Evaluation of decision trees for off-limit parameters in sterol composition for turkish olive oils to maintain authenticity

This study aims to establish decision tree alternatives mainly based on off-limit values detected for Turkish Olive Oils; possibly caused by environmental factors but not due to fraud. Olive oil is adultered since ancient times contributed to its well known reputation and added value due to health benefits and claims with numerous methods. Most recently; scientific works stated that deviations from regulations at some constituents of olive oils are observed due to geographical and climatical factors as well as variety responses to climatical changes; although there is no doubt about authenticity. Turkey suffered for at least a decade on Δ-7 stigmastenol value found over 0,5 %; which stands out to be neither a fraud nor an anomaly; but a reality of Southern Anatolian Region climate. Nevertheless; recent data reveals an apparent deviation for delta-7 stigmastenol and appearent beta-sitosterol values in North and South Aegean Regions including virgin and lampante olive oils in Turkey. Involvement of olive oils; exerting deviations and anomalities from regulations without fraud; into international and national trade is of crucial importance regardless of the reason behind that deviations. Major methodology on building a decision tree is to determine a statistical approach based on regular chemometric data; involving a logical proposal to determine the extent of deviations that should be permitted; while eliminating the risk of adulteration and fraud. This study includes statistical evaluation of two year data on Turkish olive oils; to determine the situation of Turkish Olive Oils when subjected to existing decision trees published by IOC; and search for solutions if there exists specific anomalities and deviations.