Búsqueda de nuevos marcadores bioquímicos capaces de detectar carnes de vacuno defectuosas a tiempos postmortem tempranos

Abstract

[EN] Meat, which is widely consumed in the world, is affected in its quality by many factors dependent and independent of the animal, the breed or the processing conditions, such as preslaughter stress, temperatures, the breed of the animal or the water it drinks). This leads to a high variability in the final quality of the product and it is not possible to predict the final tenderness of the pieces. The aim of this study is to look for biochemical markers that indicate that a meat is defective from the point of view of tenderness, and to achieve this we focused on the protein profile of the samples. To achieve this, different beef samples were analysed at different times after the death of the animal in order to see how its protein profile evolves between slaughter and the second week. Both myofibrillar and sarcoplasmic protein extracts were analysed, with inconclusive results for the latter. SDS-PAGE polyacrylamide gel electrophoresis techniques were used to separate the different protein fractions and mass spectrometry coupled to LC-MS/MS liquid chromatography together with a bioinformatics analysis with the MASCOT search engine to identify the proteins and/or fragments that could be present in the different samples. All the finalised results are from the myofibrillar protein samples. As results, different fragments of degraded protein due to meat maturation were isolated. The most repeated were from the proteins "Creatine kinase M-type", "Troponin T, fast skeletal muscle" and "MYBPC1 protein". The intact form of "Troponin T, fast skeletal muscle" was also identified, notably before and after undergoing the degradation process. These proteins are good candidates as biochemical markers capable of detecting defective beef at early postmortem times.

[ES] En una primera etapa, el estudiante trabajará en la preparación de extractos musculares a partir de muestras de carne pertenecientes a distintas razas de vacuno españolas. Posteriormente, el estudiante aprenderá las técnicas relacionadas con el fraccionamiento/separación del proteoma de vacuno muscular y del plasma/suero sanguíneo, tales como la electroforesis en gel (SDS-PAGE) o el isoelectroenfoque en medio líquido (OFFGEL). El objetivo final será caracterizar y cuantificar aquellas proteínas clave que puedan ser indicadores de la condición de estrés pre-sacrificio de los animales. Para la identificación de las proteínas, el estudiante aprenderá los protocolos básicos de trabajo en Proteómica basados en el análisis de cromatografía líquida acoplada a la espectrometría de masas (LC-MS), así como las herramientas bioinformáticas adecuadas para una correcta interpretación de los datos MS/MS generados.