Recebido em 23/1/08; aceito em 29/9/08; publicado na web em 5/2/09 VOLATILE cOmpOsITION OF INTRINsIc DEFEcTIVE cOFFEE BEANs By Gc/ms-hEADspAcE. About 20% of Brazilian raw coffee production is considered inappropriate for exportation. consequently, these beans are incorporated to good quality beans in the Brazilian market. This by-product of coffee industry is called pVA due to the presence of black (p), green (V) and sour (A) defective beans which are known to contribute considerably for cup quality decrease. Data on the volatile composition of Brazilian defective coffee beans are scarce. In this study, we evaluated the volatile composition of immature, black-immature, black defective beans and pVA compared to good quality beans. potential defective beans markers were identified.Keywords: defective coffee beans; coffee flavor; volatile compounds. introdUçãoO café é o segundo produto mais comercializado do mundo, depois do petróleo. 1 As duas espécies de café economicamente mais importantes são Coffea arabica e Coffea canephora. Estas possuem características físico-químicas bem diferenciadas, que acabam por produzir bebidas com características sensoriais distintas. A espécie Coffea arabica é de grande significado econômico para as Américas e demais regiões que a cultivam. seu produto é de qualidade superior e de maior aceitação em todos os mercados. Atualmente, esta espécie é responsável por cerca de 64% da produção mundial de café.O Brasil é o maior produtor e exportador mundial de grãos de café, sendo também atualmente o segundo maior consumidor. 2 Devido ao grande volume de produção, o Brasil adota preferencialmente técnicas de colheita como a derriça e a colheita mecânica, nas quais todos os frutos são colhidos de uma só vez no pano ou no chão. O cafeeiro possui várias floradas e por isso encontramos, em um mesmo período, frutos com diferentes graus de maturação. conseqüentemente, frutos verdes, maduros e passados são colhidos. por estas razões, cerca de 20% da produção brasileira (mais de 8 milhões de sacas) correspondem a grãos defeituosos que, por serem considerados impróprios para exportação, são incorporados no mercado interno. 3 O café é oficialmente qualificado pela ABIc (Associação Brasileira das Indústrias de café) por critérios como tipo de colheita, tipo de beneficiamento, tamanho e cor dos grãos, safra, presença de defeitos, entre outras. Os defeitos, por sua vez, são classificados como extrínse-cos e intrínsecos. 4 Defeitos extrínsecos são decorrentes de impurezas incorporadas ao café durante a colheita, como pedras, gravetos, cascas, cocos, entre outros. Defeitos intrínsecos são decorrentes de grãos alterados devido à imperfeição de processos agrícolas, modificações fisiológicas ou genéticas do fruto, ou por práticas de beneficiamento inadequadas. Exemplos de defeitos intrínsecos são: verde, ardido, preto, preto-verde, stinker, brocado, mal-granado, concha, quebrado, entre outros. Grãos verdes são originados pela colheita de grãos ainda não amadurecidos e causam o aumento da adstringência da b...

Recebido em 19/1/11; aceito em 21/5/11; publicado na web em 22/7/11 A method using LC/ESI-MS/MS for the quantitative analysis of Ochratoxin A in roasted coffee was described. Linearity was demonstrated (r = 0.9175). The limits of detection and quantification were 1.0 and 3.0 ng g -1 , respectively. Trueness, repeatability and intermediate precision values were 89.0-108.8%; 2.4-13.7%; 12.5-17.8%, respectively. To the best of our knowledge, this is the first report in which Ochratoxin A in roasted coffee is analysed by LC/ESI-MS/MS, contributing to the field of mycotoxin analysis, and it will be used for future production of Certified Reference Material.

The proficiency testing for determination of pesticides residues in mango pulp was the third work of the partnership established by INMETRO and INCQS/Fiocruz. Three mango pulp samples were sent to each participant laboratory, two being spiked with the pesticides and one exempt of pesticides. The added pesticides were: deltamethrin, ethion, fenitrothion, malathion, and permethrin. The evaluation of the results of the homogeneity and the stability tests, as well as the determination of the assigned value was made in agreement with ISO GUIDE 35 and ISO 13528, assuming the samples were considered homogeneous and stable for the studied period. The assigned values and the standard deviation for proficiency evaluation was calculated using the robust algorithm, according to ISO 13528, and the evaluation of the results was carried through in accordance with ABNT ISO/IEC Guide 43-1. The z-score graphs and confidence ellipse was also used in the evaluation of the results. In the evaluation carried through from the values of the z-scores, 71% of the reported results were considered satisfactory based on the results found for this index. The evaluation of the analytical viability for the determination of each pesticide and of the analytical capacity of the participant laboratories was carried through. A summarized view of the chromatographic techniques and of preparation of sample used by the participant laboratories was also carried through in this work.

Background: Coffee is an important agricultural commodity with technical barriers for exportation because of possible contamination with ochratoxin A (OTA), a mycotoxin nephrotoxic and carcinogenic. The maximum limit for OTA in roasted coffee is 5.0 μg/kg in the European Union and 10 μg/kg in Brazil, and the use of certified reference materials (CRM) is required for reliable measurements. Objective: This paper describes the development of a candidate CRM of OTA in roasted coffee following the requirements of ISO 17034 and ISO Guide 35. Methods: A primary method of isotope dilution MS was developed and validated using (13C20)-OTA as internal standard. The sample preparation was based on AOAC Official Methods of AnalysisSM using immunoaffinity column. Results: The linear working range is 2.0–15.0 μg/kg, with recoveries of 92.2–110.8% and relative SDs lower than 12.4%. The method was successfully applied to the feasibility study, which defined the procedure for preparation of a large batch around 5 μg/kg. It was produced by spiking blank roasted coffee with OTA standard, mixing and filling in amber flasks with 50 g of coffee, and storing at −80°C. The homogeneity study showed an acceptable degree of heterogeneity of 1.44%, and the short-term-stability study defined the conditions for transportation as maximum temperature of 50°C up to 28 days. Conclusions: These results show that certification is possible. Highlights: The long-term stability study at −20°C is in progress, and the characterization will be conduzed by a interlaboratory comparison. This material will be an important tool for QC in laboratories.

Background: Coffee is an important agricultural commodity with technical barriers for exportation because of possible contamination with ochratoxin A (OTA), a mycotoxin nephrotoxic and carcinogenic. The maximum limit for OTA in roasted coffee is 5.0 μg/kg in the European Union and 10 μg/kg in Brazil, and the use of certified reference materials (CRM) is required for reliable measurements. Objective: This paper describes the development of a candidate CRM of OTA in roasted coffee following the requirements of ISO 17034 and ISO Guide 35. Methods: A primary method of isotope dilution MS was developed and validated using (13C20)-OTA as internal standard. The sample preparation was based on AOAC Official Methods of AnalysisSM using immunoaffinity column. Results: The linear working range is 2.0–15.0 μg/kg, with recoveries of 92.2–110.8% and relative SDs lower than 12.4%. The method was successfully applied to the feasibility study, which defined the procedure for preparation of a large batch around 5 μg/kg. It was produced by spiking blank roasted coffee with OTA standard, mixing and filling in amber flasks with 50 g of coffee, and storing at −80°C. The homogeneity study showed an acceptable degree of heterogeneity of 1.44%, and the short-term-stability study defined the conditions for transportation as maximum temperature of 50°C up to 28 days. Conclusions: These results show that certification is possible. Highlights: The long-term stability study at −20°C is in progress, and the characterization will be conduzed by a interlaboratory comparison. This material will be an important tool for QC in laboratories.