Dec 07

Total Polar Compounds in frying oil

TRIAL SAMPLE: 796 (February 2017)

Oils and fats represent one of the three major classes of food constituents together with carbohydrates and proteins. Deep-fat frying is one of the most popular cooking procedures and leads to the production of both desirable and undesirable compounds. The cooking process affects the physicochemical characteristics and quality of the frying medium and the fried product itself.

French fries

The quality of oils and fats during the frying process has a major influence on the quality of the final product. Thermal processing of frying oils leads to oxidative and hydrolytic reactions i.e. hydrolysis and polymerisation and these chemical and physical changes lead to the formation of many volatile and non-volatile decomposition products. The majority of the non-volatile compounds formed during frying are, for convenience, classified as “Total Polar compounds” (TPC) and the formation of such compounds during repeated frying has been shown to increase with the degree of oil unsaturation.

The determination of the percentage of Total polar compounds (% TPC) is one of the most reliable methods for monitoring the quality changes in oils during the frying process and it reflects the degradation of the oil after repeated use. In order to protect consumers, several countries and International bodies have issued recommendations or a regulation which set maximum limits for the percentage of TPC, and regulates the use of oils & fats subjected to frying. Countries that control the quality of frying oil include:


1 France Legislation 25
2 Germany Recommendations by the German Society for Fat Science (DGF) 24
3 Italy Legislation 25
4 Poland Legislation 25
5 Spain Legislation 25
6 Brazil Recommendation 25
7 South Africa Regulation 25


The Food Safety & Standards Authority of India (FSSAI) released a statement dated 23rd September 2016, which addresses the issue of or repeated use of edible oils in cooking and frying of food by amending current standards (Food Products Standards and Food additives-FSS) to set a maximum limit for % TPC.

In light of the increasing concern, LGC Standards has included a new sample, total polar compounds in frying oil to the food chemistry proficiency testing scheme (QFCS). Palm oil was chosen as a material for this proficiency testing (PT) trial sample.  It is extensively used in commercial frying, fat spreads and generally in the food industry as it is the cheapest of all major edible oils and it is produced in the greatest quantity worldwide.  The fatty acid composition of palm oil is 50% saturated and 50 % unsaturated fat, it is relatively stable to oxidation and is naturally semi solid in room temperature, so does not require hydrogenation to become solid. You can find more details in Scheme Documentation.

By Savvas Xystouris, Technical/Development Manager, Proficiency Testing, LGC Standards

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