## 3 Discussion
Because most essential odorants have low odor detection thresholds, the odor of these compounds can be detected when they are at low concentrations. To estimate odor potency, the OAV is used. This is the ratio of the concentration of a volatile compound to its odor detection threshold. The relevant odor descriptors of the compounds determined by GC-MS (SPME) in roasted samples of the insect larvae studied can be divided into general groups: fruity-floral, roast, bread-like, and burnt. The results obtained in the sensory analysis are supported by the chemical analysis of the aroma compounds and in respect with their OAV values (%OAV). For insects roasted at the lowest temperature (TMPSI, TMBCI, MPSI, ZMBCI), the highest OAV was found for isobutylpyrazine (**34**) and 2,5-dimethylpyrazine (**7**) and was more than 90% and about 20%, respectively (Tables 5 and 6). Their presence determined mainly the aroma of the roast. As the roasting temperature of the insects was increased, a burning smell developed. The isobutylpyrazine (**34**) content (%OAV) decreased (roast aroma) and the 2,5-dimethylpyrazine (7) content increased (burnt aroma). Pyrazines occur naturally in heat-treated food products and are produced on a mass scale by extraction from natural products, chemical synthesis, and biocatalysis (enzymatic, microbiological) [66]. They are used as flavor- and aroma-enhancing compounds. In the \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Insect**} & \multirow{2}{*}{**Feed**} & \multicolumn{2}{c}{**Roasting**} & \multicolumn{2}{c}{**Roasting Time**} & \multirow{2}{*}{**Sample Code**} \\  & & **Temperature** [\({}^{\circ}\)C] & & **[min]** \\ \hline _Tenebrio molitor_ & Blue corn flour & 160 & 20 & TMBCI \\  & & 180 & 15 & TMBCIII \\  & & 200 & 10 & TMBCIIII \\  & Potato starch & 160 & 20 & TMSI \\  & & 180 & 15 & TMSII \\  & & 200 & 10 & TMSIII \\ _Zophobas morio_ & Blue corn flour & 160 & 20 & ZMBCI \\  & & 180 & 15 & ZMBCIII \\  & & 200 & 10 & ZMBCIIII \\  & Potato starch & 160 & 20 & ZMPSI \\  & & 180 & 15 & ZMPSII \\  & & 200 & 10 & ZMPSIII \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Roasting condition and sample codes. \begin{table}
\begin{tabular}{c c} \hline \hline
**Grade** & **Score** \\ \hline Like extremely & 9 \\ Like very much & 8 \\ Like moderately & 7 \\ Like slightly & 6 \\ Neither like or dislike & 5 \\ Dislike slightly & 4 \\ Dislike moderately & 3 \\ Dislike very much & 2 \\ Dislike extremely & 1 \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Nine-point hedonic scale was used in the preference test. case of alkyll pyrazines, the increasing demand can no longer be supplied economically from natural sources. The natural occurrence of the main seven alkyl pyrazines in foods in Europe in tons per year was 2157 tons per year (in 2004). In contrast, the annual volume of use of the same pyrazine derivatives used as flavoring agents in Europe was 2157 kg per year, which represents 0.85% of naturally occurring compounds [67]. Therefore, new, preferably natural, sources of pyrazines are being sought. Roasted insects can find use as food additives that are a source of natural pyrazines. In January 2021, specialists from the European Food Safety Authority (EFSA) gave a positive opinion on insect-based food products [68]. The project has not yet been approved by the European Commission, but specialist voices indicate that such approval is likely to be given. The novelty of using insects in food has aroused great interest among the public (potential consumers). Various insect-derived foods could be applied as a source of protein, lipids, vitamins, macro- and microelements, or volatile compounds for the diet.