Development of a new method for fast measurement of water sorption isotherms in the high humidity range Validation on gelatine gel

• Published in: Journal of food engineering Vol. 44; no. 2; pp. 97 - 107
• Main Authors: Baucour, P, Daudin, J.D
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-05-2000; Elsevier
• Subjects: Biological and medical sciences; Chemical and Process Engineering; Engineering Sciences; Food engineering; Food industries; Food microbiology; Food process; Fundamental and applied biological sciences. Psychology; Gelatine; General aspects; Life Sciences; Methods of analysis, processing and quality control, regulation, standards; Sorption equation; Sorption isotherm; Water activity; Water transfer; Sorption equation; Water activity; pH; Water transfer; Gelatine; Sorption isotherm; Food process; Adsorption isotherm; Model study; Foodstuff; Protein; Colloidal gel; Sorption; Rapid technique; Gelatin; Humidity; Animal protein; Solid form; Desorption isotherm; Measurement method; Physicochemical properties
• ISSN: 0260-8774; 1873-5770
• DOI: 10.1016/S0260-8774(99)00171-5

A fast and accurate method has been set up to measure sorption isotherms of solid foods in the water activity range 0.9–1. In a purpose-built device thin slices of the studied material are submitted to an air flow of very high velocity (more than 10 m s
−1), at any temperature between 4°C and 40°C. Air relative humidity is controlled by a reduction in pressure of a saturated air. This method was validated over the range 0.7–0.9 using gelatine gel samples by comparison with the standard saturated salt method. Results obtained at two temperatures (3.5°C, 20°C) and three values of pH (4, 5.2 and 8) were used to test the ability of different fitting models.