Definition of a mechanical glass transition temperature for dehydrated foods.
A new concept of the mechanical glass transition temperature (T(g)) is presented with application in dehydrated high-sugar/gelatin mixtures, fish, and fruits. The macroscopic basis and manner of relaxation processes during vitrification of these foodstuffs are developed using small deformation dynamic oscillation, the master curve of viscoelasticity, and the time-temperature superposition principle. The quantitative features of the mechanical T(g) are based on the combined framework of free volume/WLF theory and the Andrade equation. It is proposed that the thermal profile of storage modulus on shear is a fundamental index of monitoring changes in a glassy structure, and several cases are presented in support of this concept.
Kasapis
Stefan
S
Department of Food Science and Nutrition, College of Agricultural and Marine Sciences, Sultan Qaboos University, P O Box 34, Al-Khod 123, Sultanate of Oman. stefan@squ.edu.om
D000818:Animals; D002241:Carbohydrates; D005399:Fishes; D005519:Food Preservation; D005638:Fruit; D005780:Gelatin; D005898:Glass / Q000737:chemistry*; D019563:Mechanics; D013696:Temperature
D002241:Carbohydrates; D005780:Gelatin