Table ronde : les analyses biochimiques de PLG dans la chair des coquillages

Proximate biochemical analysis (proteins, lipids and carbohydrates) are performed on a regular basis by the various laboratories fom the Aquaculture Resources Directorate. Methods initially developed to analyse hydrological parameters were firstly transfered to assess meat components.1t appears now important to review and update the commonly used methods (Lowry et al., (1951), Dubois et al.,(l956), Marsh et Weinstein, (1966)), for our specifie purposes. A round table was organized to facilitate discussion among researchers and technicians from both Directorates 'Aquaculture Resources' and 'Product Valorization'and external partners, University of Caen. Several communications reviewing former and recent studies were done. Colleagues from the Directorate 'Product Valorization', specialized on biochemical analysis brought new insights on curent and new methodologies. Over the course of the discussion, it was emphasized that while several analysis were carried out on a regular basis, no specific objectives and data treatment have been systematically developed. This should be reformatted accordingly for further programs. It was stated that biochemical analysis were considered as an appropriate tool to facilitate understanding of biological phenomenon assuming appropriate metodologies were used. It was reported that precise oyster biochemical composition was still difficult to estimate while it is do ne on a regular basis in other domains such as food industry. The current methods were discussed, with special emphasis on uncertainties resulting from protein analysis. The use of Bradford or CHN methods, rather than Lowry method, would improve significantly estimates. Although of interest, Kjeldall methodology appears difficult to implement at the laboratory level for numerous analysis. Glycogen assessment should be improved by a preliminary treatment using cold precipitation. Lipids analysis should be performed on wet meat rather than on dry meat. In the near future, the MNR methodology should be assessed as a possible alternative method.