論文ID: jag.JAG-2021_0007
Wheat flour-based batter containing 0% to 20% trehalose was deep-fried, dried and held in various water activity (αw) conditions. The effects of trehalose content and αw on oil content, water sorption, isothermal mechanical relaxation, and fracture properties were investigated. For comparison, the fracture properties of freeze-dried porous waxy corn starch solids were also investigated. The 10% trehalose sample had the lowest oil content, water content, and αw. A force-reduction value (ΔF) of the samples was evaluated as a typical mechanical relaxation parameter. ΔF gradually increased with increasing αw and sharply increased above a specific αw presumed to be associated with the glass to rubber transition. Compared to ΔF values among the glassy samples, 10% and 20% trehalose samples had higher ΔF values (were more rigid) than 0% and 5% trehalose samples. From the fracture measurements of the glassy samples, the first fracture force increased linearly and the number of fracture peaks decreased linearly with increasing αw. At each αw, 10% trehalose had the lowest first fracture force and the highest the number of fracture peaks. Freeze-dried porous waxy corn starch solids showed similar fracture properties to deep-fried samples. These findings suggest that around 10% trehalose content is optimal for producing deep-fried foods with a brittle texture.
