Improving the Sustainability of Processing By-Products: Extraction and Recent Biological Activities of Collagen Peptides

Effect of extraction temperature on the detection in characteristic peptides of gelatin from grass fish scale and its identification in different food systems

In this study, the effects of different extraction temperatures and food systems on the traceability and identification of gelatin from grass carp scales were investigated. Based on the sequence of grass carp type I collagen, 268 and 56 common characteristic peptides were obtained at different extraction temperatures and food systems, respectively. Further, 75 common and 41 unique characteristic peptides unaffected by extraction temperature were identified in bulk freshwater fish gelatin and grass carp gelatin, respectively. Additionally, 17 common and 10 unique peptides unaffected by food systems were obtained. Among these peptides, 2 common characteristic peptides of bulk freshwater fish gelatin that were unaffected by extraction temperature and food systems, and 8 unique characteristic peptides of grass carp gelatin that were unaffected by extraction temperature and food systems were consistently detected. In addition, the combination of common and unique peptides could improve the accuracy of fish gelatin traceability and identification.

Exploring the impact of bioactive peptides from fermented Milk proteins: A review with emphasis on health implications and artificial intelligence integration

This review explores the health benefits of bioactive peptides (BAPs) from fermented milk proteins, emphasizing the transformative role of artificial intelligence (AI) and machine learning (ML) in advancing this field. BAPs exhibit diverse biological activities, including antimicrobial, antihypertensive, antioxidant, and immunomodulatory effects, making them promising for functional foods and nutraceuticals. However, challenges such as stability, bioavailability, and cost-effective production remain. This review highlights how AI/ML-driven tools, including data mining, sequence analysis, and predictive modeling, revolutionize peptide discovery, optimize fermentation, and enable personalized nutrition. By accelerating the identification of novel peptides and enhancing production efficiency, AI/ML offers innovative solutions to overcome existing limitations. The integration of AI/ML not only improves research efficiency but also opens new avenues for personalized nutrition and therapeutic applications. This review underscores the potential of interdisciplinary collaboration to harness the benefits of BAPs fully, driving future advancements in functional foods and health promotion.

Unlocking the potential of fishery waste: exploring diverse applications of fish protein hydrolysates in food and nonfood sectors

Fish and their byproducts play a pivotal role as protein sources. With the global population increasing, urbanization on the rise and increased affluence, efficient utilization of available protein resources is becoming increasingly critical. Additionally, the need for sustainable protein sources is gaining recognition. By 2050, the world's protein demand is expected to double, driven not only by population growth but also by heightened awareness of protein's role in maintaining health. The fishery industry has experienced continuous growth over the last decade. However, this growth comes with a significant challenge: inadequate waste management. The fisheries industry discards 35% to 70% of their production as waste, including fillet remains, skin, fins, bones, heads, viscera and scales. Despite the importance of these byproducts as protein sources, their effective utilization remains a hurdle. Various strategies have been proposed to address this issue. Among them, the production of protein hydrolysates stands out as an efficient method for value addition. Protein hydrolysis breaks down proteins into smaller peptides with diverse functional and bioactive properties. Therefore, fish protein hydrolysates have applications in both the food and nonfood sectors. Utilizing fishery byproducts and waste represents a sustainable approach toward waste valorization and resource optimization in the fishery industry. This approach offers promising opportunities for innovation and economic growth across multiple sectors. This comprehensive review explores fish protein hydrolysates derived from fishery byproducts and wastes, focusing on their applications in both the food and nonfood sectors.

Characteristics and food applications of aquatic collagen and its derivatives: A review

Collagen and its hydrolysates have high bioavailability, good biocompatibility, biodegradability, and biological activity which has meant that they have been widely used in food, medicine, cosmetics, and other industries. Although the properties and applications of collagen have been reviewed recently, few studies have focused on aquatic collagen. To provide readers with a deeper understanding of aquatic collagen, this review addresses the structure and properties of aquatic collagen and compares them with mammalian collagen, as well as the differences between collagen, gelatin, and collagen peptides. In contrast to mammalian collagen, aquatic collagen prevents zoonotic diseases, reduces environmental pollution, improves the utilization of aquatic resources, and facilitates the extraction and separation of active oligopeptides. Additionally, methods for screening functional peptides using in vitro digestion have been introduced. Finally, the review focuses on the applications of collagen and its derivatives in food preservation (packaging films, coatings, additives, and antifreeze peptides), drug delivery (microcapsules, emulsions, nanoparticles, and hydrogels), nutrition, and healthcare.

