evaluation of chemical characteristics of extra virgin olive oils extracted from three monovarieties of mari, arbequina and koroneiki in fadak and gilvan regions

Olive oil in general due to it monounsaturation, stability, nutritive value, consistency, taste and aroma might be considered as a valuable and luxury oil. annual importation of olive oil to iran from mediterranean countries is on a large scale although some olive oils are produced in iran particularly in the north and some plantation has been applied in different provinces particularly in fars. the value of this luxury oil either imported or produced internally provides a ground for adulteration. the aim of this work is to evaluate the chemical characteristics of three varieties (mari, arbequina, koroneiki) of olive oils from two regions (fadak and gilvan).three varieties of olive fruit in two regions were selected and the extracted oils were subjected to a series of chemical tests consisting of acid value, peroxide value, iodine value, fatty acid profile as well as phenolic content and sterol composition. the results indicated that all of the samples in terms of acid and peroxide values were consistent with the values defined for extra virgin olive oil. the fatty acid composition indicated that oleic acid was the predominant fatty acid ranging from 56 to 77% of the total fatty acids indicating the italian and spanish origins. the analysis of sterol fraction showed that b-sitosterol was the major and the predominant sterol (88%). the phenolic concentration in this study was 100-250 mg/kg as gallic acid. the study illustrated that the investigated samples were in agreement with the standard of codex and the iranian national standard in spite of differences obtained.