Comparative study on volatile compounds, fatty acids, squalene and quality parameters from whole fruit, pulp and seed oils of two tunisian olive cultivars using chemometrics

Abstract

The oils of olive fruits, pulps and seeds of two main Tunisian cultivars of olive trees (Chemlali and Oueslati) were extracted at two different indices of maturity. The free acidity, peroxide value, spectrophotometric indices, chlorophyll content, squalene, fatty acids, aroma, and sensory profiles of oils were analyzed. Fruits and pulp oils had similar fatty acids compositions. While, seed oils have fatty acid profile that are different from both varieties. For the first time in this work, squalene content in the fruit, pulp, and seeds oils were measured by gas chromatography and it decreased during maturation. Its concentration in the seed oils were lower than those found in fruit and pulp oils. The volatile profiles of twelve Tunisian olive oils obtained from different parts of fruits were established by solid phase micro-extraction (SPME) coupled with gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). Sixty-six compounds were identified and characterized, representing 92.4 and 97.6% of the total volatiles. Principal component analysis showed that olive oil quality is strongly affected by olive cultivar, maturity index and the different olive parts