Qualitative analysis of volatiles in rabbiteye blueberry cultivars at various maturities using rapid solid-phase micro extraction

Authors: Beaulieu, John; Stein, Rebecca; Boykin, Deborah

Submitted to: Journal of the American Society for Horticultural Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/23/2013
Publication Date: 1/11/2014
Publication URL: https://handle.nal.usda.gov/10113/59770
Citation: Beaulieu, J.C., Stein, R.E., Boykin, D.L. 2014. Qualitative analysis of volatiles in rabbiteye blueberry cultivars at various maturities using rapid solid-phase micro extraction. Journal of the American Society for Horticultural Science. 139(2):167-177.

Interpretive Summary: Recently, superfruits, such as blueberries, have received much attention as scientists, marketers, and consumers push forward knowledge and demand for high antioxidant, healthier diets. Blueberry-rich diets deliver anti-inflammatory, anti-carcinogenic, and anti-mutagenic components that help protect the brain, cardiovascular and central nervous system, and reduce cancer, obesity, and type 2 diabetes. Subsequently, production and consumption of rabbiteye and southern highbush blueberries are steadily increasing in the Southeast; however, there are very few studies detailing the aroma, astringency, and flavor of rabbiteye blueberries and products derived from them. An overall goal exists to build a database of possible flavor and aroma compounds in local blueberries. The objectives were to investigate the rapid and qualitatively solid phase microextraction gas chromatographic-mass spectrometry volatile composition of several local rabbiteye blueberry cultivars. A rapid method routinely captured 53 volatiles in five Louisiana-grown rabbiteye cultivars (‘Brightwell’, ‘Climax’, ‘Premier’, ‘Powder Blue’ and ‘Tifblue’). Seventeen of the 33 compounds considered important in the blueberry literature were recovered. Ten compounds were recovered for the first time in blueberry. In general, terpenoid compounds and their sub-class linalools were the most significant volatiles recovered, followed closely by esters, aldehydes, then alcohols. From the suite of 17 of the 33 important compounds, 10 (linalool, methyl 3-methylbutanoate, 1,8-cineole, (E)-2-hexanal, (Z)-3-hexenal, (Z)-3-hexenyl acetate, limonene, hexyl acetate, hexanal and a-terpineol) were recovered that displayed a high level of significance. A useful volatiles database geared toward viewing changes in rabbiteye blueberries, juices, byproducts, and value-added products has been established.

Technical Abstract: Recently, superfruits, such as blueberries, have received much attention as scientists, marketers, and consumers push forward knowledge and demand for high antioxidant, healthier diets. Production and consumption are steadily increasing. Yet, there are very few studies detailing the aroma, astringency, and flavor of rabbiteye blueberries and products derived from them. The objectives were to investigate the rapid and qualitatively solid phase microextraction gas chromatographic-mass spectrometry volatile composition of several local rabbiteye blueberry cultivars, with an overall goal to build a database of possible flavor and aroma compounds. Volatile profiles were obtained in five Louisiana-grown rabbiteye cultivars (‘Brightwell’, ‘Climax’, ‘Premier’, ‘Powder Blue’ and ‘Tifblue’) assayed at four maturities (mature-green, pink, firm-ripe and soft-ripe. The method routinely captured 53 volatiles, including 12 aldehydes, 6 alcohols, 11 esters, 4 ketones, 17 terpenoids, 1 furan and 2 aromatics. Seventeen of the 33 compounds considered important in blueberries were recovered in the rabbiteye cultivars assessed. Ten compounds were recovered for the first time in blueberry and five compounds (2-ethylfuran, (E)-2-pentenal, (Z)-dehydroxylinalool oxide, (E)-dehydroxylinalool oxide and 1,4-cineole) were confirmed with standards. The literature and our data indicated that blueberry volatiles varied substantially (locations, within season, and between maturities and cultivars); therefore, analysis of variance omitting zeros for no detection was performed on volatile measurements, and compounds were ranked based on overall effects of cultivar and maturity by ANOVA F-values. In general, terpenoids and their sub-class linalools, were the most significant volatiles, followed closely by esters, aldehydes, then alcohols. Terpenoids and linalools displayed the greatest significant differences in ‘Powder Blue’ and ‘Premier’ cultivars. Esters and aldehydes were the most important compound classes, based upon cultivar effect per maturity in firm-ripe fruit. From the suite of 17 of the 33 important compounds, 10 were recovered across the five cultivars at four maturities that displayed a high level of significance. These were linalool, methyl 3-methylbutanoate, 1,8-cineole, (E)-2-hexanal, (Z)-3-hexenal, (Z)-3-hexenyl acetate, limonene, hexyl acetate, hexanal and a-terpineol. This data will be useful to evaluate rabbiteye blueberry aroma and changes in processed and value-added byproducts.