Algorithms for the detection of hazelnut oil in olive oil

The fraudulent addition of hazelnut oil to olive oil can be only detected i n high proportions (20-25%) using the Delta7-stigmastenol and the differenc e between triacylglycerols of equivalent carbon number 42, determined exper imentally by HPLC and calculated theoretically from the fatty acid composit ion (Delta ECN42). A new method lies on a sequential comparison of the valu es of several algorithms with a database built with data obtained from genu ine virgin olive oils. The algorithms are: LLLexp vs %L; (LLL/OLLn)(exp) - (LLL/OLLn)(theor), vs Delta ECN44 and (ECN44/LLL)(exp) vs %L; being: LLLn(e xp) OLLn(exp) and ECN44(exp) the percentage of triacylglycerols determined by HPLC, LLLtheor, OLLn(theor) and ECN44(theor), the percentage of those ca lculated theoretically from the fatty acid composition; Delta ECN44 the dif ference between the experimental and theoretical value of ECN44; and finall y %L the percentage of linoleic acid. The database has been built consideri ng the values obtained from olive oils of different fatty acid composition and from admixtures between them. The method allows the detection of low pe rcentages of hazelnut oil in olive oil (5%),