. Different bioactive peptides show various structural characteristics and amino acid composition due to their diverse mechanism of action. Furthermore, walnut protein and its hydrolysate present a high bioavailability in human gastrointestinal digestive system. Improving the bioavailability of walnut peptides is needful in the development of walnut industry. However, future research still needs to exploit energy conservation, high efficiency, environmentally friendly and low-cost production method of walnut bioactive peptide. The molecular mechanisms of different bioactive walnut peptides still need to be explored at the cell and gene levels. Additionally, the digestion, absorption, and metabolism processes of walnut peptides are also the focus of future research.

Investigation of the intestinal trans-epithelial transport and antioxidant activity of two hempseed peptides WVSPLAGRT (H2) and IGFLIIWV (H3)

A preceding paper has shown that a hempseed peptic hydrolysate displays a cholesterol-lowering activity with a statin-like mechanism of action in HepG2 cells and a potential hypoglycemic activity by the inhibition of dipeptidyl peptidase-IV in Caco-2 cells. In the framework of a research aimed at fostering the multifunctional behavior of hempseed peptides, we present here the identification and evaluation of some antioxidant peptides from the same hydrolysate. After evaluation of its diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, a trans-epithelial transport experiment was performed using differentiated Caco-2 cells that permitted the identification of five transported peptides that were synthesized and evaluated by measuring the oxygen radical absorbance capacity (ORAC), the ferric reducing antioxidant power (FRAP), and the 2,2-azino-bis-(3-ethylbenzothiazoline-6-sulfonic) acid (ABTS), and diphenyl-2-picrylhydrazyl radical DPPH assays. The most active peptides, i.e. WVSPLAGRT (H2) and IGFLIIWV (H3), were then tested in cell assays. Both peptides were able to reduce the H₂O₂-induced reactive oxygen species (ROS), lipid peroxidation, and nitric oxide (NO) production levels in HepG2 cells, via the modulation of Nrf-2 and iNOS pathways, respectively.

Enzymatic hydrolysis and microbial fermentation: The most favorable biotechnological methods for the release of bioactive peptides

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Peptide release methods influence its bioactivity by generating different sequences.

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The absorption, toxicity and taste of peptides is influenced by the production method.

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The most used methods are enzymatic hydrolysis and microbial fermentation.

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The most used methods are biotechnological and differ in their process.

Bioactive peptides are biomolecules derived from proteins. They contain anywhere from 2 to 20 amino acids and have different bioactivities. For example, they have antihypertensive activity, antioxidant activity, antimicrobial activity, etc. However, bioactive peptides are encrypted and inactive in the parental protein, so it is necessary to release them to show their bioactivity. For this, there are different methods, where biotechnological methods are highly favorable, highlighting enzymatic hydrolysis and microbial fermentation.

The choice of the method to be used depends on different factors, which is why it is essential to know about the process, its principle, and its advantages and disadvantages. The process of peptide release is critical to generate various peptide sequences, which will produce different biological effects in the hydrolysate. This review focuses on providing extensive information on the enzymatic method and microbial fermentation to facilitate selecting the method that provides the most benefits.

Peptides derived from the gastrointestinal digestion of amaranth 11S globulin: Structure and antioxidant functionality

The relationship between structural and physicochemical properties and antioxidant activity of peptides from amaranth 11S-globulin was studied. Peptides AWEEREQGSR, TEVWDSNEQ, IYIEQGNGITGM and YLAGKPQQEH had the greatest in vitro activity (ORAC, HORAC). GDRFQDQHQ, HVIKPPSRA and KFNRPETT were the most active ones against Cu⁺²/H₂O₂-induced-LDL oxidation. In a cellular system (H₂O₂-induced-Caco2-TC7), TEVWDSNEQ, IYIEQGNGITGM, GDRFQDQHQ, LAGKPQQEHSGEHQ and KFNRPETT were the most effective in decreasing ROS, while the effects on SOD, GPx, and GSH were variable. To understand the structure-antioxidant activity relationships, the content of aromatic and acidic amino acids, the degree of hydrophobicity and the charge distribution on the accessible surface of peptides structures obtained by molecular dynamics were analysed. The low correlation between in vitro, ex vivo and cellular activities could be explained by the influence of physicochemical and structural properties on the interaction with complex systems (LDL/cells), peptide modifications and/or mechanisms other than direct ROS inhibition in the cells.

