In vitro antioxidant activity and in vivo anti-fatigue effect of loach (Misgurnus anguillicaudatus) peptides prepared by papain digestion

Hybrid hydrolysates of soy protein and lactoferrin exerts synergistic antioxidant and anti-fatigue effect by modulating Keap1/Nrf2/HO-1 pathways

Oxidative stress is an important cause of exercise fatigue formation. Nutritional intervention is an important way to modulate exercise fatigue. Lactoferrin (LF) and soybean protein (SP) are potential antioxidant bioactive components. Our findings demonstrate that SP-LF hybrid hydrolysates had effective 2,2-diphenylpicrylhydrazyl (DPPH) and 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) radical scavenging activity and iron ion reducing ability. The synergistic effect between these hybrid hydrolysates were found to be superior to the single hydrolysate in terms of antioxidant level by the joint index analysis. These hybrid hydrolysates are characterized by high levels of amino acids with potential anti-fatigue effect: tyrosine (Tyr), phenylalanine (Phe), hydrophobic amino acid (HAAs) and branched-chain amino acids (BCAAs). In murine models, hybrid hydrolysates significantly prolonged weight-bearing swimming time, increased muscle/liver glycogen levels, decreased lactate, urea nitrogen, and malondialdehyde levels, and increased glutathione peroxidase, superoxide dismutase, catalase and ATPase activities. Pearson's correlation analysis established significant associations between antioxidant capacity and anti-fatigue efficacy. It alleviated fatigue through activating the Keap1/Nrf2/HO-1 signaling pathway, while increasing the expression levels of PGC-1α. These results collectively suggest that SP-LF hybrid hydrolysates demonstrate significant synergistic antioxidant and anti-fatigue activity and could be incorporated into functional foods as a dietary supplement to reduce fatigue.

An acid polysaccharide from Mentha haplocalyx exerts the antifatigue effect via activating AMPK

Fatigue is a pathological state that can impair physical and cognitive performance, making the development of effective therapeutic strategies crucial. In this study, an acid polysaccharide (MHa) was isolated from Mentha haplocalyx. Structural analysis showed that MHa (40.7 kDa) has a backbone consisting of 4-α-GalAp, 6-α-Galp, and 4,6-α-Galp, with branches at the C6 of 4,6-α-Galp linked to four distinct side chains, including 4-α-Galp, 3,6-β-Manp, t-α-Araf, t-α-Rhap, t-α-Glcp, and t-β-Rhap. MHa possesses a triple-helix conformation with a sheet-like appearance, which may contribute to its biological stability and activity. Functionally, MHa exhibited significant antifatigue effects, with the 400 mg/kg dose showing the most potent activity. Compared to the model group, treatment with 400 mg/kg of MHa increased the exhaustive swimming time by 1.89-fold in fatigued mice, reduced blood lactate and urea nitrogen levels by 24.21 % and 35.57 %, respectively, and enhanced liver glycogen, muscle glycogen, and ATP levels by 20.08 %, 46.52 %, and 50.43 %, respectively. MHa improved the activities of Ca2+-Mg2+-ATPase and Na+-K+-ATPase, while also enhancing antioxidant defense. Mechanistically, MHa promotes mitochondrial biogenesis and enhances oxidative defense via activating AMPK. These findings highlight the potential of MHa as a promising candidate for developing antifatigue supplements, offering a novel strategy to mitigate fatigue.

Regulation of redox enzymes by nutraceuticals: a review of the roles of antioxidant polyphenols and peptides

Redox enzymes are essential components of the cellular defence system against oxidative stress, which is a common factor in various diseases. Therefore, understanding the role of bioactive nutraceuticals in modulating the activity of these enzymes holds immense therapeutic potential. This paper provides a comprehensive review of the regulation of redox enzymes in cell and animal models by food-derived bioactive nutraceuticals, focusing on polyphenols and peptides. Specifically, this paper discusses the regulation of superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT), NAPDH oxidase, xanthine oxidase (XO), myeloperoxidase (MPO), and haem oxygenase (HO) in cell and animal models. Polyphenols, which are abundant in fruits, vegetables, and beverages, have diverse antioxidant properties, including direct scavenging of reactive oxygen species and regulation of transcription factors such as nuclear factor erythroid 2-related factor 2, which leads to the increased expression of the redoxenzymes SOD, HO, and GPx. Similarly, bioactive peptides from various food proteins can enhance antioxidative enzyme activity by regulating gene expression and directly activating the enzyme CAT. In other cases, an antioxidative response requires the downregulation or inhibition of the redox enzymes XO, MPO, and NAPDH oxidase. This paper highlights the potential of bioactive nutraceuticals in mitigating oxidative stress-related diseases and their mechanisms in modulating the redox enzyme expression or activity. Furthermore, the review highlights the need for further research to uncover new therapeutic strategies using nutraceuticals for enhancing cellular antioxidant defence mechanisms and improving health outcomes.

The Antioxidant and Anti-Fatigue Effects of Rare Ginsenosides and γ-Aminobutyric Acid in Fermented Ginseng and Germinated Brown Rice Puree

γ-aminobutyric acid (GABA) and rare ginsenosides are good antioxidant and anti-fatigue active components that can be enriched via probiotic fermentation. In this study, ginseng and germinated brown rice were used as raw materials to produce six fermented purees using fermentation and non-fermentation technology. We tested the chemical composition of the purees and found that the content of GABA and rare ginsenoside (Rh4, Rg3, and CK) in the puree made of ginseng and germinated brown rice (FGB) increased significantly after fermentation. The antioxidant activity of the six purees was determined using cell-free experiments, and it was found that FGB had better ferric-ion-reducing antioxidant power (FRAP) and 1,1-diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging rates, exhibiting better antioxidant effects. We then evaluated the antioxidant effect of FGB in HepG2 cells induced by H2O2 and found that FGB can reduce the generation of reactive oxygen species (ROS) in HepG2 cells and increase the membrane potential level, thereby improving oxidative damage in these cells. In vivo experiments also showed that FGB has good antioxidant and anti-fatigue activities, which can prolong the exhaustive swimming time of mice and reduce the accumulation of metabolites, and is accompanied by a corresponding increase in liver glycogen and muscle glycogen levels as well as superoxide dismutase and lactate dehydrogenase activities. Finally, we believe that the substances with good antioxidant and anti-fatigue activity found in FGB are derived from co-fermented enriched GABA and rare ginsenosides.