Revisiting the potential of natural antimicrobial peptides against emerging respiratory viral disease: a review

This review assesses the antiviral capabilities of antimicrobial peptides (AMPs) against SARS-CoV-2 and other respiratory viruses, focussing on their therapeutic potential. AMPs, derived from natural sources, exhibit promising antiviral properties by disrupting viral membranes, inhibiting viral entry, and modulating host immune responses. Preclinical studies demonstrate that peptides such as defensins, cathelicidins, and lactoferrin can effectively reduce SARS-CoV-2 replication and inhibit viral spread. In addition, AMPs have shown potential in enhancing the host's antiviral immunity. Despite these promising outcomes, several challenges require assessments before transforming into clinical translation. Several issues related to peptide stability, cytotoxicity, and efficient delivery systems pose significant limitations to their therapeutic application. Recent advancements in peptide engineering, nanotechnology-based delivery systems, and peptide conjugation strategies have improved AMPs stability and bioavailability; however, further optimization is essential. Moreover, whilst AMPs are safe, their effects on host cells and tissues need a thorough investigation to minimise potential adverse reactions. This review concludes that whilst AMPs present a promising route for antiviral therapies, particularly in targeting SARS-CoV-2, extensive clinical trials and additional studies are required to overcome current limitations. Future research should focus on developing more stable, less toxic AMPs formulations with enhanced delivery mechanisms, aiming to integrate AMPs into viable therapeutic options for respiratory viral diseases, including COVID-19 and other emerging infections.

Exploring the influence of different processing conditions on DNA quality of collagen peptides and the feasibility of its raw material traceability

In this work, we have presented a new method for species origin verification of collagen peptides based on DNA techniques. First, we investigate the changes in DNA during the preparation of collagen peptides including the total amount of collagen peptide DNA and the DNA degradation under different processing conditions. Secondly, we discussed the possibility of using polymerase chain reaction (PCR) for follow-up detection of collagen peptides. The results showed that the total amount of DNA decreased as the treatment intensity increased. The size of the cleaved fragments of DNA are mainly concentrated between 200 and 500 bp. On this basis, the combined PCR results finally determined that trace collagen peptide DNA can be effectively amplified with amplicons of about 300 bp to complete the verification of the species origin of collagen peptide. This study provides a new strategy for determining the authenticity of food labels for bovine collagen peptides.

Microbial collagenases: an updated review on their characterization, degradation mechanisms, and current applications

Collagen, recognized as a fundamental protein present in biological tissues and structures, plays a crucial role in maintaining organ structure and tissue integrity. Microbial collagenases are specific for the degradation of collagen. The specific three-stranded helix region of natural collagen can be identified and hydrolyzed by microbial collagenases under physiological conditions, producing collagen peptides with high physiological activity. This article describes microbial collagenases, providing an introduction to the structure, physiological characteristics, factors affecting enzyme activity, and hydrolysis mechanisms of various classes of these enzymes. Microbial collagenase is the most widely used class of collagenase and plays an important role in all aspects of human life, and various applications of microbial collagenases in food industry, healthcare and environmental protection will be addressed in this review. In addition to its beneficial functions, microbial collagenase can exist as a virulence factor for pathogenic bacteria, and enhanced research on its structure and mechanism of action will help us to investigate more effective inhibitors as well as therapeutic agents and tools for the treatment of the corresponding diseases. Finally, this review critically analyses existing challenges and outlines prospects for future advancements in the field.

Deciphering the Wound-Healing Potential of Collagen Peptides and the Molecular Mechanisms: A Review

Collagen peptides have been reported to display various bioactivities and high bioavailability. Recently, increasing evidence has revealed the excellent wound-healing activity of collagen peptides, but their molecular mechanisms remain incompletely elucidated. This review systematically evaluates the therapeutic efficacy of collagen peptides from diverse sources based on various wound models. Furthermore, the structure-activity relationships of collagen peptides and wound-healing mechanisms are discussed and summarized. Characterized by their low molecular weight and abundant imino acids, collagen peptides facilitate efficient absorption by the body to deliver nutrition throughout the wound-healing process. The specific mechanism of collagen peptide for wound healing is mainly through up-regulation of related cytokines and participation in the activation of relevant signaling pathways, such as TGF-β/Smad and PI3K/Akt/mTOR, which can promote cell proliferation, angiogenesis, collagen synthesis and deposition, re-epithelialization, and ECM remodeling, ultimately achieving the effect of wound healing. Collagen peptides can offer a potential therapeutic approach for treating incision and excision wounds, mucosal injuries, burn wounds, and pressure ulcers, improving the efficiency of wound healing by about 10%-30%. The present review contributes to understanding of the wound-healing potential of collagen peptides and the underlying molecular mechanisms.

