Fermented brown rice (FBR) is a functional food created when the whole grain is subjected to controlled microbial action. This process transforms brown rice, enhancing its nutritional accessibility and introducing new bioactive compounds. The microbial conversion changes the rice’s fundamental composition, offering potential health advantages that differ from its unfermented counterpart. This article details the process of making FBR, the resulting chemical changes, and the systemic effects these changes have on the human body.
The Process of Fermenting Brown Rice
The fermentation relies on the metabolic activity of specific microorganisms, commonly involving lactic acid bacteria (LAB) such as Lactobacillus plantarum and fungal strains like Aspergillus oryzae (koji). The process begins by soaking the brown rice kernels, which breaks down the grain’s structure and makes starches accessible to the microbes. This initial step is performed at a controlled temperature, often between 25 and 40 degrees Celsius, to encourage microbial growth.
The microbial agents are then introduced using either solid-state fermentation, where microbes grow on the moist grain, or submerged fermentation in a liquid medium. During this period (16 to 48 hours), the microbes consume carbohydrates and produce organic acids, peptides, and amino acids. This conversion alters the flavor and texture of the rice and significantly increases its content of functional compounds, making the final product softer, easier to digest, and nutritionally enhanced.
Nutritional Changes After Fermentation
Fermentation alters the nutritional profile of brown rice by increasing the bioavailability of existing nutrients and synthesizing new bioactive molecules. One significant change is the reduction of phytic acid, an anti-nutrient that binds to minerals like zinc and iron, inhibiting their absorption. Fermentation activates the enzyme phytase, which can reduce phytic acid levels by over 50%, significantly improving mineral uptake.
Microbial activity also leads to the synthesis of various functional compounds, most notably gamma-aminobutyric acid (GABA), a non-protein amino acid and neurotransmitter. FBR contains substantially higher concentrations of GABA compared to unfermented brown rice, with levels potentially increasing by more than double. Furthermore, the process enhances the antioxidant capacity of the rice by increasing phenolic compounds and flavonoids. Complex starches and proteins are hydrolyzed into simpler components, making the fermented rice easier for the human digestive system to process.
Systemic Health Effects
The altered nutritional composition of FBR translates into several effects on systemic health, particularly concerning the digestive and nervous systems. The lactic acid bacteria in FBR may exert a probiotic effect, supporting the balance of the gut microbiota. These bacteria contribute to the production of short-chain fatty acids (SCFAs) like butyrate, which serve as an energy source for colon cells and help maintain the integrity of the intestinal barrier.
The substantial increase in GABA content offers a direct link to nervous system function, contributing to better stress management and sleep quality. As an inhibitory neurotransmitter, GABA slows down nerve impulses in the brain, promoting calmness and relaxation. This influence on the gut-brain axis suggests that consuming FBR can indirectly support emotional balance and cognitive function.
FBR can also play a supportive role in managing blood sugar levels, offering an advantage over unfermented grains. The breakdown of complex carbohydrates results in a product with a lower glycemic index, meaning glucose is released more slowly into the bloodstream. This slower absorption rate helps regulate the insulin response, contributing to improved post-meal glucose control. Enhanced levels of compounds like ferulic acid and specific peptides further contribute to improving lipid and glucose metabolism.
How to Consume Fermented Brown Rice
Fermented brown rice is available in several convenient forms, making it simple to incorporate into a regular diet. One common form is as a whole grain, which can be cooked and eaten as a side dish or base for meals, often having a softer texture and a slightly tangy flavor. It is also processed into fine powders or flours that can be mixed into smoothies, yogurts, or used in baking.
Other forms include pastes or beverages like amazake, a traditional Japanese drink. FBR is also found in supplement form, typically encapsulated or as a powdered extract. When introducing FBR, start with small portions to allow the digestive system to adjust to the increased fiber and beneficial bacteria. Store any homemade or perishable forms in the refrigerator to maintain freshness.