RESUMO
The present work aims to evaluate the roles of methyl jasmonate (MeJA) in the formation of volatile organic compounds (VOC) from grape tomatoes during ripening. Fruits were treated with MeJA, ethylene, 1-MCP (1-methylcyclopropene), and MeJA+1-MCP, with analyses of the VOC and levels of the gene transcripts for the enzymes lipoxygenase (LOX), alcohol dehydrogenase (ADH), and hydroperoxide lyase (HPL). An intimate relationship between MeJA and ethylene in aroma formation was detected, mainly among the VOC from the carotenoid pathway. Expression of the fatty acid transcripts, LOXC, ADH, and HPL pathway genes, was reduced by 1-MCP, even when associated with MeJA. In ripe tomato, MeJA increased most of the volatile C6 compounds, except 1-hexanol. The MeJA+1-MCP treatment followed most of the increases in volatile C6 compounds that were increased by MeJA alone, which evidenced some ethylene-independent mechanism in the production of the volatile C6 compounds. In ripe tomato, MeJA and MeJA+1-MCP increased the levels of 6-methyl-5-hepten-2-one, which is derived from lycopene, evidencing an ethylene-independent biosynthetic process.
Assuntos
Solanum lycopersicum , Vitis , Compostos Orgânicos Voláteis , Frutas/metabolismo , Solanum lycopersicum/genética , Vitis/metabolismo , Compostos Orgânicos Voláteis/metabolismo , Etilenos/metabolismo , Oxilipinas/farmacologia , Oxilipinas/metabolismo , Ciclopentanos/farmacologia , Ciclopentanos/metabolismo , Acetatos/farmacologia , Acetatos/metabolismo , Regulação da Expressão Gênica de PlantasRESUMO
BACKGROUND: The quality and power of each odorous volatile present in the headspace of unifloral honey velame branco (Croton heliotropiifolius Kunth) prepared by stingless uruçu (Melipona scutellaris Latrelle) were evaluated using the gas chromatography-olfactometry Osme technique. Five trained panellists evaluated the sensory chromatographic effluent in three replications, and the results were integrated by SCDTI software. RESULTS: Of the 42 compounds identified in the chromatogram, 17 odorous stimuli were detected by the sensory panel. Among these compounds, the most odoriferous impacts were pentanoate acetate 'ripe fruit', safranal green, medicinal plant and methyl eugenol 'clove, tea'. The furaneol compounds, hotrienol and benzaldehyde showed aroma notes associated with honey. CONCLUSION: These results are important since, in addition to revealing the presence of compounds that are not identified by other analytical methods, they can also assist in the verification of monofloral honeys compliance. © 2019 Society of Chemical Industry.
Assuntos
Aromatizantes/química , Mel/análise , Odorantes/análise , Compostos Orgânicos Voláteis/química , Cromatografia Gasosa , Humanos , Olfatometria , PaladarRESUMO
BACKGROUND: There is a considerable loss of volatile compounds during the thermal concentration of cashew apple juice, damaging product quality, and as yet there is little research on the subject. Thus the purpose of this research was to identify the aroma volatiles evaporated off from cashew apple juice and recovered in the water phase during concentration of this beverage in an industrial plant. Water phase volatiles were extracted using dichloromethane, concentrated under a nitrogen flow, separated by gas chromatography (GC) and identified by GC-mass spectrometry. In order to determine the contribution of each volatile to the cashew aroma, five trained judges evaluated the GC effluents using the Osme GC-olfactometry technique. RESULTS: 71 volatiles were identified; of these, 47 were odour active. Alcohols were preferentially recovered in the cashew water phase, notably heptanol, trans-3-hexen-1-ol and 3-methyl-1-butanol, representing 42% of the total chromatogram area and imparting green grass and fruity aroma notes to the water phase. Esters represented 21% of the total chromatogram area, especially ethyl 2-hydroxyhexanoate, ethyl trans-2-butenoate and ethyl 2-methylbutanoate, and were responsible for the fruity/cashew-like aroma of the water phase. On the other hand, 3-methylbutanoic and 2-methylbutanoic acids were the volatiles that presented the greatest odour impact in the GC effluents of the water phase. CONCLUSION: Overall, the results of the present study strongly indicated that further concentration of the esters recovered in the water phase, either by partial distillation or by alternative technologies such as pervaporation, could generate a higher-quality natural cashew apple essence.