Spectrophotometric determination of saponin in Yucca extract used as food additive.

A spectrophotometric method was developed for the determination of saponin in Yucca extract or its preparation for food additive use. A saponin fraction of Yucca extract was prepared by column chromatography with porous polymer, and hydrolyzed with a 2 mol/L mixture of hydrochloric acid-ethanol (1 + 1) to generate sapogenin. Sapogenin amounts were determined by measuring absorbance at 430 nm, based on the color reactions with anisaldehyde, sulfuric acid, and ethyl acetate. Recoveries from Yucca extracts were 91.5-95.1%, and the detection limit was 10 microg/kg. Commercial Yucca extracts for food additive use were composed of 5.6-6.4% (w/w) saponin, making it a minor component.