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Compositional Influence on the pH of Reduced‐Moisture Solutions
Author(s) -
BELL L.EONARD N.,
LABUZA T.HEODORE P.
Publication year - 1992
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.1365-2621.1992.tb08083.x
Subject(s) - chemistry , aqueous solution , water activity , ionic strength , buffer (optical fiber) , phosphate , phosphate buffered saline , moisture , buffer solution , water content , activity coefficient , inorganic chemistry , ionic bonding , chromatography , ion , organic chemistry , computer science , engineering , telecommunications , geotechnical engineering
The pH of reduced‐moisture systems is not the same as in hydrated systems. As aqueous phosphate buffer solutions become concentrated, the pH of the system decreases. The pH of citrate buffer solutions decreases, then increases as the concentration increases. Identical buffer solutions whose water activity is reduced by the addition of nonionic solutes indicate no correlation of pH with either the water activity reduction or the change in dielectric constant. The response of pH to added solutes appears to be dependent on the chemical nature of the solute and its interaction with water. This study also confirmed the limitations of several theoretical models of ionic activities.