Comprehensive review on collagen extraction from food by-products and waste as a value-added material

The consumption of animal products has witnessed a significant increase over the years, leading to a growing need for industries to adopt strict waste control measures to mitigate environmental impacts. The disposal of animal waste in landfill can result in diverse and potentially hazardous decomposition by-products. Animal by-products, derived from meat, poultry, seafood and fish industries, offer a substantial raw material source for collagen and gelatin production due to their high protein content. Collagen, being a major protein component of animal tissues, represents an abundant resource that finds application in various chemical and material industries. The demand for collagen-based products continues to grow, yet the availability of primary material remains limited and insufficient to meet projected needs. Consequently, repurposing waste materials that contain collagen provides an opportunity to meet this need while at the same time minimizing the amount of waste that is dumped. This review examines the potential to extract value from the collagen content present in animal-derived waste and by-products. It provides a systematic evaluation of different species groups and discusses various approaches for processing and fabricating repurposed collagen. This review specifically focuses on collagen-based research, encompassing an examination of its physical and chemical properties, as well as the potential for chemical modifications. We have detailed how the research and knowledge built on collagen structure and function will drive the new initiatives that will lead to the development of new products and opportunities in the future. Additionally, it highlights emerging approaches for extracting high-quality protein from waste and discusses efforts to fabricate collagen-based materials leading to the development of new and original products within the chemical, biomedical and physical science-based industries.

Biocompatibility Study of Purified and Low-Temperature-Sterilized Injectable Collagen for Soft Tissue Repair: Intramuscular Implantation in Rats

The clinical application of collagen-based biomaterials is expanding rapidly, especially in tissue engineering and cosmetics. While oral supplements and injectable skin boosters are popular for enhancing skin health, clinical evidence supporting their effectiveness remains limited. Injectable products show potential in revitalizing skin, but safety concerns persist due to challenges in sterilization and the risk of biological contamination. Traditional methods of sterilization (heat and irradiation) can denature collagen. This study addresses these issues by introducing a novel technique: the double filtration and low-temperature steam sterilization of a collagen gel. In vitro tests documented the sterility and confirmed that the collagen did not show cytotoxicity, degradation, integrity, and viscosity characteristics changes after the processing and sterilization. The collagen gel induced new collagen expression and the proliferation of human dermal fibroblasts when the cells were cultured with the collagen gel. An in vivo study found no adverse effects in rats or significant lesions at the implantation site over 13 weeks. These results suggest that this novel method to process collagen gels is a safe and effective skin booster. Advanced processing methods are likely to mitigate the safety risks associated with injectable collagen products, though further research is needed to validate their biological effectiveness and clinical benefits.

Stem-Cell-Regenerative and Protective Effects of Squid (Symplectoteuthis oualaniensis) Skin Collagen Peptides against H2O2-Induced Fibroblast Injury

Recently, there has been a growing interest in collagen peptides derived from marine sources for their notable ability to protect skin cells against apoptosis induced by oxidants. Therefore, the current study aimed to investigate the fundamental properties of collagen peptides, including their physicochemical, thermal, structural, stem-cell-regenerative, and skin-cell-protective effects, in comparison to commercial collagen peptides. The acid-soluble (ASC) and pepsin-soluble (PSC) collagens exhibited three distinct bands on SDS-PAGE, namely α (α1 and α2), β, and γ chains, confirming a type I pattern. The thermal profiles obtained from TG and DSC analyses confirmed the denaturation of PSC and ASC at temperatures ranging from 51.94 to 56.4 °C and from 52.07 to 56.53 °C, respectively. The purified collagen peptides were analyzed using SDS-PAGE and MALDI-TOF mass spectrometry, revealing a mass range of 900-15,000 Da. Furthermore, the de novo peptide sequence analysis confirmed the presence of the Gly-X-Y repeating sequence in collagen peptides. Collagen peptide treatments significantly enhanced HFF-1 cell proliferation and migration compared to the control group. ELISA results confirmed the potential interactions between collagen peptides and HFF-1 cells through α2β1, α10β1, and α11β1 integrin receptors. Notably, collagen peptide treatment effectively restored the proliferation of HFF-1 cells damaged by H2O2. Consequently, the advantageous characteristics of squid skin collagen peptides highlight their promising role in regenerative medicine.

