The effect of amylolytic activity and substrate availability on sugar release in non-yeasted dough

• The relative importance of enzymes and substrate in sugar release was studied.
• β-Amylase can provide a high amount of maltose in absence of α-amylase.
• α-Amylase activity and damaged starch content are limiting factors for sugar release.
• Increment of maltose level requires higher levels of α-amylase and/or damaged starch.

During bread making, the sugar content in dough changes continuously due to enzymatic starch degradation. Despite its importance, the relation between amylase activity and sugar release in dough is ill documented. In this work, the relative importance of α- and β-amylase activity and substrate availability on the dynamics of sugar release in dough was studied. Analysis of non-yeasted dough samples from Bilux flour (Falling number [FN] 477 s) and Bison flour (332 s) revealed that maltose was released quickly during mixing (≈1.0% dm) and reached ≈2.0% dm after resting (180 min). Inhibition of α-amylase in Bilux flour indicated that >85% of the maltose release during resting could be attributed to endogenous β-amylase activity. α-Amylase supplementation markedly increased maltose release from 2.0 to 4.7% dm after resting. Barley β-amylase addition, on the contrary, left maltose levels virtually unchanged. Maltose concentrations were also increased, up to 3.6% dm, by increasing the damaged starch content from 6.4 to 10.6% dm. In conclusion, this work shows that β-amylase can provide a relatively high amount of maltose in the absence of α-amylase. Higher maltose levels require either higher levels of endogenous or added α-amylases or increased damaged starch levels.