CONICET | Buscador de Institutos y Recursos Humanos

Meat colour is frequently used by consumers as an indicator of the degree of cooking. It is a key parameter to acceptance or rejection of the meat sample, strongly related to microbiological and physical quality. During meat cooking as the temperature increases, the muscle becomes progressively opaque, changing from red to pink to brown. The possibility to follow these changes in real process time is crucial to understand cooking process and final meat quality. The main objective of this work was to develop and evaluate a methodology to determine meat colour changes during heating recording the process with video camera. Slabs of Semitendinosus muscle (approx. 40g) were heated by immersion in hot water (40, 50, 60, 70, 80 and 90 ºC) for 30 min. Samples were horizontally oriented and fixed to a grid, immersed about 1 cm below water surface. The camera, placed parallel to the surface, recorded the heating process. A colour pattern ColorChecker was included in the scene in order to calibrate the conversion of RGB images into the CIELab space. The video was processed with a program developed in MATLAB which allows selecting the number of frames to perform image processing (calibration, ROI selection, and colour space conversion). Additionally, the heating experiments (same conditions described above) were performed measuring colour with a MINOLTA colorimeter at 2, 4, 6, 8, 10, 15, 20, and 30 minutes. In general, there was observed a good agreement between colour parameters measured by video processing and colorimeter, with a correlation coefficient of 0.7928, 0.7608, 0.61444 for L*, a*, b*, respectively. In this sense, the developed system applying video recording allows to obtain reliable information during the process without interfering with it. As a disadvantage, particularly in this food system, fat deposition in the water was observed which gives dispersion in the measurements.