Recovery of Phenolic Antioxidants and Functional Compounds from Coffee Industry By-Products

Abstract

The recovery process of the phenolic compounds from the coffee industry by-products and their antioxidant activity were investigated in this work. The coffee by-products (coffee pulp, husk, silver skin, and spent coffee) were obtained from coffee processing industry. The phenolic conserves were extracted using solvent mixture of isoproponal and water. The yield of the conserve was highest in case of silver skin (25%) followed by spent waste (19%) and cherry husk (17%) when pretreated with viscozyme. The conserve enclosed chlorogenic acid as major component when analyzed with high-performance liquid chromatography. The bioactive conserves prepared from coffee by-products possessed 65%–70% antioxidant activity. Apart from these, the coffee by-products encompassed total dietary fiber of 40%–80%. Whereas the soluble and insoluble fiber proportion of the coffee by-product ranged between 16–35% and 18–64%, respectively. The antioxidant activity of coffee by-product fiber ranged from 1.5 to 2.0 mmol trolox/100 g and is analogous to that of widespread fruits and fresh vegetables. The hydration properties such as water holding capacity of each by-product was strictly related to the amount of insoluble fiber and to the granulometry. This is the first report on the isolation of bioactive and functional compounds from coffee by-products and can be a source of new value-added products such as phenolic antioxidant adjunct for food processing.