Effect of transglutaminase on the interaction between gluten and soy proteins

ROCCIA P; PABLO DANIEL RIBOTTA; GT PEREZ; AE LEON

Nantes, Francia

Congreso; IUFOST XIIIth World Congress of Food Science and Technology "FOOD IS LIFE".; 2006

IUFOST - INRA

Soybean has found increasing acceptance in diets due to the FDA claim of linking the consumption of soy protein with a lower risk of heart disease (FDA 1999). Incorporating high levels of soy protein in bread depresses loaf volume and gives poor crumb characteristics. The transglutaminase (TG) catalyzes the formation of inter- and intra-molecular å-(ã-glutamyl)lysine crosslinks in several food proteins such as soy and wheat proteins. The polymerization and gelation of food proteins with TG may affect qualities of many foods by modifying its physicochemical properties, including viscoelasticity. Basman et al (2003) found that TG did not improve the quality of soy flour–supplemented breads. A better understanding of the physicochemical changes in soy-wheat protein may lead to acceptable formulations. The aim of this work was to study the effect of TG on the interactions between gluten and soy proteins after mixing. TG changed the solubility patterns of soy-gluten proteins in buffer systems with specific chemical action on proteins and it was related with the formation of new covalent bonds between proteins. SDS-PAGE allowed identifying some protein bands which seemed to be involved in covalent cross-link between proteins. The TG addition caused a more compact microstructure in gluten-ISP "dough".