## 1 Introduction
In fact, MDA only forms from fatty acid chains containing at least three double bonds, such as linoleic acid. In this way, the decomposition products of the peroxidation of linoleic and oleic acid are excluded. Moreover, the TBARS test is not specific for MDA since thiobarbituric acid (TBA) can react with other aldehydes, browning reaction products, protein and sugar degradation products, amino acids and nucleic acids [2]. The TBARS test can be used to assess the extent of oxidation rather than to quantify MDA [1; 22]. In recent years, different methods of recovering secondary products have been proposed. Some of these products are considered to be highly specific markers of the lipid oxidation of a particular polyunsaturated fatty acid family. For instance, propanal is regarded as the main oxidation marker of \(n\)-3 fatty acids, while hexanal and pentanal are reputed to be good oxidation markers of \(n\)-6 fatty acids. In particular, hexanal, as its formation is usually greater than that of other secondary products, is the most used marker for lipid oxidation [6]. In several studies on food, solid-phase microextraction coupled with gas chromatography (SPME/GC) has been used to detect lipid oxidation products such as hexanal [1; 22; 23; 24]. Although the use of this technique is increasing due to its sensitivity and simplicity, it is not always reported as the most suitable technique for detecting the extent of lipid oxidation, and it is still controversial as a replacement for the TBARS test. Some studies have found a perfect correlation between the SPME/GC technique and that of TBARS [22], while in other cases, TBARS proved to be more sensitive and accurate oxidation markers [1]. In this work, the effects of two antioxidants, VE and Economics(tm) (EcoE), on lipid oxidation are considered by comparing two different analytical methods. Hence, the effect of EcoE, a patented premixture of nutritional additives consisting mainly of Se, was compared with that of VE in rabbit hamburgers during refrigerated storage. The study of antioxidant supplementation appears to be of great interest, in particular in meat preparations because they might be more easily exposed to oxidative processes as well as bacteria contamination, and cold storage is not always sufficient to contain these problems. The choice of rabbit meat was related to its valuable nutritional characteristics that, due to its greater richness in PUFAs, make it more susceptible to oxidative processes; moreover, rabbit meat has been studied much less than other meats despite its nutritional value and its increased use in recent years [25]. In particular, the principal aim of this study was to evaluate the effects and the specificity of VE or Se dietary supplementation on the lipid stability of rabbit hamburger meat during refrigerated storage, measuring the secondary products of oxidation through TBARS spectrophotometric analysis and the SPME/GC determination of the hexanal content. In parallel, the possible relationship between the data related to the peroxidation products and those related to meat colour and pH, quality parameters often related to oxidation processes, was considered. The sensory discriminability among cooked rabbit hamburgers obtained from the different dietary groups was also assessed using triangle tests.