Studies on the Density of Water Adsorbed on Low‐Protein Fraction of Flour

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.