TY - JOUR
T1 - Comparison between water vapor sorption isotherms obtained using the new dynamic dewpoint isotherm method and those obtained using the standard saturated salt slurry method
AU - Schmidt, Shelly J.
AU - Lee, Joo Won
N1 - Funding Information:
This project was supported in part by the USDA National Institute of Food and Agriculture, Hatch project number 385. In addition, the authors gratefully acknowledge the financial support of the 2008 Marcel Loncin Research Prize from the Institute of Food Technologists and the 2008 Midwest Advanced Food Manufacturing Alliance (University of Nebraska-Lincoln) grant. The helpful scientific discussions with Brady Carter of Decagon Devices (Pullman, WA, USA) and Dr. Anthony J. Fontana, Jr. of Silliker, Inc. (Homewood, IL, USA) are also gratefully acknowledged.
PY - 2012/3/1
Y1 - 2012/3/1
N2 - The Dynamic Dewpoint isotherm method directly determines sample a w using chilled-mirror technology, while changes in sample weight are tracked gravimetrically. The objective of this research was to compare the Dynamic Dewpoint isotherms to saturated salt slurry isotherms for five materials: dent corn starch, isolated soy protein, microcrystalline cellulose, crystalline sucrose, and corn flakes. The Dynamic Dewpoint isotherms were obtained using the AquaSorp Isotherm Generator between 0.10 and 0.95 a w at 25°C. Comparison working isotherms were obtained using 12 saturated salt slurries, between 0.064 and 0.973 a w in desiccators and proximity equilibration cells at 25°C. The Dynamic Dewpoint isotherms exhibited similar sorption behavior to the saturated salt slurry isotherms, except for corn flakes, where there was a marked decrease in moisture content compared to the saturated salt slurry isotherms between 0.40 and 0.70 a w. This difference was attributed to the slow diffusion of water into the very dense laminated corn flake matrix, highlighting the rate of sorption (time) dependency of the Dynamic Dewpoint isotherm method. The Dynamic Dewpoint isotherm method offers the opportunity for real-time investigation of water sorption-related material properties, such as the glass to rubbery transition, recrystallization, hydrate formation, and deliquescence.
AB - The Dynamic Dewpoint isotherm method directly determines sample a w using chilled-mirror technology, while changes in sample weight are tracked gravimetrically. The objective of this research was to compare the Dynamic Dewpoint isotherms to saturated salt slurry isotherms for five materials: dent corn starch, isolated soy protein, microcrystalline cellulose, crystalline sucrose, and corn flakes. The Dynamic Dewpoint isotherms were obtained using the AquaSorp Isotherm Generator between 0.10 and 0.95 a w at 25°C. Comparison working isotherms were obtained using 12 saturated salt slurries, between 0.064 and 0.973 a w in desiccators and proximity equilibration cells at 25°C. The Dynamic Dewpoint isotherms exhibited similar sorption behavior to the saturated salt slurry isotherms, except for corn flakes, where there was a marked decrease in moisture content compared to the saturated salt slurry isotherms between 0.40 and 0.70 a w. This difference was attributed to the slow diffusion of water into the very dense laminated corn flake matrix, highlighting the rate of sorption (time) dependency of the Dynamic Dewpoint isotherm method. The Dynamic Dewpoint isotherm method offers the opportunity for real-time investigation of water sorption-related material properties, such as the glass to rubbery transition, recrystallization, hydrate formation, and deliquescence.
KW - AquaSorp Isotherm Generator
KW - Dynamic Dewpoint isotherm
KW - Isotherm
KW - Saturated salt slurries
KW - Water activity
UR - http://www.scopus.com/inward/record.url?scp=84863141748&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84863141748&partnerID=8YFLogxK
U2 - 10.1080/10942911003778014
DO - 10.1080/10942911003778014
M3 - Article
AN - SCOPUS:84863141748
SN - 1094-2912
VL - 15
SP - 236
EP - 248
JO - International Journal of Food Properties
JF - International Journal of Food Properties
IS - 2
ER -