Submitted to: Carbohydrate Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 22, 2000
Publication Date: September 8, 2000
Interpretive Summary: Hesperidin, a flavonoid compound, is present in fruit, leaves and bark of orange and some other citrus species. Several thousand tons can be annually recovered from citrus processing residues in Florida, Brazil and other orange processing areas. Hesperidin can be hydrolyzed to valuable chemicals and chemical intermediates, such as rhamnose and hesperetin-7- glucoside. Both acid and enzyme catalyzed hydrolysis of hesperidin is hampered by its low solubility in water and many organic solvents. We investigated hydrolysis of hesperidin in dilute sulfuric acid at temperatures ranging from 25-180C and observed significant increase in the reaction rate at 120C and above. This increase is caused by increased solubilization of hesperidin in water at high temperatures. Hesperetin-7- glucoside and rhamnose were prepared by partial hydrolysis of hesperidin at 140C and a simple procedure for separation of hesperetin-7-glucoside and dhesperetin by a stepwise solvent extraction has been developed.
Technical Abstract: Dilute sulfuric acid was used as a catalyst for hydrolysis of hesperidin suspensions in water at temperatures ranging from 25 to 180 degrees C. Significant acceleration of the reaction was observed at 120 degrees C and higher temperatures. This increase in the rate of hydrolysis can be attributed to increased solubilization of hesperidin in water at higher temperatures. Partial hydrolysis of hesperidin at 140 degrees C was used for the preparations of hesperetin-7-glucoside, which has a value for synthesis of dihydrochalcone sweeteners. Simple separation of hesperetin and hesperetin-7-glucoside by extraction with dry acetone or lower alcohols has been developed.