INVESTIGATION OF MELATONIN CONTENT AND ANTIOXIDANT CAPACITY IN GRAPE BERRIES

Abstract

In this study, six berry fruits; goji berry/wolfberry (Lycium barbarum), black mulberry (Morus nigra), white mulberry (Morus alba), blackberry (Rubus fructicous L.), purple mulberry (Morus rubra) and Bursa Black mulberry (unknown) were analyzed by HPLC-FD to determine whether they present melatonin. The melatonin was detected different amounts in all samples. Besides, the total phenolic content and antioxidant capacity were studied in all fruit samples. DPPH and ABTS tests were applied to determine the antioxidant capacity. It was observed that the amount of melatonin in the fruit samples varied between 123.44 and 1600.48 ng/gFW. It was found that the concentration of melatonin in goji berry (BF1) was higher than other berry fruits. The highest total phenolic content and antioxidant capacity to were obtained from purple mulberry (BF6) as 276.83 mg GAE/100 gFW, 452.38 mg TE/100 gFW (DPPH) and 555.73 mg TE/100 gFW (ABTS), respectively. Results reveals a significant positive correlation between the total phenolic content with antioxidant capacity.