What is Rice Bran Extracted From? The Definitive Guide

December 9, 2025 •

2 min read

Rice is a staple food for over half the world's population, and during its processing, a valuable byproduct is created. The outer layer of the rice kernel, rich in nutrients, is known as rice bran, and it is extracted during the refining stages of rice milling. This extraction is a critical step that transforms a simple grain byproduct into a versatile ingredient with numerous applications.

Quick Summary

Rice bran is a byproduct obtained from the outer layer of the rice kernel during the milling process. The bran, along with the germ, is stripped away to produce refined white rice. This process yields a nutrient-dense material with applications ranging from edible oils and food products to animal feed.

Key Points

Source of Extraction: Rice bran is the brown outer layer of the rice kernel, consisting of the pericarp, aleurone layer, and germ, removed during the milling and polishing of rice.
Primary Extraction Method: The bran is mechanically stripped from the inner white rice grain during the milling process.
Lipase and Rancidity: Raw rice bran contains the enzyme lipase, which causes it to become rancid quickly, necessitating immediate stabilization after milling.
Stabilization Techniques: Common methods include thermal treatment (steam, microwave, extrusion) or chemical treatment to deactivate the rancidity-causing lipase enzyme.
Oil Extraction Methods: Rice bran oil is extracted using methods like solvent extraction (most common commercially), mechanical pressing, or supercritical CO2 extraction.
Versatile Applications: The extracted bran and oil are used in food products, animal feed, cosmetics, and for biofuel production.
Nutritional Value: Rice bran is a rich source of dietary fiber, protein, vitamins (B and E), minerals, and bioactive compounds like γ-oryzanol.

What Exactly is Rice Bran?

Rice bran is the nutrient-rich outer layer of the rice grain, consisting of the pericarp, aleurone layer, and germ. It is created as a byproduct when paddy rice is milled to produce white rice. While whole brown rice retains this layer, the milling process removes it to achieve the polished white grain preferred by many consumers. This mechanical separation is the primary method for producing rice bran in large quantities.

The Rice Milling Process: A Step-by-Step Overview

Rice bran is a byproduct of the rice milling process, which transforms paddy rice into polished white rice. The process involves several stages:

Pre-cleaning and De-stoning: Removing impurities from the rough rice.
Hulling/Dehusking: Removing the outer husk to get brown rice.
Bran Separation (Whitening/Polishing): Abrading the brown rice to remove the bran and germ layers, yielding white rice and rice bran.
Grading and Sorting: Separating broken grains for a quality final product.

The Extraction and Stabilization of Rice Bran

Once extracted, raw rice bran is prone to rancidity due to high lipase enzyme activity. Stabilization is crucial to deactivate these enzymes and extend shelf life.

Methods include:

Thermal Treatment: Using heat (steam, dry heat, microwave).
Extrusion: Combining heat, pressure, and shear forces.
Chemical Stabilization: Using acids like HCl.

The Extraction of Rice Bran Oil (RBO)

Stabilized rice bran is used to extract rice bran oil, known for its high smoke point. Common extraction methods include:

Solvent Extraction: Using a solvent like hexane.
Mechanical Pressing: Applying high pressure.
Supercritical CO2 Extraction: Using supercritical carbon dioxide.

Comparison of Oil Extraction Methods


Feature	Solvent Extraction (Hexane)	Mechanical Pressing (Cold)	Supercritical CO2 Extraction
Yield	Very high yield (up to 99%)	Lower yield (approx. 9-10% of bran weight)	High yield, comparable to hexane
Cost	Cost-effective and widely used commercially	Lower equipment cost, less energy-intensive	High initial equipment cost due to pressure requirements
Environmental Impact	Uses flammable and potentially hazardous chemical solvent	Very low environmental impact, no chemical waste	Green, non-toxic, and produces no solvent residue
Oil Quality	Requires further refining to remove solvent traces	Often yields higher quality oil with more nutrients	Produces very high-purity oil, ideal for sensitive compounds

Diverse Uses for Rice Bran

Rice bran has numerous applications:

Animal Feed: A valuable energy source for livestock and poultry.
Human Consumption: Added to foods for fiber and nutrients.
Cosmetics: Rice bran oil is used for its antioxidants and Vitamin E.
Fuel and Energy: De-oiled bran can produce biogas.
Pharmaceuticals: Bioactive compounds are used in supplements.

The Conclusion: From Byproduct to Valuable Commodity

Rice bran, a nutrient-rich byproduct extracted during rice milling, is a versatile resource. It is removed from the outer layers of the rice kernel when producing white rice and requires stabilization to prevent rancidity caused by lipase enzymes. Both the bran and its oil, extracted through methods like solvent extraction or mechanical pressing, have wide-ranging applications in food, cosmetics, animal feed, and energy, showcasing its importance in sustainable resource management.

Frequently Asked Questions

The primary source is the rice kernel during the milling process. The outer brown layer of whole-grain rice, which includes the pericarp, seed coat, and germ, is removed to produce polished white rice, yielding the byproduct known as rice bran.

Rice bran must be stabilized because it contains the enzyme lipase, which becomes active when the bran is separated from the rice kernel. This enzyme breaks down the oil in the bran, causing it to go rancid very quickly, making it unfit for human consumption or oil extraction without stabilization.

Brown rice is a whole-grain rice that retains its bran and germ layers, which gives it a chewy texture and nutty flavor. White rice has had these outer layers, including the bran, removed and polished, resulting in a whiter appearance and a milder flavor.

Yes, stabilized rice bran is edible and can be a healthy addition to the human diet. It is a rich source of dietary fiber, protein, and beneficial antioxidants. It is often incorporated into baked goods, cereals, and health supplements.

Rice bran oil is a versatile cooking oil known for its high smoke point and neutral flavor, making it suitable for various high-temperature cooking methods like stir-frying. It is also widely used in cosmetics for its moisturizing and anti-aging properties.

In solvent extraction, stabilized rice bran is soaked in a solvent, typically hexane, which dissolves the oil. The oil-rich solvent mixture is then distilled to evaporate the solvent, leaving behind the crude rice bran oil for further refining.

Yes, as a byproduct of rice milling, rice bran is considered a sustainable resource. Its utilization in a wide array of products, from food and cosmetics to animal feed and biofuels, reduces waste and adds significant economic value to rice production.