## 3 Results and Discussion
### Volatile Composition
SFL2 (air-oven dried) presented a significant highest level of 2(5H)-furanone (V14) (452 \(\upmu\)g/g), while SFL1 (air-oven dried) showed the lowest concentration (4.11 \(\upmu\)g/g). However, the generation of furanone, such as 2(5H)-furanone, may be due to several processes: via oxidation reactions, by microorganisms, or spontaneous formation via the Maillard reaction between sugars and amino acids during heating [40]. Thus, the content of this volatile compound could be related mainly to the sugar and amino acid composition of the fresh flowers SFL1 and SFL2, leading to different concentrations of 2(5H)-furanone in the air-oven dried flowers. Moreover, 2(5H)-furanone is authorized as a flavoring substance by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) and is defined in its specification as a \"rich winey meat-like aroma\". This fact could be interesting for the use of dried saffron flowers as food ingredients. This compound has also been studied as bactericidal [41]. Phenylethyl alcohol was present in the SFL2 (air-oven dried) sample in high concentrations (35.63 \(\upmu\)g/g). However, minimal concentrations were found in the SFL1 (air-oven dried) sample (0.49 \(\upmu\)g/g). This volatile was also found in other flower extracts (rose, hyacinth, geranium), presenting a rose-like odor and antimicrobial and antifungal properties, and it is widely used in foods and cosmetics [42]. It should be noted that safranal (V39) was only found in SFL2 (fresh and air-oven dried) but in very low amounts (0.11 and 7.53 \(\upmu\)g/g, respectively). This could be due to the presence of traces of saffron stigmas in the floral by-products, with the amount of safranal higher in SFL2 (air-oven dried) since it is generated at the temperatures used (50-55 \({}^{\circ}\)C) for drying. Moreover, isophorone (V35) was also present in SFL2 (22.28 \(\upmu\)g/g) which may be produced from safranal and/or from other precursors formed in the oven during the heating process. Other compounds that should be highlighted due to their high concentration were 3-hydroxy 2-butanone (acetoin, V4) and butanoic acid, 3-methyl (isovaleric acid, V9). These volatiles were found in fresh SFL1 at 299.42 \(\upmu\)g/g and 177.52 \(\upmu\)g/g, respectively. Acetous, which exist widely in nature, are mainly found in higher plants that have the ability to synthesize them using different enzymes, but their biological mechanisms remain unclear; however previous studies have shown their antimicrobial actions [43]. Isovaleric acid is an isomer of valeric acid, which is a compound naturally present in plants as a metabolite that could be formed by the secondary metabolism of plants [44]. Moreover, these volatiles were only found in fresh samples, meaning that they may be degraded by heat. In summary, some volatiles present in fresh flowers increased by air drying in the oven due to the thermal treatment, and new volatiles also appears in the air-dried flowers. Some volatile compounds (V3, V17, V26, V32, V44) were only found in SFL2 (air-oven dried) samples, which showed the highest concentration of total volatile compounds (833.49 \(\upmu\)g/g). These results are justified by the generation of volatiles from other non-volatile precursors by heat processing. Thus, the post-harvest procedures, such as drying, are very important when considering the volatile quality in terms of the contribution of the volatile compounds that are generated during this processing step. \begin{table}
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