Detection of hazelnut oil in virgin olive oil by assessment of free sterols and triacylglycerols.
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 deltaECN42, but although it possessed a discriminating capacity, it alone could not distinguish the aforementioned groups with sufficient certainty. Free delta7-sterols data were combined with deltaECN42 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 delta7-sterol data and deltaECN42 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.
Vichi
S
S
Udine University, Food Science Department, Italy.
Pizzale
L
L
Toffano
E
E
Bortolomeazzi
R
R
Conte
L
L
D002849:Chromatography, Gas; D002855:Chromatography, Thin Layer; D005227:Fatty Acids / Q000032:analysis; D005506:Food Contamination / Q000032:analysis; D008745:Methylation; D009754:Nuts / Q000737:chemistry*; D000069463:Olive Oil; D010938:Plant Oils / Q000032:analysis*; D015203:Reproducibility of Results; D013261:Sterols / Q000032:analysis*; D014280:Triglycerides / Q000032:analysis*
D005227:Fatty Acids; D000069463:Olive Oil; D010938:Plant Oils; D013261:Sterols; D014280:Triglycerides