Abstract The effects of ractopamine and immunological castration on belly characteristics, processing yield, physicochemical and sensory quality of bacon were investigated from two crossbred pigs under different conditions of animal production, diet, management and slaughter arranged in factorial design using 2 ractopamine levels (0 and 7.5 ppm) and 3 genders (barrows, immunocastrated and gilts). Before processing, belly firmness, weight, length, width and thickness were measured, and then, bacon processing yield evaluated. After processing, bacon slices were digitally imaged and analyzed for lean meat and fat areas, pH, instrumental color of meat and fat, cooking loss and sensory quality. The ractopamine did not alter belly characteristics, but significantly increased the process yield and decreased cooking loss. Barrows and immunocastrated pigs showed firmer bellies, which could be advantageous for bacon processing and slicing. Barrows presented the highest total area of bacon slices. The results of this study indicate that both techniques ractopamine in the finishing diets and immunocastration of pigs can be combined with no further consequences for belly processing and to bacon quality and with some advantages.

Abstract The effects of immunocastration and ractopamine in the diet on the belly quality were investigated from two crossbred pigs under different conditions of production, diet, management, and slaughter arranged in factorial design using two levels of addition of ractopamine in the diet, 0 and 7.5 ppm, and three genders (gilts, immunocastrated and barrows). The quality of bellies were analyzed for chemical composition, pH, meat and fat color, backfat thickness and fatty acid profile of the fat. The addition of ractopamine showed no significant influence on pH, color and chemical composition in two crossbred pigs. The immunocastrated had thicker belly backfat compared to the bellies of the gilts. The contents of fatty acids polyunsaturated, linoleic, linoleic, arachidonic, total omega 3 and omega 6 were higher for immunocastrated pigs, as well as presenting values greater than 0.4 for the PUFA:SFA ratio, thus, providing bellies with better nutritional quality. The bellies of the gilts and immunocastrated pigs had higher concentrations of iodine value, indicative of higher unsaturated fat content. The results indicated that the addition of ractopamine and immunocastration had little influence on the quality of bellies as well as in their fatty acid profiles, suggesting the continuity of implementation of these techniques.