Volatile, anthocyanidin, quality and sensory changes in rabbiteye blueberry from whole fruit through pilot plant juice processing.

Authors: Beaulieu, John; STEIN-CHISHOLM, REBECCA - Emerge Interactive; Lloyd, Steven; Bett Garber, Karen; Grimm, Casey; Watson, Michael; Lea, Jeanne

Submitted to: Journal of the Science of Food and Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/6/2016
Publication Date: 5/31/2016
Citation: Beaulieu, J.C., Stein-Chisholm, R.E., Lloyd, S.W., Bett Garber, K.L., Grimm, C.C., Watson, M.A., Lea, J.M. 2016. Volatile, anthocyanidin, quality and sensory changes in rabbiteye blueberry from whole fruit through pilot plant juice processing.. Journal of the Science of Food and Agriculture. DOI: 10.1002/jsfa.7748.

Interpretive Summary: 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, consumption and production of rabbiteye and southern highbush blueberries are steadily increasing in the Southeast, and more uses are required for the abundant harvests. Highly colored fruits and berries often have several constituents (polyphenolics, anthocyanins, terpenoids) that make them bitter or astringent, especially when processed. Pilot plant equipment and ultrafiltration were employed to investigate the anthocyanidin profiles, qualitative volatile compositions and sensorial attributes in not-from-concentrate ultrafiltered and unfiltered ‘Tifblue’ rabbiteye blueberry juices. Processing steps prior to pasteurization generally resulted in L* and hue angle color increases, while a*, b*, and C* decreased, and °Brix markedly increased. At the end of pasteurized storage, non-clarified juice (NCP) lost 73.8 % of total volatiles compared with 70.9 % in clarified juice (CJP). Total anthocyanidins and most individual anthocyanidins decreased substantially with processing and storage in both NCP and CJP juices. There was a total anthocyanidin decrease of 84.5 % and 85.5 % after 4 months storage in NCP and CJP, respectively. Yet storage itself only resulted in 14.2 % and 7.2 % anthocyanidin loss after pasteurization in NCP and CJP. Four months storage significantly affected nine flavor properties in juices. Yet, there were no significant differences in blueberry, strawberry, purple grape, floral, sweet aroma, and sweet taste between processed and stored juices, indicating the juice maintained desirable flavors. Overall, highly significant volatile and anthocyanin losses occurred in processed blueberry juices and we did not prevent losses using a heated steam-jacket kettle (“blanching”) and ultrafiltration with NFC juices. However, lack of sensory displeasure and maintenance of color and flavor indicate that the NFC juices could have an advantage over more abusive methods often used in commercial juice operations.

Technical Abstract: BACKGROUND: High antioxidant content and keen marketing have increased blueberry demand and increased local production which in turn mandates new uses for abundant harvests. Pilot scale processes were employed to investigate the anthocyanidin profiles, qualitative volatile compositions, and sensorial attributes in not-from-concentrate (NFC) ‘Tifblue’ rabbiteye blueberry juices. RESULTS: Processing prior to pasteurization generally resulted in increased L* and hue angle color, while a*, b*, and C* decreased. After 4 months pasteurized storage, non-clarified juice (NCP) lost 73.8% of total volatiles compared with 70.9% in clarified juice (CJP). There was a total anthocyanidin decrease of 84.5% and 85.5% after 4 mo. storage in NCP and CJP, respectively. Storage itself resulted in only 14.2% and 7.2% anthocyanidin loss after pasteurization in NCP and CJP. Storage significantly affected nine flavor properties in juices, however, there were no significant differences in the blueberry, strawberry, purple grape, floral, sweet aroma, or sweet tastes between processed and stored juices. CONCLUSIONS: NFC pasteurized blueberry juices maintained desirable flavors even though highly significant volatile and anthocyanidin losses occurred through processing. Maintenance of color and flavor indicate that NFC juices could have an advantage over more abusive methods often used in commercial juice operations.