Polysaccharides from Artemisia argyi leaves: Environmentally friendly ultrasound-assisted extraction and antifatigue activities

Artemisia argyi leaf polysaccharide (AALPs) were prepared through ultrasound-assisted extraction (UAE), and their antifatigue activities were evaluated. Extraction was optimized using response surface methodology (RSM), which yielded the following optimal UAE conditions: ultrasonication power of 300 W, extraction temperature of 51 °C, liquid:solid ratio of 20 mL/g, and ultrasonication time of 47 mins. The above optimal conditions resulted in the maximum extraction rate of 10.49 %. Compared with hot water extraction (HWE), UAE supported higher yields and total sugar, uronic acid, and sulfate contents of AALPs. Meanwhile, AALP prepared through UAE (AALP-U) exhibited higher stability due to its smaller particle size and higher absolute value of zeta potential than AALP prepared through HWE (AALP-H). In addition, AALP-U demonstrated stronger antioxidant activity than AALP-H. In forced swimming tests on mice, AALP-U could significantly prolong swimming time with a dose-dependent effect, increase liver and muscle glycogen levels, and improve other biochemical indices, thus showing great potential for application in functional food.

The anti-fatigue and sleep-aiding effects vary significantly among different recipes containing Ganoderma lucidum extracts

Aims

This study aims to delve into the anti-fatigue and sleep-aiding effects of various formulations containing Ganoderma lucidum extracts.

Materials and methods

PGB [incorporating Ganoderma lucidum extract (GE), broken Ganoderma lucidum spore powder (GB) and Paecilomyces hepiali mycelium (PH)] and GBS [composed of GE, GB, and Ganoderma sinense powder (GS)] were chosen as representative recipes for this study. Mice were treated with these recipes or key components of Ganoderma lucidum for 14 consecutive days. Subsequently, a weight-bearing swimming experiment was conducted to assess the mice's exhaustion time and evaluate the anti-fatigue properties of the recipes. Sleep-aiding effects were analyzed by measuring the sleep latency and duration. Furthermore, levels of blood lactic acid, serum urea nitrogen, hepatic glycogen, muscle glycogen, and malondialdehyde (MDA) were measured in the livers and muscles.

Key findings

The anti-fatigue abilities of the tested mice were significantly improved after treatment with PGB and their sleep quality improved as well with GBS treatment. PGB treatment for 14 days could significantly prolong the exhaustion time in weight-bearing swimming (from 10.1 ± 0.5 min to 15.2 ± 1.3 min). Meanwhile, glycogen levels in the livers and muscles were significantly increased, while the levels of serum lactic acid, serum urea nitrogen, and MDA in the livers and muscles were significantly decreased. In contrast, mice treated with GBS for 14 days experienced significant improvements in sleep quality, with shortened sleep latency (from 6.8 ± 0.7 min to 4.2 ± 0.4 min), extended sleep duration (from 88.3 ± 1.4 min to 152.5 ± 9.3 min), and decreased muscle MDA levels. These results indicated that Ganoderma lucidum extracts can be used for anti-fatigue and or aid in sleeping, depending on how they are prepared and administered.

Significance

This study provides experimental evidence and theoretical basis for the development of Ganoderma lucidum recipes that are specifically designed to help with anti-fatigue and sleep.

Characterization and Exploration of the Neuroprotective Potential of Oat-Protein-Derived Peptides in PC12 Cells and Scopolamine-Treated Zebrafish

Neurodegenerative disorders pose a substantial risk to human health, and oxidative stress, cholinergic dysfunction, and inflammation are the major contributors. The purpose of this study was to explore the neuroprotective effects of oat protein hydrolysate (OPH) and identify peptides with neuroprotective potential. This study is the first to isolate and identify OPH peptides with neuroprotective potential, including DFVADHPFLF (DF-10), HGQNFPIL (HL-8), and RDFPITWPW (RW-9), by screening via peptidomes and molecular-docking simulations. These peptides showed positive effects on the activity of antioxidant enzymes and thus reduced oxidative stress through regulation of Nrf2-keap1/HO-1 gene expression in vitro and in vivo. The peptides also significantly ameliorated scopolamine-induced cognitive impairment in the zebrafish model. This improvement was correlated with mitigation of MDA levels, AChE activity, and levels of inflammatory cytokines in the brains of zebrafish. Furthermore, these peptides significantly upregulated the mRNA expression of Bdnf, Nrf2, and Erg1 in the brains of zebrafish with neurodegenerative disorders. Collectively, oat peptides have potential for use as active components in nutraceutical applications for the prevention of neurodegenerative diseases.

Effect of Yeast-Derived Peptides on Skeletal Muscle Function and Exercise-Induced Fatigue in C2C12 Myotube Cells and ICR Mice

In our previous study, the antioxidant peptides (XHY69AP, AP-D, YPLP, and AGPL) were obtained from potential probiotic yeast (Yamadazyma triangularis XHY69), which was selected by our lab from dry-cured ham. This work aimed to explore the effects of yeast-derived peptides on skeletal muscle function and muscle fatigue. Results showed that yeast-derived peptides up-regulated slow-twitch fiber expression and down-regulated fast-twitch fiber expression in C2C12 cells (p < 0.05). The peptides improved mitochondrial membrane potential, adenosine triphosphate generation, and expression of cytochrome-relative genes, thus promoting mitochondrial function. Among these peptides, YPLP up-regulated the relative gene expression of the AMP-activated protein kinase (AMPK) pathway and activated AMPK by phosphorylation. Moreover, YPLP could prolong treadmill time, increase muscle and liver glycogen contents, reduce lactic acid and urea nitrogen contents, and alleviate muscle tissue injury in ICR exercise mice. These results demonstrate that yeast-derived peptides could change the muscle fiber composition, improve muscle function, and relieve muscle fatigue.

Structural Identification and Antioxidant Activity of Loach Protein Enzymatic Hydrolysates

Loach, rich in nutrients, such as proteins, amino acids, and mineral elements, is being gradually favored by consumers. Therefore, in this study, the antioxidant activity and structural characteristics of loach peptides were comprehensively analyzed. The loach protein (LAP) with a molecular weight between 150 and 3000 Da was graded by ultrafiltration and nanofiltration processes, which exhibited excellent scavenging activity against DPPH radical (IC50 2.91 ± 0.02 mg/mL), hydroxyl radical (IC50 9.95 ± 0.03 mg/mL), and superoxide anion radical (IC50 13.67 ± 0.33 mg/mL). Additionally, LAP was purified by gel filtration chromatography, and two principal components (named as LAP-I and LAP-II) were isolated. A total of 582 and 672 peptides were identified in LAP-I and LAP-II, respectively, through structural analysis. The XRD results revealed that LAP-I and LAP-II had an irregular amorphous structure. The 2D-NMR spectroscopy results suggested that LAP-I had a compact stretch conformation in the D₂O solution, while LAP-II had a folded conformation. Overall, the study results suggested that loach peptide could be a potential antioxidant agent and might provide valuable information for chain conformation and antioxidant mechanism research further.

