|YANG, HUQING - Zhejiang A & F University|
|BOURCIER, ELISE - Agro Paris Tech|
|BALDWIN, ELIZABETH - Retired ARS Employee|
|IREY, MIKE - Southern Gardens Citrus|
Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/16/2021
Publication Date: 4/6/2021
Citation: Sun, X.N., Yang, H., Zhao, W., Bourcier, E., Baldwin, E.A., Plotto, A., Irey, M., Bai, J. 2021. Huanglongbing and Foliar Spray Programs Affect the Chemical Profile of “Valencia” Orange Peel Oil. Frontiers in Plant Science. 12:611449. https://doi.org/10.3389/fpls.2021.611449.
Interpretive Summary: Citrus peel oil is the first byproduct obtained during the processing of citrus fruits, and is widely used in beverages, including juices and juice concentrates. Citrus peel oil is also extensively used to flavor products in the food industry, including desserts, confections, chewing gum and soft drinks. The volatile composition of citrus peel oil has been extensively studied. However, there has been little research concerning the impact of huanglongbing (HLB) and nutritional sprays on citrus peel oil volatiles. This study showed that HLB disease altered the volatile profile of ‘Valencia’ orange peel oil in that many terpene compounds were accumulated but some key aldehydes in peel oil were suppressed which may negatively impact peel oil quality. A foliar spray program shifted the chemical profile of HLB peel oil to resemble that of non-disease fruit.
Technical Abstract: Florida orange trees have been affected by huanglongbing (HLB) for more than a decade. To alleviate disease-caused tree decline, maintain fruit productivity and reduce disease transmission, enhanced foliar spray programs combining vector control and nutritional supplementation were applied to healthy and diseased trees. The aim of this research was to discover if such foliar sprays affect fruit peel oil chemical components. In this study, ‘Valencia’ orange trees, with or without HLB (HLB+/-), were treated with the grower standard program (control, C) or one of four enhanced foliar spray programs (N1, N2, N3 and N4) over 16 months. Compared to HLB-, HLB+ samples had lower concentrations of typical peel oil components, including valencene, octanal and decanal, and were abundant in oxidative/dehydrogenated terpenes, such as carvone and limonene oxide. However, limonene, the dominant component was not affected by any treatment. Control and three out of four enhanced foliar spray programs, N2, N3 and N4, had very little influence on the chemical profiles of both HLB- and HLB+ samples, while N1 treatment greatly altered the chemical profile of HLB+ samples, resulting in peel oil similar to HLB- samples.