Functional properties of coffee and coffee by-products

Coffee, one of the most popular beverages, is consumed by millions of people every day. Traditionally, coffee beneficial effects have been attributed solely to its most intriguing and investigated ingredient, caffeine, but it is now known that other compounds also contribute to the valuable properties of this beverage. The role of coffee brew consumption in preventing some severe and prevalent diseases justifies its classification as a functional beverage. These properties are determined directly by the composition of the green beans and the changes that occur during roasting. On the other hand, by-products of coffee fruit and bean processing can also be considered as potential functional ingredients for the food industry. The coffee husks, peel and pulp, which comprises nearly 45% of the cherry, are one of the main by-products of coffee agro-industry and might be a valuable material for several purposes, including extraction of caffeine and polyphenols. Other by-products of coffee processing have been less studied, such as the mucilage and the parchment; however, they might have a high potential as a source of important ingredients as well. Furthermore, the use of the roasted coffee silverskin as a dietary fiber rich ingredient and for its antioxidative properties has also been evaluated. Finally, spent beans have been studied mainly for their antioxidative properties. The aim of this paper is to compile recent information on the functional properties of coffee, coffee beans and by-products in terms of the associated potential health benefits. The data in this review have been organized in sections according to the coffee product or by-product.