Orange fruits from huanglongbing (HLB)-infected trees do not fully mature and show a severe off-flavor described as bitter-harsh, metallic, and less juicy and fruity. The investigation of juice from HLB-infected (HLBOJ) and healthy control oranges (COJ) by gas chromatography-mass spectrometry showed higher concentrations of fruity esters, such as ethyl butyrate and ethyl 2-methylbutyrate, and soapy-waxy alkanals, such as octanal and decanal, in the COJ, whereas the HLBOJ showed higher concentrations of green aldehydes such as hexanal and degradation compounds of limonene and linalool such as α-terpineol. Application of aroma extract dilution analysis on terpeneless peel oil led to the identification of long-chained aldehydes such as ( E, E)-2,4-decadienal, ( Z)-8-tetradecenal, trans-4,5-epoxy-( E)-2-decenal, ( Z)-4-decenal, and octanal with the highest flavor dilution factors among 25 odor-active volatiles in the peel oil of healthy oranges. Taste-guided fractionation and identification of the HLBOJ secondary metabolites followed by sensory validation revealed that flavanoids such as hesperidin may modulate the flavor to evoke the unacceptable harsh/metallic taste impression. Quantitation of the bitter components showed good correlation between the limonoid and flavanoid concentrations with the off-flavor and quality of the oranges obtained throughout the season.

Jasminum flexile flower absolute from the south of India and the corresponding vacuum headspace (VHS) sample of the absolute were analyzed using GC and GC-MS. Three other commercially available Indian jasmine absolutes from the species: J. sambac, J. officinale subsp. grandiflorum, and J. auriculatum and the respective VHS samples were used for comparison purposes. One hundred and twenty-one compounds were characterized in J. flexile flower absolute, with methyl linolate, benzyl salicylate, benzyl benzoate, (2E,6E)-farnesol, and benzyl acetate as the main constituents. A detailed olfactory evaluation was also performed.

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Two Chinese black cardamom oils ( Amomum tsao-ko) were analyzed using GC and GC/MS and compared to 2 Indian cardamom oils from the species Amomum subulatum and Elettaria cardamomum, respectively. The main constituents of A. tsao-ko oils were eucalyptol, geranial, geraniol, trans-2,3,3A,7A-tetrahydro-1 H-indene-4-carbaldehyde, (2 E)-decenal, neral, and 4-indanecarbaldehyde. Special attention was given to the 1 H-indene-carbaldehyes, which are frequently wrongly assigned in previous literature. A detailed odor evaluation of the oils was also carried out. In addition, composition variations of 28 main constituents of 8 E. cardamomum oils were investigated, taking various factors like origin, production methods, plant material, and drying stage into consideration.

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