The increase in global Atlantic salmon production has generated a substantial amount of processing waste. A new scientific review published by researchers from Pukyong National University, Jashore University of Science and Technology, and Flinders University delves into the promising utilization of these by-products, focusing on the production and applications of protein hydrolysates.
The researchers explore various hydrolysis techniques, including enzymatic, chemical, and subcritical water hydrolysis, and analyze the biofunctional properties of the resulting hydrolysates, such as antioxidant, antihypertensive, and antidiabetic activities.
The study, published in the journal Food Chemistry, highlights potential applications of these hydrolysates across various sectors, including human nutrition, animal feed, pharmaceuticals, and cosmetics. It also addresses the challenges associated with large-scale production and proposes strategies to overcome these limitations, paving the way for a more sustainable and value-added utilization of Atlantic salmon waste.
The environmental impact of salmon processing
Atlantic salmon processing generates a substantial amount of waste, including heads, spines, skin, viscera, and trimmings, which account for approximately 40-50% of the fish’s total biomass. This waste stream, often discarded, represents a valuable source of high-quality proteins, essential fatty acids, and other bioactive compounds.
Recognizing the environmental and economic importance of waste minimization, researchers have increasingly focused on valorizing Atlantic salmon waste through protein hydrolysate production.
Hydrolysis, a process that breaks down proteins into smaller peptides and amino acids, enhances their bioavailability, digestibility, and functional properties.
Production of protein hydrolysates from Atlantic salmon waste
Several techniques are employed to produce protein hydrolysates from Atlantic salmon waste, each with its own advantages and drawbacks:
- Enzymatic Hydrolysis: This widely used method employs enzymes to selectively cleave protein bonds, resulting in hydrolysates with specific properties.
- Chemical Hydrolysis: This approach uses acids or alkalis to break down proteins, often leading to amino acid racemization and potential environmental concerns.
- Subcritical Water Hydrolysis: This emerging technology uses water at elevated temperatures and pressures to hydrolyze proteins, offering benefits such as reduced environmental impact and better recovery of bioactive compounds.
Biofunctional properties of protein hydrolysates from Atlantic salmon waste
Research has demonstrated that protein hydrolysates from Atlantic salmon waste possess various valuable biofunctional properties:
Antioxidant activity
Hydrolysates can scavenge free radicals, protecting cells from oxidative damage. Different salmon parts, such as heads, muscle, skin, viscera, and fins, produce hydrolysates with varying radical scavenging capacities; however, viscera exhibit the highest oxygen radical absorbance capacity (ORAC) values.
Antihypertensive activity
Certain peptides in hydrolysates can inhibit angiotensin-converting enzyme (ACE), leading to reduced blood pressure. However, ACE inhibitory activity varies depending on the enzyme type used for hydrolysis and the fish parts utilized.
Antidiabetic activity
Some hydrolysates improve glucose metabolism and insulin sensitivity. Peptides derived from salmon skin showed antidiabetic effects comparable to metformin in a mouse model, while skin hydrolysates promoted insulin secretion in pancreatic cells.
Anti-inflammatory activity
Hydrolysates can modulate inflammatory responses, offering potential benefits for various health conditions. A fraction of Atlantic salmon protein hydrolysate has shown anti-inflammatory effects by suppressing pro-inflammatory cytokines and nitric oxide production. Additionally, an anti-allergic peptide derived from Atlantic salmon residues through pepsin hydrolysis demonstrated antiallergic activity by inhibiting β-hexosaminidase release.
Applications of protein hydrolysates from Salmon waste
The diverse biofunctional properties of protein hydrolysates from Atlantic salmon waste open a wide range of potential applications:
Human nutrition
Incorporation into functional foods, nutraceuticals, and dietary supplements to enhance nutritional value and provide health benefits. Salmon protein hydrolysates are easily absorbed nutritional supplements used in various metabolic processes.
Animal feed
Utilization as a high-quality protein source in aquaculture and livestock feed to improve animal growth and health. For instance, Atlantic salmon protein hydrolysates are a valuable nutrient source for farm animals due to their high bioactive peptide and essential amino acid content.
Pharmaceuticals
Development of new drugs and nutraceuticals for the prevention and treatment of various diseases. Fish hydrolysates are used in the nutraceutical industry for their antioxidant, anti-obesity, anticancer, anticoagulant, immunomodulatory, and antihypertensive activities.
Cosmetics
Incorporation into skin and hair care products for their antioxidant and anti-aging properties. Due to their antioxidant activity and moisturizing properties, hydrolysates are used to enhance skin hydration and protect against UV-induced damage.
Challenges and future prospects
Despite the promising potential of protein hydrolysates from Atlantic salmon waste, several challenges hinder their large-scale commercialization:
- Sensory Restrictions: Unpleasant flavors and odors may limit the acceptability of hydrolysates in food applications.
- Safety Issues: The potential presence of contaminants and allergens necessitates rigorous quality control measures.
- Economic Viability: Developing cost-effective and scalable production processes is crucial for commercial success.
Overcoming these challenges requires a multifaceted approach:
- Optimizing Hydrolysis Processes: Refining techniques to maximize yield, minimize undesirable by-products, and enhance desired biofunctional properties.
- Developing Novel Processing Technologies: Exploring advanced technologies like membrane filtration and chromatography to purify and fractionate hydrolysates.
- Integrating Value Chains: Establishing collaborations among researchers, industry partners, and regulatory agencies to facilitate product development and commercialization.
Conclusion
Utilizing Atlantic salmon waste for protein hydrolysate production presents a significant opportunity to enhance the sustainability of the aquaculture industry while providing valuable sources of bioactive compounds.
The scientific review highlights the various production methods, biofunctional properties, and potential applications of these hydrolysates. By addressing challenges and fostering innovation, we can unlock the full potential of this valuable resource, contributing to a more circular and sustainable food system.
The study was funded by the Brain Pool program supported by the Ministry of Science and ICT through the National Research Foundation of Korea.
Contact
Byung-Soo Chun
Department of Food Science and Technology, Pukyong National University
45, Yongso-ro, Nam-gu, Busan 48513, Republic of Korea.
Email: bschun@pknu.ac.kr
Reference (open access)
Haq, M., Ali, M. S., Park, J., Kim, J., Zhang, W., & Chun, B. (2025). Atlantic salmon (Salmo salar) waste as a unique source of biofunctional protein hydrolysates: Emerging productions, promising applications, and challenges mitigation. Food Chemistry, 462, 141017. https://doi.org/10.1016/j.foodchem.2024.141017
