## 3 Results
### NMR Analysis  
The \({}^{1}\)H NMR spectrum of the hydroalcoholic extracts of cricket powder is presented in Figure 1. The metabolite assignment was obtained by means of 2D experiments and literature data regarding other biological matrices analyzed in the same NMR experimental conditions [14; 19]. Moreover, when spin correlations in the 2D experiments were not adequate for confirming the presence of the metabolites, standard compound addition was carried out.  
The following compounds, reported in Table 1, were assigned and quantified: nineteen amino acids and derivatives (alanine, aspartate, betaine, citrulline, glycine, glutamate, glutamine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, taurine, threonine, tryptophan, tyrosine, valine), five organic acids (acetate, formate, fumarate, lactate, succinate), and other compounds, namely choline and glycerol.  
Figure 1: The 600 MHz \({}^{1}\)H NMR spectrum of _A. domesticus_ hydroalcoholic extract in a 200 mM phosphate buffer (pH 7.4)/D\({}_{2}\)O mixture with 0.4 mM of 3-(trimethylsilyl)-propionic-2,2,3,3-d4 acid sodium salt (TSP).  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Metabolite** & **Assignment** & \({}^{1}\)**H (ppm)** & \begin{tabular}{c} **Multiplicity** \\ **[/Hz]** \\ \end{tabular} & \
\begin{tabular}{c} **\({}^{13}\)C** \\ **(ppm)** \\ \end{tabular} &
\begin{tabular}{c} **mg/100 g of** \\ **Sample** \\ \end{tabular} \\ \hline \multicolumn{5}{c}{**Amino acids and derivatives**} \\  & COO’ & & & 176.8 & 931.43 \(\pm\) 18.06 \\ Alanine & \(\alpha\)-CH & 3.80 & q [7.3] & 51.5 & \\  & \(\beta\)-CH\({}_{3}\) & 1.49 * & d [7.3] & 17.2 & \\ Aspartate & \(\alpha\)-CH & 3.92 & & 52.4 & 78.00 \(\pm\) 2.69 \\  & \(\beta\), \(\beta\)’-CH\({}_{2}\) & 2.70; 2.82 * & dd [17.4; 3.8] & 37.7 & \\ Betaine & N(CH\({}_{3}\))\({}_{3}\)\({}^{+}\) & 3.27 * & s & 54.6 & 100.16 \(\pm\) 1.44 \\  & \(\alpha\)-CH\({}_{2}\) & & & 67.7 & \\  & \(\alpha\)-CH & 3.14 * & m & & 397.96 \(\pm\) 8.38 \\ Citrulline & \(\beta\)-CH\({}_{2}\) & 1.89 & & & \\  & \(\gamma\)-CH\({}_{2}\) & 1.60 & & & \\ Glycine & COO’ & & & 175.0 & 631.41 \(\pm\) 35.29 \\  & \(\alpha\)-CH\({}_{2}\) & 3.57 * & s & 42.6 & \\  & \(\alpha\)-CH & 3.78 & & 55.6 & 464.30 \(\pm\) 19.24 \\ Glutamate & \(\beta\), \(\beta\)’-CH\({}_{2}\) & 2.07; 2.14 & & 28.0 & \\  & \(\gamma\)-CH\({}_{2}\) & 2.36 * & m & 34.8 & \\  & \(\delta\)-COO’ & & & 182.6 & \\  & \(\alpha\)-CH & 3.81 & & & 265.74 \(\pm\) 11.73 \\ Glutamine & \(\beta\), \(\beta\)’-CH\({}_{2}\) & 2.15 & & & \\  & \(\gamma\)-CH\({}_{2}\) & 2.46 * & m & 31.8 & \\ Histidine & CH-3, ring & 8.04 * & s & & 120.36 \(\pm\) 6.88 \\  & CH-5, ring & 7.15 & s & & \\  & \(\alpha\)-CH & 3.69 & & 60.7 & 189.50 \(\pm\) 9.24 \\  & \(\beta\)-CH & 1.99 & & 37.0 & \\ Isoleucine & \(\gamma\)-CH\({}_{3}\) & 1.02 * & d [7.1] & 15.8 & \\  & \(\gamma\)’-CH & 1.29 & & 25.6 & \\  & \(\delta\)-CH\({}_{3}\) & 0.94 & t [7.4] & 12.3 & \\  & \(\alpha\)-CH & 3.74 & & 54.4 & 417.98 \(\pm\) 3.21 \\ Leucine & \(\beta\)-CH\({}_{2}\) & 1.72 & & 40.8 & \\  & \(\delta\), \(\delta\)’-CH\({}_{3}\) & 0.96; 097 * & d [6.2] & 23.0 & \\  & \(\alpha\)-CH & 3.74 & & 54.5 & 351.05 \(\pm\) 9.41 \\  & \(\beta\)-CH\({}_{2}\) & 1.91 & & 30.9 & \\ Lysine & \(\gamma\)-CH\({}_{2}\) & 1.48 & & 21.2 & \\  & \(\delta\)-CH\({}_{2}\) & 1.75 & & 27.5 & \\  & \(\varepsilon\)-CH\({}_{2}\) & 3.02 * & t [7.3] & 40.2 & \\  & \(\alpha\)-CH & 3.74 & & 55.0 & 23.69 \(\pm\) 1.58 \\ Methionine & \(\beta\)-CH\({}_{2}\) & 2.25 & m & 30.5 & \\  & \(\gamma\)-CH\({}_{2}\) & 2.65 * & t [7.4] & 30.0 & \\  & \(\delta\)-CH\({}_{3}\) & 2.16 & s & 14.9 & \\ \hline \hline \end{tabular}
\end{table}
Table 1: Metabolites identified in the 600.17 MHz \({}^{1}\)H-NMR spectra of spray-dried _A. domesticus_. Bligh–Dyer hydroalcoholic extracts dissolved in 100 mM phosphate buffer/D\({}_{2}\)O containing TSP 0.4 mM. Quantitative results of the three analyzed batches are expressed as mg/100 g of sample \(\pm\)SD.