木姜叶柯甜茶的甜味成分及抗氧化性研究OA

This study aimed to reveal the associations of phlorizin and trilobatin with the antioxidant activity of sweet tea(Lithocarpus litseifolius).Phlorizin and trilobatin were extracted from different grades(classified by tenderness)of sweet tea,and the extraction conditions—ethanol concentration and ultrasonic time—were optimized.Furthermore,the scavenging rates of the extracts of different grades of sweet tea and the extracts at different concentrations against DPPH,ABTS+,and·OH free radicals were compared based on the content of phlorizin and trilobatin extracted from different grades of sweet tea.The experiments showed that 60%ethanol and the ultrasonic extraction time of 30 min were the optimal extraction conditions,under which the yields of phlorizin and trilobatin were the highest.The content of phlorizin and trilobatin varied in the leaves of different grades.Specifically,the content of phlorizin was higher in older leaves,while that of trilobatin was higher in tender leaves.The extracts of sweet tea at different grades showed good antioxidant activity,with the free radical scavenging rates increased with the increase in extract concentration.The content of phloridzin and trilobatin in sweet tea of different grades exhibited a clear pattern,while the scavenging rates of free radicals did not demonstrate the corresponding pattern.This indicated that phlorizin and trilobatin,the two sweet components,were not direct factors influencing the antioxidant activity of sweet tea.