The effect of sonication times on bioactive compounds, antioxidant activity and phenolic constituents of sumac (Rhus coriaria L.) fruits extracted by ultrasound extraction system

In current investigation, the bioactive compounds, antioxidant capacities (DPPH and FRAP) and phenolic constituents of sumac fruits sonicated at different times (5,15, 30 and 45 min.) were determined. Total phenolic and flavonoid contents of sumac fruits sonicated at different times changed between 1275.24 (45 min) and 1481.59 mg GAE/100 g (15 min) to 1295.71 (5 min) and 1427.14 mg/100 g (15 min), respectively. While the total phenol content of sumac fruits increased until the 15th minute of sonication, it decreased in the following periods. However, it was observed that the total flavonoid contents of sumacs increased with the increase of sonication time (except 5 min.). The highest total phenol and flavonoid contents were assigned at the 15th minute of sonication. Antioxidant activities (DPPH and FRAP) of sumac fruits sonicated at different times changed between 16.37 (5 min) and 16.49 mmol/kg (45 min.) to 120.77 (5 min.) and 124.35 mg/g (15 min.), respectively. Results on phenolic compounds exhibited some differences depending on different sonication times. Except for cinnamic acid and kaempferol, the phenolic component amounts of the control and sumacs sonicated at different times were quite high. The phenolic components of sumac fruit increased with the sonication time. Gallic acid and catechin amounts of sumach fruits sonicated at different sonication times were detected to be between 1258.82 (45 min.) and 2012.80 mg/100 g (15 min.) to 238.76 (30 min.) and 629.80 mg/100 g (45 min.), respectively. In general, the highest quantities of phenolic compounds were observed at the 15th and 30th minutes of sonication.