Enhancement of transglutaminase-induced protein cross-linking by preheat treatment of cows' milk: A statistical approach

Optimization of heat treated milk towards protein cross-linking induced by transglutaminase was carried out. Capillary electrophoresis was employed to study the extent of cross-linking under different preheating temperatures (70-90 degrees C) and times (15-60 min). The experiments were arranged according to a central composite statistical design (3(2) +centre points). Response surface methodology was used to assess factor interactions and empirical models regarding relative peak area (%) of individual protein (alpha(s2)-casein, alpha(s1)-casein, alpha(s0)-casein, kappa-casein, beta-casein A(1), beta-casein A(2), alpha-lactalbumin and beta-lactoglobulin) and total alpha(s)-caseins, total beta-caseins and whey proteins (sum of alpha-lactalbumin and beta-lactoglobulin). Multi-response optimization was also performed on the total alpha(s)-caseins, total beta-caseins, kappa-casein and whey proteins data set of the factorial design. The desirability function was the statistical too] employed in this multi-optimization step. The optimum preheating conditions that maximized the cross-linking reactions catalyzed by transgiutaminase were achieved within 60 min at 84.5 degrees C. (c) 2005 Elsevier Ltd. All rights reserved.