Effects of transglutaminase catalysis on the functional and immunoglobulin binding properties of peanut flour dispersions containing casein.

The functionality of light roasted peanut flour (PF) dispersions containing supplemental casein (CN) was altered after polymerization with microbial transglutaminase (TGase). The formation of high molecular weight covalent cross-links was observed with likely development of PF-PF, PF-CN, and CN-CN polymers based on Western blotting patterns visualized using antiserum directed against Ara h 1, Ara h 2, Ara h 3, or casein. The gelling temperature of TGase-treated PF dispersions containing 2.5% CN was significantly raised compared to the nontreated PF-CN control solutions. Furthermore, the gel strength and water holding capacity of cross-linked PF-CN test samples containing 5% CN was increased, while the yield stress and apparent viscosity were lowered compared to control dispersions. The immunological staining patterns were also changed where, in some cases, IgE binding to TGase-treated PF-CN fractions appeared less reactive compared to equivalent polymeric PF dispersions lacking supplemental CN and non-cross-linked PF-CN samples. Perhaps, covalent modification masked IgE peanut protein binding epitopes, at least to some degree, on an individual patient basis. Casein proved to be an effective cosubstrate with PF for creating Tgase modified PF-CN dispersions for use as a novel high protein food ingredient.