Estudio de la fracción lipídica y de compuestos volátiles producidos en el tejido adiposo subcutáneo del Jamón Ibérico durante el proceso de curación

Resumen

Abstract The Iberian dry-cured ham is an expensive meat product elaborated following a traditional process, which is a typical way of manufacturing raw ham in the Mediterranean area. Since 1998, this product has been included in the European Union list of the Designation of Origin, which has survived due to its highly demanded characteristics, with long taste and rich nutty flavor. These appreciated organoleptic properties are due to the meat characteristics of Iberian pigs (marbling, fat composition, antioxidant status) together with a long-term maturing process which requires between 16 and 36 months. Among the biochemical reactions occurring during the ripening process, those which affect the lipid fraction are of great importance since the degradation products contribute to the overall organoleptic properties of the final products. The main objective of this Thesis is to evaluate the evolution of different components from lipid fraction and more specifically, to study the changes produced in the different molecular species of triglycerides, diglycerides, monoglycerides, total and free fatty acids of the subcutaneous fat from Iberian hams during dry-curing process. The study of phospholipid fraction has had a special consideration since the different classes of them have not been studied before in this kind of fat. These studies have been completed with the analysis of the different volatile compounds that are originated from the compounds mentioned above in the subcutaneous fat during processing, in order to understand the role of subcutaneous fat from Iberian ham in the development of the characteristic and exclusive flavor of this ham. Besides, the sweaty fat during ripening has been studied for the first time, with the aim of explaining this process and correlating this with the evolution of lipid fraction from subcutaneous fat. The chromatographic methods have allowed determining the concentration of the different molecular species of triglycerides, diglycerides, monoglycerides, total and free fatty acids of the subcutaneous fat from Iberian hams during dry-curing process. For the analysis of phospholipids, a new high-performance liquid chromatographic method with evaporative light scattering detector has been developed, since the existing methods are not applicable to this kind of sample. So, the different classes of phospholipids and their evolution during process have been described for the first time in subcutaneous fat from Iberian hams. ABSTRACT 2 Many reactions are involved in the changes that undergo the lipid and volatile fraction, such as hydrolysis, isomerisation, oxidation, and they are widely discussed. The changes in chemical composition of subcutaneous fat (alterations of the lipid and volatile fraction) could be used as good indicators to monitoring the dry-curing process to obtain hams with similar characteristics. Thus, knowing with precision the changes that occur during processing, it can be predicted if the process is making satisfactory progress or we can act on the system variables to optimize this process.