Development of Gluten-Free Bread With High-Protein Rice Flour and Effects of Alpha-Amylase Enzyme on Bread Properties

Abstract

Gluten-free products frequently contain low protein, fiber, and micronutrient levels, while being high in fat and carbohydrate content. Starch is a major component used in gluten-free foods to control texture, but this results in higher glycemic products that are less healthy for consumers who are both celiac and diabetic. The objective of this study was to incorporate two types of rice flour (brown and white) obtained from a high-protein rice cultivar into a gluten-free bread formulation to increase protein content and to assess the addition of alpha-amylase (α-amylase) enzyme as an ingredient to replace starch. Four formulations of bread (WF: high-protein white rice flour, WFE: high-protein white rice flour with α-amylase enzyme, BF: high-protein brown rice flour, BFE: high-protein brown rice flour with α-amylase enzyme) were developed. Bread samples were analyzed for nutritional composition, physical characteristics, and sensory attributes. Consumer purchase intent was assessed before and after a health claim presentation. Breads with α-amylase enzyme significantly enhanced quality, increasing specific volume and improving texture by reducing hardness and chewiness while increasing cohesiveness values. The α-amylase enzyme demonstrated no significant effect on bread's color. However, it had a positive influence on the sensory attributes, making it more appealing to consumers. Additionally, breads with α-amylase addition were more attractive to consumers both before and after reading the health claim. The study demonstrated promising potential of incorporating small amounts of α-amylase enzyme (0.1% of total dry ingredients) in combination with high-protein rice flours for developing GF breads. PRACTICAL APPLICATIONS: This study demonstrates that adding alpha-amylase enzyme to gluten-free (GF) bread formulations positively improves various desirable qualities in GF products including specific volume and texture. Furthermore, the use of high-protein rice flours not only boosts nutritional value but also increases consumer purchase intent when marketing these improved GF breads. These findings highlight exciting possibilities for advancing both the quality and marketability of GF bread products.

Keywords: alpha‐amylase; bread; high‐protein rice; texture.