Evaluation of the methods based on triglycerides and sterols for the detection of hazelnut oil in olive oil

Abstract The difference between theoretical and empirical triglyceride content is a powerful tool to detect the presence of any vegetable oil in olive oil. The current drawback of the method is the separation between equivalent carbon number ECN42 compounds, which affects the reliability of the method and, hence, its cutoff limit. The determination of the triglyceride profile by liquid chromatography using propionitrile as the mobile phase has recently been proposed to improve their quantification, together with a mathematical algorithm whose binary response determines the presence or absence of hazelnut oil. Twenty-one laboratories from 9 countries participated in an interlaboratory study to evaluate the performance characteristics of the whole analytical method. Participants analyzed 12 samples in duplicate, split into 3 intercomparison studies. Statistically significant differences due to the experimental conditions were found in some laboratories, which were detected as outliers by use of Cochran's and Grubbs' tests. The relative standard deviations (RSD) for repeatability and reproducibility were determined following the AOAC Guidelines for Collaborative Studies. The analytical properties of the method were determined by means of the sensitivity (0.86), selectivity (0.94), and reliability (72) for a cutoff limit of 8 (probability 94).

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1H NMR-Based Protocol for the Detection of Adulterations of Refined Olive Oil with Refined Hazelnut Oil

Journal of Agricultural and Food Chemistry ◽

10.1021/jf902426b ◽

2009 ◽

Vol 57 (24) ◽

pp. 11550-11556 ◽

Cited By ~ 50

Author(s):

Luisa Mannina ◽

Marco D’Imperio ◽

Donatella Capitani ◽

Serge Rezzi ◽

Claude Guillou ◽

...

Keyword(s):

Olive Oil ◽

1H Nmr ◽

Hazelnut Oil ◽

Refined Olive Oil

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Detection of Hazelnut Oil in Virgin Olive Oil by Assessment of Free Sterols and Triacylglycerols

Journal of AOAC International ◽

10.1093/jaoac/84.5.1534 ◽

2001 ◽

Vol 84 (5) ◽

pp. 1534-1542 ◽

Cited By ~ 27

Author(s):

Stefania Vichi ◽

Lorena Pizzale ◽

Emilio Toffano ◽

Renzo Bortolomeazzi ◽

Lanfranco Conte

Keyword(s):

Olive Oil ◽

Solid Phase ◽

Virgin Olive Oil ◽

Hazelnut Oil ◽

Phase Extraction ◽

Silica Column ◽

Free Sterols ◽

Oil Fractions ◽

Triacylglycerol Analysis ◽

Statistical Certainty

Abstract Free sterols were evaluated as factors for discriminating between genuine virgin olive oil and hazelnut-mixed virgin olive oil. Numeric analyses of the results amplified the differences between groups. The application of this method to virgin olive oil samples and their mixtures with 10% hazelnut oil distinguished between genuine and nongenuine virgin olive oil with statistical certainty. Triacylglycerol analysis was tested for the same purpose by using parameter ΔECN42, but although it possessed a discriminating capacity, it alone could not distinguish the aforementioned groups with sufficient certainty. Free Δ7-sterols data were combined with ΔECN42 data into a single discriminating function to improve differentiation and bring more ruggedness, and for detection of low amounts (10%) of hazelnut oil in virgin olive oil. In fact, the values obtained by addition of Δ7-sterol data and ΔECN42 data showed a higher discriminating capacity than single parameters. In a single operation the method produced all the oil fractions necessary for analysis of free sterols and triacylglycerols with ECN42. Solid-phase extraction was applied in substitution of traditional chromatography on a silica column.

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