According to Gram Research analysis, fermenting germinated brown rice milk with friendly bacteria from traditional Thai foods raised total flavonoids by 80 to 170% and kept probiotic bacteria at high levels for 7 days in the fridge. The work was done in the lab, so health benefits in people still need testing.
Gram Research analysis of a 2026 laboratory study suggests that bacteria from traditional Thai fermented foods could turn germinated brown rice into a drink with more health-linked plant compounds. Researchers collected microbes from dough balls and Khao Mak, a Thai fermented rice dessert, and screened 111 isolates. They identified 59 lactic acid bacteria, the same friendly group used to make yogurt and pickles. One strain, Lactiplantibacillus plantarum KM7, produced a high amount of GABA, a compound linked to calm nerves. When another strain, SRK5, fermented a Red Jasmine rice milk, total flavonoids rose by 80 to 170% across the tested strains, and the drink stayed stable and rich in probiotics in the refrigerator for seven days. Changes in cell membrane fats and a small peptide called REY were also observed. All of this was tested in the lab and in cells, not in people, so the drink’s effects on human health remain unproven.
Key Statistics
A 2026 laboratory study published in Food Research International found that the bacterial strain Lactiplantibacillus plantarum KM7 produced 84.72 mg per gram of GABA, a compound linked to calming nerve signals.
A 2026 laboratory study that screened 111 bacterial isolates from traditional Thai fermented foods identified 59 lactic acid bacteria, and five strains kept more than 80% viability at pH 3.0.
A 2026 study in Food Research International found that fermented germinated brown rice milk kept probiotic levels between 8.0 and 9.0 log CFU/mL over 7 days of refrigerated storage at 4 degrees Celsius.
The Quick Take
- What they studied: Can friendly bacteria from traditional Thai foods be used to ferment germinated brown rice milk into a drink that keeps well and may carry more beneficial plant compounds?
- Who participated: No people took part. Researchers started with 111 bacterial samples from traditional Thai fermented foods, identified 59 friendly lactic acid bacteria, and tested the most promising strains in the lab, in human intestinal and kidney-type cells, and in batches of three rice varieties.
- Key finding: Fermenting germinated brown rice milk with selected strains raised total flavonoids (plant antioxidants) by 80 to 170% across the tested strains and kept probiotic bacteria at high levels for 7 days in the refrigerator. One strain, KM7, made 84.72 mg per gram of GABA, a calming compound.
- What it means for you: This is early lab work, so it does not show that drinking this rice milk improves health. It does suggest that traditional fermentation microbes could one day help make rice-based drinks with more plant compounds. Anyone with health concerns should talk to a doctor before changing their diet.
The Research Details
The researchers first searched traditional Thai fermented foods, such as dough balls and Khao Mak, for helpful lactic acid bacteria. These are microbes that turn sugars into acids and are commonly used in fermented foods. From 111 samples, they identified 59 lactic acid bacteria, and nine of these were good at breaking down starch, which can help make sugars available during fermentation.
Next, the team tested which strains could fight off six foodborne pathogens, which are germs that cause food poisoning. They also checked whether strains could survive conditions that mimic the human digestive tract, including very acidic conditions and bile salts. Five strains passed these tests and did not harm human intestinal cells or kidney-type cells grown in dishes. Genetic sequencing then confirmed the identities of two of the most promising strains.
Finally, the researchers fermented germinated brown rice milk made from three Thai rice varieties for 24 hours. They measured bacteria levels, acidity, antioxidant compounds, and the full chemical profile of the drink using a high-precision laboratory instrument. They also stored the drink at 4 degrees Celsius for seven days and tracked stability and taste scores.
Using a step-by-step lab approach lets researchers see each part of the process clearly. By testing bacteria first, then their survival in digestion-like conditions, then their effects in the final rice milk, the team could connect each strain’s behavior to the drink’s final qualities. This method is useful for finding promising options before costly studies in people.
The study uses modern tools, including genetic sequencing and detailed chemical profiling, which add confidence to the bacterial identities and the drink’s chemistry. However, the work was done in test tubes, dishes, and laboratory batches, not in people or animals. Results from lab conditions do not always carry over to real-world eating. The sample size is listed as not specified, so the 111 bacterial isolates are the closest count. The journal’s impact factor was not confirmed for this review. Readers should treat the findings as preliminary.
What the Results Show
Out of 111 bacterial samples, 59 were lactic acid bacteria, and several showed strong ability to survive stomach-like acidity and bile. Five strains kept more than 80% of their viability at pH 3.0, which is very acidic, and more than 90% in bile salts. These strains also did not harm the human cell lines tested in the lab, which is an early sign of safety, though it is not proof that the bacteria are safe to eat.
During a 24-hour fermentation, the selected strains kept their bacterial numbers high while lowering the drink’s pH below 5.0, making it more acidic. Total phenolic content, a group of plant antioxidant compounds, rose by up to 27%. Total flavonoids, another group of plant compounds, increased by 80 to 170% depending on the strain and rice variety. These gains suggest that fermentation may help release or create compounds that are otherwise locked in the grain.