Effects of Hydrolyzed Collagen as a Dietary Supplement on Fibroblast Activation: A Systematic Review

BACKGROUND

Our objective was to conduct a systematic review of the effects of hydrolyzed collagen supplementation on the proliferation and activation of fibroblasts.

METHODS

The search was conducted for journals that published articles in the English language, peer-reviewed, meeting the following criteria: (a) randomized clinical trials, (b) randomized studies in animals or humans, (c) in vitro studies, (d) studies using hydrolyzed collagens or collagen peptides, and (e) studies assessing alterations on fibroblasts as the primary or secondary outcome. We utilized the main journal databases PubMed/Web of Science and ongoing reviews by PROSPERO. For bias risk and methodological quality, we used an adaptation of the Downs and Black checklist. Our review followed the PRISMA checklist, conducted from February 2024 to the first week of March 2024, by two independent researchers (P.A.Q.I. and R.P.V.).

RESULTS

Eleven studies were included in this review, where our findings reinforce the notion that hydrolyzed collagens or collagen peptides at concentrations of 50-500 μg/mL are sufficient to stimulate fibroblasts in human and animal tissues without inducing toxicity. Different enzymatic processes may confer distinct biological properties to collagens, allowing for scenarios favoring fibroblast promotion or antioxidant effects. Lastly, collagens with lower molecular weights exhibit greater bioavailability to adjacent tissues.

CONCLUSIONS

Hydrolyzed collagens or collagen peptides with molecular sizes ranging from <3 to 3000 KDa promote the stimulation of fibroblasts in human tissues.

Feasibility of Enzymatic Protein Extraction from a Dehydrated Fish Biomass Obtained from Unsorted Canned Yellowfin Tuna Side Streams: Part II

The enzymatic extraction of proteins from fish biomasses is being widely investigated. However, little or almost no research has paid attention to the exploitation of unsorted fishery biomasses. This work is part of a larger study, Part I of which has already been published, and focuses on an extensive characterization of two collagenous samples, namely gelatin (G) and hydrolyzed gelatin peptides (HGPs), extracted from a dehydrated fish biomass coming from unsorted canned yellowfin tuna side streams. The results indicate crude protein fractions of 90-93%, pH values between 3 and 5, white-yellow colors, collagen-like FTIR spectra, and 17% in terms of total amino acid content. Viscosity and the study of dynamic viscous-elastic behavior were analyzed. Thermo-gravimetric analysis was performed to assess the residual ashes. Both samples were investigated to determine their molecular weight distribution via size-exclusion chromatography, with a higher total average molecular weight for G compared to HGPs, with values of 17,265.5 Da and 2637.5 Da, respectively. G demonstrated technological properties similar to analogous marine gelatins. HGPs demonstrated antioxidant activity as per FRAP assay. All the results open up new perspectives for the potential use of these substances in biodegradable packaging, dietary supplements, and skin care cosmetics.

The targeted development of collagen-active peptides based on composite enzyme hydrolysis: a study on the structure-activity relationship

Fish collagen, derived from sustainable sources, offers a valuable substrate for generating peptides with diverse biofunctionalities. In this study, alkaline, papain, and ginger protease were used to enzymatically hydrolyze fish skin collagen. The peptide molecular weight distribution and sequence were measured using HPLC and ICP-MS-MS, with papain/alkaline protease (AP) and papain/alkaline/ginger protease (APG) hydrolyzed samples compared. As the results showed, the incorporation of ginger protease was useful for increasing the degree of hydrolysis, with the content of <400 Da peptides increasing from 49.82% to 58.56%. The identified peptide sequence in the APG sample had more proline at the C-terminal. The peptides were separated into two components (different in molecular weight) using gel column chromatography. The molecular weight distribution, amino acid composition, ACE inhibitory activity, and fibroblast proliferation activity of the collected components were measured. In comparison, the contents of proline and hydroxyproline in the larger peptides decreased obviously after combined hydrolysis by ginger protease, reflecting the formation of a peptide sequence of smaller molecular weight containing glycine and hydroxyproline. The combined hydrolysis of ginger protease was beneficial for the improvement of the ACE inhibitory activity of the sample. However, the fibroblast proliferation activity of AP was higher than that of APG, indicating that further hydrolysis by ginger protease may destroy the hydroxyproline at the end of the peptide sequence. This study proposed a creative directional hydrolysis method and provided practical guidance for the production of collagen peptides with enhanced functional activity.