Anti-fatigue properties of the ethanol extract of Moringa oleifera leaves in mice

BACKGROUND

Moringa oleifera (M. oleifera) leaves are rich in nutrients and bioactive ingredients. This study was aimed at evaluating the anti-fatigue effect of the ethanol extract of M. oleifera leaves (MLEE) on mice and its primary mechanism of action using a weight-loaded forced swimming test. In the present study, MLEE was prepared by ultrasound-assisted extraction, and its anti-fatigue effect and antioxidant capacity were evaluated in mice. Mice were administrated MLEE (320 mg kg^-1 body weight) for 15 days.

RESULTS

MLEE supplementation significantly increased levels of glucose and non-esterified fatty acids (NEFA), while decreasing levels of lactate and blood urea nitrogen in serum (P < 0.05); the levels of glycogen in the liver and muscle were also increased, as was the activity of glycogen synthase and the level of NEFA in muscle (P < 0.05). According to a Western blot analysis, MLEE increased the expression of AMPKα1, JNK, AKT and STAT3 in the muscle of mice.

CONCLUSION

Our findings indicate that MLEE has an anti-fatigue effect via the AMPK-linked route, which enables it to control energy metabolism and enhance antioxidant enzyme activity. © 2023 Society of Chemical Industry.

Study the antioxidant of Matricaria chamomilla (Chamomile) powder: In vitro and vivo

Oxidative stress is oxidative damage caused by free radicals and reactive oxygen species (ROS). These ROS can cause oxidative damage to cellular components, including membrane lipids, receptors, enzymes, proteins, and nucleic acids. It would eventually lead to cell apoptosis and the appearance of certain pathological conditions. This work investigates the antioxidant potentials of chamomile extract in vitro by evaluating the extract activity to scavenge 2,2-Diphenyl-1-picrylhydrazyl (DPPH), also in vivo by investigating its effects on oxidative stress-induced rats by assessing the total oxidant status (TOS) and total antioxidant capacity in the radiation exposed rats with and without the treatment with chamomile extract. The results have shown that chamomile extract contains materials with antioxidant properties. The in vitro analyses have indicated activity to detoxify the DPPH radicals almost as powerful as pure ascorbic acid. Furthermore, rats exposed to electromagnetic radiation have shown a disturbance in the balance of oxidants and antioxidants, in which the levels of TOS were elevated while the levels of TAC were reduced. Chamomile extract has been shown to exhibit a powerful function as an antioxidant in vivo. It has enhanced the antioxidant capacity of rats, reduced their total oxidant status, and protected exposure to radiation. Keywords: Total antioxidant capacity, peach fruit, rats, DPPH, total oxidant status.

Multiple Bioactivities of Peptides from Hydrolyzed Misgurnus anguillicaudatus

Misgurnus anguillicaudatus (loach) is a widely distributed benthic fish in Asia. In this study, the alkaline protease was used to hydrolyze loach, and the hydrolysate products of different molecular weights were obtained by membrane separation. In vitro antioxidant assays showed that the <3 kDa fraction (SLH-1) exhibited the strongest antioxidant activity (DPPH, hydroxyl radical and superoxide radical scavenging ability, and reducing power), while SLH-1 was purified by gel filtration chromatography, and peptide sequences were identified by LC-MS/MS. A total of six peptides with antioxidant activity were identified, namely SERDPSNIKWGDAGAQ (D-1), TVDGPSGKLWR (D-2), NDHFVKL (D-3), AFRVPTP (D-4), DAGAGIAL (D-5), and VSVVDLTVR (D-6). In vitro angiotensin-converting enzyme (ACE) inhibition assay and pancreatic cholesterol esterase (CE) inhibition assay, peptide D-4 (IC50 95.07 μg/mL, 0.12 mM) and D-2 inhibited ACE, and peptide D-2 (IC50 3.19 mg/mL, 2.62 mM), D-3, and D-6 acted as pancreatic CE inhibitors. The inhibitory mechanisms of these peptides were investigated by molecular docking. The results showed that the peptides acted by binding to the key amino acids of the catalytic domain of enzymes. These results could provide the basis for the nutritional value and promote the type of healthy products from hydrolyzed loach.

Milk Fat Globule Membrane Relieves Fatigue via Regulation of Oxidative Stress and Gut Microbiota in BALB/c Mice

Milk fat globule membranes (MFGMs) are complex structures that incorporate bioactive proteins and lipids to assist in infant development. However, the antifatigue and antioxidant potentials of MFGM have not been investigated. In this study, repeated force swimming measured fatigue in male BALB/c mice fed MFGM and saline for 18 weeks. The MFGM supplementation increased the time to exhaustion by 42.7% at 6 weeks and 30.6% at 14 weeks (p < 0.05). Fatigue and injury-related biomarkers, including blood glucose, lactic acid, and lactate dehydrogenase, were ameliorated after free swimming (p < 0.05). The activity of antioxidant enzymes in blood serum increased at 18 weeks, while malondialdehyde (MDA) content decreased by 45.0% after the MFGM supplementation (p < 0.05). The Pearson correlation analysis showed a high correlation between fatigue-related indices and antioxidant levels. The increased protein expression of hepatic Nrf2 reduced the protein expression of Caspase-3 in the gastrocnemius muscle (p < 0.05). Moreover, the MFGM supplementation increased the relative abundance of Bacteroides, Butyricimonas, and Anaerostipes. Our results demonstrate that MFGM may maintain redox homeostasis to relieve fatigue, suggesting the potential application of MFGM as an antifatigue and antioxidant dietary supplement.

