Quality Characteristics of Black Rice Cookies as Influenced by Content of Black Rice Flour and Baking Time

摘要

Response surface methodology was used to investigate the cookie manufacturing process with black rice flour. A three-variable, three-level central composite design was employed where the independent variables were the amount of black rice flour (0-20%), baking time (10 - 14 min), and sugar type (sucrose, aspartame, and oligosaccarides). pHs of dough and cookie tended to increase with the addition of black rice flour. Moisture content of dough slightly increased with the addition of black rice flour but nearly affected by baking time. Spread factor increased with the addition of black rice flour and it was more evident in the samples prepared with sucrose. L*-value decreased but a*-value increased significantly with the addition of black rice flour.Generally the amount of black rice flour in the sample did not affect the textural characteristics of cookie. As the amount of black rice and baking time increased, sensory flavor became stronger. Sensory sweetness as well as hardness increased but sensory color became darker with the addition of black rice flour. In addition, the response surface models developed in this study for most of physicochemical and sensory characteristics of black rice cookie were adequate.