## 3 Results and Discussion
### Miscellaneous Compounds
#### 3.2.2 Quantitation of Selected Key Odorants and OAVs
Methyl 3-methylbutyrate changed in concentration from 9.21 \(\mathrm{\SIUnitSymbolMicro g}\)/kg to 22.33 \(\mathrm{\SIUnitSymbolMicro g}\)/kg from SC to SI, then decreased in S2 (6.79 \(\mathrm{\SIUnitSymbolMicro g}\)/kg), and, finally, increased slightly in SW3 (15.5 \(\mathrm{\SIUnitSymbolMicro g}\)/kg). On the contrary, the concentration and the OAVs of ethyl 3-methylbutyrate exhibited little change. Their concentrations were within the expected concentration range reported for 'Snowchaser' (Methyl 3-methylbutyrate: 39-128 \(\mathrm{\SIUnitSymbolMicro g}\)/kg and ethyl 3-methylbutyrate: 0-8 \(\mathrm{\SIUnitSymbolMicro g}\)/kg) as determined by SPME [26]. Regarding hexanal, one of the green aromas, the concentration dramatically dropped down from 84.09 \(\mathrm{\SIUnitSymbolMicro g}\)/kg in SC to 9.72 \(\mathrm{\SIUnitSymbolMicro g}\)/kg in S1; then, it slightly increased in S2 (10.82 \(\mathrm{\SIUnitSymbolMicro g}\)/kg) and built up to 16.74 \(\mathrm{\SIUnitSymbolMicro g}\)/kg, which agreed with the study by [PERSON] et al. [6], who observed the same cold versus warm storage effect with rabbiteye blueberries. The values in SC were within the previous range of 'Snowchaser' (66-198 \(\mathrm{\SIUnitSymbolMicro g}\)/kg) [26]. For the lignin-derived compounds, i.e., vanillin and guaiacol, despite their high FDs, their OAVs were relatively low. Vanillin remained relatively similar across treatments, while guaiacol increased in both measures at the highest temperature of storage (S3). Disparities exist between the changes in FDs and OAVs from SC throughout storage and the degree of change for some odorants in this present study (Tables 3 and 4). FD factors provide guides to which compounds are possibly odor-important. They are generally not considered absolute because they do not consider recovery factors in the analysis. On the other hand, OAVs are calculated based on accurate concentrations and published odor detection thresholds. Imperfect relationships between FDs and OAVs have been mentioned in prior blueberry aroma research [8] and other research as well [52]. Regarding previous research,AEDA uses air as the matrix, whereas OAVs are calculated from the odor thresholds in water, leading to differences in the results [14; 53]. Various studies have critically compared different OAV calculation methodologies, based on either the ODT in water or OTD in actual food matrices, with the variation in the results being due to the different principles applied, each subject to methodology advantages and limitations. The calculation of OAVs relies on measuring the concentration accurately and on the determined odor threshold in the food matrix [54], as a relatively high ODT and food matrix affect aroma release [48; 55]. Therefore, there is no universal standard method or technique to determine the relative importance of odorants. Additionally, sometimes, using different analytical approaches combined with GC-O will enable more information and reduce the errors associated with the use of only a single method [15]. The loss of concentrations in key aroma volatiles due to cold storage found in this study was also observed in prior studies with tomatoes, apples, and peaches [25; 31; 32; 56]. If blueberries or other fruits were to be consumed immediately after cold storage, there would likely be a loss in aroma and a potential loss in flavor due to the loss of important volatiles. However, fruit briefly held at a warmer temperature prior to being sold is generally part of the commercial marketing process and, as indicated in this study, only a short amount of time is required at either 10 \({}^{\circ}\)C or, preferably, 20 \({}^{\circ}\)C to recover some of the key odorants in blueberries. Many volatiles in fruit that were previously depleted during cold storage will recover at warm temperatures, with the potential reasons for this being the regaining of enzymatic activity needed for volatile synthesis [25] and the availability of volatile precursors that accumulated during cold storage [31].