首页 | 本学科首页   官方微博 | 高级检索  
     


Water Activity Calculation by Direct Measurement of Vapor Pressure
Authors:A. L. BENADO  S. S. H. RIZVI
Affiliation:Authors Benado and Rizvi are with the Inst. of Food Science, Stocking Hall, Cornell Univ., Ithaca, NY 14853.
Abstract:An improved method for calculation of water activity from vapor pressure manometric data, which takes into account the volume expansion of nonadsorbing gases, the initial pressure in the desiccant flask and the pressure exerted by the desiccant, was developed. The water activity of pure water was measured over a range of nonadsorbing gas pressures and initial pressures in the desiccant flask. Standard deviations in aw of pure water calculated using no corrections, corrections for volume expansion only, and full corrections were 0.221, 0.011, and 0.005, respectively. Correction only for volume expansion may under some conditions result in larger errors than when no corrections are made at all. Based on the improved equation, an experimental modification which reduces loss of water from samples during measurement was proposed.
Keywords:
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号