Aplicación de técnicas no destructivas para la determinación de parámetros de calidad y clasificación de canales de cerdo ibérico

Abstract

The Iberian pig is an indigenous breed associated with the dehesa ecosystem, which is located in the southwest of the Iberian Peninsula. It is well known for the remarkable organoleptic quality of its derivatives. The high demand for Iberian products, together with the limited production of Iberian pigs reared extensively and fed on acorns and grass (the montanera system), has led to intensive rearing of this breed and also to its crossbreeding with improved breeds. The final quality of the meat from these animals and their products is strongly correlated with different factors such as animal production, the breed, the feeding regime, and the age or slaughter weight. Several analytical techniques have been studied and applied to guarantee the authenticity of the breed and the feeding regime. However, there is currently no official analytical method for the purpose. Near Infrared Spectroscopy (NIR) is a multi-parametric tool which has been widely used to assess meat characteristics and meat product quality. In the sector of the Iberian breed, NIR technology has been applied to quantify protein, fat, and moisture, to predict the fatty acid profile, and to determine the feeding regime during the fattening period. This analytical methodology allows immediate individualised results to be obtained without sample destruction and in an environmentally friendly manner. However, the spectra obtained need to be interpreted by complex chemometric methods. This PhD thesis proposes the use of NIRS technology for predicting parameters which determine the quality of Iberian pig fat, such as the lipid profile and the carbon isotopic ratio δ13 C (‰). The application of NIRS technology and gas chromatography together with ion mobility spectrometry (GC-IMS) for classification/authentication purposes is also addressed. Finally, this study analyses the viability of using portable equipment, which facilitates work in situ and has experienced a boom in recent years. The first article included in the PhD thesis evaluated the feasibility of predicting the lipid profile composition and the δ13 C (‰) of intact subcutaneous fat by using a portable NIRS device. The results were compared with those obtained by using benchtop NIRS equipment on both extracted and intact fat.In the second article, the changes in the lipid profile and the carbon isotope ratio observed before and after the fattening period on the montanera were evaluated. The influence of different montanera times on these parameters was also analysed. Significant correlations between the δ13 C isotope (‰) and the different fatty acids were studied in order to classify the samples according to animal feeding. The third article compares the classification ability of NIRS and GC-IMS technologies when applied at slaughter to subcutaneous fat. The aim was to achieve a correct classification according to the breed and the number of days spent feeding under the montanera system. The conclusions deriving from the present studies indicate that the application of NIR spectroscopy, using both benchtop and portable equipment, is suitable for predicting the quality parameters of Iberian fat. This technology could replace costlier and less environmentally-friendly laboratory chemical analyses. The combination of chemometric tools with NIRS and GC-IMS technologies has made it possible to classify Iberian fat correctly according to the fattening time and the breed. All these results point to the enormous potential of NIRS technology to guarantee the authenticity of Iberian pig carcasses. In fact, it offers the possibility of ascertaining the results immediately which allows for routine operations on the slaughter lines.