MEASUREMENT OF ADULTERATION OF OLIVE OILS BY NEAR-INFRARED SPECTROSCOPY

Authentication of olive oils is of great importance, not only because they command a high price but also because of the health implications of adulteration with seed oils. A method for predicting the level of a dulteration in a set of virgin and extra-virgin olive oils adulterated with corn oil, sunflower oil, and raw olive residue oil by near-infra red spectroscopy is presented. The best result was a correct predictio n for 98% of the samples. Principal component analysis was used to pre dict the type of adulterant. The best result was a 75% prediction rate . From these results, it is concluded that it is possible to design a quality control system, which uses near-infrared technology to measure the level of adulteration. In the case where the only test is whether the sample is adulterated or not, a simple calibration for adulterati on can be used. The results suggest that principal component analysis may offer a means of identifying the adulterant, although more work is required to give an acceptable level of accuracy.