## 3 Results and Discussion
### Discriminant Analysis  
The results of the discriminant analysis including all the data variables are shown in Figure 1. Each animal group is clearly placed in each quadrant of the plot. Root 1 separates light Mallorquina lambs raised on pasture or concentrate from suckling lambs or the Roja Mallorquina breed. Root 2 separates ML and MP from MC and RC groups. ML and MP are placed close together because both groups had high availability of access to mother's milk. Normally, grazing lambs remain with their mothers during the day, taking advantage of the pastures, and are rounded up at night in the sheepfold with their mothers, where they continue to feed on their mother's milk. The use of concentrated feed in the rearing of lambs allows us to situate the MC and RC groups in the lower part of the plot.  
Table 6 shows the best selection of variables chosen to discriminate meat from the Mallorquina and Roja Mallorquina breeds raised on their traditional production system in the Spanish Mediterranean Islands. Seventeen variables were included in a multinomial logistic regression to calculate the probability of a carcass belonging to their group of traditional production. According to the matrix classification proposed including these seventeen variables, 90.21 and 82.43% of the carcasses were correctly classified into ML and MP, respectively, while 100% of carcasses were correctly classified into MC or RC. The best variables selected (higher F value) to predict belonging to a group of lambs raised are linked to the polyunsaturated fatty acid (\(p<0.001\)) and monounsaturated acid content (C18:1n-9c and 17:1; \(p\leq 0.001\)). According to [PERSON] et al. [59], a high content of polyunsaturated fatty acids has been described in meat from animals raised on pasture, while a high content of monounsaturated fatty acids is observed in the meat of lambs fed using concentrates.  
The parameters related to the juiciness of the meat (WHC and final juiciness) are the variables that best mark the discrimination of the different traditional systems for raising lambs from the Spanish Mediterranean. Among all the aromatic compounds detected in the meat of the reared lambs, aromatic hydrocarbons are the ones that best mark the differentiation of the traditional systems of lamb meat production in the Balearic Islands. Finally, saturated fatty acids such as C10:0 and C12:0 contribute to the differentiation of  
Traditionally, the characterization of livestock breeds has been studied from the genetic point of view and from the assessment of the quality of their products. This has been the way to recognize the origin of livestock breeds and value the quality of the products of local breeds. However, new technologies based on knowledge of muscle protein are now being used to monitor systems of animal production and their product quality. In fact, proteomic investigations [61] have been reported in improved livestock breeds with the aim of gathering relevant information to help improve the meat quality in cost-effective and efficient production systems or even to monitor specific differences among breeds [62]. Advanced proteomic techniques to help characterize production models and identify the origin of animal products are usually applied to improved livestock breeds. However, in the future, these techniques could be used in local breeds with a reduced number of flocks, as has occurred in the breeds of Spanish Mediterranean islands.