title: A PHYSICO-CHEMICAL STUDY OF THE MECHANICAL PROPERTIES OF LOW AND INTERMEDIATE MOISTURE FOODS.
abstract: A number of textural properties of precooked, freeze-dried beef were examined by a cutting-extrusion test (force) and by a compression test (seven different properties). The tests were performed at different points of the moisture sorption isotherm over the complete range of water activity, Aw. In cutting-extrusion experiments (Allo Kramer Shear Press), a maximum in the force vs. Awcurve was observed at about Aw= 0.85. In compression experiments (Instron Universal Testing Apparatus), important changes of the textural properties were found in the range Aw= 0.15-0.30. These changes were paralleled by changes in the thermodynamic functions of water vapor sorption, especially in the standard differential entropy. Thermodynamic theory and mechanical measurements were used to interpret the textural changes in terms of increased crystallinity and subsequent swelling of the food structure.
authors.affiliation: U. S. Army Natick Laboratories, Natick, Mass., U. S. A.
authors.forename: J G
authors.initials: JG
authors.lastname: Kapsalis
authors.affiliation: U. S. Army Natick Laboratories, Natick, Mass., U. S. A.
authors.forename: J E
authors.initials: JE
authors.lastname: Walker
authors.affiliation: U. S. Army Natick Laboratories, Natick, Mass., U. S. A.
authors.forename: M
authors.initials: M
authors.lastname: Wolf