Óleos essenciais cítricos brasileiros (mandarina, laranja, limão, bergamota e tangerina) foram analisados a fim de determinar resíduos de pesticidas organoclorados (aldrin, clordano, dieldrin e dicofol) e organofosforados (clorpirifós metílico, dimetoato, metidationa e paration metílico). Um estudo comparativo entre cromatografia gasosa acoplada a espectrometria de massas em modo de monitoramento seletivo de íons (CG-EM-MSI) e cromatografia gasosa com detector por captura de elétrons (CG-DCE) foi realizado usando extração em fase sólida (EFS) com fase Florisil® para pré-concentração dos pesticidas. A recuperação média dos pesticidas foi de 71 a 83% por CG-EM-MSI e de 99 a 104% por CG-DCE. O limite de quantificação foi de 0,93 a 3,93 mg L-1 por CG-EM-MSI e de 0,09 a 0,12 mg L-1 por CG-DCE. Quinze amostras comerciais de óleos essenciais cítricos brasileiros foram analisadas e seis amostras apresentaram contaminação com valores acima do limite máximo de resíduos (LMR) permitido pelo Codex Alimentarius.

Brazilian citrus essential oils (mandarin, orange, lemon, bergamot and tangerine) were analyzed for the determination of pesticides residues of organochlorine (aldrin, chlordane, dieldrin and dicofol) and organophosphorus (methyl chlorpyrifos, dimethoate, methidathion and methyl parathion) . A comparative study between gas chromatography-mass spectrometry in selective ion monitoring mode (GC-MS-SIM) and gas chromatography-electron capture detector (GC-ECD) was performed using solid phase extraction (SPE) with Florisil® cartridge for the pre-concentration of pesticides. The average recovery of pesticides was from 71 to 83% as determined by GC-MS-SIM analysis and 99 to 104% by GC-ECD. The limit of quantification was from 0.93 to 3.93 mg L-1 in GC-MS-SIM and 0.09 to 0.12 mg L-1 in GC-ECD. Fifteen samples of commercial Brazilian citrus essential oils were analyzed and six samples showed contamination with values above the maximum residue limit (MRL) allowed by the Codex Alimentarius.

The influence of pre-processing of arabica coffee beans on the composition of volatile precursors including sugars, chlorogenic acids, phenolics, proteins, aminoacids, trigonelline and fatty acids was assessed and correlated with volatiles formed during roasting. Reducing sugars and free aminoacids were highest for natural coffees whereas total sugars, chlorogenic acids and trigonelline were highest for washed coffees. The highest correlation was observed for total phenolics and volatile phenolics (R= 0.999). Experimental data were evaluated by Principal Components Analysis and results showed that washed coffees formed a distinct group in relation to semi-washed and natural coffees.

A fruit chemical composition reflects its maturation stage. For coffee, it is also the reflex of the post-harvesting processing type, dry, semi-wet and wet. The object of this work was to verify if headspace solid phase microextraction coupled to gas chromatography (HS-SPME-GC) could be used to discriminate between samples harvested in different maturation stages and treated by different processes. With application of principal component analysis to the area of 117 compounds extracted by SPME, using divinylbenzene/Carboxen/polydimethylsiloxane fiber, it was possible to discriminate, in the roasted and ground coffee, the maturity stage and processing type used .