## Results and Discussion
### Comparison of Aroma-Active Compounds in Wild Lowbush and Cultivated Highbush Blueberries
Score 1 was driven by alcohol, acid, straight-chain ester and total volatile content and score 2 was driven by branched-chain ester, hydrocarbon and ketone content. Differences were seen between the wild lowbush and the cultivated highbush fruit, with the former found in the right of the plot and the latter in the left. Wild lowbush fruit from NB and QC were similar, while those from NS and PE differed reflecting differences in total volatiles, acids, alcohols and esters. Among the highbush cultivars, 'Brigitta' and 'Jersey' were similar, while 'Duke' differed and associated with monoterpenoid content. Figure 1: The distribution of volatile compounds in the headspace of wild lowbush and cultivated highbush blueberry fruit grouped according to chemical properties. Values represent the mean area counts collected from wild lowbush fruit samples from three commercial fields located in four provinces in eastern Canada (\(n\) = 12) and five cultivars of cultivated highbush fruit collected from three fields and two harvests (\(n\) = 30). These differences in volatile profiles were reflected in the differences in aroma-active compounds. Wild lowbush blueberry aroma was dominated by esters, while cultivated highbush fruit was dominated by monoterpenoids. In wild lowbush blueberry fruit, the five most aroma-active compounds were esters (Table 1), while in highbush fruit, three of the five were monoterpenoids and none were esters (Table 2). Lowbush fruit had two monoterpenoids that ranked eleventh and twelfth of the most aroma-active compounds, while esters in highbush fruit ranked ninth, twelfth, fifteenth and twenty-fourth, and each ester was not found in all cultivars. Alcohols, ketones and aldehydes all contributed similarly to the aroma of fruit from both blueberry species, although specific differences were observed in compounds and concentrations. The method of volatile collection and analysis can affect volatile profiles and aroma-activity assessment [13; 24; 38]. All methods have advantages and disadvantages, and no method is ideal. In our study, headspace volatiles were collected from fruit homogenized in saturated salt using a DVB/CAR/PDMS SPME fiber, and aroma activity was accessed by GC-O using a sensory panel that consisted of nine evaluators. SPME fibers have a degree of selectivity and have good sensitivity for compounds with low molecular weight and high volatility but may underestimate those with low volatility [24; 38]. In contrast, solvent extraction of fruit and concentration of volatiles using solvent extract dilution analysis (SAFE) is more effective in capturing volatile compounds with low volatility, including acids and hydroxyl-containing compounds. Using a total extract and SAFE, [PERSON] et al. [20] reported vanillin as an odorant in highbush blueberry, but did not report the presence of vanillin when using SPME analysis [33]. However, the total extracts obtained by solvent extraction are less reflective of the head space volatile composition that induces the olfactory response of the consumer, and valid olfactory rankings are only obtained after odor activity values are calculated using odor thresholds for each compound [24]. In our study, aroma activity was assessed using a direct intensity measure that integrated an intensity rating and the detection frequency of panelists. The panel helps to account for variability in aroma sensitivity among individuals. Additional studies could be conducted using different analytical method such as SAFE and dilution analysis to further assess the contribution of volatiles to the aroma of wild lowbush blueberry. Figure 2: Principal component analysis of the volatile composition of wild lowbush blueberry fruit from four provinces and five cultivars of highbush blueberry fruit. To further compare the sensory impact of the aroma-active compounds of wild low-bush and cultivated highbush blueberry fruit, the frequency of descriptors chosen by sensory panelists to describe the aroma-active peaks was analyzed by ANOVA and illustrated using a radar plot (Figure 3).