Abstract

Chétoui and Chemlali olive fruits were stored at two different temperatures (ambient and 5°C) for different periods before oil extraction at 0, 7, 14, 21 and 28 days to investigate the effect of postharvest fruit storage on olive oil quality. Conventional analyses (acidity, peroxide value, specific extinction coefficient at 232 and 270 nm and fatty acid composition) and non conventional analyses (pigments, total phenols, oxidative stability and radical scavenging capacity) were carried out in order to evaluate the oil quality. Results showed that fruit storage at ambient temperature led to the deterioration of the oil parameter qualities such as acidity, K232 and K270 which is more rapidly in Chemlali oils than that of Chétoui cultivar. In the same way, the trend of total phenols, oxidative stability and radical scavenging capacity of the studied olive oils showed a decrease during the fruit storage at ambient temperature. This reduction was more severe in Chemlali olive oils than those of Chétoui cultivar. Storage of fruits at 5°C prevented the fast alteration that is produced in oils extracted from fruits stored at ambient temperature.

Key words: Olive storage, oil quality, fatty acids, stability.

Abbreviation

DPPH, 1,1-Diphenyl-2-picrylhydrazyl radical; RSA, radical scavenging activity; PV, peroxide value; MUFA, monounsaturated fatty acid; SFA,saturated fatty acids; PUFA, polyunsaturated fatty acid.