Utilization of okara in daily meals : Properties and sensory evaluation of boiled rice, bread and udon containing okara as a part of ingredients

Abstract

  Okara, a significant byproduct of soy milk and tofu manufacturing, is so rich in dietary fiber that the increase of its intake is strongly recommended to prevent lifestylerelated diseases. However, the utilization of okara as a food ingredient is practically limited and a large amount of okara is treated as industrial waste that can cause environmental pollution. In the present study, the inclusion of okara into staple food, such as boiled rice, bread and udon, was tried in order to attain a daily intake of okara, and then the acceptability and the physical properties of the products ; the surface structure, the color and the texture were also evaluated.
  Two types of freeze-dried okara powders were used ; one (FD okara) was prepared by direct freeze-drying and another (HFD okara) was freeze-dried after homogenization of okara slurry in order to decrease the size of okara fibers. Boiled rice containing up to 1% okara powders was acceptable. The products containing more than 2% okara powders were not accepted due to the coarse surface texture caused by adhering okara powders. Bread with the replacement of flour with 5% and 10% okara powders was acceptable. The products with 5% replacement were as soft in texture as controls without replacement but the 10% replacement gave a little harder texture. In the case of udon, 10% replacement was acceptable. HFD okara gave a little better evaluation than FD okara. Okara was thus applicable to staple food to some extent and therefore the utilization of okara in daily meals should be expected.