ABSTRACT

This research aimed to study the simple, objective and measurable methods for evaluating the coffee quality. Evaluation was performed for the effects of storage time on quality of the natural, pulped and green coffee as well as the activity of the polyphenoloxydase enzyme (PPO) measured in spectrophotometer as an objective method for determining coffee quality. This method was compared with the classic sensorial method. The sensorial evaluation was performed at the Cooperativa dos Produtores de Café de Guaxupé - MG, where the classifying tests were conducted for type and color. For objective evaluation, the chemical tests were performed to determine the activity of the polyphenoloxydase enzyme using the methodology developed by Fujita et al. (1995). Based on the obtained results it was concluded that the drink quality evaluated by "cupping" maintained constant during the storage time except for pulped coffee, which presented quality decline from six month. There is a positive correlation between color (PPO) and drink quality. During the storage time all coffee types presented color variation tending to whitening. This tendency was more evident in the green coffee.

Key words:
coffee; drink; enzyme; spectrophotometer