Evaluation of glucomannan as a fat replacer in the dough and cookies made from fermented cassava flour and soy protein concentrate

This work evaluated the structure and quality parameters of dough and cookies prepared using fermented cassava flour, soy protein concentrate, and glucomannan. Glucomannan was incorporated as a fat replacement. The levels of fat replacement were 0%, 10%, 20%, and 30% (CS100, GL90, GM80, and GH70, respectively) relative to the original fat content. Rheological analysis showed that the loss tangent of GH70 dough was the lowest (0.39) with an angular frequency of 0.62 rad/s. Thus, glucomannan affected the dough and caused it to exhibit more solid-like behaviors. Glucomannan covered the starch granules, which mimicked that of fat. A complex interaction was confirmed among starch, glucomannan, and protein in the dough. Glucomannan decreased dough hardness and adhesiveness but significantly increased (p < 0.05) cookie hardness, crispiness, and spread ratio. Dough with low rheological properties, adhesiveness, and hardness will produce good-quality cookies. Glucomannan can be applied as a fat replacer in cookies.