Quality control of commercial quillaja (quillaja saponaria molina) extracts by reverse phase hplc

Abstract

Saponin-rich extracts of the Chilean indigenous tree Quillaja saponaria Molina are widely used as natural foaming agents in foods and beverages, food emulsifiers, photographic emulsions, vaccine adjuvants, etc. However, with the exception of the vaccine industry, saponin concentration is not adequately quantified. Normally, the quality and price of the extracts are determined using simple foam tests. This may not be adequate, since similar foam levels can be obtained by blending quillaja extracts with other low-cost saponin sources (eg Yucca shidigera extracts). Also, many products are diluted with high amounts of carriers, reducing significantly their saponin concentration. To overcome these problems and standardise the qualify of commercial extracts, the use of reverse phase HPLC techniques is explored. It is shown that RP-HPLC yields consistent and repetitive results and can be easily implemented to control the quality of quillaja extracts. Commercial non-refined extracts contain 190-200 g saponins kg(-1) solids, while semi-refined extracts contain 750-800 g saponins kg(-1) solids. Also, extracts derived from quillaja bark (traditional raw material) and whole quillaja wood (novel ecological production method) have similar saponin composition and concentration. (C) 2000 Society of Chemical Industry.