Bioactive Peptides: A Promising Alternative to Chemical Preservatives for Food Preservation

Bioactive peptides used for food preservation can prolong the shelf life through bacteriostasis and antioxidation. On the one hand, bioactive peptides can inhibit lipid oxidation by scavenging free radicals, interacting with metal ions, and inhibiting lipid peroxidation. On the other hand, bioactive peptides can fundamentally inhibit the growth and reproduction of microorganisms by destroying their cell membranes or targeting intracellular components. Besides, bioactive peptides are biocompatible and biodegradable in vivo. Therefore, they are regarded as a promising alternative to chemical preservatives. However, bioactive peptides are easily affected by the external environment in practical application, which hinders their commercialization. Currently, the studies to overcome the weakness focus on encapsulation and chemical synthesis. Bioactive peptides have been applied to the preservation of various foods in experimental research, with good results. In the future, with the deepening understanding of their safety and structure-activity relationship, there may be more bioactive peptides as food preservatives.

Oligopeptides from Jinhua ham prevent alcohol-induced liver damage by regulating intestinal homeostasis and oxidative stress in mice

The current study aimed to evaluate the protective activity of peptides isolated from Jinhua ham (JHP) against alcoholic liver disease (ALD) and the mechanisms by which JHP prevents against ALD. The tangential flow filtration (TFF) combined with size exclusion chromatography (SEC) and reversed-phase high performance liquid chromatography (RP-HPLC) were used to isolate the JHP. Then the hepatoprotective activity of peptides was evaluated through experiments in mice. The primary structure of the peptide with the strongest liver protective activity was Lys-Arg-Gln-Lys-Tyr-Asp (KRQKYD) and the peptide was derived from the myosin of Jinhua ham, which were both identified by LC-MS/MS. Furthermore, the mechanism of KRQKYD prevention against ALD was attributed to the fact that KRQKYD increases the abundance of Akkermansia muciniphila in the gut and decreases the abundance of Proteobacteria (especially Escherichia_Shigella). The LPS-mediated liver inflammatory cascade was reduced by protecting the intestinal barrier, increasing the tight connection of intestinal epithelial cells and reducing the level of LPS in the portal venous circulation. KRQKYD could inhibit the production of ROS by upregulating the expression of the NRF2/HO-1 antioxidant defense system and by reducing oxidative stress injury in liver cells. This study can provide a theoretical foundation for the application of JHP in the protection of liver from ALD.

Lupin-Derived Bioactive Peptides: Intestinal Transport, Bioavailability and Health Benefits

There is a renewed interest on the reliance of food-based bioactive compounds as sources of nutritive factors and health-beneficial chemical compounds. Among these food components, several proteins from foods have been shown to promote health and wellness as seen in proteins such as α/γ-conglutins from the seeds of Lupinus species (Lupin), a genus of leguminous plant that are widely used in traditional medicine for treating chronic diseases. Lupin-derived peptides (LDPs) are increasingly being explored and they have been shown to possess multifunctional health improving properties. This paper discusses the intestinal transport, bioavailability and biological activities of LDPs, focusing on molecular mechanisms of action as reported in in vitro, cell culture, animal and human studies. The potentials of several LDPs to demonstrate multitarget mechanism of regulation of glucose and lipid metabolism, chemo- and osteoprotective properties, and antioxidant and anti-inflammatory activities position LDPs as good candidates for nutraceutical development for the prevention and management of medical conditions whose etiology are multifactorial.

Bioactive peptides from foods: production, function, and application

Bioactive peptides are a class of peptides with special physiological functions and have potential applications in human health and disease prevention. Bioactive peptides have gained much research attention because they affect the cardiovascular, endocrine, immune, and nervous systems. Recent research has reported that bioactive peptides are of great value for physiological function regulation, including antioxidation, anti-hypertension, antithrombosis, antibacterial properties, anti-cancer, anti-inflammation, anti-diabetic, anti-obesity, cholesterol-lowering, immunoregulation, mineral binding and opioid activities. The production of food-derived bioactive peptides is mainly through the hydrolysis of digestive enzymes and proteolytic enzymes or microbial fermentation. The purpose of this review is to introduce the production, function, application, challenges, and prospects of food-derived bioactive peptides.

