## 3 Results  
### Volatile Organic Compounds Profile  
The sensory experience of eating is significantly influenced by volatile compounds in food, contributing to flavour, texture, and overall appeal [37]. The composition of volatile organic compounds obtained through GC-MS analysis is outlined in Table 2. Notably, aldehydes constitute a significant portion (17.2% in _C. vulgaris_), as do alcohols (6.7% and 31.4% in _T. duii_ and _P. tricornutum_, respectively), ketones (22.9% in _T. duii_), alkanes (16.8% in _C. vulgaris_), alkenes (ranging from 0.2% in _T. duii_ to 22.1% in _C. vulgaris_), and alkenes (from 0.1% in _T. duii_ to 12.0% in _C. vulgaris_). Additionally, N-based compounds were identified across different microalgae strains, with around 48% featuring in _T. duii_. Terpenoids represented 13% of all compounds in _P. tricornutum_. The presence of 2-pentylfuran was also noted in smaller amounts (1-4%).  
Examining each microalgae strain individually, _T. duii_ stood out for its richness in N-based compounds (48% of all compounds). Ketones represented around 23% of all compounds. Aldehydes, terpenoids, alcohols, and S-based compounds constituted 10%, 7%,  
\begin{table}
\begin{tabular}{l c c c} \hline \hline
**Compound** & **Cv** & **Pt** & **Tc** \\ \hline Aldehydes & 17.2 \(\pm\) 1.28 & 8.6 \(\pm\)2.03 & 10.4 \(\pm\) 1.03 \\ Alcohols & 11.5 \(\pm\) 1.66 & 31.4 \(\pm\) 3.50 & 6.7 \(\pm\) 0.80 \\ Ketones & 2.2 \(\pm\) 0.56 & 4.1 \(\pm\) 0.48 & 22.9 \(\pm\) 9.48 \\ Alkanes & 16.8 \(\pm\) 4.00 & 5.6 \(\pm\) 1.34 & 1.2 \(\pm\) 0.22 \\ Alkenes & 22.1 \(\pm\) 3.46 & 0.7 \(\pm\) 0.00 & 0.2 \(\pm\) 0.03 \\ Alkylynes & 12.0 \(\pm\) 0.90 & - & 0.1 \(\pm\) 0.00 \\ S-based compounds & 4.2 \(\pm\) 0.31 & - & 3.0 \(\pm\) 0.01 \\ N-based compounds & 9.4 \(\pm\) 1.60 & 32.4 \(\pm\) 4.75 & 47.5 \(\pm\) 6.58 \\ Terpenoids & 2.1 \(\pm\) 0.36 & 12.9 \(\pm\) 2.12 & 6.9 \(\pm\) 0.89 \\ Other & 0.4 \(\pm\) 0.13 & 0.6 \(\pm\) 0.40 & 0.6 \(\pm\) 0.44 \\ Total identified compounds & 97.8 \(\pm\) 7.44 & 96.2 \(\pm\) 12.46 & 99.4 \(\pm\) 14.93 \\ \hline Non-identified compounds & 2.2 & 3.8 & 0.5 \\ Total & 100.0 & 100.0 & 100.0 \\ \hline \hline \end{tabular}
\end{table}
Table 2: The volatile compounds composition of microalgae biomasses: _Chlorella vulgaris_, _Phaeodactylum tricornutum_ and _Tetraselmis chuii_. _Chlorella vulgaris_ (Cv), _Phaeodactylum tricornutum_ (Pt) and _Tetraselmis chuii_ (Tc).  
7%, and 3%, respectively. Alkanes, alkenes, and alkynes collectively represented under 2% of all compounds identified in _T. chuii_. The volatile composition exhibited significant variation within the same microalgae strain, influenced by growth conditions, harvesting, and storage [37]. For _C. vulgaris_, alkenes constituted 22% of all compounds. Aldehydes ranked as the second most abundant volatile class. Alkanes, alkynes, and alcohols represented approximately 17%, 12%, and 12% of all identified compounds, respectively. N-based compounds were identified in the _C. vulgaris_ biomass, accounting for 9% of all compounds. Some authors highlighted aldehydes and _S_-based compounds as major identified volatiles in _C. vulgaris_[38]. _P. tricornutum_ showcased richness in both alcohols and N-based compounds, representing around 63% of all identified compounds. Terpenoids accounted for 13% of all compounds. Aldehydes were identified in considerable amounts (around 9%), while alkanes and ketones were identified in smaller amounts (6% and 4%, respectively).  
As shown in a previous publication about gluten-free breads and the addition of different microalgae species [39], alcohols and terpenes/terpenoids are the main compounds contributing to the overall unpleasant aroma in microalgae-containing breads.