Proanthocyanin(PA)dimers isolated from Acacia mearnsii bark were enzymatically acylated with palmitic acid as the acyl donor by immobilized Candida antarctica lipase on acrylic resin(Novozym 435).The acylation reactio...Proanthocyanin(PA)dimers isolated from Acacia mearnsii bark were enzymatically acylated with palmitic acid as the acyl donor by immobilized Candida antarctica lipase on acrylic resin(Novozym 435).The acylation reaction conditions were optimized by comparing the amount of enzyme,the temperature,the reaction solvents,initial water content,substrate molar ratios and reaction time.The highest acylation conversion of 96.53%was achieved under the follow conditions:PA dimers/palmitic acid at a molar ratio of 1꞉10 in tert-amyl alcohol;initial water content of 5%at 60℃ for 12 h with 30 g/L enzyme dosage.Introducing palmitic acid into PA dimers significantly improved both the lipophilicity and antioxidant properties.The 1-octanol/water partition coefficient of the PA dimers and their derivatives showed that the lipophilicity of the derivatives were 2.4 times higher than that of the PA dimers.The derivatives exhibited strong antioxidant scavenging capacities,approximately 1.6 times greater than the original dimers.This work is of great significance to expand the application of natural PA dimers in cosmetic and food industries and also lay a foundation for the high value-added utilization of A.mearnsii.展开更多
以现有生物入侵风险评价体系为基础,根据温州地区的自然环境和外来入侵植物调查结果,建立了区域性较强的"温州外来入侵植物风险评价体系",并以外来植物黑荆(Acacia mearnsii De Wild.)为例对这一评价体系进行了验证。整个评...以现有生物入侵风险评价体系为基础,根据温州地区的自然环境和外来入侵植物调查结果,建立了区域性较强的"温州外来入侵植物风险评价体系",并以外来植物黑荆(Acacia mearnsii De Wild.)为例对这一评价体系进行了验证。整个评价体系由境内外重视程度、地理分布、入侵途径、传播与繁殖方式、危害性和影响以及防除处理难度6个一级指标和15个二级指标组成,并采用"层次分析法"(analytic hierarchy process,AHP)确定各指标的权重,按不同的权重赋予各指标不同的分值(评价总分为100分),各指标的得分总和即为最终的评价得分(R值)。使用该评价体系对黑荆进行风险评价和赋值,结果显示,在温州地区,黑荆的风险评估得分R值为64分,风险程度中等,要加以一定程度的监控管理。温州外来入侵植物风险评价体系具有区域可行性,可以为温州外来入侵植物的科学管理提供依据。展开更多
基金supported by National Key Research&Development Program of China(No.2019YFB1504002)Topnotch Academic Programs Project(TAPP)Education Institutions.
文摘Proanthocyanin(PA)dimers isolated from Acacia mearnsii bark were enzymatically acylated with palmitic acid as the acyl donor by immobilized Candida antarctica lipase on acrylic resin(Novozym 435).The acylation reaction conditions were optimized by comparing the amount of enzyme,the temperature,the reaction solvents,initial water content,substrate molar ratios and reaction time.The highest acylation conversion of 96.53%was achieved under the follow conditions:PA dimers/palmitic acid at a molar ratio of 1꞉10 in tert-amyl alcohol;initial water content of 5%at 60℃ for 12 h with 30 g/L enzyme dosage.Introducing palmitic acid into PA dimers significantly improved both the lipophilicity and antioxidant properties.The 1-octanol/water partition coefficient of the PA dimers and their derivatives showed that the lipophilicity of the derivatives were 2.4 times higher than that of the PA dimers.The derivatives exhibited strong antioxidant scavenging capacities,approximately 1.6 times greater than the original dimers.This work is of great significance to expand the application of natural PA dimers in cosmetic and food industries and also lay a foundation for the high value-added utilization of A.mearnsii.
