## 3 Results and Discussion  
### Microbiological and Physicochemical Characterization of Fermented Beverages  
Table 2 shows the results of the physicochemical and microbiological analyses of the fermented beverages. Significant differences were found among samples by type of beverage and type of inoculum in all studied parameters (pH, TA, and TSS), suggesting a different effect of the inoculated microorganisms on the two studied matrices. The correct development of the chosen bacterial combinations was observed during fermentation, with both microbial combinations being able to double bacterial density (Figure 1). Initial microbial populations were comparable in the two matrices at the time of inoculation, with concentrations ranging from 5-7 \(\times\) 10\({}^{7}\) CFU/mL. After inoculation, cell viability grew significantly to the range of 1-2 \(\times\) 10\({}^{8}\) CFU/mL in all samples. LLV combination presented a significantly greater growth in both the rice and dairy-fermented beverages compared to the commercial starter (CH). However, differences were only significant in the dairy milk samples. Direct inoculation of cultures, as recommended by the manufacturer, maybe a disadvantage compared to the preparation of fresh cultures ready for inoculation [21]. The matrix seemed to influence the correct development of both starter combinations, with higher bacteria counts in the rice-based beverages. A lower complexity of the matrix and a higher proportion of carbohydrates may partly account for the greater development of cultures in the rice drink. The standards of the _Codex Alimentarius_ state that dairy milk yogurt should contain a minimum of 7 log CFU/mL as the total of lactic acid bacteria microorganisms constituting the starter culture [22]. All the fermented beverages in the present study met this requirement. Dairy products have been widely studied as probiotic carriers, but the presence of live cultures in plant-based beverages is yet to be consciously measured to compare the potential benefits of these plant-based products with fermented dairy beverages. The results of the present study corroborate previous research in which plant-based matrices supported probiotic growth and maintained satisfactory viability throughout the fermentation process [23; 24; 25]. In addition, the correct application of cultures and high bacterial counts may play an important bioprotective role, reducing microbial contamination, improving product stability, and shortening fermentation times, all of them beneficial outcomes from an industrial perspective [26]. \begin{table}
\begin{tabular}{l c c c} \hline \hline
**Nutritional Value** & **Control** & **CH** & **LLV** \\
**(per 100 mL)** & **Control** & **CH** & **LLV** \\ \hline pH & & & \\ Dairy & 6.67 \(\pm\) 0.05 (a A) & 4.89 \(\pm\) 0.08 (b A) & 4.63 \(\pm\) 0.02 (c A) \\ Rice & 6.44 \(\pm\) 0.04 (a B) & 4.27 \(\pm\) 0.12 (b B) & 3.69 \(\pm\) 0.07 (c B) \\ TA (g lactic acid/100 mL) & & & \\ Dairy & 0.09 \(\pm\) 0.01 (a A) & 0.60 \(\pm\) 0.02 (b A) & 0.71 \(\pm\) 0.01 (c A) \\ Rice & 0.01 \(\pm\) 0.01 (a B) & 0.04 \(\pm\) 0.01 (b B) & 0.09 \(\pm\) 0.01 (c B) \\ TSS (\({}^{\circ}\)Brix) & & & \\ Dairy & 13.70 \(\pm\) 0.36 (a A) & 7.53 \(\pm\) 0.14 (b B) & 6.38 \(\pm\) 0.28 (c B) \\ Rice & 12.70 \(\pm\) 0.13 (a B) & 12.18 \(\pm\) 0.17 (ab A) & 11.88 \(\pm\) 0.63 (b A) \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Physicochemical characteristics (pH, TA, and TSS) after fermentation of each sample. Different lowercase letters within the rows indicate different post hoc groupings by [PERSON]’s HSD (\(p\) < 0.001); uppercase letters within the column indicate different post hoc groupings by [PERSON]’s HSD (\(p\) < 0.001). In addition to microbial viability, dairy and fermented milk products must meet certain quality requirements, such as specific pHs and TAs, the main indicators of proper fermentation processes [15].