|Baldwin, Elizabeth - Liz|
|WIDMER, WILBUR - Former ARS Employee|
|LUZIO, GARY - Former ARS Employee|
|Cameron, Randall - Randy|
Submitted to: Foods
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/23/2015
Publication Date: 1/4/2016
Citation: Bai, J., Baldwin, E.A., Mccollum, T.G., Plotto, A., Manthey, J.A., Widmer, W., Luzio, G., Cameron, R.G. 2016. Changes in volatile and non-volatile flavor chemicals of "Valencia" orange juice over the harvest seasons. Foods. 5(1)4. https://doi.org/10.3390/foods5010004.
Interpretive Summary: The effect of harvest maturity for juice oranges is well known for sugars and acids but less known for other quality factors. Therefore, ‘Valencia’ oranges were harvested over the season in 2012 in Florida, and the effects of harvest time on fruit and juice quality characteristics were investigated. The results indicated that the early harvested fruit had high juice yield, but also had undesirable levels of bitter and sour compounds and lower levels of volatiles. After reaching optimal quality in the midseason (April), monoterpene compounds, representing citrus-like aromas, decreased along with peel oil, although ethyl esters with the fruity top-note increased continually. With the SSC/TA ratio approaching 20 in later harvested samples, the juice quality falls out of the set commercial parameters for orange juice.
Technical Abstract: Florida ‘Valencia’ oranges have a wide harvest window covering four months after first reaching the commercial maturity. However, the influence of harvest time on juice flavor chemicals is not well documented with the exception of sugars and acids. Therefore, we investigated the major flavor chemicals in ‘Valencia’ juice influenced by harvest time from February to May 2012. Soluble solids content (SSC), individual sugars and SSC/titratable acidity (TA) ratio generally increased over the season and TA decreased. Bitter limonoid compounds, limonin and nomilin, decreased gradually. Out of a total of 94 volatiles, 32 increased, 47 peaked mid to late season, and 15 decreased. Juice insoluble solids and pectin content increased over the season, however, pectin methylesterase activity remained unchanged. Fruit harvested in the earlier months had higher juice production with lower flavor quality. Juice from later harvests had higher sugar/acid ratio with less bitterness, while, many important aroma compounds occurred at the highest concentrations in the middle of the season, but occurred at lower concentrations at the end of the season. The results of this study indicate that midseason (April) harvested fruit produced juice with the best flavor quality.