NON-THERMAL PLASMA AS AN INNOVATIVE ACCELERATED LIPID OXIDATION TECHNIQUE IN FISH OIL

Nowadays, saturated fatty acids are increasingly being replaced by healthier unsaturated fatty acids in food. However, these food products are more susceptible to lipid oxidation, leading to an overall quality deterioration and the development of unwanted aroma properties. To evaluate the oxidative stability of food products a wide range of techniques has been described in literature of which most are based on increased temperature. Such approaches are known to result in unrealistic oxidation chemistry in poor correlation with that observed during ambient storage. In this work, Non-Thermal Plasma Technology (Ar/0.6% O2) was used in fish oil samples as a highly innovative accelerated lipid oxidation method (Van Durme, Nikiforov, Vandamme, Leys, & De Winne, 2014; Vandamme et al., 2015). Using such technology enables to generate reactive oxidative species (hydroxyl radicals, atomic oxygen, singlet oxygen), without increasing the temperature of the treated matrix. This paper critically evaluates both a thermal as a non-thermal plasma based accelerated oxidation protocol using naturally aged fish oil as reference. Experiments were done using both virgin, as -tocopherol-enriched fish oil samples. Secondary lipid oxidation volatiles were measured using HS-SPME-GC-MS. Both accelerated oxidation techniques induced the formation of typical lipid oxidation markers (e.g. 2-propenal, (E)-2-pentenal, heptanal), however in both cases significant differences were observed compared to the naturally aged fish oil. On the other side, Non-Thermal Plasma correctly predicted an antioxidative effect when 1000 µg/g -tocopherol was added to the fish oil, while thermally based tests resulted in the induction of prooxidative chemistry. To conclude, results showed that by optimizing Non-Thermal plasma characteristics (reactor configuration, gas feed mixture, power source, …) this technology has the potential to be fine-tuned to evolve towards a technology that is capable to accelerate lipid oxidation in a highly realistic manner.status: accepte