# Using Science and Technology to Unveil The Hidden Delicacy Terfezia arenaria, a Desert Truffle
## 3 Results and Discussion
### First Steps in Developing a Non-Destructive and Rapid Identification Method for T. anemia
#### 3.3.2 Phase 2: E-Nose Identification Accuracy  
Based on their volatile profile, the e-nose Cyranose-320 accurately recognized the _T. arenaria_ samples (Terf1, Terf2 or Terf3) and rated their result with stars (Table S5). Although all _T. arenaria_ samples were identified as one of the trained volatile profiles in both pre-analysis incubation temperatures, the pre-analysis incubation temperature influenced the identification accuracy. So, when the pre-analysis incubation was performed at room  
Figure 5: Effect of the pre-analysis incubation temperature (40 \({}^{\circ}\)C and RT) on the Cyranose-320 sensor’s response to _T. arenaria_ fresh samples. (**a**) Histogram of the 5 sensors showing larger responses to _T. arenaria_ samples. Different letters show a significant effect (_p_ < 0.05) of the pre-analysis incubation temperature on the sensors responses. (**b**) Plot of the first two principal components of the PCA model built with the Cyranose-320 data related to _T. arenaria_ samples at 40 \({}^{\circ}\)C and RT. temperature, the identification of 80% of the samples was acceptable or excellent, while when the pre-analysis incubation was performed at 40 \({}^{\circ}\)C, only 45% of the samples were acceptable or excellent, and considered accurately identified (Table S5). Despite this trend, the pre-analysis incubation temperature did not affect the _T. arenaria_ samples' identification accuracy (_p_ < 0.05) (Figure 6). Nevertheless, pre-analysis incubation at room temperature improved the e-nose's capacity to distinguish _T. arenaria_ samples from those of the other edible mushrooms and truffles (_A. bisporus, L. edodes, P. ostreatus_ and _T. melanosporum_) (Figure 6). Indeed, when the pre-analysis incubation was performed at 40 \({}^{\circ}\)C, some samples were misclassified as _T. arenaria_ (Figure 6), specifically some _A. bisporus_ and _L. edodes_ samples were identified with a 100% probability of being _T. arenaria_ (5 stars). The pre-analysis incubation temperature affected the e-nose's capacity to distinguish between _T. arenaria_ and _A. bisporus_ and _L. edodes_ but not _P. ostreatus_ and _T. melanosporum_ (_p_ < 0.05). Figure 6: Effect of the pre-analysis incubation temperature (40 \({}^{\circ}\)C and RT) on the e-nose Cyanose-320 capacity to accurately identify _T. arenaria_, and distinguish it from _A. bisporus_, _L. edodes_, _P. ostreatus_ and _T. melanosporum_. The “thumbs up” symbol represents the cases when the e-nose identified the sample as being _T. arenaria_, while the “thumbs down” symbol represents the cases when the e-nose identified the sample as not being _T. arenaria_. Green thumbs indicate an accurate identification, while red thumbs indicate an inaccurate identification by the e-nose. Different letters show a significant effect (_p_ < 0.05) of the pre-analysis incubation temperature on the identification accuracy for each species. Most of the studies reporting the use of the e-nose technology on mushrooms and truffles focused on sample quality as influenced by dehydration [48; 49; 50], shelf life and packaging [43; 51], and maturation process [45]. Some studies also explored the differentiation of species by analysing their volatile profiles using the e-nose [52; 53; 54; 41; 55]. By applying the e-nose methodology for a rapid and non-destructive accurate identification of _T. arenaria_ samples, we demonstrate our approach's potential for mushrooms and truffles identification during harvest. It is important to keep in mind that _T. arenaria_ is traditionally harvested near the host plant (_Tuberaria guttata_), with the collector using a pointed stick to repeatedly explore the soil until a truffle is detected and extracted [13].