Non-thermal processing has an impact on the digestibility of the muscle proteins

Muscle proteins undergo several processes before being ready in a final consumable form. All these processes affect the digestibility of muscle proteins and subsequent release of amino acids and peptides during digestion in the human gut. The present review examines the effects of different processing techniques, such as curing, drying, ripening, comminution, aging, and marination on the digestibility of muscle proteins. The review also examines how the source of muscle proteins alters the gastrointestinal protein digestion. Processing techniques affect the structural and functional properties of muscle proteins and can affect their digestibility negatively or positively depending on the processing conditions. Some of these techniques, such as aging and mincing, can induce favorable changes in muscle proteins, such as partial unfolding or exposure of cleavage sites, and increase susceptibility to hydrolysis by digestive enzymes whereas others, such as drying and marination, can induce unfavorable changes, such as severe cross-linking, protein aggregation, oxidation induced changes or increased disulfide (S-S) bond content, thereby decreasing proteolysis. The underlying mechanisms have been discussed in detail and the conclusions drawn in the light of existing knowledge provide information with potential industrial importance.

Peptide Analogues of VPP and IPP with Improved Glucose Uptake Activity in L6 Myotubes can be Released from Cereal Proteins

VPP (Val-Pro-Pro) and IPP (Ile-Pro-Pro) are two famous antihypertensive peptides with possible benefits for type 2 diabetes mellitus (T2DM). The study was aimed to investigate the effect of peptide analogues of VPP and IPP on glucose uptake activity in L6 myotubes. The analogues were designed by replacing the N-terminal, middle, or C-terminal amino acid residues of VPP and IPP with one amino acid at a time from five amino acid groups (polar, nonpolar, basic, acidic, and aromatic amino acids). Among 26 tripeptides tested, IQP, IPQ, VPE, and VEP showed significantly higher glucose uptake activity than their parent peptides, and all were successfully released from rice proteins at the contents of 5415.82 ± 63.34, 1586.77 ± 14.94, 354.07 ± 6.56, and 596.10 ± 2.32 ng/mg dry basis, respectively, and quantified by liquid chromatography-mass spectrometry (MS)/MS using multiple reaction monitoring. All four peptides were shown to promote glucose uptake via the adenosine monophosphate-activated protein kinase pathway accompanied by glucose transporter type 4 (Glut4) translocation rather than the insulin signaling pathway.

Isolation and identification of bioactive peptides from Xuanwei ham that rescue oxidative stress damage induced by alcohol in HHL-5 hepatocytes

Peptides extracted from Xuanwei ham (XHP) can prevent free radical-induced diseases. The aim of the present study was to isolate and identify bioactive peptides from Xuanwei hams that rescue the oxidative stress damage induced by alcohol in HHL-5 hepatocytes. Alcohol-treated HHL-5 human hepatocytes were utilized as the alcohol-induced hepatocyte damage model to evaluate the effects of XHP on amounts of aminotransferase (ALT), aspartate aminotransferase (AST) and malondialdehyde (MDA). The result showed that XHP could significantly reduce ALT, AST and MDA, the major biomarkers of liver damage. The crude XHP was separated by size exclusion chromatography, followed by the evaluation of respective activities. Then, the most active components were further separated by RP-HPLC, and their activities were evaluated according to the above method. The peptide was identified as a hexapeptide with the sequence of Asn-Pro-Pro-Lys-Phe-Asp (NPPKFD) through LC-MS/MS. Further, the molecular mechanisms by which NPPKFD prevents alcohol-induced oxidative stress damage were revealed. Results showed that the hexapeptide could downregulate CYP2E1 expression, reduce generation of ROS and enhance oxidant defense systems via the activation of NrF2/HO-1 pathway. The findings suggest that Xuanwei ham can be used as a new source of bioactive peptides for protection from alcohol-induced liver damage.