High Fischer ratio peptide of hemp seed: Preparation and anti-fatigue evaluation in vivo and in vitro

The high Fischer (F) ratio hemp peptide (HFHP) was prepared by enrichment using activated carbon adsorption, ultrafiltration, and Sephadex G-25 gel filtration chromatography. The OD₂₂₀/OD₂₈₀ ratio reached 47.1 with a molecular weight distribution from 180 to 980 Da, a peptide yield up to 21.7 %, and the F value was 31.5. HFHP had high scavenging ability of DPPH, hydroxyl free radicals, and superoxide. Mice experiments showed that the HFHP increased the activity of superoxide dismutase and glutathione peroxidase. The HFHP had no effect on the body weight of mice, but prolonged their weight-bearing swimming time. The lactic acid, serum urea nitrogen, and malondialdehyde of the mice after swimming was reduced, and the liver glycogen increased. The correlation analysis indicated that the HFHP had significant anti-oxidation and anti-fatigue properties.

Euscaphic acid relieves fatigue by enhancing anti-oxidative and anti-inflammatory effects

BACKGROUND

Oxidative stress and inflammation are involved in chronic fatigue. Euscaphic acid (EA) is an active compound of Eriobotrya japonica (Loquat) and has anti-oxidative effect.

METHODS

The goal of present study is to prove whether EA could relieve fatigue through enhancing anti-oxidant and anti-inflammatory effects in in vitro/in vivo models.

RESULTS

EA notably improved activity of superoxide dismutase (SOD) and catalase (CAT), while EA reduced levels of malondiadehyde (MDA) and inflammatory cytokines without cytotoxicity in H₂O₂-stimulated in myoblast cell line, C2C12 cells. EA significantly reduced levels of fatigue-causing factors such as lactate dehydrogenase (LDH) and creatin kinase (CK), while EA significantly incresed levels of anti-fatigue-related factor, glycogen compared to the H₂O₂-stimulated C2C12 cells. In treadmill stress test (TST), EA significantly enhanced activities of SOD and CAT as well as exhaustive time and decreased levels of MDA and inflammatory cytokines. After TST, levels of free fatty acid, citrate synthase, and muscle glycogen were notably enhanced by oral administration of EA, but EA decreased levels of lactate, LDH, cortisol, aspartate aminotransferase, alanine transaminase, CK, glucose, and blood urea nitrogen compared to the control group. Furthermore, in forced swimming test, EA significantly increased levels of anti-fatigue-related factors and decreased excessive accumulations of fatigue-causing factors.

CONCLUSIONS

Therefore, the results indicate that potent anti-fatigue effect of EA can be achieved via the improvement of anti-oxidative and anti-inflammatory properties, and this study will provide scientific data for EA to be developed as a novel and efficient component in anti-fatigue health functional food.

A New Pharmacological Vitreolysis through the Supplement of Mixed Fruit Enzymes for Patients with Ocular Floaters or Vitreous Hemorrhage-Induced Floaters

Purpose: Ocular floaters caused by vitreous degeneration or blood clots may interfere with various visual functions. Our study investigated the pharmacologic effects of oral supplementation of mixed fruit enzymes (MFEs) for treating spontaneous symptomatic vitreous opacities (SVOs) and those secondary to vitreous hemorrhage (VH). Methods: 224 patients with monocular symptomatic vitreous opacities (SVOs) were recruited between September and December 2017 and received oral supplementation of MFEs (190 mg bromelain, 95 mg papain, and 95 mg ficin) for 3 months in a double-blind clinical trial. Participants were divided according to the etiology of the SVOs, spontaneous (experiment 1) versus VH (experiment 2), and then randomly assigned into four treatments groups: one group received oral vitamin C, as a placebo; and the other 3 groups received 1 capsule per day (low dose), 2 capsules per day (middle dose), or 3 capsules per day (high dose) of MFEs. The number of SVOs was determined at baseline and then 1, 2, and 3 months after initiating treatment. Further, in cases secondary to VH, the changes in corrected distance visual acuity (CDVA) were assessed after 3 months. Second, we compared the free radical scavenging capabilities of each substance: vitamin C, bromelain, papain, ficin, and MFEs (combination of bromelain, papain, and ficin) by DDPH assay. Finally, SVOs-related symptoms and satisfaction with the treatments were evaluated at the last follow-up visit Results: In experiment 1, the disappearance rate of SVOs was 55%, 62.5%, and 70% after taking 1, 2, and 3 capsules daily, respectively (total p < 0.001), in a dose-dependent manner. In experiment 2, the disappearance rate of VH-induced SVOs was 18%, 25%, and 56% (p < 0.001) after 1, 2, and 3 capsules of the supplement daily, respectively. Additionally, the patients’ vision elevated from 0.63LogMAR to 0.19LogMAR (p = 0.008). Conclusions: A pharmacological approach using a high dose of oral supplementation with MFEs (bromelain, papain, and ficin) was effective in reducing vitreous opacities, even after intraocular hemorrhage. Furthermore, pharmacologic vitreolysis with MFEs supplementation showed high patient satisfaction, and also improved CDVA in patients with vitreous hemorrhage-induced floaters

Dietary-Nutraceutical Properties of Oat Protein and Peptides

Oats are considered the healthiest grain due to their high content of phytochemicals, dietary fibers, and protein. In recent years, oat protein and peptides have gained popularity as possible therapeutic or nutraceutical candidates. Generally, oat peptides with bioactive properties can be obtained by the enzymatic hydrolysis of proteins and are known to have a variety of regulatory functions. This review article focused on the nutraceutical worth of oat proteins and peptides and also describes the application of oat protein as a functional ingredient. Outcomes of this study indicated that oat protein and peptides present various therapeutical properties, including antidiabetic, antioxidant, antihypoxic, antihypertensive, antithrombotic, antifatigue, immunomodulatory, and hypocholestrolaemic. However, most of the conducted studies are limited to in vitro conditions and less data is available on assessing the effectiveness of the oat peptides in vivo. Future efforts should be directed at performing systematic animal studies; in addition, clinical trials also need to be conducted to fully support the development of functional food products, nutraceutical, and therapeutical applications.

Preparation and identification of an antioxidant peptide from wheat embryo albumin and characterization of its Maillard reaction products

Wheat embryo albumin (WEA) extracted from wheat embryo possesses multiple effects including antioxidant, anti-inflammatory, and immunoregulatory effects. In this study, a single factor experiment was conducted to determine the optimal enzymolysis conditions of WEA. Five components (F1-F5) were obtained via ultrafiltration, among which F3 (molecular weight 3-5 kDa) displayed the best antioxidant activity. WEA and F3 were characterized by transmission electron microscopy, scanning electron microscopy, circular dichroism spectrum analysis, and amino acid composition tests. Results revealed that F3 significantly increased the contents of β-tablets, aromatic amino acids, and hydrophobic amino acids compared to WEA. LC-MS/MS analysis demonstrated that F3 had more tyrosine and histidine moieties than WEA. Moreover, analysis of the Maillard reaction products (MRPs) showed that F3-MRPs had strong browning strength, ultraviolet absorption, higher number of free amino acids, and umami amino acid ratio compared with WEA. In conclusion, enzymolysis can improve the functional properties of WEA, which broadens the application spectrum of WEA in food and pharmaceutical fields. PRACTICAL APPLICATION: This study provides a new approach for identifying potential antioxidants and developing functional foods from WEA, and broadens the application spectrum of wheat germ resources.

