Phytosterols composition of virgin olive oils from cultivars introduced in eastern Morocco in comparison to Picholine Marocaine

Abstract

The aim of this study is to characterize monovarietal virgin olive oils (VOOs) of three European cultivars (Arbequina, Arbosana and Koroneiki), grown under high-density plantation system in eastern Morocco, by comparison of their phytosterols profiles. First, physicochemical properties of these monovarietal VOOs as well as their contents of pigments and phenols were analyzed. Then, VOOs phytosterols profiles were determined by GC-FID, and show that b-sitosterol is the most abundant sterol which represent 75 to 79 % of total phytosterols in analyzed olive oils. On the basis of these results, a comparison between these monovarietal VOOs and olive oil of Picholine marocaine (autochthonous olive tree) has been carried out, and shows that majority of analytical parameters presented statistically significant differences (p < 0.05). The examined olive varieties produce excellent oils with a chemical composition within the regulatory limits and an appreciable amount of phytosterols. In addition, results showed that, total phytosterols content of olive oil from Picholine marocaine is significantly higher (2348.78 mg kg-1) than values observed for VOOs of European cultivars, which range from 1595 to 1971mg kg-1 but, Koroneiki’s VOO has the highest phenols content (493.66 mg kg-1) and the highest pigments content (3.94 and 2.17 mg kg-1 respectively for chlorophylls for carotenoids). Lastly, according to VOOs' content of minor components (phenols, pigments and phytosterols), the hierarchical cluster analysis shows a good discrimination between olive tree varieties