Preventing oxidation of omega-3 fatty acids before and after addition to alternative seafood products

Current challenge

Omega-3s are polyunsaturated fatty acids that have demonstrated a positive influence on human health and are mainly sourced from fish and other seafood. For alternative seafood to reach taste and nutritional parity with conventional seafood, they must include non-animal omega-3 fatty acids. Omega-3 fatty acids contain multiple double bonds, which are prone to oxidation and rancidity when exposed to air (oxygen), heat, light, chemical and enzymatic oxidizers, and transition metals like iron and copper. In particular, longer storage duration and higher storage temperature and increases in cooking temperature are associated with higher unsaturated lipid oxidation. The oxidation of the double bonds in omega-3s negates the nutritional benefits and produces volatile compounds with off-flavors and undesirable odors.

Solutions to deal with omega-3 oxidation issues include masking or adsorbing off-flavors. While this may help with organoleptic properties, the unsaturated fatty acids are still oxidized and thus no longer offer their health benefits. Similarly, hydrogenation stabilizes omega-3 fatty acids but results in fewer valuable unsaturated fatty acids. Some fish have demonstrated more stable unsaturated fatty acid profiles after cooking, which is hypothesized to occur due to innate stabilizing compounds within the fish. Mimicking these stabilizing properties or developing other antioxidant technologies for alternative seafood products is necessary.

Proposed solution

To prevent omega-3 oxidation, there is first a need to understand how alternative seafood formulation and processing affect omega-3 oxidation. Just as the stability of lipids from different conventional fish has been explored, specific experiments on the stability of omega-3 fatty acids in cultivated, plant-based, or fermentation-derived fish must be conducted. Specifically, there is a need for experiments that test the stability of omega-3 fatty acids in alternative seafood with various formulation components and after applying shear forces, high pressure, high temperature, and other common processing methods.

Additionally, technologies that inhibit omega-3 oxidation should be explored in the context of alternative seafood products. Previous studies have demonstrated that oil-in-water emulsions or microencapsulation of unsaturated lipids can prevent oxidation by creating microenvironments with less oxygen exposure. Additionally, metal chelating agents and molecular antioxidants have shown promise in reducing omega-3 fatty acid oxidation rates. Emulsion and microencapsulation parameters, metal chelating agents, and molecular antioxidants should be explicitly optimized for alternative seafood. 

In cultivated seafood, some of the same molecular mechanisms that inhibit the oxidation of omega-3s within conventional seafood may be relevant during the post-harvest period and during cooking. It may be necessary to explore strategies such as supplementing the culture media with antioxidants that are readily taken up by cells to inhibit oxidation during these later stages. Many of the same considerations for other alternative seafood products may apply during cultivation. The strategies discussed above related to emulsions and microencapsulation may be similarly relevant for this purpose. 

Modified atmosphere packaging and other storage techniques should also be developed to slow lipid oxidation and provide other benefits like an antimicrobial barrier and shelf life extension of alternative seafood products. These solutions can include testing existing and novel O₂ scavenger technologies, active packaging with antioxidant components integrated within the matrix, and biodegradable materials with effective gas and moisture barrier properties. Novel technologies that prevent oxidation and rancidity of omega-3s should also be explored. 

Anticipated impact

Understanding the formulations and processes that cause omega-3 oxidation and developing antioxidation methods specifically for alternative seafood will allow these products to maintain their nutritional value and decrease unpleasant off-flavors and odors. In turn, alternative seafood will be positioned to reach nutritional and organoleptic parity with conventional seafood products. More generally, rigorous evaluation of ingredient stability along their life cycle in alternative seafood products will help optimize production, leading to superior products and potentially longer shelf life, which is beneficial for both profitability and reducing food waste. Lastly, the addition of stable omega-3 fatty acids to other alternative protein foods can boost their nutritional advantage over conventional protein products, making them even more appealing to consumers.

Related efforts

• Protective effects of extra virgin olive oil against storage-induced omega 3 fatty acid oxidation of algae oil (González-Hedström et al. 2020)
• Influence of heat processing and calcium ions on the ability of EDTA to inhibit lipid oxidation in oil-in-water emulsions containing omega-3 fatty acids (Alamed et al 2006)
• Coating algae oil droplets with pea protein and flaxseed gum to reduce omega-3 off-flavors (Sun et al. 2021)
• Enhancing the oxidative stability of algal oil emulsions by adding sweet orange oil (Xu et al. 2021)

GFI resources

Formulating with animal-free ingredients

GFI scientists explain how ingredients derived from plants and fermentation can be used to create animal-free meat, egg, and dairy alternatives.