Effects of microbial transglutaminase on gluten-free sourdough bread structure and loaf characteristics

The effects of microbial transglutaminase (mTG) on structure and loaf properties of gluten-free (GF) sourdough breads containing five different flours: chickpea, brown rice, white rice, oat, and quinoa. SDS-PAGE analysis revealed that white rice, brown rice, quinoa, and chickpea proteins are adequate substrates for mTG activity, while oat proteins, without the addition of exogenous proteins, lack the characteristics suitable for mTG action. Additionally, mTG engages in self-crosslinking. The utilization of mTG in GF sourdough bread applications was shown to improve some of the final bread characteristics of GF breads. White rice- and brown rice-GF sourdough loaves at 24 h showed a 28% and 13% decrease, respectively, in crumb firmness with the addition of 2 Units mTG per gram (U/g) of dough. Quinoa-GF sourdough breads at 24 h showed a 6% increase in specific volume with the addition of 1 U/g. Oat- and chickpea-GF sourdough loaves did not show improvements in loaf quality with mTG addition.