Submitted to: American Chemical Society National Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 5/18/2009
Publication Date: 8/16/2009
Citation: Tunick, M.H. 2009. Dynamic rheology of food protein networks. American Chemical Society National Meeting.
Technical Abstract: Small amplitude oscillatory shear analyses (SAOSA) of samples containing protein are useful for determining the nature of the protein matrix without damaging it. The Dairy Processing and Products Research Unit of the Agricultural Research Service, USDA has pioneered the use of SAOSA in understanding the structure of cheese and of protein solutions. G prime (elastic or storage modulus), G double prime (viscous or loss modulus), and tan delta (ratio of G double prime to G prime) give information on the strength of the network. Strain, frequency, and temperature sweeps are performed to find the linear viscoelastic region, elastic properties of the specimen, and thermal characteristics, respectively. The gelation point may be determined by locating the time where tan delta is independent of frequency, or the temperature where G prime becomes greater than G double prime. The log of eta* (complex viscosity) may be plotted against the reciprocal of the absolute temperature, with the slope being proportional to the activation energy. Dynamic tests of protein-containing samples reveal much about their rheological characteristics, which will allow scientists to determine their suitability in food formulations.