Stability of phenolic antioxidants in coffee leaf beverage during pasteurization

Coffee leaf beverage is prepared from pasteurized Robusta coffee leaves. This work aimed to study the stability of phenolic antioxidants in coffee leaf beverages during pasteurization. Robusta coffee leaves were dried using the smoking method. They contained 6.82 g gallic acid equivalents (GAE)/100 g of total phenolic compounds and 71.15% antioxidant activity. Dried coffee leaves were brewed and pasteurized under different conditions: two different temperatures (70°C and 90°C), two duration of times (15 mins and 30 mins) and two different pH conditions (adjusted and non-adjusted). The total phenolic content and antioxidant activity of pasteurized beverages ranged between 0.48-0.61 g GAE/L and 14.72-18.58%, respectively. Caffeoylquinic acids were stable during pasteurization at 90°C for 30 mins without pH adjustment. Our results indicate that pasteurized coffee leaf beverages may be a potent source of phenolic antioxidants.