## 3 Results and Discussion
### Spirulina Effects on Mozzarella Cheese's Chemical Composition
\begin{table}
\begin{tabular}{c c c c c} \hline \hline  & **Fatty Acids** & \multicolumn{2}{c}{**Group**} & \\ \hline _Abbreviation_ & _Common Name_ & **C** & **S** & **SEM** \\ \hline C4:0 & Butriic acid & 2.74 & 2.76 & 0.034 \\ C6:0 & Caproic acid & 1.77 & 1.79 & 0.024 \\ C8:0 & Caprylic acid & 1.05 & 1.05 & 0.016 \\ C10:0 & Capric acid & 2.09 & 2.10 & 0.029 \\ C12:0 & Lauric acid & 2.60 & 2.61 & 0.035 \\ C14:0 & Myristic acid & 11.50 & 11.63 & 0.138 \\ C15:0 & Pentadecylic acid & 1.07 & 1.04 & 0.019 \\ C16:0 & Palmitic acid & 35.02 & 35.31 & 0.397 \\ C16:1 n-7 & Palmitoleic acid & 1.72 & 1.65 & 0.062 \\ C18:0 & Stearic acid & 12.76 & 12.59 & 0.169 \\ C18:1 trans 9 & Eladic acid & 0.63 & 0.64 & 0.008 \\ C18:1 trans 11 & Transvaccencia & 1.62 & 1.59 & 0.037 \\ C18:1 n-9 & Okele acid & 19.77 & 19.61 & 0.236 \\ C18:2 n-6 & Linoleic acid & 1.85 & 1.90 & 0.058 \\ C18:3 n-6 & \(\gamma\)-Linolenic acid & 0.22 & 0.23 & 0.014 \\ C18:2 c9-t11 CLA & Linolenic acid isomer & 0.66 & 0.64 & 0.015 \\ C20:0 & Eicosanoic acid & 0.23 & 0.22 & 0.004 \\ oth & others & 0.14 & 0.14 &. \\ SFA & Saturated FA & 71.66 & 71.92 & 0.313 \\ MUFA & Monounsaturated FA & 25.09 & 24.80 & 0.266 \\ PUFA & Polyunsaturated FA & 3.25 & 3.29 & 0.102 \\ n-3 & & 0.448 & 0.445 & 0.023 \\ n-6 & & 2.15 & 2.21 & 0.069 \\ \multicolumn{2}{c}{_Nutritional Index_} & & \\ UFA/SFA & & 0.395 & 0.390 & 0.007 \\ PUFA/SFA & & 0.046 & 0.046 & 0.002 \\ n-6/n-3 & & 4.840 & 4.985 & 0.161 \\ AI & Atherogenic index & 2.953 & 3.010 & 0.058 \\ TI & Thromogenic index & 3.910 & 3.965 & 0.069 \\ h/H & Hippocholesterolem/ & & 0.468 & 0.463 & 0.010 \\  & hypercholesterolemia ratio & & & \\ \hline \hline \end{tabular} SEM, Standard Error of the Mean.  
\end{table} 
Table 4: Fatty acid (FA) profiles (% on total FAs) and nutritional index of mozzarella cheese from control (C) and Spirulina (S) groups. The results of the analysis on VOCs can be found in Table 6. In total, 94 compounds were identified, and the most prevalent class in both groups is \"others\". This group covers all of the individual VOCs that do not belong to the main classes considered in this study. Although the less abundant classes are the same in both samples, including esters, aldehydes, halogenated hydrocarbons, sulphur, and nitrogen compounds (from highest to lowest), the most abundant VOC classes are different between the two groups. In the C samples, the most and least frequent classes are alcohols, ketones, hydrocarbons, and aromatic hydrocarbons, in that order. In contrast, in the S samples, the most frequent classes are hydrocarbons, alcohols, aromatic hydrocarbons, and ketones, in that order. The only class that significantly differs from the others is aromatic hydrocarbons, which are higher in the C samples than the S samples, despite being ranked fifth on the list of VOC classes for the C group (in descending order) and fourth for the S group. However, the individual VOCs that were found to be significantly different (only 4% of the VOCs detected) do not belong to this class. Specifically, toluene (\(p<0.05\)), isobutyl acetate (\(p<0.05\)), and acetic acid 2-phenylethyl ester (\(p<0.01\)) were found at higher levels in product C, while 1 Pentanol (\(p<0.01\)) was detected at lower levels (\(p<0.01\)) (Table 6). Unlike the study by [PERSON] et al. [10], where the most prevalent VOC class was ketones, particularly in the cheese from buffilos that were fed wrapped ryegrass silage, our study found that ketones ranked third and fifth in the VOC lists of the C and S groups, respectively. Moreover, the level of ketones was higher in the C samples compared to the S samples (though not significantly). This is similar to the study by [PERSON] et al. [3], where ketones were more abundant in the control sample than the experimental ones. Ketones are common in many dairy products, and their origin can be attributed to SFA \(\beta\)-oxidation. Some studies suggest that these compounds are derived from animal feeds, and silage is the primary source of ketones [3].