Chemical Fractionation of Manganese in Commercial Coffee Samples Originating from Conventional and Organic Growing Systems

Coffee can be considered an important source of mineral nutrients. Since coffee is normally consumed through infusion, the availability of nutrients is related to the solubility, that is strongly influenced by the cultivation system applied to its production, which can influence the form of minerals are storage in the coffee bean. Coffee development is influenced by nutrient absorption, metabolism and storage. This study investigated the influence of cultivation on these characteristics of conventional and organic commercial coffee. The average concentration for conventional and organic cultivation determined in this study was 45.5 ± 11.2 and 64.7 ± 9.2 mg kg − 1 respectively. This result may be related to soil characteristics, such as acidic pH and reducing environment, favored by organic cultivation and favoring Mn solubilization in the soil solution, leading to greater Mn uptake. Principal component analysis shows differences between organic and conventional samples in the fractionation study. The characterizing fraction of the organic samples was the lipid and all other fractions characterized the conventional samples. This behavior suggests an influence of cultivation on Mn metabolism and storage by coffee. However, despite these observed differences, the average levels of Mn extracted from coffee infusions did not differ significantly between cultivation.