Marine collagen: Unveiling the blue resource-extraction techniques and multifaceted applications

Marine organisms such as fish and shellfish are composed of compounds with properties and characteristics that have been proven useful in a variety of sectors such as cosmetics, healthcare (wound healing), food industries, and tissue engineering. Collagen extraction from fish waste as a "blue resource" has attracted research attention over the past decade. Around 75 % of fish waste contains a high concentration of collagen. This has driven research in the conversion of these low-cost by-products into valuable products. Collagen extracted by acidic or/and enzymatic methods is gaining a lot of attention today due to its low cost and high yield. Fermentation and enzymatic hydrolysis stand out as one of the most environmentally sustainable and ecologically friendly methods for collagen extraction. Because of its great biocompatibility, excellent bioactivity, and low antigenicity, marine collagen is receiving more attention. Furthermore, collagen-derived peptides may exhibit interesting antioxidant activity, potent antihypertensive activity, and antimicrobial activity against different strains of bacteria. This review focuses on the advancements in extraction and detection methods of marine collagen, both from a technological and legislative standpoint, in addition to exploring its diverse range of application domains.

Current and Expected Trends for the Marine Chitin/Chitosan and Collagen Value Chains

Chitin/chitosan and collagen are two of the most important bioactive compounds, with applications in the pharmaceutical, veterinary, nutraceutical, cosmetic, biomaterials, and other industries. When extracted from non-edible parts of fish and shellfish, by-catches, and invasive species, their use contributes to a more sustainable and circular economy. The present article reviews the scientific knowledge and publication trends along the marine chitin/chitosan and collagen value chains and assesses how researchers, industry players, and end-users can bridge the gap between scientific understanding and industrial applications. Overall, research on chitin/chitosan remains focused on the compound itself rather than its market applications. Still, chitin/chitosan use is expected to increase in food and biomedical applications, while that of collagen is expected to increase in biomedical, cosmetic, pharmaceutical, and nutritional applications. Sustainable practices, such as the reuse of waste materials, contribute to strengthen both value chains; the identified weaknesses include the lack of studies considering market trends, social sustainability, and profitability, as well as insufficient examination of intellectual property rights. Government regulations, market demand, consumer preferences, technological advancements, environmental challenges, and legal frameworks play significant roles in shaping both value chains. Addressing these factors is crucial for seizing opportunities, fostering sustainability, complying with regulations, and maintaining competitiveness in these constantly evolving value chains.

Fish-Derived Protein Hydrolysates Increase Insulin Sensitivity and Alter Intestinal Microbiome in High-Fat-Induced Obese Mice

Obesity and type 2 diabetes are characterized by low-grade systemic inflammation and glucose intolerance, which can be partially controlled with nutritional interventions. Protein-containing nutritional supplements possess health-promoting benefits. Herein, we examined the effect of dietary supplementation with protein hydrolysates derived from fish sidestreams on obesity and diabetes, utilizing a mouse model of High-Fat Diet-induced obesity and type 2 diabetes. We examined the effect of protein hydrolysates from salmon and mackerel backbone (HSB and HMB, respectively), salmon and mackerel heads (HSH and HMH, respectively), and fish collagen. The results showed that none of the dietary supplements affected weight gain, but HSH partially suppressed glucose intolerance, while HMB and HMH suppressed leptin increase in the adipose tissue. We further analyzed the gut microbiome, which contributes to the metabolic disease implicated in the development of type 2 diabetes, and found that supplementation with selected protein hydrolysates resulted in distinct changes in gut microbiome composition. The most prominent changes occurred when the diet was supplemented with fish collagen since it increased the abundance of beneficial bacteria and restricted the presence of harmful ones. Overall, the results suggest that protein hydrolysates derived from fish sidestreams can be utilized as dietary supplements with significant health benefits in the context of type 2 diabetes and diet-induced changes in the gut microbiome.