Stabilization of fish oil‐loaded electrosprayed capsules with seaweed and commercial natural antioxidants: effect on the oxidative stability of capsule‐enriched mayonnaise

Abstract

This study investigated the stabilization of fish oil‐loaded electrosprayed capsules with different natural antioxidants: i) an ethanol extract from the brown alga Fucus vesiculosus, or ii) a combination of δ‐tocopherol and rosemary extract. The seaweed extract enhanced the oxidative stability of fish oil‐loaded capsules with dextran as the main biopolymer wall material, but showed a prooxidant effect in fish oil‐loaded capsules having glucose syrup as the main biopolymer. These results can mainly be explained by the higher encapsulation efficiency of dextran capsules when compared to glucose capsules (90 vs. 83‐85%), which prevented interaction of metal ions present in the extract with non‐encapsulated oil. On the contrary, the addition of a lipophilic radical scavenger such as δ‐tocopherol in combination with synergistic antioxidants such as carnosic acid and carnosol present in rosemary extract improved the oxidative stability of glucose syrup capsules during 21 day storage, but not when the capsules were added to mayonnaise. Moreover, the capsule‐containing mayonnaise presented a larger droplet size and higher apparent viscosity than mayonnaise enriched with neat fish oil. Both findings indicate that the structure of capsules may have been lost when added to a water‐based food matrix (e.g. mayonnaise) and this requires further investigation.

Practical applications: Novel omega‐3 delivery systems that are more easily dispersed and still maintain their oxidative stability are needed by the food industry. Electrosprayed capsules with a reduced size when compared to spray‐dried capsules, and which are produced without the need of heat for drying emulsions are promising omega‐3 powdered encapsulates. Moreover, the addition of natural antioxidants, commonly used by the industry to further stabilize omega‐3 encapsulates, deserves scientific attention. This study reveals the effect of seaweed antioxidants (e.g. phlorotannins) and commercial natural antioxidants (e.g. δ‐tocopherol and rosemary extract) on the oxidative stability of electrosprayed capsules loaded with fish oil. In addition, the effect of adding the capsules to a food matrix such as mayonnaise has been investigated. Although further development is necessary, these results will open up new strategies to enrich food products with omega‐3 polyunsaturated fatty acids.

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