What is the Bran of Rice? Understanding its Composition and Health Benefits

December 8, 2025 •

3 min read

Rice bran constitutes approximately 10% of the rice grain's total weight, making it a significant byproduct of the milling process. The bran is the hard, outer layer that is removed to produce polished white rice, but it is also the most nutritious part of the grain. So, what is the bran of rice and what makes it so valuable for both human health and industry?

Quick Summary

The bran of rice is the fiber-rich outer layer removed during milling to produce white rice. It is a potent source of vitamins, minerals, and antioxidants like gamma-oryzanol, offering significant nutritional benefits for health and dietary applications.

Key Points

Nutrient-Rich Outer Layer: The bran of rice is the hard outer layer of the rice kernel, comprising the pericarp, aleurone, and germ, removed during the milling process.
Rich in Antioxidants: It is a powerful source of antioxidants, including gamma-oryzanol and vitamin E, which combat oxidative stress and inflammation.
Digestive and Heart Health: High dietary fiber content promotes regular digestion, while healthy fats and phytochemicals help lower cholesterol and support cardiovascular function.
Requires Stabilization: Due to an active lipase enzyme, raw rice bran must be stabilized (often with heat) immediately after milling to prevent rapid rancidity and preserve its quality.
Versatile Applications: Beyond its traditional use as animal feed, rice bran is processed into edible oil, used as a functional food ingredient, and utilized in cosmetics and nutraceuticals.

What is the Bran of Rice?

The bran of rice refers to the nutrient-rich, hard outer layer of the brown rice kernel. This layer is a key component of whole-grain rice, containing a vast majority of the grain's vitamins, minerals, and fiber. It is stripped away during the milling process to produce polished white rice, which removes a large portion of the grain's nutritional content.

The Nutritional Profile of Rice Bran

Rice bran is considered a nutritional powerhouse, packed with a wide array of beneficial compounds:

Dietary Fiber: Contains both soluble and insoluble fibers that support digestive health and help regulate blood sugar and cholesterol levels.
Vitamins: An excellent source of B vitamins (B1, B3, B6) and high levels of antioxidant vitamin E (tocopherols and tocotrienols).
Minerals: Provides significant amounts of magnesium, phosphorus, potassium, zinc, and iron, vital for various bodily functions.
Healthy Fats: The oil content is rich in monounsaturated and polyunsaturated fats, including omega fatty acids beneficial for heart health.
Bioactive Compounds: A key component is gamma-oryzanol, a unique antioxidant with cholesterol-lowering and anti-inflammatory properties, along with other phytochemicals like ferulic acid and phytic acid.

The Health Benefits of Consuming Rice Bran

The rich composition of rice bran translates into numerous health benefits:

Cardiovascular Health: Healthy fats, fiber, and gamma-oryzanol can help reduce cholesterol levels.
Antioxidant and Anti-inflammatory Effects: Abundant antioxidants neutralize free radicals and combat oxidative stress and inflammation.
Digestive Wellness: High fiber content aids in maintaining regular bowel movements and supports a healthy gut.
Potential Anti-cancer Properties: Research suggests potential in preventing certain cancers, like colorectal cancer.
Diabetes Management: Fiber helps regulate blood sugar levels, beneficial for managing type 2 diabetes.

Processing and Stabilization of Rice Bran

Raw rice bran is unstable due to an active lipase enzyme that causes rapid rancidity once separated from the endosperm. Stabilization is crucial for preservation and allows it to be used in food applications. Common stabilization methods include:

Heat Treatment: Deactivates the lipase enzyme using heat (e.g., steaming).
Extrusion: Uses high temperature and pressure to inactivate enzymes.
Acidic Treatment: Reduces enzyme activity using an acidic solution.

Comparison of Rice Bran with Other Cereal Brans

Rice bran differs from other popular brans like wheat and maize bran. A comparison of general characteristics:


Feature	Rice Bran	Wheat Bran	Maize Bran
Fat Content	High (15-20%)	Low (3-5%)	Low to Moderate
Fatty Acid Profile	Balanced, rich in oleic and linoleic acids	Lower fat content	Variable, contains linoleic acid
Unique Bioactive Compounds	Gamma-oryzanol, ferulic acid, tocotrienols	Contains ferulic acid	Contains ferulic acid, phytic acid
Protein Content	11-17% (gluten-free)	13-17% (contains gluten)	10-14%
Primary Use	Oil extraction, functional foods	Digestive aid, baking	Animal feed, biofuel production

The Versatile Uses of Rice Bran

Due to its nutritional value and functional properties, rice bran is used across several industries:

Food Industry: Stabilized bran is added to bakery items, cereals, pasta, and beverages to boost nutrition.
Rice Bran Oil: Popular for high-heat cooking due to its high smoke point and mild flavor.
Cosmetics and Skincare: Antioxidants and vitamin E are used to nourish skin and combat aging.
Nutraceuticals: Gamma-oryzanol and other phytochemicals are isolated for dietary supplements.
Animal Feed: Widely used as a nutritious feed for livestock.
Industrial Applications: Explored for use in biofuels and biodegradable plastics.

For more detailed information on its many health applications, you can explore research from the National Institutes of Health. [^1]

Conclusion

The bran of rice is a nutrient-dense component of the rice grain, offering significant health benefits and versatile applications. Rich in fiber, vitamins, minerals, healthy fats, and unique antioxidants like gamma-oryzanol, it holds substantial value. Stabilization is key to overcoming its enzymatic instability, enabling its use in foods, oil, cosmetics, nutraceuticals, and animal feed. Ongoing research continues to highlight rice bran's potential as a valuable, health-promoting resource.

[^1]: Biological Functions and Activities of Rice Bran as a ... (https://pmc.ncbi.nlm.nih.gov/articles/PMC8655829/)

Frequently Asked Questions

Brown rice is the whole rice grain with only the inedible outer husk removed. It still contains the bran layer, which is what gives it a brownish color. Rice bran is the isolated outer layer itself, removed from brown rice during the milling process to produce white rice.

No, rice bran oil is naturally cholesterol-free. It contains compounds like gamma-oryzanol and phytosterols that actually help lower LDL ("bad") cholesterol levels.

Raw rice bran contains an active lipase enzyme. When the bran is separated from the rest of the grain during milling, this enzyme is released and quickly breaks down the oil within the bran, causing it to go rancid. Heat stabilization is necessary to inactivatet this enzyme and extend the shelf life.

Yes, rice bran is naturally gluten-free. This makes it a suitable and nutritious ingredient for individuals with celiac disease or gluten sensitivities.

In cooking, rice bran is often used as oil for frying and sautéing due to its high smoke point and mild flavor. Stabilized rice bran powder can also be added to bakery items, cereals, and other food products to increase their fiber and nutrient content.

Increasing the amount of fiber in your diet, including from rice bran, can cause side effects like gas and stomach discomfort during the initial weeks as your body adjusts. People with digestive tract problems like ulcers should use caution.

Both rice bran and oat bran are good sources of dietary fiber. Rice bran is particularly noted for its unique antioxidants like gamma-oryzanol, which are not present in oat bran. Both have been shown to help lower cholesterol, though studies have indicated that rice bran oil, specifically, is a powerful cholesterol-reducer.