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Using endogenous pigments to recolour roasted green tea

Food Quality and Safety 2021年第3期5卷 231-238页

作者：朱宏凯张坚强刘飞陈琳叶阳 tea Research Institute China Academy of Agricultural SciencesHangzhouChina Key Laboratory of tea Biology and Resource Utilization Ministry of AgricultureHangzhouChina tea and fruit instructional station of yixing city YixingChina tea Research Institute of Sichuan Academy of Agricultural Science ChengduChina

Roasted green tea exhibits undesirable dark green that can seriously affect sensory quality,market price,and consumer acceptance.The aim of this work was to propose a method of improving the appearanee of the roasted green tea.In this study,rehydration with freeze-drying(RFD)was used to recolour the tea leaves by redistributing the endogenous pigments.The results indicated that the colour of the roasted green tea changed from dark green to bright green after the RFD treatme nt,the values of L^(*)and b^(*)were significa ntly in creased(Ptea leaves also induced a change in pigment contents,including chlorophylls,carotenoids,and flavonoid glycosides.The well-defined optimum parameters for the rehydration process were moisture content of tea leaves at 35 per cent,water temperature 25℃,and a standing time of 1.5 h.

关键词： Green tea colour pigments rehydration freeze-drying.

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Assessment and mapping of environmental quality in agricultural soils of Zhejiang Province, China

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Journal of Environmental Sciences 2007年第1期19卷 50-54页

作者： CHENG Jie-liang SHI Zhou ZHU You-wei Institute of Agricultural Remote Sensing and Information System Zhejiang University Hangzhou 310029 China Protection and Monitoring station of Agricultural Environment Bureau of Agriculture Zhejiang Province Hangzhou 310020 China

Heavy metal concentrations in agricultural soils of Zhejiang Province were monitored to indicate the status of heavy metal contamination and assess environmental quality of agricultural soils. A total of 908 soil samples were collected from 38 counties in Zbejiang Province and eight heavy metal （Cd, Cr, Pb, Hg, Cu, Zn, Ni and As） concentrations had been evaluated in agricultural soil. It was found 775 samples were unpolluted and 133 samples were slightly polluted and more respectively, that is approximately 14.65% agricultural soil samples had the heavy metal concentration above the threshold level in this province by means of Nemerow＇s synthetical pollution index method according to the second grade of Standards for Soil Environmental Quality of China （GB15618- 1995）. Contamination of Cd was the highest, followed by Ni, As and Zn were lower correspondingly. Moreover, Inverse Distance Weighted （IDW） interpolation method was used to make an assessment map of soil environmental quality based on the Nemerow＇s pollution index and the soil environmental quality was categorized into five grades. Moreover, ten indices were calculated as input parameters for principal component analysis （PCA） and the principal components （PCs） were created to compare environmental quality of different soils and regions. The results revealed that environmental quality of tea soils was better than that of paddy soils, vegetable soils and fruit soils. This study indicated that GIS combined with multivariate statistical approaches proved to be effective and powerful tool in the mapping of soil contamination distribution and the assessment of soil environmental quality on provincial scale, which is beneficial to environmental protection and management decision-making by local government.

关键词： agricultural soil heavy metals soil environmental quality Nemerow＇s synthetical pollution index multivariate analysis

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