Submitted to: Institute of Food Technology
Publication Type: Abstract Only
Publication Acceptance Date: 7/29/2007
Publication Date: 7/29/2007
Citation: Gharst, G., Clare, D., Davis, J.P., Sanders, T.H. 2007. The Effects of Transglutaminase on the Functional Properties of Peanut Flour Dispersions Containing Casein. Institute of Food Technology.
Technical Abstract: Light roast-12% fat peanut flour (PF) is a high protein food ingredient. Recently, we observed that microbial transglutaminase (TGase) crosslinked peanut proteins and changed the functional characteristics of the final product. Therefore, in this study, we determined the effects of TGase polymerization on PF mixed with various concentrations of casein (CN) and evaluated the functional characteristics of the potential polymeric endproducts: PF-PF, PF-CN, and CN-CN. Rheological analyses were conducted using TGase treated PF dispersions (20% w/w) containing CN at concentrations of 1%, 2.5%, and 5% (w/w) at 0 time and after treatment for 6 hr/37°C. Dispersions were heated from 40 to 90°C at 1°C/min, held at 90°C, and cooled to 40°C at a rate of 1°C/min. Rheological changes were continuously monitored under large strain deformation (50s-1) and small strain deformation with a stress of 1.5 Pa and a frequency = 0.1 Hz. Polymer formation was observed in TGase treated PF-CN dispersions and occurred more rapidly with increasing concentrations of CN as detected by SDS-PAGE. The addition of 5% CN, alone, decreased the gelling temperature compared to PF dispersions lacking CN. The gelation temperature of all TGase-treated PF dispersions was increased regardless of the CN concentration. Moreover, the viscosity of TGase treated PF-CN was decreased compared to controls that were not enzymatically crosslinked. The addition of CN increased the water holding capacity in PF-CN dispersions after polymerization for 24 hr at 37°C. Casein proved to be an effective co-substrate, together with PF, itself, and under these experimental conditions, enzymatic processing changed the rheological characteristics such that gelation temperature, viscosity, and WHC were altered. These data suggest the potential use of PF-CN polymers for use in high protein peanut-based food products, such as protein bars and shakes.