The measured specific absorbance values ​​of olive oil are considered as a measure of whether they are resistant to oxidation and are an important quality criterion.

The specific absorbance value measured in 232 nm is indicative of hydroperoxides and conjugated ones, the first step of oxidation. The specific absorbance value measured in 270 nm is indicative of carbonylic compounds and conjugetrienes, the second step of oxidation.

In olive oil with high peroxide value, K232 value is also very high. Delta K value is an important criterion which is taken into consideration in determining whether olive oil is treated with acid bleaching soils and that it contains refined or pomace oil.

The value of K270 gives information about whether or not the olive oil is cheated and whether other oils are mixed. K270 value is high in refined olive oil fraud. When pomace oils are mixed with refined or riviera type olive oils, K270 value increases. Therefore, specific absorbance analysis is one of the methods used to determine whether refined oil is mixed into natural olive oil. UV-Vis spectrophotometer is used in these analysis methods. The Delta K measurement method of the instrument is set for 274-266 nm measurement.

According to the Turkish Food Codex Communiqué on Olive Oil and Pirina Oil issued by the Ministry of Food, Agriculture and Livestock (Communiqué no: 2010 / 35), Specific absorption values ​​in ultraviolet light are as follows:

• E (232 nm)
• The smallest 2,50 in extra virgin olive oil
• Smallest 2,60 in natural first olive oil
• E (270 nm):
• The smallest 0,22 in extra virgin olive oil
• Smallest 0,25 in natural first olive oil
• The smallest 1,10 in refined olive oil
• The smallest 0,90 in Riviera olive oil
• The smallest 2,00 in refined pomace oil
• The smallest 1,70 in pomace oil

Specific absorbance in ultraviolet light is determined by authorized laboratories within the scope of chemical food analysis. During these studies, the standards published by national and international organizations are complied with.