In vitro Synthesis of Limonoid Glucoside by Albedo Extracts of Pummelo Fruit (Citrus grandis Osbeck)

Abstract

To remove limonin, the bitter compound in products, the in vitro synthesis of limonin glucoside, a non-bitter compound, in pummelo fruit (Citrus grandis Osbeck) was studied. We discovered that a crude enzyme extract prepared from the albedo of the pummelo, in sodium chloride solution, can catalyze the synthesis of limonin glucoside from limonin and uridine 5'-diphosphoglucose disodium salt (UDPG-2Na). This reaction has a wide active pH range from 3.0 to 10.0, at an optimum temperature of 37°C. Within this range, a major peak of activity is noted at pH 5.5 and a minor one at pH 8.5.