The acid value of mustard oil refers to the amount of free fatty acids (FFAs) present in the oil. FFAs are produced when the triglycerides in the oil break down, and the acid value is an indicator of the oil’s freshness and quality. A higher acid value typically indicates that the oil has undergone some degree of oxidation or degradation, which may result from factors like improper handling, exposure to heat, or prolonged storage.
To measure the acid value, a chemical test is performed, typically involving a titration process to quantify the free fatty acids in the oil. The results are expressed as milligrams of potassium hydroxide (KOH) required to neutralize the free fatty acids in 1 gram of oil. Lower acid values (around 1-2 mg KOH/g) are typically considered ideal for edible oils, indicating that the oil is of good quality. Higher acid values (above 3 mg KOH/g) suggest that the oil has deteriorated, making it potentially less safe for consumption.
A high acid value can signal poor-quality mustard oil, and if the oil has oxidized significantly, it may lose its health benefits, such as its antioxidant or anti-inflammatory properties. In some cases, oils with higher acid values can also pose health risks because they may contain harmful compounds resulting from oxidation. It’s particularly important to consider the acid value in cooking oils, as consuming oils with elevated FFAs over time may contribute to undesirable health effects.
To maintain the quality of mustard oil and keep its acid value within safe limits, it’s crucial to store it properly. Mustard oil should be stored in airtight containers in a cool, dark place to minimize exposure to heat and air, both of which accelerate oxidation. If you’re using mustard oil for cooking, ensure that it’s not overheated beyond its smoke point, as this can also increase the acid value.
Regarding certifications and testing, look for food safety certifications like FSSAI (Food Safety and Standards Authority of India) when purchasing mustard oil for consumption. Some high-quality mustard oils also undergo laboratory testing to ensure they meet safety standards, including tests for acid value, purity, and the absence of harmful contaminants.
The acid value of mustard oil is indeed an important factor when considering its quality and safety. You’re spot on—it’s a measure of the free fatty acids in the oil. The acid value is calculated by titrating the oil with a base, like potassium hydroxide, and the amount of base required gives an idea of the free fatty acid content. Generally, for edible mustard oil, an acceptable range might be up to 3 mg KOH/g oil, though this can vary slightly depending on standards and regulations.
When the acid value is high, it can suggest poor quality or even potential health risks. Prolonged exposure to heat, air, and improper storage can indeed increase this value, so it’s best to store mustard oil in a cool, dark place, preferably in a tightly sealed container. Keeping it away from direct sunlight and excessive heat is crucial.
Now, concerning its nutritional and functional properties, a higher acid value can compromise the oil’s health benefits. It can lead to rancidity, which might reduce its antioxidant and anti-inflammatory effectiveness. Rancid oil doesn’t just lose its health benefits—it can also become harmful to consume.
When you’re buying mustard oil, look for certifications like FSSAI in India or others appropriate to your country, ensuring it adheres to safety and quality standards. These certifications usually imply that the oil industry has met specific regulations on aspects like acid value.
In my own experience, I always try to check the manufacturing date and only buy in quantities I can use within a few months to avoid spoilage. Once, I had a bottle that didn’t smell right, probably due to high free fatty acids, and I just had to discard it. Better safe than sorry!
If you’re using mustard oil both for cooking and skincare, maintaining its integrity is key. It’s versatile and wonderful if it’s stored well and used within a safe timeframe.


