Evaluation of hydrolysed marine collagen from fish by-products for cosmetic application

This doctoral thesis focuses on exploring marine collagen, a type derived from tissues of marine creatures like fish, crustaceans, and squids. It aims to contribute to evaluate the potential applications in several sectors such as cosmetics and the food industry. Collagen, a primary protein in the human body, offers structural support to various tissues and undergoes complex biosynthesis, with diverse types playing unique roles. The study delves into collagen sources, emphasizing marine collagen due to its safety, higher yield, and reduced immunogenicity compared to land-based animal sources. The sources of collagen vary, spanning vertebrates, invertebrates, plants, and recombinant protein production systems. Bovine collagen, despite its advantages, raises concerns regarding disease transmission and allergies, prompting interest in safer alternatives. The thesis underscores marine collagen's advantages, particularly from fish, showcasing its safety, greater yield, and lower immunogenicity, offering an eco-friendly and cost-effective solution. In this way, it refers to the Blue Economy, which promotes the sustainable exploitation of marine resources through practices such as responsible fishing, ecotourism and innovative research. It focuses on the responsible use of marine resources to create economic opportunities while simultaneously preserving aquatic ecosystems. In particular, the main goal is to balance economic development with marine environment conservation, ensuring long-term benefits for coastal communities and ocean and sea health. The exploration of marine sources, including fish by-products, gains significance due to ethical, cultural, or religious constraints related to specific animal sources. Compliance with these norms necessitates alternatives in line with cultural and religious regulations. The cosmetic industry, aiming to meet cultural and religious requirements while ensuring quality and effectiveness for specific communities, views marine collagen as a promising solution. Collagen's mechanical strength and stability stem from its molecular structure, amino acid composition, and cross-links, influencing wound healing and tissue functionality. The study highlights collagen's pivotal role in maintaining tissue integrity, its solubility, strength, and biodegradability. Notably, marine collagen, particularly from fish sources, demonstrates significant moisturizing ability, validating its suitability for cosmetic use. The thesis underscores Food and Drugs Administration (FDA) data confirming collagen hydrolysates, soluble collagen, and gelatin among the most-used cosmetic ingredients, without causing irritation according to in vitro studies. European Cosmetic Regulation No. 1223/2009, along with similar regulations in other regions, aims to ensure cosmetic product safety, stringent production, accurate labeling, and quality, with the Scientific Committee on Consumer Safety (SCCS) evaluating ingredients based on evidence, emphasizing safety in the cosmetic industry. In this way, the project revolves around the concept of a circular economy, focusing on resource management efficiency. It explores utilizing fish by-products to extract bioactive compounds beneficial for human skin, specifically collagen from Mugil cephalus L. fish. In this way, it is known from scientific literature that collagen molecules with a low molecular weight exhibit higher cosmetic activity. Specifically, collagen molecules with a molecular weight below 3 kDa are preferable for cellular tests as their reduced size promotes better absorption within cells. These smaller molecules have a greater ability to interact with cellular receptors, triggering more directs and rapid biological responses. Additionally, they better mimic the extracellular environment, providing more precise signals for biological functions. For this reason, an initial study categorized collagen samples by molecular weight, < 3kDa and > 3kDa, examining them through various tests for molecular and biological characteristics. The analysis revealed higher collagen content in > 3kDa fractions, but cellular tests demonstrated enhanced wound healing potential in < 3kDa fractions. These initial findings laid the foundation for further analysis using diverse fish by-product samples from the EcoeFISHent project (ID number: 101036428), aiming to assess variability in extracted samples. The study required developing rapid screening tests to evaluate sample quality due to inherent variability in starting materials. Collagen extraction resulted in multiple collagen types within the samples, impacting their biological activity. The study identified effective tests like Ultra-Violet (UV) spectra, hydroxyproline content evaluation and Wound Healing (WH) assay to determine sample bioactivity. Tests indicated lower molecular weight collagen (< 3kDa) as promising for cosmetic applications due to higher added value, despite the higher collagen content in > 3kDa fractions. Subsequent experiments with Collagen Hydrolysed Standard (CHS) samples highlighted concentrations with significant impacts on cell viability, leading to targeted investigations. Tests on 3D reconstructed human skin models demonstrated collagen's anti-aging effects and identified optimal concentrations for enhanced skin benefits. These studies also revealed collagen's potential when incorporated into cosmetic product formulations, augmenting its effectiveness in promoting skin rejuvenation and hydration. The study employed screening tests to evaluate active ingredients from fish by-products for cosmetic use, refining methods using CHS samples as a reference. Results indicated promising qualities in gelatin and collagen samples from the EcoeFISHent Project, highlighting their potential for future cosmetic applications after further refining the extraction process. The research abroad focused on encapsulating commercial hydrolyzed marine collagen and demonstrated its potential to stabilize emulsions and reduce surface tension. Encapsulated collagen exhibited increased anti-wrinkle effects on 3D skin models. In conclusion, this doctoral research unveiled the potential of fish by-products for extracting valuable molecules applicable to various human uses, emphasizing the superiority of low molecular weight collagen. It also showcased the feasibility of collagen encapsulation and outlined objectives for further studies to optimize collagen extraction and develop marketable cosmetic products. This approach contributes to responsible and sustainable use of fishery resources while advancing scientific and industrial research in the cosmetic industry.