Análise da composição química e de resíduo de glifosato em amostras de grãos de café Conilon

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Data
2021-03-05
Autores
Peixoto, Priscilla Moreira Curtis
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Universidade Federal do Espírito Santo
Resumo
The risk of food contamination by pesticides has generated much concern to the public. Glyphosate-based herbicides are first in the pesticide marketing ranking in Brazil and is the most widely used form of weed control in coffee plantations. The objective of this work was to analyze volatile and nonvolatile compounds and the presence of glyphosate residue in Conilon coffee bean samples. The experiment was carried out in two coffee plantations conilon, one located in the district of Estrela do Norte, municipality of CasteloES, where the herbicide glyphosate was applied, and the other located in Lagoa Seca, rural area of the municipality of Alegre-ES, where the herbicide was not applied. The split plot scheme, 2 x 4, was used in IHD, with three replications. The plot factor corresponded to the two types of coffee samples used, being grains with and without defects. The subplot factor corresponded to the four periods in which the grains were harvested after glyphosate application in a single dose in the experimental field, and the harvest was performed at 15, 30, 45 and 60 days after herbicide application. In the experimental field that did not receive glyphosate application, samples were collected for descriptive analysis of the data, where Dic was also used, with three replications and the analysis of coffee beans with and without defects. For the analysis of volatile compounds, the hsSPME (Solide Phase Micro Extration) extraction technique and gas chromatography analysis coupled to mass spectrometry (GC-MS) were performed and for the analysis of nonvolatile compounds the high-efficiency liquid chromatography technique with ultraviolet-visible detector (HPLC-UV) was used. For the determination of glyphosate, the ELISA (Enzyme-linked immunosorbent assay) method was applied in raw coffee beans. Thirty-three volatile compounds were identified in the coffee samples of the experimental field that received glyphosate application, being the main ones of the pyrazoan classes (42.42%) and furans (15.15%), confirming the abundance of these classes in Conilon coffee. There was no trend between the values of the peak areas of the compounds of a given class depending on the type of sample (with and without defects). While in the samples of the crop that did not receive herbicide application, 22 volatiles were identified, most of them pyrazins (45.45%) and furans (18.18%) also. In grains harvested in a crop that received glyphosate application, three bioactive compounds (chlorogenic acid, caffeine and trigotein) were analyzed and for all variables significant interactions (5% probability) between the factors were observed. In grains from free crop of herbicide application, slightly higher chlorogenic acid concentrations were observed in undefective coffee samples, unlike this, higher concentrations of caffeine and trinelin were observed in defective coffee samples. The presence of glyphosate was verified in the coffees, however, it was not possible to quantify this residue, because all samples, including those collected in the greatest interval between harvest and herbicide application, exceeded the detectable and acceptable limit by buyer countries. In addition to these coffees not suitable for export, the concern with food security increases and thus, the importance of this study is evident.
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Coffea canephora , glifosato , cromatografia gasosa , cromatografia líquida de alta eficiência , ELISA
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