Antioxidative and Nitrite Scavenging Activities of Polygonatum odoratum Root Extracts with Different Steaming and Roasting Conditions

Response surface methodology (RSM) was applied to monitor the effects of steaming and roasting conditions of Polygonatum odoratum roots an total phenolics content, electron donating ability (EDA) and nitrite-scavenging ability (NSA) of the extract. In steaming and roasting processes based on the central composite design. with variations in steaming time , roasting temperature and roasting time , coefficients of determinations were 0.9356 (p at 135.59 min of steaming time, of roasting temperature and 43.47 min of roasting time. The maximum value of EDA was in 108.98 min, and 48.86 min. The maximum value of NSA (pH 3.0) was in 162.80 min, and 31.97 min, respectively. Total phenolics content of the extract was influenced by heating conditions in the order of roasting temperature, steaming time and roasting time. While EDA and NSA were appreciably influenced by roasting time, followed by roasting temperature and steaming time.