Coffee brew sweetened with stevia leaves: physicochemical and functional characterization

This study aimed to developed a coffee brew sweetened with UEM 13 variety stevia leaves. The stevia leaves were submitted to an ethanolic elution pretreatment and compared to untreated sample. The coffee brew sweetened with pretreated and untreated stevia were produced and compared to a coffee without stevia, and with a stevia tea produces with pretreated and untreated leaves. The beverages were characterized by physico-chemical and instrumental parameters, bioactive compounds, and antioxidant activity. The pretreatment was successfully performed in stevia leaves, without significant loss of steviol glycosides and minimal changes to color parameters. The coffee brew with stevia pretreated leaves kept the same steviol glycosides content than coffee with untreated ones. The stevia addition to coffees presented influence on solids due carbohydrate and reducing sugar increase, improving the coffee brew viscosity. Regarding bioactive compounds and antioxidant activity, some influence of percolation saturation process may be observed for coffee in comparison with control coffee brew and stevia tea. Although pretreated and untreated leaves did not differ for steviol glycosides content, physico-chemical influences of them were observed in coffee brew in a most pronounced way. The stevia leaves may be used as coffee sweetener replacing sucrose added in 28.98% to 38.58%.