Análise comparativa entre lixiviacao de potássio, condutividade elétrica, teor de ácido clorogenico e métodos de quantificacao da atividade da polifenol oxidase em extratos semipurificados de amostras de café de diferentes padroes de qualidade
This work was carried with the objective of conducting a comparative analysis of potassium lixivation, electric conductivity, chlorogenic acid, as well as of the quantification methods of polyphenol oxidase activity in coffee samples purified extracts from several different regions of Minas Gerais State. After they were classified by specialized panelists, the samples were taken to the laboratory where they were kept at 5°C until the analyses were performed. Based on the results the conclusions are as follows: both potassium lixiviation and electric conductivity values increased when the beverage coffee quality decreased. The chlorogenic acid level did not change according to the beverage quality. The polyphenol oxidase activity showed an overlap among the strictly soft, soft, and hard coffee, as well as between the "riado", and the hard coffee. The polyphenol oxidase activity range variation measured by both spectrofometric and oximeter methods for the six coffee classes showed an overlap among the ranges which were based on the classification made by the panelists. The potassium lixiviation, the electric conditivity, and the polyphenol oxidase activity are fitted in order to separate coffee samples considered as the best quality beverage (strictly soft, soft, and just soft) from those considered as poor quality beverage (hard and riado), and from the rio, which was the last one in the rank. These parameters were not found to be appropriate to separate those different beverage coffee classes.
| Main Authors: | , , , , , |
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| Format: | biblioteca |
| Published: |
2003
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| Subjects: | COFFEA ARABICA, FRUTO, MUESTREO, ACIDO CLOROGENICO, CATECOL OXIDASA, CONDUCTIVIDAD ELECTRICA, PROPIEDADES FISICOQUIMICAS, BRASIL, |
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