## 4 Discussion  
Rice is the seed of the grass species _O. sativa_ and takes the second place in the list of economical cereal crops consumed worldwide. It has rich nutritional constituents such as carbohydrates, proteins, fats, minerals, fibers, and vitamins characterized by their high digestibility and high content of lysine amino acid among all the cereals [4]. Our study aimed to produce new plant-based yoghurt alternative by fermenting rice milk using three different LAB strains (_L. bulgarcius_, _L. casei_, and _L. acidophilus_) as well as using commercial yogurt culture through 8 h of incubation at 37 \({}^{\circ}\)C. Our results recorded the highest LAB cell viability and the best chemical composition depending on the recorded pH, TA, and total organic acids produced by _L. bulgarcius_. Indeed, more research is needed to study the new rice-based yoghurt product for their sensory properties as well as their toxicology effects on normal and tumor human cells. According to the LAB cell viability results and the results published by [PERSON], [17] it was found that _L. bulgarcius_ and _L. casei_ were the most favorable and efficient starters for making milk rice yoghurt. Moreover, [PERSON] et al., [11] noted that LAB specific growth rates and doubling time values range between 0.12 and 0.21 h\({}^{-1}\) and 1.38 and 2.44 h, respectively. pH and TA contents of the rice milk yoghurt were determined throughout the making process during 8 h. A drop in pH was observed due to the formation of some alcohols and the development of organic acids such as lactic and acetic ones, [PERSON] et al. [18; 19]. On the other hand, a species of LAB named _Bifidobacterium infants_ 20088 was studied by [PERSON], [20] who noticed that pH values declined at maximum growth rate of 1.65 and 0.3 when used to ferment rice milk and skim milk, respectively. A study was carried out by [PERSON] et al., [10] and [PERSON] and [PERSON], [21] where a mixture of cow milk and rice milk was fermented by using LAB, and showed the highest Vmax recorded 23.33 \(\times\) 10\({}^{-3}\)P Hunits/min. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Parameters**} & \multicolumn{2}{c}{**Storage**} & \multicolumn{3}{c}{**Treatments**} \\ \cline{2-6}  & \multicolumn{2}{c}{**Time (Days)**} & \multicolumn{2}{c}{_L. acidophilus_} & \multicolumn{1}{c}{_L. casei_} & \multicolumn{1}{c}{**Yogurt Culture**} \\ \hline \multirow{4}{*}{**Viability (Log**} & 0 & 9.1\({}^{\text{a}}\) & 8.5\({}^{\text{a}}\) & 7.99\({}^{\text{a}}\) & 9.1\({}^{\text{a}}\) \\ \cline{2-6}  & 6 & 8.5\({}^{\text{b}}\) & 8.1\({}^{\text{a}}\) & 7.7\({}^{\text{a}}\) & 8.4\({}^{\text{b}}\) \\ \cline{2-6}  & 12 & 8.2\({}^{\text{b}}\) & 7.6\({}^{\text{b}}\) & 7.1\({}^{\text{b}}\) & 8.1\({}^{\text{b}}\) \\ \hline \multirow{4}{*}{**pH**} & 0 & 4.6\({}^{\text{c}}\) & 4.3\({}^{\text{c}}\) & 4.4\({}^{\text{c}}\) & 4.6\({}^{\text{c}}\) \\ \cline{2-6}  & 6 & 4.4\({}^{\text{c}}\) & 4.4\({}^{\text{c}}\) & 4.3\({}^{\text{c}}\) & 4.3\({}^{\text{c}}\) \\ \cline{2-6}  & 12 & 4.2\({}^{\text{c}}\) & 4.1\({}^{\text{c}}\) & 4.2\({}^{\text{c}}\) & 4.1\({}^{\text{c}}\) \\ \hline \multirow{4}{*}{**TA (\%)**} & 0 & 0.081\({}^{\text{d}}\) & 0.082\({}^{\text{d}}\) & 0.078\({}^{\text{d}}\) & 0.061\({}^{\text{d}}\) \\ \cline{2-6}  & 6 & 0.082\({}^{\text{d}}\) & 0.084\({}^{\text{d}}\) & 0.079\({}^{\text{d}}\) & 0.064\({}^{\text{d}}\) \\ \cline{1-1} \cline{2-6}  & 12 & 0.083\({}^{\text{d}}\) & 0.087\({}^{\text{d}}\) & 0.081\({}^{\text{d}}\) & 0.067\({}^{\text{d}}\) \\ \hline \hline \end{tabular} Different small letters (a–d) indicate significant differences.  
\end{table} 
Table 3: Viable cell count, pH, and tittatable acidity for fermented rice yogurt during storage at 5 \({}^{\circ}\)C for 12 days. Supplementing rice milk products by skim milk was applied for enhancing the fermentation process due to its high content of lactose and casein that considered the carbon and nitrogen sources needed for cellular metabolism and energy formation. [PERSON] et al.