Collagen from Fish By-Products: A Circular Approach to High-Value Ingredients

Collagen from Fish By-Products

When we think about fish as food, most of us picture neat fillets wrapped in paper or plastic, ready for the pan. What rarely crosses our mind is everything that doesn’t make it into that package: the skin, head, bones, fins, scales and viscera. In industrial fish processing, these parts are routinely removed to preserve quality, nutritional value and food safety (Gilman et al., 2020).

However, these parts are rich reservoirs of valuable compounds such as proteins, amino acids, lipids and bioactive molecules. Over the past decades, the fisheries industry has increasingly turned its attention to extracting these compounds, both to improve profitability and to reduce environmental pressure. Omega-3-rich fish oil, typically obtained from heads and viscera, is one well-known example. Another, growing even faster in importance, is collagen, extracted mainly from fish skin, bones, cartilage, fins and scales (Jafari et al., 2020).

Collagen: The Protein That Hold Us Together

Collagen is the most abundant protein in the animal kingdom and the main structural protein in vertebrates. Without collagen, our bodies would lose their shape and strength. Skin would tear easily, bones would weaken, and connective tissues would fail. At the molecular level, it is composed of three long polypeptide chains, each containing more than a thousand amino acids, tightly wound together into a triple helix (Correa et al., 2022). This configuration gives collagen its mechanical strength and explains why it behaves the way it does.

Why Look to the Sea?

Collagen can be extracted from many animal sources, particularly skin, tendons, cartilage and bones. Historically, most commercial collagen came from cattle and pigs. Mammalian collagen has served industry well, but it is not without problems. Concerns around animal diseases, toxins and pathogens persist, alongside regulatory and quality-control challenges (Jafari et al., 2020). For many consumers, religious and ethical constraints also limit acceptance of bovine or porcine products. Add to this the environmental footprint of livestock farming, and the appeal of alternative sources becomes clear.

Marine collagen, derived from seafood processing by-products, avoids many of the health, ethical and cultural concerns associated with terrestrial animals. There is also an important biochemical difference. Marine collagen contains lower amounts of the amino acids proline and hydroxyproline than mammalian collagen, a reflection of the colder environments in which fish live (Mutalipassi et al., 2021). This affects its thermal behaviour. While mammalian collagen typically denatures at temperatures close to 40 °C, marine collagen often denatures between 25 and 30 °C (Jafari et al., 2020). This lower denaturation temperature may sound like a drawback, but it can actually be an advantage in applications where gentler processing and higher bioavailability are required, particularly in biomedical and pharmaceutical fields.

From Beauty to Food Tech

One of the most striking aspects of marine collagen is the breadth of its applications, which depend largely on its molecular weight and functional properties.

In pharmaceuticals, collagen has long been used to support tissue repair and regeneration. Marine collagen has been explored as a component in treatments for wound healing, bone regeneration and connective tissue repair (Sharma et al., 2022).

Beyond pharmaceuticals, marine collagen plays an increasingly important role in biomedicine and tissue engineering. Marine collagen matrices have shown particular promise in skin healing and wound care (Furtado et al., 2022). Emerging research has even highlighted anti-inflammatory effects of collagen hydrolysates derived from Atlantic salmon skin, with potential implications for cardiovascular health (Liu et al., 2022).

In cosmetics, fish collagen has gained popularity for its moisturising, softening and anti-aging properties. Thanks to its small peptide size, hydrolysed collagen can penetrate deeper layers of the skin and stimulate fibroblast activity, supporting the formation of strong collagen fibres in the epidermis (Sionkowska, 2021). As a result, marine collagen is now widely incorporated into creams, serums, beauty masks, hydrogels, dermal fillers and even artificial skin products.

The food industry, too, has embraced marine collagen. Its ability to bind water, form films, stabilise emulsions and create foams makes it a multifunctional ingredient (Subhan et al., 2021, Tang et al., 2022). Collagen and gelatin derived from fish are also used as functional and nutraceutical ingredients that enrich protein content, improve texture and extend shelf life (Zamorano-Apodaca et al., 2020). Notably, marine collagen peptides exhibit antioxidant activity, helping to neutralise free radicals and reduce oxidative stress without adverse effects. These peptides remain stable across a wide range of pH values, temperatures and digestive conditions, enhancing both food quality and potential health benefits (Luo et al., 2022).

Collagen from fish by-products tells a powerful story about modern food systems. It shows how science and technology can redefine waste, turning overlooked materials into products that support health, industry and sustainability at the same time. This shift from waste to value sits at the heart of the VALORISH project, where collagen is part of a broader portfolio of high-value products obtained through a circular cascade approach aiming to maximise resource efficiency while minimising environmental impact.

References

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