Effect of the different infrared levels on some properties of sage leaves

This study aims to investigate the effect of different infrared powers (IP) (38, 50, 62, 74, and 88 W) on drying kinetics, total phenolic content (TPC) and individual phenolics, antioxidant activity (AA) and antibacterial activity, and color quality of sage leaves. IP level significantly affected (p<0.05) drying kinetics and bioactive contents and color quality of sage leaves. Higher TPC and AA were obtained from the sample dried at 88 W. Rosmarinic acid, caffeic acid, gallic acid, and luteolin were found as major phenolic compounds and their higher levels were obtained from the samples dried at IP level of 88 W. All samples showed antibacterial activity on test pathogens. A higher correlation was observed between TPC, rosmarinic acid level, and antibacterial activity (P>0.80). This study suggested that sage leaves should be dried at 88 W regarding lower drying times and color changes, lower phenolic degradation, and higher antibacterial activity.