Effects of high hydrostatic pressure and antioxidant blends on lipid oxidation of Tenebrio molitor paste

Tenebrio molitor is gaining high the interest in the European market since it is considered as an efficient and sustainable insect species and it has been recently approved to be commercialized as a novel food. High hydrostatic pressure processing (HHP) is a mild non thermal technology that is used mostly for microbial inactivation leading to a pasteurization effect. Compared to the traditional thermal processing, it allows to better preserve nutrients-preserving but presents the drawback of promoting lipid oxidation. The aim of the present study was to evaluate the effect of different antioxidant blends in order to control lipid oxidation of T. molitor paste after a high pressure treatment (600 MPa, 5 minutes, room temperature). Lipid oxidation was evaluated by peroxide value (POV), TBARS and p-anisidine value (AnV). Free acidity, color, pH and antioxidant recovery were also evaluated. In this study HHP had a slight impact on oxidation and contrarily to what was expected, lipid oxidation was not promoted but seemed limited instead. Therefore, the effect of antioxidants was hard to be appreciated since the oxidation parameters were in general very low, although the synthetic blend seemed more effective than the natural one. Free acidity value (AV) decreased in treated samples suggesting that HHP is able to degrade unsaturated fatty acids. Moreover, significant color changes were observed after HPP treatment.. In treated samples L* and a* values were both significantly lower than the untreated ones and as treated samples looked discolored. Further studies on the chemical changes induced by HHP and a better understanding of the mechanisms governing changes are needed. Indeed, a comprehensive understanding of these phenomena is extremely important for effective application of the technology in the food sector.