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URI permanente desta comunidadehttps://thoth.dti.ufv.br/handle/123456789/3352
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Item Teores de trigonelina, ácido 5-cafeoilquínico, cafeína e melanoidinas em cafés solúveis comerciais brasileiros(Sociedade Brasileira de Química, 2013) Marcucci, Carolina Tolentino; Benassi, Marta de Toledo; Almeida, Mariana Bortholazzi; Nixdorf, Suzana LucyCommercial Brazilian regular and decaffeinated instant coffees (33 brands) were studied. The levels ranged from 0.47 to 2.15 g 100 g-1 for trigonelline, 0.38 to 2.66 g 100 g-1 for 5-caffeoylquinic acid (5-CQA), 0.24 to 4.08 g 100 g-1 for caffeine, and 0.253 to 0.476 (420 nm) for melanoidins. Variations in bioactive compound levels among batches were observed. There was no relationship between the drying process and the composition of the products. In general, Gourmet and decaffeinated coffees had higher trigonelline and 5-CQA but lower caffeine and melanoidin content than regular products.Item A comparison between enzyme immunoassay and HPLC for ochratoxin A detection in green, roasted and instant coffee(Instituto de Tecnologia do Paraná - Tecpar, 2007-03) Fujii, Simone; Ono, Elisabete Yurie Sataque; Ribeiro, Ricardo Marcelo Reche; Assunção, Fernanda Garcia Algarte; Takabayashi, Cássia Reika; Oliveira, Tereza Cristina Rocha Moreira de; Itano, Eiko Nakagawa; Ueno, Yoshio; Kawamura, Osamu; Hirooka, Elisa YokoAn indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) for ochratoxin A (OTA) detection in green, roasted and instant coffees was developed using anti-OTA monoclonal antibody. Immunological reagents prepared were OTA-BSA (4.76 μ g/mL), anti-OTA.7 MAb (2x10 3 -fold dilution) and HRP-anti IgG (10 3 -fold dilution). The detection limit was 3.73 ng OTA/g and correlation coefficients (r) between this immunoassay and high performance liquid chromatography were 0.98 for green coffee, 0.98 for roasted and 0.86 for instant. OTA levels detected by ic- ELISA were higher than by HPLC, with ELISA/HPLC ratio of 0.66 - 1.46 (green coffee), 0.96 - 1.11 (roasted) and 0.93 - 1.82 (instant). ELISA recoveries for OTA added to coffee (5 - 70 ng/g) were 81.53 % for green coffee, 46.73 % for roasted and 64.35 % for instant, while recoveries by HPLC were 80.54 %, 45.91 % and 55.15 %, respectively. Matrices interferences were minimized by samples dilution before carrying out the ELISA assay. The results indicate that MAb-based ic-ELISA could be a simple, sensitive and specific screening tool for OTA detection, contributing to quality and safety of coffee products.Item Comparison of capillary electrophoresis and high performance liquid chromatography methods for caffeine determination in decaffeinated coffee(Sociedade Brasileira de Ciência e Tecnologia de Alimentos, 2013-01) Bizzotto, Carolina Schaper; Meinhart, Adriana Dillenburg; Ballus, Cristiano Augusto; Ghiselli, Gislaine; Godoy, Helena TeixeiraDecaffeinated coffee accounts for 10 percent of coffee sales in the world; it is preferred by consumers that do not wish or are sensitive to caffeine effects. This article presents an analytical comparison of capillary electrophoresis (CE) and high performance liquid chromatography (HPLC) methods for residual caffeine quantification in decaffeinated coffee in terms of validation parameters, costs, analysis time, composition and treatment of the residues generated, and caffeine quantification in 20 commercial samples. Both methods showed suitable validation parameters. Caffeine content did not differ statistically in the two different methods of analysis. The main advantage of the high performance liquid chromatography (HPLC) method was the 42-fold lower detection limit. Nevertheless, the capillary electrophoresis (CE) detection limit was 115-fold lower than the allowable limit by the Brazilian law. The capillary electrophoresis (CE) analyses were 30% faster, the reagent costs were 76.5-fold, and the volume of the residues generated was 33-fold lower. Therefore, the capillary electrophoresis (CE) method proved to be a valuable analytical tool for this type of analysis.