Objective:To compare effect of different drying methods on the content of sennoside B in Cassia angustifolia extracts. Method: With the content of sennoside B as index

effect of reduced pressure condensing and vacuum drying at different temperatures on the content of sennoside B were investigated by single-factor test; Orthogonal test was used to investigate influence of inlet temperature

outlet temperature and spray velocity on spray drying technology of C. angustifolia extracts. Result: Optimal temperature of reduced pressure concentrating and vacuum drying for C. angustifolia extracts were 60 ℃

their time-consuming were 87 min

58 h

respectively;Optimum spray drying technology parameters were as followings:inlet air temperature 120 ℃

outlet air temperature 55 ℃

spraying velocity 16 mL·min-1. Conclusion: Loss of sennoside B by vacuum drying was more than spray drying; spray drying was time saving and beneficial to retention of effective ingredients

optimized spray drying process was stable and feasible

and it could be used for drying of C. angustifolia extracts with thermal instability.