Effect of stepwise baking on the structure, browning, texture, and in vitro starch digestibility of cookie

- Water evaporation rates were described by two lines of Arrhenius formula.
- In vitro starch digestibility of cookie was reduced by the stepwise baking.
- Localized starch melting was suggested in the stepwise-baked cookie.

In order to demonstrate stepwise baking without starch melting of cookie, the effects of water content on the starch melting temperature (Tm) and baking temperature on the water evaporation rate were investigated in cookie dough. The Tm of starch was confirmed to increase with the decrease in water content. The water evaporation rate was evaluated by first-order kinetics, and temperature dependence of the water evaporation rate was described by two Arrhenius lines intersecting at approximately 107 °C. From these results, stepwise baking set to at least 10 °C lower than the starch Tm was designed. The spread factor of the stepwise-baked cookie was lower than that of conventionally baked cookie (control). Further, browning differed minimally and no significant difference in rupture force was observed between methods. The non-hydrolyzed starch content at a given condition was much higher in the stepwise-baked cookie than in the control.