Correlation between Chemical Analysis and Sensory Committee Tests with Total Fluorescence Characteristics of Jordanian Olive Oil

Abstract

Olive oil samples extracted from olive trees grown in different un-irrigated areas of Jordan were classified according to their quality using three different techniques. Two of the techniques; namely, chemical analysis and sensory committee tests, are recognized by the International Olive Oil Council (IOC) and considered as classical techniques. The results were compared with those of the total fluorescence spectroscopy that has been recently adopted for olive oil quality analysis. Nine different olive oil samples were subjected to the analysis by the above techniques. The analysis for each sample was repeated twice to ensure consistency of the results. Chemical analysis was used to determine their acidities, peroxide values, ∆K’s and polyphenol content parameters. The results of chemical analysis indicated that eight of the samples could be classified as EVOO and one as VOO. Sensory tests indicated that four samples could be classified as EVOO and five as VOO. Total fluorescence spectra results revealed that six samples are EVOO and three samples are VOO. The correlation of fluorescence results to chemical and sensory results indicates the ability of fluorescence technique as a powerful tool for classification of olive oil. Reference samples that were already classified by IOC were tested to ensure the accuracy of the fluorescence technique in recognizing EVOO from other types of olive oil. Moreover, fluorescence analysis proved to be fast and consumes minute amounts of samples and chemicals, in contrary to chemical analysis which is known to be time and chemicals-consuming.