The Effect of Different Drying Techniques on the Antioxidant Activity and Some Physicochemical Properties of Smilax excelsa Young Shoots

Smilax genus, which grows in tropical and temperate regions in the world, is a perennial plant with climbing branches and spiny stems from the smilacaceae family. smilax excelsa l. is widely used in the black sea region of turkey for diet and folk medicine due to its medicinal properties. in this study, green and reddish young shoots of s. excelsa l. were used. these two groups were dried by four different drying methods including lyophilization (5 mm-hg, -50°c, 20 h), microwave drying (500 w, 5 min), shade drying (25±2°c, 7 d), and drying in a drying oven (50°c, 4 h). total phenolic contents, total monomeric anthocyanin contents, antioxidant activities, moisture contents, and color values of fresh and dried green and reddish shoots were determined. antioxidant activity was determined by dpph free radical scavenging activity and fe^3+ reducing capacity (frap) methods. the moisture content of the dried shoots varied between 10.11% and 19.09%. all applied drying methods increased l* values of the shoots significantly (p<0.05). a* values of the dried plants varied between -3.24 and -7.75 in the green group and between 7.17 and 11.65 in the reddish group. b* values were higher in all groups than fresh samples (p<0.05). while the lowest δe values were determined in lyophilized dried groups, the highest values were in oven-dried groups. among the dried samples, the highest amounts of total phenolic substance and total monomeric anthocyanin were determined in the lyophilized dried red group as 33.58 mg gallic acid equivalent/ g dry weight and 0.46 mg cyanidin-3-glucoside/ g dry weight, respectively. the dpph radical scavenging activity (as ic_50) and fe^3+ reduction capacity values of the dried samples were determined in the range of 1.88-3.65 mg/ g dry weight and 2.51-5.76 gallic acid equivalent/ g dry weight, respectively. in general, all drying methods were found to decrease antioxidant activity significantly (p<0.05). among the applied drying methods, lyophilized drying was determined as the best antioxidant activity protective method.