Etude de la qualité des huiles extraites d’un poisson bleu (thon rouge Thunnus maccoyii )

Abstract

Tuna (Thunnus thynnus), an oily fish belonging to the Scombridae family, represents one of the most economically important marine species in the Mediterranean Sea. Its by-products, particularly the flesh and skin, are exceptionally rich in polyunsaturated omega-3 fatty acids, which are widely recognized for their considerable nutritional, cardiovascular, and therapeutic benefits. The valorization of these by-products therefore constitutes both an ecological and an economic opportunity of great interest. This study aims to extract and physicochemically characterize tuna oil obtained from these two biological tissues using the Soxhlet method. This technique, well established in analytical chemistry, is particularly valued for its simplicity, efficiency, and reproducibility. Samples were carefully prepared through dissection, drying, and grinding prior to extraction. The high extraction yields obtained confirm the lipid richness of both tissues and the suitability of the Soxhlet method for this type of matrix. The physicochemical analyses performed — including the refractive index, peroxide value, acid value, density, and pH — returned results fully consistent with international quality standards for fish oils. These parameters collectively indicate good chemical quality and satisfactory oxidative stability of the extracted oils, suggesting adequate preservation conditions and low levels of lipid degradation. More specifically, the skin-derived oil demonstrated the highest extraction yield, making it the most productive tissue source, while the flesh-derived oil exhibited slightly superior oxidative stability, reflecting a better resistance to rancidity over time. Taken together, these findings confirm the significant potential of valorizing tuna and its by-products as a reliable source of high-quality oil for the food, cosmetic, and pharmaceutical industries. This work contributes to promoting a more sustainable, efficient, and comprehensive exploitation of marine fishery resources, in line with current environmental and economic priorities.