ABSTRACT This study aimed to characterize the volatile composition and sensory characteristics of virgin olive oils (VOOs) from eight olive cultivars grown in the southeast region of Brazil. The volatiles were extracted by Solid Phase Micro Extraction (SPME) and analyzed by Gas Chromatography coupled to MassSpectrometry (GC-MS). The dominant sensory attributes were determined by Temporal Dominance of Sensations (TDS). C5 and C6 alcohols and C6 aldehydes were the most abundant volatiles in the investigated VOOs. E-2-hexenal was among the majorityof volatiles in all investigated olive oils, mainly in VOOs fromcultivars Arbequina, Arbosana and Grappolo 541, in which it had the most of their chromatographic area (about 60-80%). VOOs from cultivars Maria da Fé, Mission, Arbosana and Arbequina were characterized by the dominance of pungency sensation, as well as Frantoio regarding to bitter. Grappolo yielded an olive oil withpredominance of bitter, and a blended VOO (Grappolo 541 and Arbequina) had predominance of green leaf. VOO from Ascolano cultivar had dominance of fruity and pungency. Overall, pungent was the main dominant sensation in most of the investigated VOOs, which can be related to C5 and C6 volatiles.

ABSTRACT Since volatiles do not leave residues in food and cause low toxicity to humans, they can act as a skeleton for new nematicidal molecules, once they have demonstrated activity against phytonematodes. The aim of this study was to evaluate the effect of volatile organic compounds (VOCs) released by wood-associated fungi on controling second-stage juveniles (J2) of Meloidogyne incognita. All 28 wood-associated fungi isolates produced VOCs which caused in excess of 76 % immobility in exposed J2 of M. incognita. The fungus isolate VOCs also caused significant mortality compared to control when J2 were exposed to them. After 6 h of exposure, the fungus species Epicoccum nigrum and Schizophyllum commune produced VOCs that immobilized exposed J2 compounds, in relation to the control. When J2 were inoculated into tomato under greenhouse conditions, the M. incognita infectivity and reproduction were reduced by exposure to the VOCs. Volatiles produced by most of the fungi isolates and analyzed by gas chromatograph coupled to a mass spectrometer (CG-MS), included alcohols, esters, terpenes, and ketones. Certain compounds appeared only in S. commune or in E. nigrum suggesting their involvement in the high level of damage caused to nematode reproduction on tomato. Volatiles emitted by wood fungi demonstrated another mode of action of these microorganisms in nature.

Além das brassicaceas associadas à solarização do solo, novos materiais vegetais como a mandioca e a mamona têm apresentado potencial no controle de fitopatógenos de solo. Assim, objetivou-se verificar os efeitos da incorporação e decomposição de parte aérea de brócolis, mamona e mandioca brava e mansa, associadas à solarização, em conjuntos de microcosmos, sob condições de ambiente controlado, na sobrevivência das estruturas de resistência de Fusarium oxysporum f. sp. lycopersici Raça 2, Macrophomina phaseolina, Rhizoctonia solani AG-4 HGI e Sclerotium rolfsii; e identificar e apontar o(s) volátil(eis) emanado(s) pela decomposição dos materiais, que poderia(m) estar correlacionado(s) com a inativação dos fitopatógenos. Quanto à sobrevivência dos patógenos, quatro ensaios idênticos foram instalados nos microcosmos, com quatro períodos de exposição independentes (7, 14, 21 e 28 dias). A identificação dos voláteis contou com ensaios realizados sob as mesmas condições da sobrevivência, mas em frascos âmbar e com cromatografia gasosa com detectores por espectrometria de massas (GC-MS) e por ionização em chama (GC-FID), utilizando a técnica de Microextração em Fase Sólida - SPME. Os tratamentos solo+materiais vegetais, ao longo dos períodos testados, reduziram a sobrevivência das estruturas de resistência de todos os fungos. No geral, destacaram-se o brócolis e a mandioca brava, além da mandioca mansa para S. rolfsii. Os voláteis identificados foram oriundos da decomposição de brócolis, mamona e mandioca mansa. Foram identificados 26, 37 e 29 compostos voláteis para brócolis, mamona e mandioca mansa, respectivamente. Correlações positivas e negativas foram observadas entre alguns voláteis e a média dos compostos com a sobrevivência das estruturas de resistência dos fitopatogênicos.

In addition to Brassicaceae species associated with soil solarization, new materials from plants such as cassava and castor bean have shown potential to control soil phytopathogens. Thus, the present study aimed to verify the effects of incorporation and decomposition of shoot of broccoli, castor bean, and bitter and sweet cassava, associated with solarization in microcosm sets under controlled environment conditions, on the survival of resistance structures from Fusarium oxysporum f. sp. lycopersici Race 2, Macrophomina phaseolina, Rhizoctonia solani AG-4 HGI and Sclerotium rolfsii; and to identify volatile compound(s) released by the decomposition of materials, which could be related to phytopathogen inactivation. As to pathogen survival, four identical assays were installed in the microcosms, with four independent exposure periods (7, 14, 21 and 28 days). To identify volatile compounds, assays were performed under the same survival conditions, but using amber glass bottles and gas chromatography with mass spectrometry (GC-MS) and flame ionization detectors (GC-FID), and adopting the Solid-Phase Microextraction Technique - SPME. The treatments soil+plant materials, over the tested periods, reduced the survival of resistance structures for all fungi. In general, expressive results were found for broccoli and bitter cassava, as well as sweet cassava against S. rolfsii. The identified volatile compounds were from broccoli, castor bean and sweet cassava decomposition. The number of volatile compounds identified for broccoli, castor bean and sweet cassava were 26, 37 and 29, respectively. Positive and negative correlations were detected among some volatile compounds and their mean values and the survival of resistance structures from phytopathogens.

This paper presents the fundamental principles, instrumentation and selected applications of comprehensive two-dimensional gas chromatography (GC × GC). In this technique, introduced in 1991, two capillary columns are coupled and proper modulating interfaces continuously collect the eluate from the first column, transferring it to the second column. The result is a geometric increment in the chromatographic resolution, ensuring separation of extremely complex mixtures in time periods shorter or comparable to those of analysis using conventional gas chromatography and with better detectabilities and sensitivities.