Olive oil: real or refined? K270 combats adulterations and frauds

Leanalisi dell'olio di oliva rapide semplici e affidabili in frantoio o sull'impianto dell'azienda olearia: le analisi chimche non sono più unproblema

Olive oil genuineness

The K270 test provides useful information on the quality of the oil and on its degree of oxidation. It is distinguished from the other analyses you can perform on oil for an efficient quality control (Free Fatty Acids, Peroxide Value and Polyphenols) because it enables to identify rectified or different kinds of oils added to virgin olive oil and consent to escape from a fraud, in the worst case.

To define as best the oxidative condition of the oil and to remove any doubts about its genuineness it is necessary to determine parameters like K270, that measure the absorption of the ultraviolet light by the oily matter.

K270

Natural oils that are mechanically extracted do not contain fatty acids chains formed by double or triple conjugated bonds. Typically these kinds of bonds (Fig. 1) create during rectification, that is the process in which the oil is mixed with other oils, refined or particularly old. They are not present in pure and freshly extracted olive oils.

K270 parameter in the oil allows to identify adulterated and refined oils

Fig. 1 – Double bonds, Conjugated double bonds, Triple bonds, Conjugated triple bonds

The presence of these bonds in rectified oils makes them exhibit high UV absorbance values specifically in the 270 nm region, which are significantly higher if compared to those of virgin and extra virgin oils. Moreover ketone groups form during the most advanced oil oxidation stages, so that provoke a greater absorbance at 270 nm.

K270 helps to discover the great change that occurred in the oil structure and the parameter can be easily kept under control.

How to determine k270?

A simple reading of the oil at 270 nm is sufficient to perform the test. The so called coefficient of extinction (K) is measured and it gives the value of the k270 in the oil.

Spectrophotometers can perform the reading at 270 nm, and you can use the expensive and large instruments used by an equipped chemical laboratory or adopt the CDR OxiTester analysis system.

Check the k270 analysis method with CDR OxiTester.

CDR OxiTester presents the following benefits in the performance of k270 test:

  • Colour reading at 270 nm
  • Reference method compliance
  • Analysis of the sample as is
  • Use of disposable and not expensive cuvettes, not quartz cuvettes
  • Time test: immediate
  • Up to 14 samples test sessions of analysis
  • Ready to use and pre-calibrated supply

The graphic below shows the perfect correspondence between the reading with a laboratory spectrophotometer and the reading with the CDR OxiTester system.

Correlation between OxiTester method and reference method to determine K270 in olive oil

In the table below you can see the different k270 values of some kinds of oils, showing how eloquent can be the parameter to identify a particular type of oil.

Kind of oilsExtra virgin olive oilsRefined olive oilOlive Pomace oilMaize oilPeanut oil
K270 values< 0,200,651,32,007,90

Click here for further information about CDR OxiTester: Easy to use, rapid testing, results reliable and compliant

How to determine the K270 for olive oil: real or refined olive oil? was last modified: October 16th, 2017 by CDR s.r.l.