Tecnologia di prodvzione della Mortadella Bologna IGP: Effetti della dieta del suino e delle modalità di magazzinaggio sulla qualità delle materie prime congelate e dei prodotti

Two groups of 20 Duroc x Large White pigs, half of which castrated males and the other half females received isoenergetic diets (constant lysine/energy ratio) but with a 2-fold total-lipid and linoleic acid (C18:2) content in the feed administered to group I as compared to that of the control (group 2). This increase was obtained by supplementation with 3% soybean oil, At 9 months of age and at an average weight of 175 kg, the pigs were slaughtered and, from each group, the raw materials for industrial processing were prepared: boned shoulders, deltoid muscles, throats, "ganassini" (masseter), warn minced belly, warm minced lard, belly and thigh trimmings and carcass wastes. After 5 days of chilling at 0°C, a sample representative of each raw material was subjected to the control of the oxidation state of its lipid component and pigments. All the meats were vacuum-packed and frozen at -15°C at a processing establishment. All samples of the two groups were divided into two homogeneous batches and placed at -15 and -30°C. At 13, 208 and 320 storage days, the controls were repeated on the raw materials and the corresponding mortadella sausages, formulated according to production regulations for PGI Mortadella Bologna; the main quality descriptors, both analytical and sensory were evaluated. The high addition of linoleic acid (C18:2) in the pig diet increases rancidity values in the samples of fat, favours rancidity increase and colour oxidation in muscles liable to oxidation (masseter) whereas it has no significant effects on the glycolytic-type muscles (shoulders). In the corresponding products an, increase in rancidity is observed when they are entire, in addition to off flavours a not always acceptable colour of the mix after cooking. In control samples, deterioration is much slower and depends above all on storage duration of the raw material which, in this case, appears to be a critical processing parameter.