Accurate and rapid quantification of tea saponins using a thin-layer chromatography (TLC) method based on hemolysis and machine vision

Tea saponins are increasingly used in the food industries due to their biological activities. Current methods for the quantification of tea saponins are either inaccurate or time consuming and costly. In this study, a quantitative thin-layer chromatographic (TLC) method using machine vision and based on the hemolytic activity (HA) of tea saponins was developed. The optimized method consisted of ethanol extraction, sample loading, separation, color development, and smartphone-machine vision quantification. The new HA-TLC method was compared with UV spectrophotometric and liquid chromatographic methods, and achieved higher precision (RSD% = 0.75%) and accuracy (96.4%-106.2% recovery), with a limit of detection of 0.285 μg and limit of quantification of 0.95 μg. The method enables simultaneous qualitative and quantitative determination of saponins from different parts of tea plant extracts with high specificity, yet rapid and inexpensive, with high throughput and low solvent consumption, providing new options for saponin analysis in the food industry.