Coffee Taste

The overall aroma of roasted coffee powder is one of the most important factors determining its quality. The type of packaging as well as the storage conditions may, however, cause significant changes in the aroma of the ground roasted coffee and even the formation of off-flavours was observed. Up to now there is only limited knowledge concerning the aroma degradation at molecular level, particularly regarding the degree of degradation of important odorants as well as the amount of oxygen already absorbed by the coffee during the manufacturing process. Adsorption and diffusion of odorants as well as penetration of oxygen and water into the packaging are crucial factors influenced by the packaging material that may affect the overall aroma. There is an increasing interest of the industry to replace three-layer aluminium film laminates by aluminium metallized film combinations, which however show lower barrier features. Therefore, oxygen and moisture scavengers should be additionally applied.The aim of the project is to study the quantitative changes in the potent odour-active compounds of roasted coffee powder, also in dependence on the presence of different concentrations of oxygen and water vapour, and to clarify the degree of chemical degradation in comparison to physical losses by diffusion and adsorption in dependence of the packaging material. Furthermore, cheaper packaging material consisting of thinner layers with integrated oxygen and moisture absorbers should be developed. Consequently, not only the passive barrier function of the packaging materials should be supported, but also the oxygen and water vapour concentrations already present in the roasted coffee and in the headspace can be absorbed as well. At the same time, the influence of the scavengers on the aroma stability will be determined. By means of this knowledge the packaging industry will be able to produce new innovative and active packaging materials with less material and to judge the stabilizing quality of packaging material.