Mechanisms of heat-mediated aggregation of wheat gluten protein upon pasta processing

During pasta processing, structural changes of protein occur, due to changes in water content, mechanical energy input, and high temperature treatments. The present paper investigates the impact of successive and intense thermal treatments (high temperature drying, cooking, and overcooking) on aggregation of gluten protein in pasta. Protein aggregation was evaluated by the measurement of sensitivity of disulfide bonds toward reduction with dithioerythritol (DTE), at different reactions times. In addition to the loss in protein extractability in sodium dodecyl sulfate buffer, heat treatments induced a drastic change in disulfide bonds sensitivity toward DTE reduction and in size-exclusion high-performance liquid chromatography profiles of fully reduced protein. The protein solubility loss was assumed to derive from the increasing connectivity of protein upon heat treatments. The increasing degree of protein upon aggregation would be due to the formation of additional interchain disulfide bonds.