RESUMO
Along with orange and mandarin, grapefruit production in Florida has declined sharply due to Huanglongbing (HLB), or citrus greening disease, caused by Candidatus Liberibacter asiaticus (CLas). HLB affects the volatile profiles of juice and peel oil in oranges, but there is limited information on grapefruit. In this research, 'Ray Ruby' grapefruit were harvested in 2020 and 2021 from healthy (HLB-) and HLB-affected (HLB+) trees. Peel oil was extracted by hydrodistillation, and the volatiles were analyzed by direct injection of the oil samples into gas chromatography-mass spectrometry (GC-MS). Volatiles in the juice were analyzed by headspace (HS)-solid-phase microextraction (SPME) coupled with GC-MS. HLB significantly altered the volatile profiles of peel oil and juice in 'Ray Ruby' grapefruit. Juice samples of HLB+ fruits had lower decanal, nonanal, and octanal, important citrus juice flavor compounds. HLB+ samples also showed reduced content of nonterpene compounds, other aliphatic and terpene aldehydes, and terpene ketones. Ethanol, acetaldehyde, ethyl acetate, and ethyl butanoate were increased in HLB+ juice samples, indicating an HLB-induced stress response. The most abundant compounds D-limonene and ß-caryophyllene, as well as other sesquiterpenes, were increased in HLB+ juice and peel oil samples. On the other hand, the oxidative/dehydrogenated terpenes were increased by HLB in peel oil but decreased in the juice sample. Nootkatone, the key grapefruit volatile was consistently reduced by HLB in both peel oil and juice samples. The impact of HLB on nootkatone deteriorated the quality of both juice and peel oil in grapefruits.
RESUMO
Rootstocks modulate several characteristics of citrus trees, including vegetative growth, fruit yield and quality, and resistance or tolerance to pests, diseases, soil drought, and salinity, among other factors. There is a shortage of scion and rootstock cultivars among the combinations planted in Brazil. "Ponkan" mandarin and "Murcott" tangor grafted on "Rangpur" lime comprise the majority of the commercial mandarin orchards in Brazil. This low genetic diversity of citrus orchards can favor pest and disease outbreaks. This study aimed to evaluate the agronomic performance, Huanglongbing (HLB) tolerance, and fruit quality of "Emperor" mandarin on five different rootstocks for nine cropping seasons under the subtropical soil-climate conditions of the North region of the state of Paraná, Brazil. The experimental design was a randomized block, with six replications, two trees per block, and five rootstocks, including "Rangpur" lime, "Cleopatra," and "Sunki" mandarins, "Swingle" citrumelo, and "Fepagro C-13" citrange. The evaluations included tree growth, yield performance, fruit quality, and HLB disease incidence. "Emperor" mandarin trees grafted on "Rangpur" lime and "Swingle" citrumelo had early fruiting and high yield efficiency. "Rangpur" lime also induced the lowest tree growth, but low fruit quality. Trees on "Swingle" citrumelo and "Fepagro C-13" citrange showed low scion and rootstock affinity and produced fruits with high total soluble solids (TSS), with a lower number of seeds for those from trees on "Fepagro C-13" citrange. "Cleopatra" and "Sunki" mandarins induced higher juice content, while fruits from trees on "Cleopatra" also had higher TSS/titratable acidity (TA) ratio. "Emperor" mandarin trees were susceptible to HLB regardless of the rootstocks. Overall, "Cleopatra" and "Sunki" mandarins, "Swingle" citrumelo, and "Fepagro C-13" are more suitable rootstocks for "Emperor" mandarin under Brazilian subtropical conditions than "Rangpur" lime.
RESUMO
Huanglongbing (HLB) or citrus greening is the most severe citrus disease, currently devastating the citrus industry worldwide. The presumed causal bacterial agent Candidatus Liberibacter spp. affects tree health as well as fruit development, ripening and quality of citrus fruits and juice. Fruit from infected orange trees can be either symptomatic or asymptomatic. Symptomatic oranges are small, asymmetrical and greener than healthy fruit. Furthermore, symptomatic oranges show higher titratable acidity and lower soluble solids, solids/acids ratio, total sugars, and malic acid levels. Among flavor volatiles, ethyl butanoate, valencene, decanal and other ethyl esters are lower, but many monoterpenes are higher in symptomatic fruit compared to healthy and asymptomatic fruit. The disease also causes an increase in secondary metabolites in the orange peel and pulp, including hydroxycinnamic acids, limonin, nomilin, narirutin, and hesperidin. Resulting from these chemical changes, juice made from symptomatic fruit is described as distinctly bitter, sour, salty/umami, metallic, musty, and lacking in sweetness and fruity/orange flavor. Those effects are reported in both Valencia and Hamlin oranges, two cultivars that are commercially processed for juice in Florida. The changes in the juice are reflective of a decrease in quality of the fresh fruit, although not all fresh fruit varieties have been tested. Earlier research showed that HLB-induced off-flavor was not detectable in juice made with up to 25% symptomatic fruit in healthy juice, by chemical or sensory analysis. However, a blend with a higher proportion of symptomatic juice would present a detectable and recognizable off flavor. In some production regions, such as Florida in the United States, it is increasingly difficult to find fruit not showing HLB symptoms. This review analyzes and discusses the effects of HLB on orange juice quality in order to help the citrus industry manage the quality of orange juice, and guide future research needs.
RESUMO
Orange juice is a rich source of flavonoids considered beneficial to cardiovascular health in humans. The objective of this study was to analyze the pharmacokinetics of the main flavanone glycosides, hesperidin and narirutin, in humans after the consumption of two styles of orange juice, fresh-squeezed (FOJ) and commercially processed (POJ), differing in their amounts of soluble and insoluble forms of these compounds. Healthy human subjects consumed 11.5 mL/kg body weight of FOJ, and after an interval of 30 days, consumed the same quantity of POJ. The results showed that there were no significant differences in the Tmax of the pharmacokinetic curves for the metabolites of hesperidin and narirutin following the consumption of the two styles of juices, and corrected for differences in doses in the POJ and FOJ, there were also no significant differences in the AUC and Cmax values and percent absorption of these compounds.