## 3 Results
### LAB Strain Selection
\begin{table}
\begin{tabular}{l c c c} \hline _Strain_ & **A** & **Vmax** & \(\lambda\) \\ \hline _L. plantarum_ T0A10 & 2.83 \(\pm\) 0.08 a & 0.41 \(\pm\) 0.02 b  & 3.39 \(\pm\) 0.06 d  \\ _Ln. mesenteroides_ 12 MM1 & 2.47 \(\pm\) 0.05 b  & 0.41 \(\pm\) 0.03 b  & 3.46 \(\pm\) 0.05 d  \\ _L. plantarum_ LB1 & 2.41 \(\pm\) 0.06 c  & 0.39 \(\pm\) 0.01 b  & 3.31 \(\pm\) 0.02 d  \\ _L. plantarum_ T6B10 & 2.40 \(\pm\) 0.09 c  & 0.40 \(\pm\) 0.03 b  & 4.39 \(\pm\) 0.05 c  \\ _L. plantarum_ 18S9 & 2.36 \(\pm\) 0.08 d  & 0.31 \(\pm\) 0.02 c  & 3.31 \(\pm\) 0.02 d  \\ _L. plantarum_ H18 & 2.46 \(\pm\) 0.05 b  & 0.44 \(\pm\) 0.02 a  & 5.19 \(\pm\) 0.07 a  \\ _P. pentosacetus_ H22 & 2.44 \(\pm\) 0.02 b  & 0.47 \(\pm\) 0.03 a  & 5.44 \(\pm\) 0.07 a  \\ _F. rossiae_ T0A16 & 2.88 \(\pm\) 0.02 a  & 0.46 \(\pm\) 0.03 a  & 4.94 \(\pm\) 0.02 b  \\ _L. plantarum_ H64 & 2.87 \(\pm\) 0.04 a  & 0.47 \(\pm\) 0.02 a  & 4.92 \(\pm\) 0.03 b  \\ \hline \end{tabular} The data are the means of three independent experiments \(\pm\) standard deviations (n = 3). a–d Values in the same column with different superscript letters differ significantly (\(p<0.05\)).  
\end{table} 
Table 1: Parameters of the acidification kinetics. A, difference of the pH between inoculation and the stationary phase (\(\Delta\)pH); Vmax, the maximum acidification rate (\(\Delta\)pH/h); \(\lambda\), length of the latency phase (h). With the aim of investigating the effect of fermentation on the antioxidant activity of the substrate, the radical scavenging activity was determined for all fermented substrates (methanolic extracts), comparing the results to that of a non-inoculated control, before and after incubation in the same conditions of the inoculated samples. In particular, the  
Figure 1: LAB cell density (**A**) and radical scavenging activity on DPPH radical (**B**) in grape pomace substrate (GPP 2.5% \(w/v\), glucose 1% \(w/v\); yeast extract 0.5% \(w/v\), pH 6.0) inoculated (7 log cfu/mL) with _Fururilactobacillus rossiae_ T0A16 and LB5, _Lacilplinathacillus plantarum_ T6B10, T0A10, 18S9, H18, H64, and LB1, _Pediococcus acidilacid_ 10 MM0, _Leuconostoc mesenteroides_ 12 MM1, and _P. pentosacus_ H22, and fermented at 30 \({}^{\circ}\)C for 24 h. A not-inoculated control was included and analyzed before (C-T0) and after incubation (Ct-T24). Data \(\pm\) are the means of three independent analyses. \({}^{\mathrm{a-d}}\) Values with different superscript letters differ significantly (\(p<0.05\)). Bars of standard deviations are also represented. antioxidant activity was expressed in terms of percentage of DPPH radical stabilized after 10 min of reaction. The samples with the highest antioxidant activity were those fermented by _L. plantarum_ T6B10 (70.7 \(\pm\) 0.9%), T0A10 (70.6 \(\pm\) 2.5%), LB1 (69.4 \(\pm\) 0.9%), and 18S9 (66.7 \(\pm\) 1.2%), _Ln. mesenteroides_ 12 MM1 (65.5 \(\pm\) 1.8%), and _L. rossiae_ LB5 (65.3 \(\pm\) 1.2%) (Figure 1B). The radical scavenging activity observed for the substrates fermented by _L. plantarum_ T6B10, T0A10, and LB1 was comparable (\(p\) > 0.05) to that of the synthetic antioxidant BHT (75 ppm), also included in the analysis (71.21 \(\pm\) 0.50%). Markedly and significantly (\(p\) < 0.05) lower antioxidant activity was found for _P. acidi-lactic_ 10 MM0 (61.5 \(\pm\) 2.1%), _L. plantarum_ H64 (58.6 \(\pm\) 2.0%), _F. rossiae_ T0A16 (57.5 \(\pm\) 1.8%), _P. pentosaceus_ H22 (55.2 \(\pm\) 2.3%), and _L. plantarum_ H18 (49.20 \(\pm\) 1.5%) (Figure 1B). Based on the results obtained thus far, _L. plantarum_ T0A10, showing a short \(\lambda\) phase (Table 1), high final cell density (Figure 1A) and high antioxidant activity (Figure 1B), was selected for further experiments and used as starter for sourdough fermentation of wheat flour containing GPP.