PROBLEM TO BE SOLVED: To obtain high quality Brasenia schreberi through removing darkening from Brasenia schreberi without damaging the plant body. SOLUTION: The Brasenia schreberi having darkening removed is obtained by treating darkening Brasenia schreberi with a substance having chelating action and an inorganic acid. A method for removing darkening from Brasenia schreberi comprises treating darkening Brasenia schreberi from an acid state to a neutral state with one selected from or a combination of EDTA, citric acid, ascorbic acid, phosphoric acid, metaphosphoric acid, phytic acid, oxalic acid, succinic acid, fumaric acid, pyridinedicarboxylic acid, lactic acid, malic acid, glutamic acid, glucuronic acid, gluconic acid, galacturonic acid, hydrochloric acid, sulfuric acid and nitric acid. COPYRIGHT: (C)2005,JPO&NCIPI
