Effect of microwave and oven roasting methods on total phenol, antioxidant activity, phenolic compounds, and fatty acid compositions of coffee beans

Roasting is an important step of coffee processing which affects its quality characteristics. We investigated the effect of microwave and oven roasting on its physicochemical and antioxidant properties, and the fatty acids content. The oil contents of green and roasted coffee beans were determined as 5.75% (green), 9.65% (oven), and 2.70% (microwave). The total phenol content of green coffee beans was decreased by 13.59% and 16.66% on microwave and oven roasting, respectively. Microwave and oven roasting caused a decrease of 34.76% and 37.63%, respectively, in the antioxidant potential of green coffee beans. With few exceptions, the contents of most of the phenolic compounds were increased during roasting of coffee beans. The palmitic acid content decreased, while the oleic, linoleic, linolenic, and arachidonic acid contents of roasted coffee bean oils were increased during roasting. This information could be helpful for securing the maximal health benefits of coffee. Practical applications: Coffea arabica is one of the species of coffee which is highly consumed comparing with other species. The antioxidant compounds such as caffeine and chlorogenic acid in coffee beverage play an important role in reducing the prevalence of chronic diseases. Roasting is a vital step for the processing of coffee beans to be used as a beverage. It affects the main constituents of the coffee beans. This study provides the useful information of roasting process on antioxidant activity, phenolic compounds, and fatty acids of coffee beans which can be helpful for reaping the maximum health benefits of coffee.