Using RSM for Optimum of Optimum Production of Peptides from Edible Bird’s Nest By-Product and Characterization of Its Antioxidant’s Properties

In this research, the neutrase hydrolysis conditions of edible bird’s nest (EBN) by-products were optimized by response surface methodology (RSM). Antioxidant peptides were then isolated from the EBN by-products by ultrafiltration and chromatography taking the DPPH radical scavenging ability as an indicator. The antioxidant activity of the purified peptides was estimated by radical scavenging ability and sodium nitroprusside (SNP)-induced damage model in PC12 cells. When the enzyme concentration was10 kU/g-hydrolysis temperature was 45 °C, and hydrolysis time was 10.30 h, the degree of hydrolysis (DH) of EBN by-product hydrolysate (EBNH) was the highest. The purified peptide exerted strong scavenging ability with EC₅₀ values of 0.51, 1.31, and 0.65 mg/mL for DDPH, ABTS, and O₂⁻ radicals, respectively. In addition, the purified peptides could significantly reduce the SNP-induced oxidative damage of PC12 cells, and twelve peptides that were rich in leucine (Leu), valine (Val), and lysine (Lys) were identified by LC-MS/MS. These results suggested that EBN by-products have potential as new materials for natural antioxidant peptides.

The Effect of Hot Water Extract of Tilapia on Exercise Capacity in Mice

Tilapia (Oreochromis mossambicus) has become one of the main aquatic products of Taiwan. The aim of this study was to evaluate the efficacy of a hot water extract of tilapia (HWET) in relieving fatigue and enhancing exercise performance in mice in a swimming endurance test. Male ICR mice were randomly divided into four groups (n = 10 per group) and treated with either a vehicle (control group) or different doses of HWET, which were designated as HWET-L (800 mg/kg/day), HWET-M (1600 mg/kg/day), and HWET-H (4000 mg/kg/day). The results of the swimming endurance test showed that HWET treatment significantly improved exercise-induced fatigue as the swimming time of the mice increased (p < 0.05). One hour after the test, blood samples were collected from each mouse and serum biochemical parameters were measured. The serum levels of lactate, creatine kinase (CK), and blood urea nitrogen (BUN) were lower in mice treated with HWET compared to the control group. Moreover, HWET treatment increased serum glucose levels and glycogen content in the liver. Enhanced glutathione (GSH) content in the liver and muscle was also found in the HWET-M and HWET-H groups. Western blot results showed that the expression of tumor necrosis factor-α (TNF-α) in the liver tissue was downregulated by HWET treatment. Taken together, our results demonstrate that HWET supplementation could enhance exercise performance and alleviate fatigue via biochemical profile improvements. This suggests that HWET has the potential for future development into functional foods or nutritional supplements to relieve fatigue.

Soft-Shelled Turtle Peptide Supplementation Modifies Energy Metabolism and Oxidative Stress, Enhances Exercise Endurance, and Decreases Physical Fatigue in Mice

The potential of soft-shelled turtle peptides (STP) against fatigue was evaluated. Mice orally supplemented with STP significantly increased the swimming time until tiredness by 35.4–57.1%. Although not statistically significant, STP increased muscle and thymus mass. In addition, the serum lactate, ammonia, blood urea nitrogen content and creatine kinase activity in STP-fed mice were dramatically decreased when compared to the control group. Furthermore, STP supplementation increased the reserves of liver glycogen and muscle glycogen, thus improved the energy metabolism system of mice. STP treatment contributed to increased superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities as well as a decrease in malondialdehyde (MDA), indicating an improvement in oxidative stress protection. The Western blot (WB) results indicated that the STP supplement effectively altered the expression of oxidative stress-related protein by modulating the NRF2/KEAP1 pathway. In summary, STP affected NRF2/KEAP1 levels in skeletal muscle, leading to antioxidant activity and a slower time to exhaustion during exercise.

Optimization of Enzymatic Hydrolysis of Perilla Meal Protein for Hydrolysate with High Hydrolysis Degree and Antioxidant Activity

Botanical oils are staple consumer goods globally, but as a by-product of oil crops, meal is of low utilization value and prone to causing environmental problems. The development of proteins in meal into bioactive peptides, such as Perilla peptide, through biotechnology can not only solve environmental problems, but also create more valuable nutritional additives. In the present work, the hydrolysis process of Perilla meal protein suitable for industrial application was optimized with the response surface methodology (RSM) on the basis of single-factor experiments. Alcalase was firstly selected as the best-performing among four proteases. Then, based on Alcalase, the optimal hydrolysis conditions were as follows: enzyme concentration of 7%, hydrolysis temperature of 61.4 °C, liquid-solid ratio of 22.33:1 (mL/g) and hydrolysis time of 4 h. Under these conditions, the degree of hydrolysis (DH) of Perilla meal protein was 26.23 ± 0.83% and the DPPH scavenging capacity of hydrolysate was 94.15 ± 1.12%. The soluble peptide or protein concentration of Perilla meal protein hydrolysate rose up to 5.24 ± 0.05 mg/mL, the ideal yield of which was estimated to be 17.9%. SDS-PAGE indicated that a large proportion of new bands in hydrolysate with small molecular weights appeared, which was different from the original Perilla meal protein. The present data contributed to further, more specific research on the separation, purification and identification of antioxidant peptide from the hydrolysate of Perilla meal protein. The results showed that the hydrolysis of Perilla meal protein could yield peptides with high antioxidant activity and potential applications as natural antioxidants in the food industry.

Bioactivities, Applications, Safety, and Health Benefits of Bioactive Peptides From Food and By-Products: A Review

Bioactive peptides generated from food proteins have great potential as functional foods and nutraceuticals. Bioactive peptides possess several significant functions, such as antioxidative, anti-inflammatory, anticancer, antimicrobial, immunomodulatory, and antihypertensive effects in the living body. In recent years, numerous reports have been published describing bioactive peptides/hydrolysates produced from various food sources. Herein, we reviewed the bioactive peptides or protein hydrolysates found in the plant, animal, marine, and dairy products, as well as their by-products. This review also emphasizes the health benefits, bioactivities, and utilization of active peptides obtained from the mentioned sources. Their possible application in functional product development, feed, wound healing, pharmaceutical and cosmetic industries, and their use as food additives have all been investigated alongside considerations on their safety.

