TY - JOUR
T1 - The effect of surface active agents on sorption isotherms of a model food system
AU - Labuza, Theodore P.
AU - Rvtman, Max
PY - 1968/10
Y1 - 1968/10
N2 - The extent of the capillary condensation phenomenon in the sorption of water by a model food system was studied. The system, composed of microcrystalline cellulose, a hydrocarbon oil, and water, was treated with non‐ionic surface active agents at various concentrations. Desorption and adsorption isotherms were made for triplicate control and treated systems at 37°c., using a desiccator method. During desorption, the surfactants increased the water equilibrium vapor pressure of the model system for all moisture contents, but with adsorption, this effect was observed only up to 50 to 60% RH. The magnitude of the hysteresis loop was diminished in all cases. These over‐all effects were due mainly to a lowering of the liquid surface tension of the water in the pores of the model. Capillarity was analyzed by the Kelvin Equation and existed down to 20% RH, which is close to the monolayer value for most models. In addition, data from low surfactant concentrations indicated that capillarity may extend even below the monolayer. The diminished hysteresis found in our experiments supports the “ink‐bottle” theory of hysteresis.
AB - The extent of the capillary condensation phenomenon in the sorption of water by a model food system was studied. The system, composed of microcrystalline cellulose, a hydrocarbon oil, and water, was treated with non‐ionic surface active agents at various concentrations. Desorption and adsorption isotherms were made for triplicate control and treated systems at 37°c., using a desiccator method. During desorption, the surfactants increased the water equilibrium vapor pressure of the model system for all moisture contents, but with adsorption, this effect was observed only up to 50 to 60% RH. The magnitude of the hysteresis loop was diminished in all cases. These over‐all effects were due mainly to a lowering of the liquid surface tension of the water in the pores of the model. Capillarity was analyzed by the Kelvin Equation and existed down to 20% RH, which is close to the monolayer value for most models. In addition, data from low surfactant concentrations indicated that capillarity may extend even below the monolayer. The diminished hysteresis found in our experiments supports the “ink‐bottle” theory of hysteresis.
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U2 - 10.1002/cjce.5450460515
DO - 10.1002/cjce.5450460515
M3 - Article
AN - SCOPUS:84984087829
SN - 0008-4034
VL - 46
SP - 364
EP - 368
JO - The Canadian Journal of Chemical Engineering
JF - The Canadian Journal of Chemical Engineering
IS - 5
ER -