Stability of the color of roasted coffees stored in different packaging

Abstract

The aim of this study was to evaluate the color behavior (L* and Ag) and the stability of melanoidin molecules in roasted coffees with different roasting levels, types of packaging and storage conditions. Two roasting intensities were performed (medium roast and dark roast), following the SCA protocol for specialty coffees. The samples were stored in two types of packaging (permeable packaging and hermetic packaging with valve) and evaluated in eight storage times (1, 24, 48, 72, 240, 480, 1080 and 1440 hours) after roasting. The packaging interfered in the preservation of both the color of the roasted coffee and the melanoidin content over time. The permeable packaging allowed greater color loss, a difference also noted when evaluating the L*. For medium roast coffees stored in hermetic packaging, the maximum storage time should be up to 200 hours, while for dark roast beans when stored in hermetic packaging, the storage time was up to 480 hours. Greater stability of melanoidins was observed for coffees stored in hermetic packaging, with averages of 0.37 g.100 mL-1, while for coffees stored in permeable packaging the average was 0.34 g.100 mL-1, probably due to the oxidation of melanoidin molecules that reacted with oxygen and relative humidity of the ambient air. It is concluded that hermetic packaging presented a greater capacity for preserving the initial characteristics over the storage time, while permeable packaging allowed the loss of color of the roasted beans due to storage and possible modifications of the melanoidin molecules.