## 3 Results and Discussion
### Volatile Compounds  
The volatile flavor compounds of the dessert yogurts made from cow and goat milk, using three different cultures (sweet, classic, and acidic), with or without the addition of probiotic bacterial strains are presented in Tables 1-4. These include aldehydes, alcohols, ketones, acids, hydrocarbons and terpen. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Compound** & \(\mathbf{RI_{exp}}\) & \(\mathbf{RI_{lit}}\) & **Mild** & **Classic** & **Acidic** \\ \hline \multicolumn{6}{c}{_Aldehydes_} \\ \hline acetaldehyde & - & - & - & 54.87 \(\pm\) 12.15 [FOOTNOTE:]Footnote : \(\mathrm{R}_{\mathrm{lit}}\):  
\begin{table}
\begin{tabular}{c c c c c c} \hline
**Compound** & **RI\({}_{\text{exp}}\)** & **RI\({}_{\text{lit}}\)** & **Mild** & **Classic** & **Acidic** \\ \hline \multicolumn{6}{c}{_Aldehydes_} \\ \hline Acetaldehyde & & & - & 21.59 \(\pm\) 15.97 b  & 6.60 \(\pm\) 0.12 ab  \\ Pentanal & 697 & 695 & - & 4.75 \(\pm\) 3.36 a  & 4.53 \(\pm\) 0.1 a  \\ Hexanal & 801 & 798 & - & 5.41 \(\pm\) 2.95 b  & - \\ Nonanal & 1108 & 1105 & - & - & 1.73 \(\pm\) 0.25 a  \\
**Total** & & & - & 30.36 \(\pm\) 23.66 & 12.86 \(\pm\) 0.47 ** \\ \hline \multicolumn{6}{c}{_Alcohols_} \\ \hline
1,8-Cineole & 1044 & 1038 & \(1.81\pm 1.01\) a  & - & - \\ \hline \multicolumn{6}{c}{_Ketones_} \\ \hline
2-Propanone & - & 500 & - & 28.84 \(\pm\) 0.52 b  & 10.52 \(\pm\) 0.10 ab  \\
2,3 Butanedione & 566 & 584 & 21.28 \(\pm\) 12.16 ab  & 30.20 \(\pm\) 0.15 abc  & 55.11 \(\pm\) 1.06 d  \\
2-Pentanone & 681 & 689 & - & 6.11 \(\pm\) 0.71 b  & - \\
2,3-Pentanedione & 693 & 700 & - & 8.39 \(\pm\) 0.58 b  & - \\
3-Hydroxy-2-butanone & 720 & 721 & 39.25 \(\pm\) 22.96 a  & 58.03 \(\pm\) 16.99 a  & 120.42 \(\pm\) 4.67 b  \\
2-Heptanone & 891 & 899 & 7.86 \(\pm\) 4.33 a  & 11.89 \(\pm\) 4.88 a  & 13.57 \(\pm\) 0.13 a  \\
2-Nonanone & 1093 & 1095 & - & - & 2.57 \(\pm\) 0.02 b  \\
**Total** & & & 68.39 \(\pm\) 39.45 & 143.46 \(\pm\) 23.83 & 202.52\(\pm\) 59.8  \\ \hline \multicolumn{6}{c}{_Carboxylic Acids_} \\ \hline Acetic acid & 923 & 934 & 151.46 \(\pm\) 77.25 & - & 119.94 \(\pm\) 84.81 \\ \hline \multicolumn{6}{c}{_Hydrocarbons_} \\ \hline
1-Decene & 992 & 990 & 1.91 \(\pm\) 0.51 b  & 1.94 \(\pm\) 0.65 b  & 3.27 \(\pm\) 0.65 c  \\ Nonanene & 900 & 900 & 3.55 \(\pm\) 0.63 b  & 4.88 \(\pm\) 0.12 b  & 5.12 \(\pm\) 0.83 a  \\ Toluene & 774 & 771 & 2.12 \(\pm\) 1.22 a  & - & - \\ Decane & 1000 & 1000 & 5.15 \(\pm\) 1.29 a  & 5.76 \(\pm\) 0.86 a  & 7.42 \(\pm\) 1.33 a  \\
1-Methyl-2-(1-methylethyl)-benzene & 1039 & 1041 & 1.15 \(\pm\) 0.79 a  & - & - \\ Dodecane & 1193 & 1199 & 2.52 \(\pm\) 0.70 b  & - & 4.08 \(\pm\) 1.63 ab  \\ Total & & & 16.41 \(\pm\) 5.12 & 12.58 \(\pm\) 1.63 & 19.89 \(\pm\) 4.41 \\ \hline \multicolumn{6}{c}{_Terpenes_} \\ \hline
2-Pinene & 936 & 943 & - & 1.50 \(\pm\) 0.43 a  & - \\ Limonene & 1044 & 1039 & 3.01 \(\pm\) 2.71 ab  & 4.15 \(\pm\) 1.31 b  & 3.12 \(\pm\) 0.94 ab  \\ Total & & & 3.01 \(\pm\) 2.71 & 5.65 \(\pm\) 1.74 & 3.12 \(\pm\) 0.94  \\ \hline \multicolumn{6}{c}{_Total volatiles_} \\ \hline  & & 271.44 \(\pm\) 125.54 & 192.05 \(\pm\) 50.86 & 358.33 \(\pm\) 96.61 \\ \hline \multicolumn{6}{c}{_Aldehydes_} \\ \hline Acetaldehyde & - & - & 7.12 \(\pm\) 4.08 a  & 66.09 \(\pm\) 18.12 b  & - \\ \hline \multicolumn{6}{c}{_Ketones_} \\ \hline
2-Propanone & - & 500 & 33.50 \(\pm\) 24.73 a  & - & 33.22 \(\pm\) 11.10 a  \\
2,3 Butanedione & 566 & 584 & 37.24 \(\pm\) 19.76 a  & 97.19 \(\pm\) 18.72 ab  & 116.37 \(\pm\) 48.60 ab  \\
2-Pentanone & 681 & 689 & 7.58 \(\pm\) 1.09 c  & 4.30 \(\pm\) 0.10 b  & 7.50 \(\pm\) 1.40 c  \\
2,3-Pentanedione & 693 & 700 & 20.42 \(\pm\) 9.77 ab  & 17.11 \(\pm\) 4.59 ab [FO