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WATER ACTIVITY and PHYSICAL STATE EFFECTS ON AMORPHOUS FOOD STABILITY
Author(s) -
ROOS YRJÖ H.
Publication year - 1993
Publication title -
journal of food processing and preservation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.511
H-Index - 48
eISSN - 1745-4549
pISSN - 0145-8892
DOI - 10.1111/j.1745-4549.1993.tb00221.x
Subject(s) - water activity , chemistry , adsorption , amorphous solid , sorption , food science , glass transition , water content , organic chemistry , geology , geotechnical engineering , polymer
Water‐adsorption data and glass transition temperatures (T g ) of maltodextrins with dextrose equivalent (DE) values ranging from 4 to 38, horseradish roots, and strawberries were used to establish relationships between water activity (a w ), water content (m), and Tg. Critical m values were considered as those depressing T g to 25C. Corresponding values of critical a w were obtained from GAB isotherms that were used to model water adsorption. the use of BET isotherms was tested, but the model showed poor correlation with experimental data at high a w values, especially for low DE maltodextrins. Critical m and aw values were lowest for strawberries (1.5 g H 2 O/g solids; 0.07 a w ). the values increased with decreasing DE, ranging from 7.2 (0.44 a w ) to 11.2 g H 2 O/g solids (0,70 a w ). Understanding of water‐sorption properties and T g is valuable in controlling processability and stability, and for determining of food‐packaging requirements.