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Water Activity Determination with the Proximity Equilibration Cell
Author(s) -
McCUNE T. D.,
LANG K. W.,
STEINBERG M. P.
Publication year - 1981
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.1981.tb04542.x
Subject(s) - sorption , calibration , calibration curve , chemistry , water content , linear equation , standard deviation , sample (material) , analytical chemistry (journal) , thermodynamics , chromatography , mathematics , statistics , physics , mathematical analysis , geology , adsorption , geotechnical engineering , organic chemistry , detection limit
The objective was to develop a new method for water activity (a w ) determination. A reference material (circle of filter paper) of known sorption isotherm was equilibrated to the sample. Sorption isotherm data for this paper were obtained by equilibrating for 24 hr to each of six salt slushes; these data were described well by a linear equation relating moisture content to log (1 − a w ). This equation served as the calibration curve. Results showed that this new method (1) does not require a vacuum, (2) gives a linear calibration equation, (3) is applicable over the a w range from 0.40–0.98, and (4) with minor replication can bring the standard deviation of the mean to less than ± 0.01.