Recent Progress in Enzymatic Release of Peptides in Foods of Animal Origin and Assessment of Bioactivity

There is a wide variety of peptides released from food proteins that are able to exert a relevant benefit for human health, such as angiotensin-converting enzyme inhibition, antioxidant, anti-inflammatory, hypoglucemic, or antithrombotic activity, among others. This manuscript is reviewing the recent advances on enzymatic mechanisms for the hydrolysis of proteins from foods of animal origin, including the types of enzymes and mechanisms of action involved, the strategies followed for the isolation and identification of bioactive peptides through advanced proteomic tools, and the assessment of bioactivity and its beneficial effects. Specific applications in fermented and/or ripened foods where a significant number of bioactive peptides have been reported with relevant in vivo physiological effects on laboratory rats and humans as well as the hydrolysis of animal food proteins for the production of bioactive peptides are also reviewed.

Bioactive peptides from food fermentation: A comprehensive review of their sources, bioactivities, applications, and future development

Bioactive peptides (BPs) are specific protein fragments that exert various beneficial effects on human bodies and ultimately influence health, depending on their structural properties and amino acid composition and sequences. By offering promising solutions to solve diverse health issues, the production, characterization, and applications of food-derived BPs have drawn great interest in the current literature and are of particular interest to the food and pharmaceutical industries. The microbial fermentation of protein from various sources is indubitably a novel way to produce BPs with numerous beneficial health effects. Apart from its lower cost as compared to enzymes, the BPs produced from microbial fermentation can be purified without further hydrolysis. Despite these features, current literature shows dearth of information on the BPs produced from food via microbial fermentation. Hence, there is a strong necessity to explore the BPs obtained from food fermentation for the development of commercial nutraceuticals and functional foods. As such, this review focuses on the production of BPs from different food sources, including the extensively studied milk and milk products, with emphasis on microbial fermentation. The structure-activity (antihypertensive, antioxidant, antimicrobial, opiate-like, anti-inflammatory, anticancer/antiproliferative, antithrombotic, hypolipidemic, hypocholesterolemic, and mineral binding) relationship, potential applications, future development, and challenges of BPs obtained from food fermentation are also discussed.

Quantitative changes in peptides derived from proteins in beef tenderloin (psoas major muscle) and striploin (longissimus lumborum muscle) during cold storage

Peptides derived from whole proteins in beef tenderloin (M. psoas major, PM) and striploin (M. longissimus lumborum, LL) associated with meat quality and muscle fiber composition were identified and quantified during 21 days of aging. Peptide quantification revealed 40-43 proteins to be significantly degraded during all aging time, and these were mostly sarcoplasmic proteins. Cooking loss of both muscles was not changed by aging (P > 0.05), whereas Warner-Bratzler shear force and meat color were affected by aging. Sensory tenderness increased in PM after 14 days of aging (P < 0.05). PM had a higher type I fiber content, whereas LL had a higher type IIX fiber content (P < 0.05), resulting in differences in proteolysis during all aging periods tested. These findings improve our understanding of different biochemical and physicochemical changes in aged meat according to the muscle type.

Advances on Food-Derived Peptidic Antioxidants-A Review

The oxidation process is considered to be the main reason behind human aging, human degenerative diseases and food quality degradation. Food-derived peptidic antioxidants (PAs) have wide sources and great activity, and have broad application prospects in removing excess reactive oxygen species in the body, anti-aging and preventing and treating diseases related to oxidative stress. On the other hand, PAs are expected to inhibit the lipid peroxidation of foods and increase the stability of the food system in the food industry. However, the production pathways and action mechanism of food-derived PAs are diverse, which makes it is difficult to evaluate the performance of PAs which is why the commercial application of PAs is still in its infancy. This article focuses on reviewing the preparation, purification, and characterization methods of food-derived PAs, and expounds the latest progress in performance evaluation and potential applications, in order to provide an effective reference for subsequent related research of PAs.

