# Using Science and Technology to Unveil The Hidden Delicacy Terfezia arenaria, a Desert Truffle
## 3 Results and Discussion
### Volatiles Profile by GC-MS  
Volatile profiles, particularly in mushrooms and truffles, are crucial in determining their characteristic odours and strongly influence consumers' preferences. _T. arenaria_'s distinct volatile profile serves as a key characteristic and significantly impacts consumers' preferences. Thirty-two VOCs were identified in _T. arenaria_ fresh samples, i.e., eight hydrocarbons, six alcohols, five aldehydes, three ketones, three esters, two terpenes, and five other compounds. Among them, the most abundant were the eight carbon (C-8) compounds and Hexanal, with 1-octen-3-ol being the main volatile (64%) in _T. arenaria_ (see Tables S3 and S4). 1-Octen-3-ol is generally referred to as the mushroom alcohol and is one of the most abundant VOCs produced by fungi [95; 96]. This is consistent with the fact that C-8 compounds are the main volatile components found in several edible mushrooms and truffles [97; 98; 99; 100] (Tables S3 and S4). Despite using similar methodologies, [PERSON] et al. (2010) identified 27 VOCs in _T. arenaria_, but only three compounds were common with our study (nonanal, 3-octanone and 2-octenal) [34]. Both internal factors (e.g., maturity stage, tissue specificity and postharvest storage [101]) and external factors (e.g., place of origin, interaction with microorganisms [102]), result in distinct metabolic processes within the fungi, which alters their VOCs profile. The main volatiles identified in _T. arenaria_ were C-8 compounds resulting from the breakdown of fatty acids (such as linoleic acid) by lipoxygenase and related enzymes (Table 3), which is in agreement with the evidence that the umami taste, so characteristic of mushrooms, is associated with the fatty acid metabolism [103]. Lipoxygenases are pivotal in the biosynthesis of leukotrienes, associated with various inflammatory conditions such as cancer, arthritis, asthma, and allergies [104]. Given their role in these disease processes, lipoxygenase inhibitors are being explored as potential therapeutic options for preventing and managing these inflammatory disorders [105; 106]. Notably, certain mushroom extracts have demonstrated the ability to inhibit these enzymes, offering potential health benefits [105; 107; 108]. These extracts have been used to enhance the nutritional value of pasta, contributing to healthier products [107; 108]. Exploring the potential inhibitor of _Terfezia_ may be necessary for incorporating this product in food formulations. Nine VOCs identified in _T. arenaria_ (i.e., 1-octen-3-ol, 3-octanol, 3-octanone, 2-octenal, hexanal, nonanal, benzeneacetaldehyde, eicosane, limonene and \(\alpha\)-pinene) had been previously reported for the desert truffles _T. boudieri_ and _T. claveryi_[35; 36; 109]. These compounds are also prevalent in commercial edible mushrooms and truffles such as _A. bisporus_, _L. edodes_, _P. ostreatus_ and _T. melanosporum_[98; 99; 100; 110]. On the other hand, 18 VOCs detected in _T. arenaria_, had not been reported for other _Terfezia_ spp. or _A. bisporus_, _L. edodes_, _P. ostreatus_ and _T. melanosporum_ (Table S4). Additionally, a review of the reported VOCs composition of these species revealed that only three compounds are common between _T. arenaria_ and these four commercial species (Figure 3). These VOCs, which are C-8 compounds (i.e., 1-octen-3-ol, 3-octanol, 3-octanone), are abundant in _A. bisporus_, _L. edodes_, _P. ostreatus_ and _T. arenaria_ and greatly contribute to their floral and green aromas [37] (Tables 2 and S3). They are also present in _T. melanosporum_, but in lower quantities [18; 102]. When comparing _T. arenaria_'s aroma profile with that from other edible mushrooms and truffles (_A. bisporus_, _L. edodes_, _P. ostreatus_, and _T. melanosporum_) (Figure 3, Table S4), _T. arenaria_ exhibits a distinct composition. Figure 4 highlights potential differences between _T. arenaria_ and the other edible mushrooms and truffles in terms of the number and quantity of compounds per main functional group. In _T.