Anti-fatigue and anti-oxidant effects of curcumin supplementation in exhaustive swimming mice via Nrf2/Keap1 signal pathway

Demands for dietary supplements with anti-fatigue effects are growing fast due to increasing societal demands. Moreover, in highly physically active individuals, there are also significant needs for supplements to improve exercise performance. The present study evaluated the potential anti-fatigue and anti-oxidant effects of curcumin in mice using exhaustive swimming test. Male C57BL/6J mice were randomized into six groups: blank control (Rest), swimming control (Con), Vitamin C (Vc), low-dose curcumin (C₅₀), middle-dose curcumin (C₁₀₀), and high-dose curcumin (C₂₀₀). After a 4-week intervention, the mice in all groups except the Rest group were subject to an exhaustive swimming test. Then, mice were sacrificed to examine serum biochemical markers and fatigue-related enzymes. Moreover, the gene and protein expressions of signal transduction factors involved in the Nrf2/Keap1 signaling pathway were measured. The results indicated that curcumin significantly enhanced the exercise tolerance of mice in the exhaustive swimming test. Particularly, the swimming time of mice in the C₁₀₀ group was increased by 273.5% when compared to that of mice in the Con group. The levels of blood urea nitrogen, blood ammonia, lactic acid, creatine kinase and lactate dehydrogenase in the C₁₀₀ group were decreased by 13.3%, 21.0%, 18.6%, 16.7% and 21.9%, respectively, when compared to those of mice in the Con group. Curcumin alleviated exercise-induced oxidative stress and significantly enhanced the activities of superoxide dismutase, catalase and glutathione peroxidase by activating the Nrf2 signaling. These findings indicated that curcumin supplementation exerted remarkable anti-oxidant and anti-fatigue effects in mice, providing additional evidence supporting the use of curcumin as functional food, especially by those engaged in sports-related activities.

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Curcumin exerted remarkable anti-oxidant and anti-fatigue effects in mice.

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Curcumin can activate anti-oxidant response via Nrf2/Keap1 signaling pathway.

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Curcumin greatly enhanced the exercise tolerance of mice in exhaustive swimming test.

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Curcumin alleviated exercise-induced oxidative stress by its anti-oxidant effects.

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Curcumin can be an anti-fatigue promising candidate improving exercise performance.

In vitro dynamic digestion and antifatigue effects of wheat germ albumin

Wheat germ protein including wheat germ albumin (WGA) demonstrated extensive biological activities. In vitro dynamic digestion of was carried out under simulated gastrointestinal conditions. Antifatigue effects of WGA were evaluated...

Anti-fatigue effect of Auxis thazard oligopeptide via modulation of AMPK/ PGC-1α pathway in mice

In this study, the anti-fatigue effect and mechanism of Auxis thazard oligopeptide (ATO) were studied by exhaustive swimming in mice. The results showed that ATO could significantly prolong the exhaustive...

Oxidative stress suppression in C. elegans by peptides from dogfish skin via regulation of transcription factors DAF-16 and HSF-1

Functional peptides were obtained via enzymatic hydrolysis of smooth dogfish (Mustelus canis) skin. The enzyme-assisted process was optimized to achieve high yield of smooth dogfish skin peptides (SDSP). Fractions of SDSP (MW < 2 kDa, 2-5 kDa, 5-10 kDa and >10 kDa) showed in vitro antioxidant activities. The peptides <2 kDa (SDSP_{<2 kDa}) significantly improved motility, reduced ROS and H₂O₂ levels of Caenorhabditis elegans, and increased its resistance to oxidative stress compared to the other peptide fractions. In vivo function of SDSP_{<2 kDa} could be explained by their capacity to increase the expression of stress-response genes. The enhanced resistance to oxidative stress mediated by SDSP_{<2 kDa} was dependent on DAF-16 and HSF-1. The amino acid residues and sequences of SDSP_{<2 kDa} were characterized and revealed a higher content of hydrophobic versus polar amino acid contents. This study (especially the in vivo investigation) explored new potent antioxidant peptides derived from dogfish skin.

Effect of Lactobacillus fermentum HFY03 on the Antifatigue and Antioxidation Ability of Running Exhausted Mice

Yak yogurt is mainly produced in Qinghai-Tibet Plateau. It is a kind of naturally fermented dairy product. It contains abundant microorganisms. Lactobacillus fermentum (LF) HFY03 is a lactic acid bacteria derived from it. Our main research content is to study the influence of LF-HFY03 on the antifatigue and antioxidation ability of running exhausted mice. We gave different doses of LF-HFY03 to mice by gavage for 4 weeks. We selected vitamin C as the positive control group, mainly to study the relationship between antioxidant capacity and fatigue resistance and LF-HFY03 in mice with running exhaustion. The results showed that LF-HFY03 and vitamin C could significantly improve the running time of mice. And with the increase in LF-HFY03 concentration, the exhaustion time of mice was also extended. LF-HFY03 can reduce the content of urea nitrogen and lactic acid and also can increase the content of free fatty acids and liver glycogen. The levels of alanine aminotransferase, serum creatine kinase, and aspartate aminotransferase in mice decreased gradually as the antioxidant peptide level of walnut albumin increased. LF-HFY03 can reduce malondialdehyde (MDA) levels in a quantification-dependent manner and can also increase catalase (CAT) and superoxide dismutase (SOD) levels. LF-HFY03 can also increase the expressions of CAT mRNA, Cu/Zn-SOD, and Mn-SOD in the liver of mice. At the same time, LF-HFY03 can also increase the expression of protein of threonine transporter 1 (AST1)/alanine/cysteine/serine, mRNA, nNOS, and eNOS. At the same time, the solution could reduce the expression of TNF-α, syncytin-1, and inducible nitric oxide synthase (iNOS). The results showed that LF-HFY03 has a high development and application prospect as an antifatigue probiotic nutritional supplement.

