Development of Low-Calorie Oat Bars Fortified with Soy Protein

Abstract

This research aimed to develop low-calorie oat bars fortified with soy protein by substituting sugar with stevia syrup. The sensory evaluation of oat bars with the substitution of stevia syrup at 0% (control), 30%, 50%, and 70% showed no significant differences (p>0.05) in color, aroma, and taste. However, the 50% formulation received the highest overall preference score (7.66). Color analysis showed no significant differences (p>0.05) in L* values among
the formulations. The 50% formulation exhibited higher redness (a* = 1.15) and yellowness
(b* = 8.70). The study of soy protein supplementation in stevia syrup-substituted-oat bars at 0% (control), 10%, 15%, 20%, and 30% found that 10% soy protein formulation received the highest sensory evaluation scores in color, texture, and overall preference, with scores of 7.26, 7.03, and 7.31, respectively. Increasing the soy protein content resulted in an increasing trend in the lightness (L*) value of the product. Similarly, the redness (a*) and yellowness (b*) values also increased, ranging from 1.09 to 1.47 and 7.50 to 9.76, respectively. The 10% supplementation formulation had the lowest moisture content (2.35%) and the lowest water activity (0.27). As soy protein content increased, the hardness of the product tended to decrease. The 10% formulation exhibited the highest hardness (528.51 Newtons), adhesiveness (9.04), and chewiness (325.90 Newtons). The proximate analysis showed that oat bar supplemented with 10% soy protein had significantly higher protein (21.81%), fat (1.24%), ash (2.51%), and dietary fiber (8.30%) contents compared to the control. Additionally, this formulation provided lower energy content than the control formulation.