The Benefits of Oat Flour in Gluten-Free Fermented Rice Cake: A Unique Summary of Processing, Quality, and Health Effects

Celiac.com 08/15/2025 - As more people are diagnosed with celiac disease and other gluten-related health issues, the need for nutritious, high-quality gluten-free foods is growing rapidly. One popular gluten-free food in many Asian cultures is fermented rice cake, a soft, steamed treat made primarily from refined rice flour. However, while it’s naturally gluten-free, refined rice flour lacks some important nutrients and has limitations when it comes to texture, shelf life, and digestibility.

This study explored whether substituting oat flour into fermented rice cake recipes could improve both the nutritional and functional qualities of the product. The research investigated how different levels of oat flour—ranging from 0% to 40%—influenced dough properties, cake texture, aroma, storage performance, and starch digestibility. The goal was to see if oat flour could be a useful ingredient for creating better gluten-free options for people with celiac disease or other dietary concerns.

Why Oat Flour?

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Oats are well-known for their health benefits. They are rich in fiber—especially a type called beta-glucan—as well as vitamins, minerals, and antioxidants. Regular consumption of oats has been linked to lower cholesterol, improved blood sugar control, and enhanced immunity. Importantly, pure oats are naturally gluten-free, although those with celiac disease must ensure the oats are processed in a gluten-free facility to avoid cross-contamination.

In this study, the researchers chose oat flour not only for its nutritional benefits but also for its potential to improve the texture and shelf life of rice-based baked goods. Oat flour has been shown in previous research to work well in some gluten-free applications, though its effects can vary depending on the specific product and processing method.

How the Study Was Conducted

The researchers made several batches of fermented rice cakes using a blend of rice flour and oat flour. The substitution levels of oat flour were set at 0%, 10%, 20%, 30%, and 40%. The cakes were prepared using traditional fermentation methods with yeast and Lactobacillus plantarum, a beneficial bacterium that enhances flavor and nutritional content.

They examined multiple characteristics of the dough and the final product, including:

• Water absorption and swelling capacity (hydration)
• Texture and elasticity (rheological properties)
• Cooking behavior and energy use (thermal properties)
• Cake volume and crumb structure
• Aroma and sensory evaluations
• Shelf life and retrogradation
• Digestibility of starch (using lab simulations of human digestion)

Key Findings: Processing and Texture

One of the main improvements observed was that oat flour helped the mixed dough absorb more water and swell more during fermentation. This led to better batter volume and structure. The oat flour also increased the dough’s elasticity and integrity, making it easier to work with and less prone to breaking apart.

Interestingly, even though oat flour reduced the peak viscosity and breakdown values during cooking (indicators of how the dough behaves under heat), the cakes still retained excellent shape and texture. At 20% oat flour substitution, the fermented rice cake had the best springiness and overall acceptability, with a soft yet resilient crumb.

Visual and Sensory Appeal

The microstructure of the cakes also improved. Cakes made with oat flour had a finer, more uniform internal texture, with fewer large holes or air pockets. This helped make the cake more cohesive and less crumbly.

Aroma was another area where oat flour made a difference. Using advanced techniques to analyze the volatile compounds responsible for smell, the researchers found that oat flour introduced unique nutty and sweet notes that were not present in the rice-only cakes. These pleasant aromas boosted the sensory scores during taste tests, with the 20% oat flour cake earning the highest overall satisfaction rating.

Storage and Shelf Life

A common problem with rice-based baked goods is that they harden quickly over time due to a process called retrogradation, where starch molecules realign and expel moisture. This study found that oat flour helped slow down this retrogradation. The water molecules in the oat-enhanced cakes were more tightly bound, helping the cake stay moist and soft for longer periods. This could significantly extend shelf life and reduce waste.

Health and Digestibility

From a health standpoint, one of the most meaningful findings was that oat flour slowed the digestion of starch. In lab simulations mimicking the human digestive system, cakes with oat flour released sugars more slowly than those without. This slower digestion is beneficial because it helps maintain steady blood sugar levels and can reduce the risk of insulin spikes, making it a potentially better option for people with diabetes or those watching their carbohydrate intake.

This effect was partly due to the formation of starch-lipid complexes and the structure created by oat beta-glucan, which resists quick enzymatic breakdown.

Why This Study Matters for People with Celiac Disease

For individuals with celiac disease, finding gluten-free foods that are not only safe but also enjoyable to eat and nutritionally complete can be a challenge. This study offers encouraging evidence that oat flour—when certified gluten-free—can enhance both the experience and the health impact of fermented rice cake, a naturally gluten-free staple.

By improving the cake’s texture, flavor, and shelf life while also offering slower digestion and better nutritional value, oat flour becomes a promising ingredient in the evolution of gluten-free foods. Moreover, the study contributes valuable insights into how alternative flours affect food structure and digestibility, paving the way for broader application in gluten-free baking.

Final Thoughts

This study successfully demonstrated that adding oat flour to fermented rice cake can yield a product that is healthier, more palatable, and longer-lasting. The ideal substitution level appears to be around 20%, which offers a balance between improved texture, flavor, and nutrition without compromising the quality of the product.

For the gluten-free community, especially those with celiac disease, these findings offer a new, evidence-based approach to enhancing traditional gluten-free foods. With oat flour’s ability to improve quality and function, it holds great promise in creating the next generation of safe, satisfying gluten-free products.

Read more at: sciencedirect.com