Description of the work performed since the beginning of the project and the main results achieved

The objectives for the first period of the project are two develop two laboratory prototypes: A dielectric spectroscopy (DS) system and Video Image Analysis (VIA) system to perform trials at laboratory scale with real samples of meat.

Design and implement a dielectric spectroscopy (DS) system to perform trials at laboratory scale.

A DS has been implemented to perform trials with real samples of meat at laboratory scale. First results have showed very promising results.

The DS system is to allow the characterisation of the dielectric properties (real and imaginary parts of the complex conductivity) of different fresh pork meat cuts (ham, loin and belly) over a wide range of excitation frequencies. The key objective was to design a system capable to extract electrical properties of meat. In particular, the research aims to understand the likely performance envelop of DS and quantify performance limits. These parameters have been quantified in the laboratory with purpose designed sensor head and acquisition system. Initial tests have been performed on phantoms of known conductivity and permittivity and the results have been compared against prediction from advanced 3D time domain and frequency domain electromagnetic models, in order to validate the performance of the technique and the system.

Finally, the system has been tested with a series of meat pieces (pork loins) to confirm that it is possible to extract the electrical information from the different pieces of meat. First results have confirmed that the DS system is capable to determine Water Holding capacity in fresh pork loins with significant accuracy. The next step is to test the system for other pork pieces like ham and belly.

Design and implement a Video Image Analysis system to perform trials at laboratory scale.

The aim of this work package is to design a Video Image Analysis system to determine different visual properties of meat such as colour and size (2D image). The determination of meat colour has been made using a digital colour camera. The objective is to correlate the R,G,B components provided by the camera with meat colour brightness (i.e. CIE LAB L* value). Different devices (including the RGB camera) have been used to easily determine the size of the different pork meats (hams, loin and bellies). This visual information can be used in the future for the interpretation of the data acquired by the DS system. Area and length are the main parameters extracted from the samples.

Experiments carried out at laboratory with the DS and VIA system.

A first experiment has been carried out at laboratory scale using 26 pork loins with a water holding capacity ranging from 1.75% to 16%, pH values ranging from 5.37 to 5.89 and L* ranging from 47 to 65 (Minolta CR-410).

  • VIA system vs. reference method (Minolta CR-410): The pork loins were scanned with the VIA system and then measured with the reference method. The RGB information extracted by the camera is converted by the VIA system to L*a*b* and then the results can be directly compared with the reference method (Minolta CR-410 colorimeter). The correlation index achieved is R2 0.97.
  • DS and VIA: The pork loins were scanned with the DS system at different frequencies. DS measurements and Lightness information (i.e. L*) extracted from the VIA system were combined to establish a correlation with the % drip loss. The correlation index obtained is R2 =0.936 with RMSEC=1.0, RMSEV=2.4.