Rumeshani, K.L.G.Aruppala, A.L.Y.H.Abeyrathne, E.D.N.S.2019-07-092019-07-0920189789550481194http://erepo.lib.uwu.ac.lk/bitstream/handle/123456789/1424/98-2018-Antioxidant%20Activity%20of%20the%20Crude%20Extract%20of%20Ulva%20lactuca%20%28Sea%20Lettuce%29%20.pdf?sequence=1&isAllowed=yUlva lactuca is one of the famous edible seaweeds around the world. It is a rich source of many nutrients and bioactive compounds. Solvent extraction method is commonly used in extracting bioactive compounds in seaweeds which may be nonfood grade. The objective of this study was to develop a simple, food grade extraction method to extract bioactive compounds from Ulva lactuca and identify the antioxidant activity of the crude water soluble extract and compare with a commonly used solvent extraction method. Four types of seaweed treatments (05 g) namely Fresh, Air-dried (AD), Oven-dried (OD) and Freeze-dried (FD) were used for the water extraction using three different ratios as 1:10, 1:20 and 1:30 and Airdried sample using Methanol as the control. The crude extracts derived from different extraction methods were used for analyzing the antioxidant activity by Thiobarbituric Reactive Substance (TSARS) assay and 2,2-dipheny1-1- picrylhydrazyl (DPPH) free radical scavenging assay. All the trials were done in triplicates. Data were analyzed using the Minitab 18. In TBARS assay, methanol extracts showed the lowest TEARS value (-1.10±0.08) and AD (1:30) and OD (1:10, 1:20, 1:30) showed no significant difference (p > 0.05) compared to antioxidant activity of the methanol extracts. Almost all the samples showed antioxidant activity except Fresh (1:10, 1:20) and AD (1:10). However, In DPPH scavenging assay, DPPH scavenging activity of Fresh (1:10, 1:20, 1:30), AD (1:10, 1:20, 1:30), OD (1:10. 1:30) and FD (1:30) showed no significant difference (p > 0.05) compared to that of methanol extracts. AD (1:10) showed the highest DPPH scavenging activity (89.54±4.56%) which is higher than methanol (87.75±2.87) and Ascorbic acid (85.73±0.19). Therefore it can be concluded that considering the time of production, simplicity, toxicity and cost; water extraction of Fresh (1:10) or AD (1:10) can be used as a best extraction for producing antioxidant agents in food industry.enBiotechnologyBioprocess TechnologyBio Chemicals EngineeringOther