Exploitation of Aureobasidium pullulans NRRL Y-2311-1 xylanase in mulberry and rice flours-based gluten-free cookie formulation: Effects on dough properties and cookie characteristics.

Xylanases are mainly utilized in bakery industry for the hydrolysis of dietary fiber-based fractions. Their applications in gluten-free products have not been considered before. In the present study, the xylanase produced by Aureobasidium pullulans NRRL Y-2311-1 was utilized in a mulberry and rice flours-based gluten-free cookie formulation for the first time. Effects of various xylanase concentrations on gluten-free dough rheology and cookie characteristics were elucidated. Only rice flour-based cookie and only wheat flour-based cookie formulations were also prepared as comparison. Incorporation of xylanase into all cookie recipes resulted in softer cookie doughs with lower absolute stickiness. The hardness and absolute stickiness of the cookie doughs prepared by the mixture of mulberry and rice flours decreased by the addition of the enzyme into the formulation in a concentration-dependent manner. Enzyme concentrations above 100 U/100 g flour did not provide statistically significant further changes on gluten-free cookie doughs. Incorporation of xylanase into the cookie recipes resulted in increased baking loss and spread ratio in an enzyme concentration-dependent manner for all cookie types. Hardness values of both types of gluten-free cookies decreased by xylanase incorporation. Different effects on fracturability were observed depending on the cookie type and enzyme concentration. Enzyme concentration of 100 U/100 g flour provided mulberry and rice flours-based cookies with a more flexible and softer structure. No significant effects on color parameters of cookies were observed by xylanase incorporation.