Publication no. C-2001-1205-07R |  VIEW ARTICLE

Effect of Glass Transition and Cross-Linking on Rheological Properties of Gluten: Development of a Preliminary State Diagram.

Imad Toufeili (1,2), Ian A. Lambert (3), and Jozef L. Kokini (3). (1) Department of Food Technology and Nutrition, American University of Beirut, Beirut, Lebanon. (2) Corresponding author. E-mail: <toufeili@aub.edu.lb> Fax: 961-1-744460. (3) Center for Advanced Food Technology, Department of Food Science, Rutgers, The State University Of New Jersey, P.O. Box 231, New Brunswick, NJ 08903-0231. Cereal Chem. 79(1):138-142. Accepted September 4, 2001. Copyright 2002 American Association of Cereal Chemists, Inc.

The glass transition temperature of gluten at different moisture levels was determined by differential scanning calorimetry and mechanical spectrometry. The dynamic moduli (G(prime) and G(double prime)) of gluten with 10-40% moisture were measured as a function of temperature by pressure rheometry. At 10% moisture, gluten exhibited entangled polymer flow at 92-140°C and networking reactions at higher temperatures. At higher moisture levels, gluten experienced structured flow before networking cross-linking reactions. The onset temperature of the reaction zone was 120°C in 20% moisture gluten and 93ºC at moisture levels of 30-40%. Softening of the vitrified network occurred at 184, 181, and 170ºC in 20, 30, and 40% moisture gluten, respectively. A preliminary state diagram of gluten as a function of moisture and temperature was developed.