Coffee Silverskin as a Potential Bio-Based Antioxidant for Polymer Materials: Brief Review

Coffee silverskin is one of the byproducts generated by the coffee industry. Although it is not the most burdensome one, because it stands only for ~4.2 wt % of coffee, it seems like an auspicious raw material for industrial processes. Coffee silverskin is characterized by a relatively low moisture content of ~5–7%, so it often does not require quite energy-consuming drying processes. The chemical composition of coffee silverskin, as well as other renewable materials, may be significantly affected by its type and origin, in this case, plant Coffea. Nevertheless, due to high fiber content, it could be considered as exciting material for the manufacturing of wood polymer composites. At the same time, it contains noticeable amounts of proteins, which may provide additional features to polymer composites. However, what is most important is the high content of antioxidants, which could noticeably enhance their lifetime by inhibition of the oxidation reactions. In the presented paper, attempts of coffee silverskin incorporation into different polymer matrices were summarized and discussed. Moreover, potential future trends in this area of research were proposed.