Abstract:

The objective of this study was to establish a rapid, simple and accurate colorimetric method for the determination
of saponin in starfish. Asterias amurensis was selected as the raw materials. The effects of colorimetric conditions such as
sulfuric acid dosage, reaction temperature and reaction time as well as sample preparation procedures such as decoloration
and degreasing on saponin determination were analyzed. It was shown that addition of sulfuric acid in a proportion of
10% (V/V) and reaction temperature at 60 ℃ for 30 min were suitable colorimetric conditions, and the pretreatment steps
decoloration, degreasing and acetone precipitation could significantly improve the accuracy of determination. The results
of precision and spiked recovery experiments showed that RSDs (relative standard deviations) for three groups with low,
medium and high saponin contents were 4.71%, 1.61% and 1.52%, respectively, and the average recovery was 99.64%.
Asterias amurensis was detected to contain 3.65 mg/g saponin (dry basis). The digestive gland of Asterias amurensis showed
the highest saponin content, followed by the body wall and gonad.

Key words: saponin, Asterias amurensis, colorimetric method