FIG 7.
Parameters differentiating the cultures. Shown is a biplot of the first two dimensions of principal-component analysis performed using 33 variables: 12 selected volatile compounds expressed as a culture/control (noninoculated CDM PROT) ratio; 2 acidification parameters, maximal acidification rate (Vmax) and final pH; 3 carbohydrates, expressed as the percentage of carbohydrate consumed (lactose [LAC], sucrose [SUC], and raffinose [RAF]), and 16 variables that describe the content in free amino acids and peptides: 13 essential amino acids, free NH2 groups, concentration in free amino acids (FAA), and concentration in peptides (PEPT) measured in CDM PROT fermented by the monocultures of the strains Efa2412, Lla2125, and Lla244 and their cocultures with three receiver strains Lla450, Lpl465, and Lpl1524. Replicate experiments are represented using the same symbols. For volatile-compound abbreviations, see Table 2. The ellipses result from a hierarchical clustering performed on the PCA data set. For strain codes, see Table 4.