PENENTUAN FENOLIK, VITAMIN C DAN AKTIVITAS ANTIOKSIDAN TANAMAN SELADA (Lactuca sativa L.) YANG DIRAWAT DENGAN EKSTRAK TANAMAN TERFERMENTASI

Abstract

Lettuce (Lactuca sativa L) can serve as a source of vitamins, minerals and natural antioxidants. The cultivation system organically and conventionally can influence the nutrients and antioxidant contents. In this study, the total phenolic, flavonoid, vitamin C content, antioxidant activity and flavonoid composition of lettuce extract were carried out. Fresh weight and percentage of damaged leaves of lettuce were determine too as physical analysis. Two different treatment (FPE and control) were used for organic lettuce. The results showed that the fresh weight of plants were not significantly different. Organic lettuce with FPE treatment (5,10%) had lower (P0,05) percentage of leaves damaged than control treatment (18,23%). Compared to conventional lettuce, organic lettuce with FPE (9,873 GAE mg/g) and control (9,000 GAE mg/g) treatment had a significantly (P0,05) higher content of phenolic. Organic lettuce with FPE treatment showed higher flavonoid (10,681 QE mg/g) and vitamin C (0,460 AAE mg/g) content. For antioxidant activities, organic lettuce with FPE treatment gave the best FRAP (0,234 mmol Fe2+/g), FTC (55,05%), DPPH (482,33 g/mL) and NO radical scavenging (4,619 mg/mL) values. Determination of flavonoid composition showed that lettuce extracts didn’t contain standards of flavonoid compound (quercetin, catechin, naringin, and rutin). Lettuce extracts could be contained other flavonoid compounds. From this study, it can be concluded that the percentage of phenolic and vitamin C might be contributed to the antioxidant activity and the amount of total phenolic and vitamin C content which might be influenced by the cultivation system.