Identification of novel antioxidant peptide from porcine plasma hydrolysate and its effect in in vitro digestion/HepG2 cells model

A novel antioxidant peptide EDEQKFWGK from porcine plasma hydrolysate (PPH) was separated by chromatography, HPLC, and identified by LC-MS/MS. Results showed that EDEQKFWGK had better antioxidant ability (Hydroxyl RAS 32.19%, ABTS RAS 92.93% and DPPH RAS 26.76%) compared with glutathione (30.11%, 82.01%, 26.44%) due to the presence of hydrophobic, aromatic acids (F, W) and acidic amino acids (E, D), decreasing ROS by providing hydrogen atom and chelating metal ions. Furthermore, the antioxidant properties of synthetic EDEQKFWGK still significant despite in vitro digestion because of the production of smaller active peptide. Additionally, it could increase SOD, CAT, GSH-Px to resist oxidative damage in HepG2 cells by inhibiting ROS (O₂ ^- , OH·), forming complexes to prevent OH· from destroying DNA and binding to ARE to promote antioxidase expression. Thereby, the novel peptide EDEQKFWGK from porcine plasma had much stable antioxidant properties and hade great potential in formulating functional foods. PRACTICAL APPLICATIONS: This research isolated a novel antioxidant peptide. Moreover, the antioxidant effects of peptide were confirmed under the in vitro digestion model and oxidative damage HepG2 cells model. The results showed the antioxidant peptide could play better effect after digestion and protect the cells from oxidative damage. These data could expand the sequence data of antioxidant peptides and promote the high-value utilization of PPH.

Structural characterization, erythrocyte protection, and antifatigue effect of antioxidant collagen peptides from tilapia (Oreochromis nilotica L.) skin

Tilapia (Oreochromis nilotica L.) skin collagen is a meritorious commercial resource to be exploited. The purpose of this study was to obtain, evaluate, and characterize tilapia skin collagen-derived antioxidant hydrolysates (TSCP). AAPH-induced erythrocyte hemolysis assay and antifatigue test in mice were implemented. It was indicated that TSCP treatment at 1 mg mL-1 could effectively attenuate AAPH-induced erythrocyte hemolysis rate from 56.35 ± 2.46% to 18.78 ± 2.48% (p < 0.01). A 2.5 mg/(10 g d) dose of TSCP intragastric administration could observably prolong the exhaustive swimming time of the loaded mice and its mechanism was multiple, including the decrease in the levels of serum lactic acid, serum urea nitrogen, and creatine kinase activity, thus improving the contents of liver and muscle glycogen and endogenous SOD activity. Five oligopeptides from the antioxidant fraction were identified as Gly-Hyp, Glu-Asp, Asp-Hyp-Gly, Glu-Pro-Pro-Phe, and Lys-Pro-Phe-Gly-Ser-Gly-Ala-Thr and then synthesized. Among them, the octapeptide exhibited the strongest antioxidant capacity. Therefore, tilapia skin-derived collagen is a meritorious edible resource for producing commercial functional foods, thus helping to scavenge radicals, protecting erythrocytes, and further resisting fatigue.

The Preparation, Antioxidant Activity Evaluation, and Iron-Deficient Anemic Improvement of Oat (Avena sativa L.) Peptides-Ferrous Chelate

Iron-chelating peptides have been widely considered as one of the best iron supplements to alleviate the iron deficiency. In this study, a novel oat peptides-ferrous (OP-Fe2+) chelate was prepared from antioxidant oat peptides obtained in the laboratory of the authors. The optimal preparation condition was obtained through the single-factor and response surface methodology, and the chelating rate could reach up to 62.6%. After chelation, the OP-Fe2+ chelate exhibited a significantly higher 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity than oat peptides. It was discovered that the hemoglobin concentration and the number of red blood cell levels in OP-Fe2+-treated iron-deficient anemic (IDA) rats were significantly higher than untreated IDA rats. The OP-Fe2+ chelate could also improve the hypertrophy of the spleen, serum iron (SI), total iron and binding capacity, and serum ferritin levels in the IDA rats. In addition, the OP-Fe2+ treatment significantly increased the antioxidant activities of super oxidase and glutathione in the liver homogenate of the IDA rats. Therefore, the OP-Fe2+ chelate is an effective type of iron supplement for IDA rats, which could be a promising source with anti-anemia and antioxidant activity.

Bioactive peptides from fisheries residues: A review of use of papain in proteolysis reactions

Papain is a cysteine endopeptidase of vegetal origin (papaya (Carica papaya L.) with diverse applications in food technology. In this review we have focused our attention on its application in the production of bio-peptides by hydrolysis of proteins from fish residues. This way, a residual material, that can become a contaminant if dumped without control, is converted into highly interesting products. The main bioactivity of the produced peptides is their antioxidant activity, followed by their nutritional and functional activities, but peptides with many other bioactivities have been produced. Thera are also examples of production of hydrolysates with several bioactivities. The enzyme may be used alone, or in combination with other enzymes to increase the degree of hydrolysis.

Characterization of Protein Hydrolysates from Fish Discards and By-Products from the North-West Spain Fishing Fleet as Potential Sources of Bioactive Peptides

Fish discards and by-products can be transformed into high value-added products such as fish protein hydrolysates (FPH) containing bioactive peptides. Protein hydrolysates were prepared from different parts (whole fish, skin and head) of several discarded species of the North-West Spain fishing fleet using Alcalase. All hydrolysates had moisture and ash contents lower than 10% and 15%, respectively. The fat content of FPH varied between 1.5% and 9.4% and had high protein content (69.8-76.6%). The amino acids profiles of FPH are quite similar and the most abundant amino acids were glutamic and aspartic acids. All FPH exhibited antioxidant activity and those obtained from Atlantic horse mackerel heads presented the highest 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, reducing power and Cu2+ chelating activity. On the other hand, hydrolysates from gurnard heads showed the highest ABTS radical scavenging activity and Fe2+ chelating activity. In what concerns the α-amylase inhibitory activity, the IC50 values recorded for FPH ranged between 5.70 and 84.37 mg/mL for blue whiting heads and whole Atlantic horse mackerel, respectively. α-Glucosidase inhibitory activity of FPH was relatively low but all FPH had high Angiotensin Converting Enzyme (ACE) inhibitory activity. Considering the biological activities, these FPH are potential natural additives for functional foods or nutraceuticals.

