**2. Materials and Methods**

#### *2.1. Whey Fermentation*

The whey used for fermentation was collected after cheese manufacture from a mixture of ewe, goat, and cow´s milk using an industrial starter mix (Danisco, Sassenage, France) of *Lactococcus lactis* subsp. *lactis*, *Lactococcus lactis* subsp. *cremoris*, *Lactococcus lactis* subsp. *lactis* biovar *diacetylactis*, *Streptococcus thermophilus*, and *Lactobacillus delbrueckii* subsp. *bulgaricus*, containing approximately <sup>10</sup><sup>7</sup> cfu·mL−<sup>1</sup> of whey. It was kept at <sup>−</sup>18 ◦C until fermentation assays. Bacterial cell enumeration

was performed on Man Rogosa and Sharp medium (MRS broth) (Biokar DiagnosticTM, Beauvais, France), containing 2% (*w*/*v*) agar (Difco, Quilaban, Portugal). Incubation was done at 37 ◦C ± 1 ◦C for 48 h ± 2 h. The samples of whey were obtained after manufacture of cheese from a mixture of ewe, goat, and cow´s milk, containing 0.04% (*w*/*v*) NaCl, pH 6.65 (Lab 850, Schott AG, Mainz, Germany) and 30 g·L−<sup>1</sup> lactose, quantified by HPLC (High-performance liquid chromatography) ion exchange chromatography, as in a previous work [41], was used for the fermentation assays. Whey was divided into 500 mL aliquots in Erlenmeyer flasks, and assays were conducted at 37 ◦C for 120 h. Over time, at regular intervals, 5 mL samples were taken for pH measurement (Lab 850, Schott AG, Mainz, Germany) and HPLC determinations, as previously described by Santos et al. [41].
