Frying is a widely used method in food preparation. However, the repeated use of oils at high temperatures leads to thermal degradation, oxidation, and polymerization processes, resulting in the progressive formation of total polar compounds and other potentially harmful by-products.

Continuous exposure to degraded oils is associated with health risks, including:

Increased cardiovascular risk

Potential exposure to substances with toxic activity

Higher oxidative load in the diet

Possible association with chronic inflammatory processes

For this reason, Portuguese legislation (Portaria No. 1135/95) establishes that oils used in food preparation must not exceed 25% total polar compounds, a threshold considered critical for consumer protection.

It is important to note that oil degradation is not always visually detectable. The absence of significant changes in color or odor does not guarantee legal compliance or safety for consumption.

Systematic monitoring of frying oil quality is therefore a concrete public health measure, contributing to:

Reduction of population exposure to degraded compounds

Compliance with legal obligations of food business operators

Strengthening of food safety culture

Active protection of the final consumer