Characteristics of Subcritical Water Extraction and Kinetics of Pentacyclic Triterpenoids from Dry Loquat (Eriobotrya japonica) Leaves

In this study, pentacyclic triterpenoids (PTTs) were extracted from loquat leaves by subcritical water extraction (SWE) technique in a dynamic mode. The results revealed that PTTs yield increased up to 5.38±0.12 mg/g with the increasing temperature at 180 °C for corosolic acid (CA) and up to 7.20±0.11 mg/g at 200 °C for ursolic acid (UA) within experimental times. The optimum flow rates to obtain concentrated CA and UA extracts were found to be 33.33 and 41.67 mL/min, respectively. Furthermore, extraction temperatures strongly influenced the extraction rate as demonstrated by the rate constant of each temperature tested. Moreover, the kinetic rate constant decreased as the function of temperature indicating the yield of both CA and UA were significantly influenced by subcritical temperatures and extraction times.