During frying, oil undergoes degradation due to their exposure to elevated temperatures which result in changes in the physio-chemical, nutritional and sensory properties of oil. Polar compounds are formed during frying. The toxicity of these compounds is known to have adverse health effects on humans.
Total polar compounds test is a widely accepted test to check the safety of cooking oil used for preparation of food. The TPC value is considered a better indicator since it refers to all degraded products from the initial triglycerides present in the oil.
TUV India food testing laboratory at Pune, does testing for total polar compounds in cooking oil. FSSAI has set clear instructions to all food business operators that reuse of cooking oil for frying should be avoided. Re-use of leftover cooking oil should be avoided.
In order to safeguard consumer health, FSSAI released a notification and fixed a limit for Total polar compounds in cooking oils.
|Type of Cooking oil||Limit prescribed by FSSAI|
|Unused/fresh vegetable oil/fat||NMT 20 %|
|Used vegetable oil/fat||NMT 25 %|
The technique of deep frying involves a series of complex process that affect the composition of both the oil and the product being fried. Each type of product has several variables that affect the optimum deep frying condition:
- Temperature of the oil
- Frying time
- Continuous or discontinuous deep frying
- Composition of the oil
- Food moisture
- Food coating
- Food volume/surface
TUV India uses column chromatography with a method based on AOAC to analyse the amount of total polar compounds in cooking oil. The chromatography technique is based on adsorption which achieves both total polar and non-polar compounds separately by applying different organic solvents.