## 3 Discussion
In more detail, the detection of the highest values for L* in the freeze-dried sea fennel samples was in line with the data collected by [PERSON] et al. [25] and [PERSON] et al. [26]; furthermore, the increase in C in the dried samples agreed well with the results reported by [PERSON] et al. [25]. Finally, the lowest reduction in the hue angle calculated for the samples subjected to MD and FD was again in line with the findings of [PERSON] et al. [25], suggesting that these two drying methods generated a color that could potentially be perceived as more like fresh sea fennel [25]. When evaluating the effect of the drying methods on VOCs, a decrease in the content of some aroma compounds was observed in the dried samples compared to fresh sea fennel, with the effect being strictly dependent on the specific drying method adopted for most compounds. Limonene, gamma-terpinene, cymene, and sabinene, which occurred at the highest levels in fresh sea fennel, were drastically reduced after drying. The most important changes were observed in the oven-dried and freeze-dried sea fennel samples, where a drastic reduction in terpene hydrocarbons and an increase in some compounds, such as alcohols and esters, were observed. A more moderate reduction was observed in the sea fennel samples subjected to MD, while RTD had the least effect on the aroma pattern. [PERSON] et al. [65] also found that air drying of parsley at ambient temperature resulted in a small loss of volatile compounds compared to fresh herb, whereas oven drying at 45 \({}^{\circ}\)C and freeze drying caused a decrease in the concentrations of most volatile components, especially those with the greatest impact on parsley aroma. Furthermore, another research study carried out on dill revealed no differences in the volatile profile of freeze-dried and oven-dried samples [66]. Moreover, a moderate increase in the amount of some volatile compounds, such as aldehydes, alcohols, and esters, was observed in dried sea fennel, as a feasible consequence of the degradation of glycosylated forms, dehydration reactions, oxidation reactions, esterification reactions, or the release of compounds due to the rupture of cell walls, as previously suggested in other research studies [67; 68; 69]. Moreover, [PERSON] and [PERSON] [70] reported the formation of secondary aroma compounds, such as alcohols, aldehydes, peroxides, and ketones, during the drying process of essential oils, which substantially altered the volatile aroma profile of the final product. Nevertheless, the secondary products detected in our dried samples constituted a very low percentage of the total volatile content in the dried products. The sensory analysis carried out by a panel of trained assessors allowed the qualitative and quantitative evaluation of key sensory parameters of dried sea fennel spices. As expected, odors and flavors typically associated with sea fennel, such as herbal and kerosene-like notes, were intensely perceived [17]. Although the application of different dehydration methods has previously been supposed to lead to changes in the volatilome of herbs, with consequent modification of their sensory parameters [71], no dramatic differences were observed when comparing the four drying methods investigated in this study. However, slight differences emerged as a more intense perception of herbal notes in the freeze-dried samples, or a higher intensity of earthy odor and tobacco flavor in the oven-dried samples, which agreed with the data previously reported by [PERSON] and [PERSON] [24]. Regarding overall appreciation, the microwave-dried samples received the highest scores, which was again in agreement with the data collected by [PERSON] et al. [25], by comparing dried sea fennel spices obtained via air drying (at 45, 60, and 75 \({}^{\circ}\)C), microwave drying, freeze drying, and a combination of the latter two. Color, volatilome, and sensory traits are very important parameters in the study and production of dried spices.