Optimization of extraction of polyphenols from pomegranate peel by orthogonal experiment design and antioxidant activity

The aim of this study was to investigate the extraction process and antioxidant activity of polyphenols from Yunnan Mengzi pomegranate peel.Single factor and orthogonal test were used as optimize the extract rate(ER)of polyphenols from pomegranate peel(PGP).The polyphenols antioxidant activity was evaluated by DPPH·,·OH and total reducing ability,and compared with that of Vc.The optimum extraction conditions of polyphenols were as follows:ethanol concentration of 50%,liquid-solid ratio of 50:1,extraction temperature of 90°C,extraction for 4 h.Under these conditions,the ER of polyphenols from GPG was 8.15%.The results showed that the scavenging effects of polyphenols and Vc on DPPH·,·OH increased with increasing concentration,and the scavenging effect of polyphenols on DPPH·was higher than Vc in rang of 0.1-1.6µg/mL.When the concentration is greater than 0.6µg/mL,the scavenging effects of plyphenols on·OH is higher than Vc.The total reducing ability of polyphenols from PGP improved with the increase of concentration,and when the concentration was 8µg/mL,the total reducing ability was 114 U/mL.

Polyphenol content and antioxidant activity in mulberry powder treated at high temperature

The aim of this study was to investigate changes of polyphenols content and the antioxidant activity of mulberry fruit powder after heating at high temperature.The mulberry fruit powder was heated by baking method at different temperature and time.The DPPH scavenging ability,the OH^(•-) scavenging ability and the O_(2)^(•-) scavenging ability were used to evaluate the changes in the antioxidant activity of the mulberry fruit powder after the heat treatment.The results showed that 74.87%of the polyphenols in the mulberry powder were lost after heating at 150℃for 5 min,and almost all the polyphenols were lost with the increase of the heating time and temperature.The antioxidant experiment showed that the DPPH scavenging rate,OH^(•-) scavenging rate and O_(2)^(•-) scavenging rate of mulberry fruit powder were 68.90%,39.15%and 14.09%,respectively after treatment at 150℃ for 5 min.Mulberry fruit powder still has some potential to be added to baked goods as a functional ingredient.

中美主要科研资助机构减轻科研项目申报行政负担的对比和启示

以主要科研资助机构为例,比较中美两国在政府、资助机构及研究机构层面形式审查具体政策和举措,提出优化我国项目管理、减轻科研申报行政负担的建议。分析发现,美国联邦政府通过颁布法案和指南,促使资助机构积极响应,建立跨机构的法规适用性保证机制、建立集中的研究者档案数据库、统一和简化项目申请格式和程序;研究机构也为科研人员提供高质量管理服务;我国政府也强调减轻科研人员负担充分释放科技活力,通过扩大无纸化范围、简化填写信息等措施致力于减轻研究者行政负担。为进一步落实科研人员减负的战略任务,可以完善申报系统功能和提示、强化对于科研诚信等核心要素的把控、加强联动改进流程等。