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Studies on the Density of Water Adsorbed on Low‐Protein Fraction of Flour
Author(s) -
GURARIEH C.,
NELSON A. I.,
STEINBERG M. P.
Publication year - 1967
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.1365-2621.1967.tb09706.x
Subject(s) - moisture , adsorption , water content , particle density , fraction (chemistry) , chemistry , water activity , bulk density , number density , transition point , analytical chemistry (journal) , thermodynamics , chromatography , volume (thermodynamics) , organic chemistry , soil science , physics , soil water , environmental science , geotechnical engineering , engineering
SUMMARY— A pycnometric method was used to measure the density of a low‐protein fraction of flour at different moisture levels. At a given moisture content the flour density was independent of the particle size distribution within the range studied. The density of flour remained constant over a moisture content range from 0 to 7%. In the range of 0‐26% moisture two definite transition points exist in the density of adsorbed water. The first occurs at approximately 7% and this is equivalent to a mono‐molecular layer. The density of this adsorbed water is strikingly high, 1.48 g/cc. After the first transition point, the density of adsorbed water decreases to 1.11 g/cc. The second transition point occurs at approximately 14% moisture and from there on to the highest moisture measured, 26%, the density of adsorbed water remains constant at 0.97 g/cc.