What Oils Can Be Hydrogenated for Commercial Use?

December 14, 2025 •

4 min read

The commercial process of hydrogenation, invented in the early 20th century, transformed the food industry by converting liquid vegetable oils into solid or semi-solid fats. Primarily, any unsaturated fat can be hydrogenated to alter its physical and chemical properties. This chemical modification is widely used to create stable ingredients for food, cosmetics, and industrial products, and its application depends on the original oil's fatty acid profile.

Quick Summary

A diverse range of unsaturated oils, including soybean, canola, and palm oils, can be hydrogenated to become solid or semi-solid fats. This process enhances their shelf life, texture, and stability for various applications. It involves adding hydrogen atoms to the oil's double bonds under specific conditions. Both partial and full hydrogenation modify the final product's characteristics, with full hydrogenation eliminating the harmful trans fats found in partially hydrogenated oils.

Key Points

Any Unsaturated Oil: The core principle of hydrogenation is adding hydrogen to unsaturated double bonds, meaning any liquid oil with these bonds can be modified.
Common Examples: Frequently hydrogenated oils include soybean, canola, palm, and cottonseed oils to improve stability and texture.
Purpose: Hydrogenation converts liquid oils into solid or semi-solid fats, increasing their shelf life and stability for applications in food and cosmetics.
Partial vs. Full: Partial hydrogenation, now largely banned for food use, created unhealthy trans fats, while full hydrogenation produces saturated fats with no trans fats.
Modern Application: Today, fully hydrogenated oils are used as a trans-fat-free hardstock for blending with liquid oils to achieve desired consistency.
Process Control: The extent of the hydrogenation process determines the final product's physical properties, such as melting point and hardness.

Common Vegetable Oils for Hydrogenation

The process of hydrogenation is applicable to a variety of oils, particularly those with a high degree of unsaturation (presence of double bonds in their fatty acid chains). These liquid oils are converted into more solid fats, which have a longer shelf life and desired textural properties for manufacturing. The most commonly hydrogenated oils include soybean oil, canola oil, and cottonseed oil, along with several others derived from plant sources.

Soybean Oil

Soybean oil is one of the most widely used vegetable oils in the world and is frequently hydrogenated. Its natural form contains high levels of polyunsaturated fats, which are susceptible to oxidation and spoilage. Hydrogenation increases its stability and raises its melting point, making it suitable for creating margarine, shortening, and other commercial products. The hydrogenation process can be controlled to achieve different degrees of saturation for various applications.

Canola Oil

Canola oil, derived from rapeseed, is another oil commonly subjected to hydrogenation. The process converts its liquid form into a semi-solid fat used for margarine and shortening, extending its shelf life and improving its functional properties. Historically, partial hydrogenation of canola oil contributed to the trans fat content in food products, but industry efforts and regulatory changes have pushed for healthier alternatives, often using fully hydrogenated canola oil blended with unhydrogenated oils.

Cottonseed Oil

Historically, cottonseed oil was one of the first oils to be hydrogenated commercially to create alternatives to animal fats like lard. The process increases its stability and melting point, producing a solid or semi-solid fat with a mild flavor, which is used in shortenings and bakery goods. It's also utilized in cosmetics for its moisturizing and emollient properties. Studies have compared the hydrogenation of cottonseed oil versus soybean oil, noting that cottonseed oil tends to produce less trans fatty acid content under similar hydrogenation conditions.

Palm Oil and Palm Kernel Oil

Palm oil and palm kernel oil are often hydrogenated to increase their saturation levels, which makes them more stable and solid. This process is used for applications requiring a higher melting point, such as specific types of margarine, shortenings, and cosmetic ingredients. Full hydrogenation of palm oil is sometimes used to create a non-trans fat hardstock for blending.

Other Oils

Many other oils can be hydrogenated, depending on the desired outcome:

Sunflower Seed Oil: Can be hydrogenated to increase stability for specific uses.
Coconut Oil: Already highly saturated, but can be fully hydrogenated to create a very solid fat with a high melting point for confectionery and coatings.
Fish Oil: Can be hydrogenated to create a palatable, solid fat for certain food products, as the process removes the fishy odor and taste.

