Pressure-enhanced solid-liquid extraction of rutin from Chinese scholar-tree flower: Kinetic modeling of influential factors

The rutin is an important bioactive flavonoid glycoside with wide application in food and pharmaceutical industry. The flowers of Chinese scholar-tree are known to contain significant amount of rutin. The objective of this work is to evaluate the influences of the process factors (pressure, temperature, ethanol concentration and liquid-solid ratio) on the pressure-enhanced solid-liquid extraction (PSE) kinetics of rutin from Chinese scholar-tree flower. The kinetics is mathematically described using the second-order rate model, power-law model and two-site kinetic model to understand the extraction process. The power-law model appears to be the best suitable to model the PSE kinetics at tested conditions. The results indicate that increasing the pressure, temperature and liquid-solid ratio lead to the higher rutin yields and extraction rate; the ethanol concentration have significantly positive effects only on the rutin yields, but not on the extraction rate. The destruction of pressure on the cellular walls can be seen on the transmission electron micrographs.