Synthesis, stability and anti-fatigue activity of selenium nanoparticles stabilized by Lycium barbarum polysaccharides

Lycium barbarum polysaccharides (LBP) with different molecular weights (LBP1, LBP2 and LBP3) of 92,441 Da, 7714 Da, and 3188 Da were used as stabilizers and capping agents to prepare uniformly dispersed selenium nanoparticles (SeNPs), and determined the storage stability. In addition, the anti-fatigue activity of LBP-decorated SeNPs with the best stability (LBP1-SeNPs) was estimated by using forced swimming test. The results showed that LBP1-SeNPs exhibited smaller particle size and more excellent stability than those of LBP2-SeNPs and LBP3-SeNPs when the storage time was extended to 30 days, and the average particle size was maintained at about 105.4 nm. The exhaustion swimming time of all tested dose groups of LBP1-SeNPs was significantly longer than the control group (p < 0.05), and the high-dose group among them was even obviously longer than the positive group (p < 0.05). The results of glycogen, blood urea nitrogen (BUN), blood lactic acid (BLA), superoxide dismutase (SOD), and malondialdehyde (MDA) levels were further confirmed that LBP1-SeNPs could relieve fatigue by increasing the reserve of glycogen, enhancing antioxidant enzyme levels and regulating metabolic mechanism. These results demonstrated that LBP1-SeNPs could be developed as a potential anti-fatigue nutritional supplement.

Anti-Fatigue Effect of a Dietary Supplement from the Fermented By-Products of Taiwan Tilapia Aquatic Waste and Monostroma nitidum Oligosaccharide Complex

The Taiwan Tilapia is an important aquaculture product in Taiwan. The aquatic by-products generated during Tilapia processing, such as fish bones and skin, are rich in minerals and protein. We aimed to explore the effect of a dietary supplement, comprising a mixture of fermented Tilapia by-products and Monostroma nitidum oligosaccharides as the raw materials, combined with physical training on exercise performance and fatigue. We used a mouse model that displays a phenotype of accelerated aging. Male senescence-accelerated mouse prone-8 (SAMP8) mice were divided into two control groups-with or without physical training-and supplemented with different doses (0.5 times: 412 mg/kg body weight (BW)/day; 1 time: 824 mg/kg BW/day; 2 times: 1648 mg/kg BW/day) of fermented Tilapia by-products and Monostroma nitidum oligosaccharide-containing mixture and combined with exercise training groups. Exercise performance was determined by testing forelimb grip strength and with a weight-bearing exhaustive swimming test. Animals were sacrificed to collect physical fatigue-related biomarkers. Mice dosed at 824 or 1648 mg/kg BW/day showed improvement in their exercise performance (p < 0.05). In terms of biochemical fatigue indicators, supplementation of 824 or 1648 mg/kg BW/day doses of test substances could effectively reduce blood urea nitrogen concentration and lactate concentration and increase the lactate ratio (p < 0.05) and liver glycogen content post-exercise (p < 0.05). Based on the above results, the combination of physical training and consumption of a dietary supplementation mixture of fermented Tilapia by-products and Monostroma nitidum oligosaccharides could improve the exercise performance of mice and help achieve an anti-fatigue effect.

Enzymatic Degradation of Gracilariopsis lemaneiformis Polysaccharide and the Antioxidant Activity of Its Degradation Products

Gracilariopsis lemaneiformis polysaccharides (GLP) were degraded using pectinase, glucoamylase, cellulase, xylanase, and β-dextranase into low-molecular-weight polysaccharides, namely, GPP, GGP, GCP, GXP, and GDP, respectively, and their antioxidant capacities were investigated. The degraded GLP showed higher antioxidant activities than natural GLP, and GDP exhibited the highest antioxidant activity. After the optimization of degradation conditions through single-factor and orthogonal optimization experiments, four polysaccharide fractions (GDP1, GDP2, GDP3, and GDP4) with high antioxidant abilities (hydroxyl radical scavenging activity, DPPH radical scavenging activity, reduction capacity, and total antioxidant capacity) were obtained. Their cytoprotective activities against H2O2-induced oxidative damage in human fetal lung fibroblast 1 (HFL1) cells were examined. Results suggested that GDP pretreatment can significantly improve cell viability, reduce reactive oxygen species and malonaldehyde levels, improve antioxidant enzyme activity and mitochondria membrane potential, and alleviate oxidative damage in HFL1 cells. Thus, the enzyme degradation of GLP with β-dextranase can significantly improve its antioxidant activity, and GDP might be a suitable source of natural antioxidants.

Application of Amino Acids in the Structural Modification of Natural Products: A Review

Natural products and their derivatives are important sources for drug discovery; however, they usually have poor solubility and low activity and require structural modification. Amino acids are highly soluble in water and have a wide range of activities. The introduction of amino acids into natural products is expected to improve the performance of these products and minimize their adverse effects. Therefore, this review summarizes the application of amino acids in the structural modification of natural products and provides a theoretical basis for the structural modification of natural products in the future. The articles were divided into six types based on the backbone structures of the natural products, and the related applications of amino acids in the structural modification of natural products were discussed in detail.

Antioxidant and functional properties of cowhide collagen peptides

In the present study, antioxidant activities and functional properties of cowhide collagen antioxidant peptides (CCAPs) with different molecular weight (MW) were investigated. The optimum preparation conditions of CCAPs were hydrolysis time of 1.53 hr, temperature of 54.9 °C, pH 7.38, and neutral enzyme to trypsin ratio of 0.048 g: 0.016 g according to single factor test and response surface methodology (RSM). Three fractions (CCAP-I, CCAP-II, and CCAP-III) were obtained by ultrafiltration and lyophilization. Antioxidant activities revealed that CCAP-III had high reducing power activity (0.323 ± 0.035) and scavenging effect on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals (64.30 ± 5.99%), 2,2-azino-bis-(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS) radicals (75.25 ± 3.14%), and hydroxyl radicals (68.26 ± 6.74%) compared to the other fractions. In addition, LC-MS/MS analysis showed that Ala-Gly-Glu-Arg, Gly-Ile-Ala-Gly-Glu-Arg, Gly-Pro-Ala-Gly-Pro-Ala-Gly-Pro-Arg, Gly-Val-Val-Gly-Pro-Glu-Gly-Ala-Arg and Gly-Phe-Ser-Gly-Leu-Asp-Gly-Ala-Lys were the major peptides of CCAP-III. CCAP-III showed good hygroscopicity (HYG), water holding capacity (WHC), and oil holding capacity (OHC) when compared with CCAP-I and CCAP-II. However, CCAP-II has great emulsifying properties, and CCAP-I has excellent foaming properties. Therefore, CCAPs can be used as a promising source of functional peptides with antioxidant properties. PRACTICAL APPLICATION: This study demonstrated the peptides of cowhide collagen has superior antioxidant and functional properties. This study provided a scientific basis for the preparation of antioxidant peptides from cowhide collagen.