Sunflower oil has been found to be adulterated with edible and non-edible oils in the past. Some of the common adulterants are palm oil, castor oil, rapeseed oil, cottonseed oil, corn oil and paraffin oil. Out of these castor oil and paraffin oils are not recommended for cooking because of the health hazards associated with their usage.
Adulteration is done with these oils because these match physical or chemical properties of sunflower oil and are much cheaper than sunflower oil. So, adulteration with these oils brings more profits.
Checking Sunflower Oil adulteration
It is not possible to check adulteration of sunflower oil at home in most of the cases using our senses (smelling, tasting, etc.). However, there are elaborate procedures available in labs for testing adulteration with different types of other oils or impurities.
1/4. Mixing of Sunflower oil with Palm Oil
Mixing of Sunflower oil with Palm Oil can be detected by checking fatty acid components, or by checking presence or absence of carotenoids, a colour pigment, in oils.
Pure Sunflower oil does not have carotenoids but palm oil does have these. Presence of carotenoids is a clear indication of adulteration. Similarly, presence of more saturated fatty acids than are usually found in pure sunflower oil is indicative of adulteration with palm oil.
2/4. Mixing of Sunflower oil with Castor Oil
Castor oil is also used in adulteration with sunflower oil, even though it is not recommended for cooking or for ingesting. Castor Oil is a stimulant laxative and reduces the natural muscle tone in intestines leading to chronic constipation.
The best way to check for this Castor Oil adulteration is to let the sunflower oil settle for a few hours without disturbing it. The density of castor oil is more than sunflower oil and, therefore, it will settle down. If that happens, presence of denser liquid such as castor oil can be found.
3/4. Mixing of Sunflower oil with Paraffin Oil
Paraffin oil is another adulterant which is not recommended for ingestion or usage in cooking. Ingesting it can cause intestinal issues and inhaling it can use irritation in respiratory tract. Also, if it is not highly refined, it can cause cancer as well. However, it is used as an adulterant with sunflower oil because it blends well with it. The best way to check it is by using the colorimeter method which uses colour wavelength absorption technique for detecting adulteration.
4/4. Mixing of Sunflower oil with Rapeseed Oil
Sunflower oil is also found to be adulterated with rapeseed oil. Rapeseed has little amounts of erucic acid and brassicasterol present which are not present in sunflower oil. So, if these are detected on conducting lab test, the same indicates adulteration.
Is adulteration of Sunflower Oil harmful?
Whether sunflower oil is harmful or not depends on what it has been adulterated with. If this has been mixed with inedible oils, such as paraffin oils, it becomes harmful for health. If this is mixed with other edible oils it might lose or reduce its own beneficial characteristic properties, which may or may not harm the consumer.