## 3 Results and Discussion
### Effect of Storage Conditions on Character Impact Odorants of Blueberries
#### 3.2.1 AEDA Analysis by GC-MS-O
These compounds are responsible for the formation of membrane structure, photosynthesis, redox chemistry, growth regulation, plant defense, and the response to stress [33; 34]. Eucalypt, linalool, \(\alpha\)-terpineol, citronello1, nerol, geraniol, and geranyl acetone were found to have odor potentials with FDs \(\geq\) 64 in this study. With the exception of nerol and linalool, the predominant FD change in S1 relative to SC was to increase or stay the same. Meanwhile, when the blueberries were subjected to S2, the FDs stayed the same or declined, except for large increases in the FDs of \(\alpha\)-terpineol and nerol. However, an impressive enhancement in the FDs was indicated for linalool (16,384) and geraniol (8192) following S3. Among these terpen, the highest FDs were observed for linalool, nerol, and geraniol, which peaked at 16,384. This is in agreement with previous research that demonstrated that these odorants had large FDs in 'Bluecrop' and 'Elliot' blueberries relative to the others identified [8]. Generally, linalool and geraniol have been noted to make significant aroma contributions to highbush blueberry [8; 35; 36]. A decline in terpen during cold storage of fruits has been commonly reported in blueberries [6; 30], muscat grapes [37; 38], and peaches [32]. It was proposed that in grapes, this loss was due to emission from the berry surface during cold storage [38; 39]. An increase in terpenoids, as was seen in this study with linalool, can occur when fruits are warmed after cold storage, which was demonstrated to occur in peaches [32] and muscat grapes [38], although the authors did not propose a reason for this. Eucalypt is responsible for the minty note in blueberries, and its odor importance (high FDs) agrees with previous research on 'Bluecrop' blueberries [8]. Benzenoids and Phenolic Compounds: Derived Products of Phenylalanine  
Benzenoid and phenylpropanol volatile compounds are derived primarily from phenylalanine involving several enzymes for their synthesis. They contribute to the aromas and scents of plants and are involved in plant communication with the environment [33; 34; 40; 41]. In this study, guaiacol, 4-vinylguaiacol, m-cresol, eugenol, (Z)-isoeugenol, and vanillin showed potential as key odorants with FDs \(\geq\) 64. Clove, smoky, phenolic, and spicy sensory notes are delivered by guaiacols, phenols, and cresols in a large variety of foods and beverages [42]. In this research, the FD of guaiacol increased from SC (16, 8) to S1 (1024); then, it gradually decreased until the end of storage. The highest FD for eugenol was SC, with lesser values throughout storage. The patterns in FDs for 4-vinylguaiacol, (Z)-isoeugenol, and vanillin varied, with peaks occurring in S2 and in SC for vanillin. Guaiacol has been previously detected in blueberries [43], but its odor potential based on AEDA and FDs was reported in this present study for the first time, as well as the detection of 4-vinylguaiacol and its odor potency in blueberries. The cause of the changes in FDs during storage is unclear, but it is likely tied to how the berry's metabolism and enzymatic reactions were altered by storage. To our knowledge, this was the first time that these two odorants were detected in 'Snowchaser' blueberries. Eugenol is a cinnamate derivative commonly found in clove oil [44], which is responsible for clove-like notes; meanwhile, vanillin contributes to the vanilla note and is a well-known component of vanilla beans [45]. Both eugenol and vanillin have been reported to contribute to character-impact odorants of the 'Bluecrop' and 'Elliot' [8] and bog blueberry varieties in previous research [45]. In this study, eugenol showed the tendency to gradually decrease in cold storage from S1 to S2; then, the aroma potency was restored in S3. Whereas for vanillin, a pattern of fluctuation was indicated from the decrease in FD in SC (1024 and 256) to 128 in S1, then a restored S2 level, and, finally, the decrease in S3 (128).