| The objectives of this study are to (1) qualitatively and quantitatively measure the odor-active compounds in 'Marion' blackberry (2) compare the aroma profiles of advanced selections and new cultivars of thornless blackberry cultivars with 'Marion' (3) study the development of furaneol in 'Marion' during ripening and (4) investigate the distribution of odor-active compounds and their precursors in the selections that contributed to 'Marion's pedigree.Aroma of 'Marion' blackberry was analyzed with LiChrolut-EN solid-phase extraction (SPE) and microvial insert thermal desorption GC-MS-olfactometry. The results showed that LiChrolut-EN had limited absorption of sugars, pigments, and other non-volatile compounds, while extracting a vast majority of polar and non-polar aroma compounds. The potential odorants identified in 'Marion' included furaneol, linalool, beta-ionone, hexanal, ethyl hexanoate, hexyl acetate, 2-heptanol, cis-3-hexenol, and trans-2-hexenol. Furaneol was considered the impact characteristic aroma compound in 'Marion'. A method used for the determination of furaneol was further developed using SPE-GC-MS operated in the selected ion mode. Furaneol could be effectively isolated by LiChrolut-EN cartridge and completely eluted out with 1 mL of methanol, which could be directly analyzed on GC-MS using an automated microvial insert thermal desorption technique without further purification and concentration.The aroma constituents of 'Black Diamond' blackberry were identified and the predominant odor-active compounds in 'Black Diamond' were ethyl butanoate, ethyl hexanoate, 1-octen-3-one, 2-heptanol, cis-3-hexenol, nonanal, trans-2-hexenol, methional, linalool, ethyl 3-hydroxyhexanoate, alpha-ionone, beta-ionone, and furaneol. A comparison of volatiles in 'Black Diamond' and 'Marion' was conducted using SPE-GC-MS and stir bar sorptive extraction (SBSE)-GC-MS over two growing seasons. Although seasonal variations were present, the overall volatile profile in 'Black Diamond' and 'Marion' were very similar, but the concentrations of some aroma compounds varied greatly. Odor activity values (OAVs) indicated that furaneol, linalool, beta-ionone, and hexanal were the most important odor-active compounds in 'Marion', while in 'Black Diamond', the most important compounds were linalool, beta-ionone, furaneol, and 2-heptanol. The major difference between two cultivars was that 'Marion' had a five times higher OAV of furaneol than 'Black Diamond', while 'Black Diamond' had a three times higher OAV of linalool than 'Marion'.Furaneol, linalool, beta-ionone, 2-heptanol, and carvone were the major aroma compounds in blackberries.Free furaneol and furaneol glycoside were further studied in 'Marion' during ripening. Free furaneol was analyzed by SPE-GC-MS with PVPP decoloration of juice. Furaneol glucosides were isolated with XAD-2 sorbent, hydrolyzed with beta-glucosidase, and the released aglycone was analyzed using SPE-GC-MS. Seasonal variation was observed however, the tendency of the change in each year's berry flavor profile was similar. Dramatic chemical composition changes occurred after the mottled stage. Only trace levels of free furaneol and furaneol glycoside were detected before the mottled stage.The distribution of volatile constituents and volatile precursors in the genotypes that are in 'Marion's pedigree was investigated. Volatiles were analyzed using SBSE-GC-MS and SPE-GC-MS. Volatile precursors were isolated with C18 cartridge, enzymatically hydrolyzed, and released aglycons were analyzed using GC-MS. The results indicated each cultivar in the 'Marion' pedigree had a specific volatile and volatile precursor pattern. Wild 'Himalaya' had predominant volatiles of terpenes and furanones. The beta-ionone content in 'Meeker' was over 40 times the amount in other cultivars. The concentration of furaneol in 'Marion' was higher than in its parents, 'Chehalem' and 'Olallie'. The distribution of volatile precursor pattern in the 'Marion' pedigree was similar to the free form. The chiral isomeric ratios of 13 pairs of compounds were studied using a Cyclosil B column. Strong chiral isomeric preference was observed for the most of compounds, and each cultivar had its unique chiral isomeric ratio distribution. (Abstract shortened by UMI.)... |
