Caractéristiques organoleptiques de fromages de chèvre fabriqués à partir de laits contenant des variants génétiques différents de la caséine α_s1

Abstract - Sensory characteristics of goat cheeses made from milks containing different genetic types of αs1-casein
Cheeses made from goat's milk were evaluated for their sensory quality with the aim of determining a possible relationship between goat genetic type and texture and flavour of the finished product. Milk with a high or normal content of α_s1-casein obtained from selected goats of the A and F type respectively, was sampled at early, mid- and final stages of lactation. Soft cheeses of the "Pélardon" mold-ripened type and paraffin-coated semi-hard cheeses of the Gouda type were produced from both milk samples. Sensory evaluation took place at the mid- and final stage of cheese ripening. After preliminary training of panel members, a vocabulary specific to the different cheese types was developed. Sensory trials were carried out with rating on a 5-point category scale and using non-parametric statistics for processing the data. It was found that milk appears to account at least partly for the differences evidenced in ripened cheeses. Genetic type rather than lactation stage seems to be involved in reported texture and flavour changes. Whatever the process used in cheese manufacturing, milk high in α_s1-casein is associated with less intensity in characteristic goat flavour and with firmer and smoother cheese texture. As regards the differences in flavour intensity noted for the studied cheese types, lipolysis is assumed to play a role in the expression of so-called "goat flavour" although the mechanism(s) involved as well as the compounds responsible for typical "notes" still have to be identified.

Résumé - Des fromages de chèvre ont été fabriqués à partir de laits contenant les variants génétiques A et F de la caséine α_s1. Des fabrications de type pâte molle et pâte pressée ont été réalisées dans un atelier pilote. Les caractéristiques organoleptiques des fromages ont été évaluées, à différents stades d'affinage, par un jury entraîné. Les fromages F possèdent plus de "goût chèvre" et de piquant, ainsi qu'un arrière-goût plus persistant. Les fromages A sont jugés plus fermes et plus lisses, à la fois visuellement et en bouche. La composition de la matière première apparaît capable de déterminer, jusqu'à un certain point, les caractéristiques finales du produit.