## 4 Discussion
When the diastatic activity was measured in two types of honey stored at 35 \({}^{\circ}\)C, the values below the limit threshold of 6 months for floral honey were found, while the values below 8 DN were detected at 12 months in only 3 samples out of 15 of honeydew honey, which in itself is characterized by a high content of diastase [34]. The trend of HMF content at three different temperatures confirms that honey stored at 15 \({}^{\circ}\)C maintains the characteristics of freshness for durability of 18 months. At temperatures equal to or higher than 25 \({}^{\circ}\)C, honey degrades, particularly quickly, if stored at 35 \({}^{\circ}\)C. The furans content over time at the three different storage temperatures follows the same trend of HMF, with a dramatic increase at the highest temperature. Heat can cause chemical changes in honey, among which the ones due to the reaction of Maillard are noteworthy. Indeed, during the reaction at pH 7 or below, the Amadori product undergoes enolization with the formation of HMF or furfural when hexoses or pentoses are involved, respectively [2]. The average furfural content at 35 \({}^{\circ}\)C is most likely attributable to the degradation of sugars, while the small percentage in fresh honey may be transported from comb wax [35]. Ketones increased during storage at all three temperatures, in contrast to what was reported by other authors [36]. Among ketones, the most represented compounds were acetone at 15 \({}^{\circ}\)C and hydroxyacetone at 35 \({}^{\circ}\)C: the former is normally present in acacia honey [12], while the latter derives from the Amadori product during the Maillard reaction [2]. The reduction in alcohols, observed at 35 \({}^{\circ}\)C during storage, was observed in Brazilian honey over six months and was probably due to volatilization, ester formation, and oxidative processes [36]. On the contrary, at 15 \({}^{\circ}\)C and 25 \({}^{\circ}\)C, the trend shows a parabolic shape with a limited loss of these compounds at the end of the conservation period. This is in agreement with results from previous research reporting that 87% of 33 honey samples stored at 20 \({}^{\circ}\)C for one year had an increase and a subsequent decrease in ethanol, which is the largest percentage compound [37]. During storage, the trend of hydrocarbons does not show significant differences at three temperatures; however, hexane and phenylbutene have been found in both samples collected in Poland and South Africa [3,4], the latter only at 35 \({}^{\circ}\)C. These compounds can derive from changes caused by processes such as specific enzymes present in honey, high temperatures, and long storage periods [1] or can arise from beeswax, which has not been completely separated during harvest and processing [38]. The acid class included only non-aromatic acids, with the exception of benzoic acid. It seems that many non-aromatic acids are intermediate to the Krebs cycle or similar pathways and that they can be synthesized from nectar's sugars both by the action of worker bee enzymes or directly [6]. Acids decrease during storage, especially acetic acid and formic acid: the latter compound is present in fresh honey due to its natural presence in plants that are visited by honeybees, and rapid decrease in its content in hive matrices is also reported after application as an acaricidal treatment against the mite Varroa destructor through removable strips [39]. It should be considered that acetic acid may also be produced in honey as a result of mild fermentation phenomena that can start at higher storage temperatures; this may have contributed to the concentration trend observed in the present study, which declined not as fast as it might have been expected during storage. Furthermore, the percentage of this chemical class at 35 \({}^{\circ}\)C appears more stable in time for some compounds compared to lower storage temperatures; for instance, at 35 \({}^{\circ}\)C, butenoic acid and 2-butenoic acids are present in higher percentages.