Global production of farmed marine species such as salmon is increasing every year. Consequently, there is a great need for sources of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) which are essential for aquaculture feed. Nowadays, the availability of marine oils as a source of these long-chain polyunsaturated fatty acids (PUFAs) is quite limited, so a new interest has arisen in seeking a new renewable source of PUFAs, such as microalgae.
Microalgae oil (MO) contains about 60% PUFAs, of which the EPA+DHA content is usually between 40-45%. This could impact in MO oxidative stability, since PUFAs are the fatty acids most susceptible to oxidation, which could be a disadvantage for quality of oil blends. This study pretends to evaluate the effect of Microalgae oil addition on the oxidative stability of Fish oil and Soybean oil blends.
For study this effect, it was used a Simplex-Lattice Mixture Design, Special Cubic model with 3 aleatory replicates. The variables studied were the soybean oil (SO), fish oil (FO) and microalgae oil (MO) concentrations. The model responses were the induction period (IP) in a Rancimat, measured at 100°C and with a 20 mL/min airflow, and the difference between initial and final PUFAs content of each mixture after 18 h oxidation under these conditions (ΔPUFA).
The model results showed no significant differences between the effect of fish oil and microalgae oil on the oxidative stability, while the soybean oil is the most stable (Figure 1).
To evaluate the changes in the oxidative stability of different oil blends by adding microalgae oil, the oxidative parameters were predicted using the statistical model (Table 1). It was observed that, the increase in MO content slightly decreases the IP but also decreases the oxidation of the PUFAs, while the desirability did not show significant changes when the FO content decreases and MO increases, maintaining the oxidative stability.
We can conclude that it is possible to add microalgae oil as a sustainable source of EPA and DHA without significantly altering the oxidative quality of the oil blends that are currently used for aquaculture feed.