The strain KM7 produced 84.72 mg per gram of GABA, a compound that acts as a calming signal in the nervous system. In Red Jasmine rice milk fermented by SRK5, the chemical profile showed major shifts, including changes in lysophospholipids and sphingoids, which are fats that form cell membranes. The drink also appeared to make a small peptide called Arg-Glu-Tyr, or REY, which some early research has linked to cartilage cell activity. This link is speculative and has not been tested in people.
Over seven days of refrigerated storage, the fermented drink kept probiotic levels between 8.0 and 9.0 log CFU/mL, which is a high concentration of live bacteria. Its chemistry remained stable, and sensory scores on a scale of 5 to 8 suggested acceptable taste and texture for most tasters.
Beyond the main results, the researchers found that several strains could break down starch, which may help the rice drink ferment smoothly and develop flavor. The stability of the drink over a week suggests it could potentially be sold as a refrigerated product. The authors describe the drink as a shelf-stable functional beverage, but the phrase should be read cautiously, since ‘shelf-stable’ usually means it can stay on a shelf without refrigeration, while this product was tested only in a refrigerator.
Previous research has shown that fermenting cereals and grains with lactic acid bacteria can increase antioxidant levels and create compounds such as GABA. This study adds to that body of work by focusing on germinated brown rice, a grain that is often overlooked, and on bacteria from traditional Thai foods. The strong flavonoid increases fit with earlier findings that fermentation can unlock plant compounds, though the exact results depend heavily on the strain and rice type.
The study was conducted in the lab, so it cannot tell us how the drink affects the human body. The cell tests used standard cell lines, which are simplified models and do not reflect the full complexity of a living person. The REY peptide’s possible effect on cartilage is a speculative idea that needs direct testing. The study also did not measure how people digest or absorb the drink’s compounds, and it did not test whether the drink tastes good enough to be widely accepted. Finally, the sample size of participants is not applicable because no humans were enrolled.
The Bottom Line
Based on current evidence, the strongest conclusion is that certain traditional Thai bacteria can ferment germinated brown rice milk into a drink that keeps well in the refrigerator and contains higher levels of some plant compounds. Confidence in these lab-level findings is moderate. Confidence that the drink improves human health is low, because no human trials have been done. People should not treat this as a health product or a substitute for medical care.
Food scientists, fermented-beverage producers, and researchers interested in rice-based probiotic drinks should find this work useful. People who follow plant-based diets or enjoy fermented foods may find it interesting as a future product. People who need medical treatment for conditions such as digestive disorders, joint problems, or anxiety should not rely on this research. Pregnant women, people with weakened immune systems, and anyone with food allergies should speak with a healthcare provider before trying new fermented drinks.
Because this is an early lab study, any real health benefit would take years to confirm. Typical steps include small human safety trials, then larger studies measuring digestion, absorption, and health outcomes. Realistically, consumers would likely wait several years before commercial versions of this drink, if they appear, could be backed by human evidence.
Frequently Asked Questions
Can fermented brown rice milk have more antioxidants than regular rice milk?
Lab research on germinated brown rice milk fermented with selected Thai bacteria found total flavonoid levels rose by 80 to 170% depending on the strain and rice variety. Total phenolic content increased by up to 27%. These results come from laboratory testing, not human studies, so the health impact is still unknown.
What is GABA and does the bacteria in fermented rice milk produce it?
GABA is a compound that helps calm signals in the nervous system. A 2026 lab study found that the strain Lactiplantibacillus plantarum KM7 produced 84.72 mg per gram of GABA during fermentation of rice milk. Whether drinking this would affect mood or sleep in people has not been tested.
How long does homemade probiotic rice milk stay fresh in the fridge?
In a 2026 laboratory study, fermented germinated brown rice milk stored at 4 degrees Celsius kept high probiotic levels and stable chemistry for 7 days. These results came from controlled lab conditions, so home preparations may differ. Check for off smells, mold, or unusual texture before drinking.
Are fermented rice drinks with probiotics proven to improve gut health?
Not yet. This research tested bacteria and rice milk in laboratory settings and cell cultures, not in people. The bacteria survived very acidic conditions and bile in lab tests, which is an early sign they may survive digestion, but gut health benefits have not been shown in human studies.
Want to Apply This Research?
- If you are trying a fermented rice drink, log how many servings you have per day, the brand or preparation method, and any digestive changes such as bloating, gas, or comfort, rating each on a simple 1 to 5 scale. Note the date the drink was opened to track how long it stays fresh in your refrigerator.
- Use the app to set a goal of trying one fermented food a day in place of a sugary snack, and record how you feel afterward. Store opened fermented drinks in the refrigerator, and use the app’s reminder feature to check expiration dates after opening. Keep your overall diet varied, since no single drink replaces vegetables, fruits, whole grains, and protein.
- Track fermented food intake, digestive comfort, and energy levels over a 4 to 8 week period, then review patterns with a healthcare provider if you have any ongoing concerns. Compare these notes with blood sugar or other health markers only if your doctor recommends it. Update your log whenever a new fermented product is introduced so you can spot any reactions early.
This article summarizes a laboratory study of bacteria and rice-based drinks. The research was not conducted in people, so its findings cannot confirm health benefits, safety, or effects on any medical condition. This content is for general education only and is not medical advice. Consult a qualified healthcare provider before making changes to your diet, especially if you are pregnant, nursing, managing a health condition, or taking medication.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.