Partial vs. Full Hydrogenation

Understanding the difference between partial and full hydrogenation is crucial, particularly concerning the formation of trans fats and their health implications. Partial hydrogenation, historically used to produce semi-solid fats, was the primary source of industrial trans fats. These artificial trans fats have been linked to an increased risk of heart disease. Regulatory actions, such as the FDA's ban on partially hydrogenated oils (PHOs) for food use, have largely eliminated their presence in the food supply.

Full hydrogenation, in contrast, drives the reaction to completion, converting all unsaturated bonds to saturated bonds. This process creates a very hard, solid fat that contains virtually no trans fats. Food manufacturers now often use fully hydrogenated oils as a 'hardstock' and blend them with unhydrogenated liquid oils to achieve the desired consistency without generating trans fats.

Comparison of Hydrogenated Oil Types


Feature	Partially Hydrogenated Oil	Fully Hydrogenated Oil
Saturation Level	Incomplete saturation of double bonds.	Complete saturation of all double bonds.
Consistency	Semi-solid at room temperature, like soft margarine.	Very hard, solid fat at room temperature.
Trans Fat Content	Contains significant levels of industrial trans fats.	Contains virtually no trans fats.
Health Implications	Linked to negative health effects like heart disease.	Considered a healthier alternative to PHOs, though high in saturated fat.
Shelf Life	Increased due to improved oxidation resistance.	Increased due to highest oxidation resistance.
Food Applications	Historically used in margarine, shortening, and processed foods; now largely phased out.	Used as a trans-fat-free 'hardstock' for blending to achieve texture in modern products.

Conclusion: The Evolution of Hydrogenated Oils

The question of what oils can be hydrogenated is fundamentally tied to the presence of unsaturated fatty acids within their molecular structure. The hydrogenation process allows for the transformation of any unsaturated liquid oil, from common sources like soybean and canola to more specialized oils like cottonseed and fish oil, into a solid or semi-solid fat. The control over this process, particularly the distinction between partial and full hydrogenation, has been a central theme in food science and public health for decades. The phase-out of partially hydrogenated oils has prompted the food industry to innovate, shifting towards fully hydrogenated oils and interesterification to achieve desired product textures without the associated health risks of industrial trans fats. This evolution underscores the continuous effort to balance food functionality with consumer health considerations, demonstrating how scientific understanding and regulatory pressure can drive significant change in food manufacturing processes.

Learn more about the chemical process of hydrogenation on Wikipedia's article on fat hydrogenation.

Frequently Asked Questions

The primary purpose is to convert liquid unsaturated oils into solid or semi-solid fats, which increases their melting point, extends shelf life by improving oxidation resistance, and enhances product texture.

Yes, coconut oil can be fully or partially hydrogenated. As it is already naturally high in saturated fat, full hydrogenation is used to create a very hard, high-melting-point fat for specific confectionery and cosmetic applications.

Partially hydrogenated oil contains industrial trans fats, which are linked to negative health effects like heart disease. Fully hydrogenated oil, in contrast, contains virtually no trans fats and is considered a healthier alternative, though it is high in saturated fat.

The food industry moved away from partially hydrogenated oils due to overwhelming evidence linking the trans fats they contain to heart disease. Regulatory actions, including bans by the FDA, prompted this shift towards healthier alternatives.

Fully hydrogenated soybean oil is still used in food manufacturing as a trans-fat-free hardstock, often blended with other liquid oils to achieve a desired consistency. The partially hydrogenated version, which contained trans fats, has been phased out.

Yes, hydrogenation significantly increases the stability of oils. By converting unsaturated double bonds into saturated single bonds, it makes the oil less susceptible to oxidation, which causes rancidity and spoilage.

Historically, partially hydrogenated oils were common in margarine, vegetable shortening, packaged baked goods, fried foods, and processed snacks. Most of these products have been reformulated to remove PHOs.