Enhanced Shelf-Life of Fish Fillets with Optimized Antioxidant Mixture

Greg Howard
28th February, 2024

Enhanced Shelf-Life of Fish Fillets with Optimized Antioxidant Mixture

Image Source: Natural Science News, 2024

Key Findings

  • Scientists in Rio de Janeiro found a natural way to preserve rainbow trout using essential oils
  • A mix of 66% lemongrass and 34% oregano oil kept the fish fresh as long as synthetic preservatives
  • This blend reduced spoilage microbes, slowed fat and protein breakdown, and maintained fish color and texture
In the quest for natural preservation methods, scientists at the Federal University of Rio de Janeiro (UFRJ) have made a significant breakthrough[1]. They have developed an optimized blend of essential oils (EOs) that can significantly extend the shelf life of rainbow trout fillets during refrigeration. This discovery could revolutionize the way we preserve fish, offering a natural alternative to synthetic preservatives. Rainbow trout, a popular fish in culinary circles, is prone to spoilage due to factors like microbial growth and oxidation processes that affect fats and proteins. This not only leads to a loss of nutritional quality but also impacts the taste, texture, and color of the fish, making it less appealing to consumers. The challenge has been to find a way to keep the fish fresh for longer without relying on synthetic chemicals. The UFRJ study tackled this problem by using a statistical method known as the augmented simplex-centroid mixture design. This approach helps researchers determine the most effective combination of ingredients using the fewest possible experiments. The goal was to find the ideal mix of EOs that would maximize antioxidant activity, which is crucial for inhibiting the oxidation that leads to spoilage. The researchers focused on lemongrass and oregano essential oils, known for their strong antioxidant properties. Through meticulous testing, they discovered that a blend of 66% lemongrass and 34% oregano essential oil provided the best results. When applied to rainbow trout fillets at a concentration of 2000 parts per million (ppm), this EO blend was as effective as butylated hydroxytoluene (BHT), a common synthetic antioxidant, used at 100 ppm. The study's findings are significant for several reasons. First, the EO blend was effective in reducing the total aerobic psychrotrophic count (TAPC), which is a measure of the number of spoilage-causing microorganisms present in the fish. It also mitigated lipid and protein oxidation by 12.95% and 76.13%, respectively. These are the processes that lead to rancidity and the breakdown of fish tissue, affecting both taste and texture. Moreover, the EO blend helped preserve the fish's natural color, which is an important quality attribute for consumers. It reduced discoloration by 38.83% and was more effective than BHT in preserving the texture of the fish fillets. This means that the fish maintained its firmness and did not become mushy as quickly as it would without the EO treatment. The success of this EO blend can be attributed to the synergistic effects of its components. Previous studies have shown that certain combinations of essential oils can exhibit enhanced antioxidant activity when used together[2]. For instance, a mixture of citronella, thyme, cedarwood, and basil essential oils was found to have higher antioxidant activity than the average activity of the individual oils. Similarly, the UFRJ study demonstrates that the right combination of lemongrass and oregano can produce a powerful antioxidant effect that is beneficial for food preservation. The use of essential oils as natural preservatives aligns with the global trend towards sustainable and green alternatives in the food industry. Not only do they offer a way to reduce the use of synthetic additives, but they also come from renewable sources and can be integrated into active packaging solutions[3]. For example, chitosan films modified with natural starch and essential oils have been developed to enhance the antimicrobial and antioxidant properties of food packaging. In conclusion, the UFRJ study presents a promising natural solution for extending the shelf life of rainbow trout fillets. The optimized blend of lemongrass and oregano essential oils offers a potent antioxidant effect that can keep fish fresher for longer, without the need for synthetic preservatives. This research not only contributes to food safety and quality but also supports the food industry's move towards more sustainable practices. As the demand for natural and eco-friendly food preservation methods grows, studies like this one pave the way for innovative solutions that benefit both consumers and the environment.

NutritionBiotechAnimal Science


Main Study

1) Oil-in-water emulsion loaded with optimized antioxidant blend improved the shelf-life of trout (Oncorhynchus mykiss) fillets: a study with simplex-centroid design.

Published 27th February, 2024


Related Studies

2) Synergistic Antioxidant Activity of Four-Component Mixture of Essential Oils: Basil, Cedarwood, Citronella and Thyme for the Use as Medicinal and Food Ingredient.


3) Valorisation of lemongrass essential oils onto chitosan-starch film for sustainable active packaging: Greatly enhanced antibacterial and antioxidant activity.


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