Changes in the extent and products of In vitro protein digestion during the ripening periods of Chinese dry-cured hams

A long ripening period is essential for developing dry-cured ham flavor, but the effect of ripening process on its in vitro digestion product has not been extensively studied. Here, we investigated the in vitro digestion profiles from Chinese dry-cured ham (Jinhua, Rugao and Xuanwei) with different ripening periods by particle size measurement, gel eletrophoresis analysis and nano liquid chromatography-tandem mass spectrometry. The results showed that the in vitro digestibility of ham was in a good agreement with the particle size of digestion products. Among the three types dry-cured ham, Xuanwei showed the highest digestibility (93.46%), followed by Jinhua (74.46%). In term of ripening period, the 2-year Xuanwei and Jinhua showed the diversity of peptides (especially for peptide with molecular weight < 2500 Da), besides their good digestibility. Moreover, the highest amount of peptides (404) was observed in 2-year Jinhua compared to other hams. Our finding gave a new insight into the digestion profiles and nutritional properties of Chinese dry-cured hams.

Relationship between Diet, Menstrual Pain and other Menstrual Characteristics among Spanish Students

This study sought to describe and compare adherence to the Mediterranean diet and consumption of local foods from the Huelva region among Spanish university women in relation to menstrual pain and other menstrual characteristics. This cross-sectional study included 311 health science students. The study variables were sociodemographic and gynecologic characteristics, adherence to the Mediterranean diet using the KIDMED questionnaire, alcohol consumption (SDU) and consumption of local food. A descriptive bivariate analysis and multiple binary regression were performed for menstrual pain. Up to 55.3% of participants had moderate adherence to the Mediterranean diet and only 29.6% had high adherence. Women with low adherence had longer menstrual cycles (p < 0.01). Eating less than two pieces of fruit per day (OR = 3.574; 95%CI = 1.474-8.665; p < 0.05) and eating pulses more than one day a week (OR = 2.320; 95%CI = 1.006-5.348) raised the probability of suffering menstrual pain. A positive correlation between SDU and cycle length was identified (r = 0.119, p = 0.038), and menstrual bleeding was lower in women who consumed olive oil daily (p = 0.044). In conclusion, the Mediterranean diet, alcohol consumption and consuming typical foods from southern Spain appear to influence cycle length, menstrual flow and menstrual pain. Further research is necessary to confirm and expand these findings.

Effect of Gelatin Coating Enriched with Antioxidant Tomato By-Products on the Quality of Pork Meat

The use of edible biopolymers and natural additives obtained from food processing by-products is a sustainable strategy for food packaging applications. Gelatin is a biopolymer with great potential as a coating due to its low cost, high availability, and technological and functional properties. Among them, gelatin can be used as a carrier of bioactive compounds such as antioxidants, which can retard oxidation processes and thus extend the shelf-life of highly-perishable products. This study evaluated the effect of gelatin coating enriched with antioxidant tomato by-products hydrolysate (TBPH) on the quality of pork meat during cold storage. Results showed that TBPH obtained from Alcalase hydrolysis presented antioxidant activity with good stability against cooking. Additionally, chromatographic and mass spectrometry techniques, as well as in silico analysis, were used for the peptidomic characterisation of TBPH. The application of enriched gelatin coating on meat led to some physicochemical changes including increased weight loss and colour differences; however, the pH and water activity, which control meat spoilage, were maintained during storage. Moreover, coating prevented lipid oxidation of meat, and enriched-coated meat presented high antioxidant activity after cooking. These results suggest the positive role of gelatin coating enriched with TBPH in extending the shelf-life of meat during storage.

The chemistry behind the antioxidant actions of soy protein isolate hydrolysates in a liposomal system: Their performance in aqueous solutions and liposomes

Soy protein isolate (SPI) and its derived hydrolysates (SPIHs) are popular food ingredients due to their demonstrated antioxidant, stabilizing and emulsifying properties. However, little is known about the interplays among these functions. This study aimed to fill this knowledge gap through comparing the antioxidant activities in single-phase assays systems and biphasic liposomal systems of the SPIHs produced by pepsin, trypsin or alcalase with/without flavourzyme. The peptide fraction of SPIHs with molecular weight < 1 kDa generally contributed more to the detected antioxidant activity. The combination hydrolysis of flavourzyme with pepsin/trypsin/alcalase significantly influenced SPIH's reducing power and Fe2+ chelating capacity. In liposomal systems, SPIHs influenced positively system's stability while inhibiting primary and secondary lipid oxidation products. Besides the factors affecting SPIH's antioxidant activity in the aqueous system (like amino acid composition, sequence and peptide chain length), interactions of peptides/amino acids with liposomal membrane and its lipid components also played critical roles.