Study of the cultivar-composition relationship in Sicilian olive oils by GC, NMR, and statistical methods.
The aim of this research is to find if there is direct evidence relating the fatty acid composition of olive oils to specific cultivars grown within a well-limited geographical region. To group olive oils according to their own cultivars,(13)C high-field nuclear magnetic resonance (NMR) and gas chromatography (GC) were used to analyze 60 extra virgin olive oils from the same Italian region (southwestern Sicily) obtained from four monovarietal cultivars. The (13)C NMR spectrum provides information about glycerol triesters of olive oils, i.e., about the acyl composition of major components and about the fatty acids' positional distribution on the glycerol moiety. GC gives the complete fatty acid profile of olive oil samples. Selection of NMR and GC peaks on the basis of their sensitivity to the different cultivars was performed by using multivariate analysis of variance (MANOVA). Principal component analysis, tree clustering analysis, multidimensional scaling (MDS), and linear discriminant analysis (LDA) were then performed on the MANOVA-selected peaks. Results obtained from (13)C NMR and GC techniques combined with the multivariate statistical procedure are in good agreement and prove the usefulness of fatty acids analysis to group the monovarietal olive oils belonging to the same cultivars. Grouping of olive oils according to their cultivars occurs for particular (13)C resonances all belonging to fatty chains in the sn 1,3 position of the glycerol moiety.
Mannina
Luisa
L
Dipartimento S.T.A.T., Facoltà di Scienze MM.FF.NN., Università del Molise, Via Mazzini 8, 86170 Isernia, Italy. mannina@mlib.cnr.it
Dugo
Giacomo
G
Salvo
Francesco
F
Cicero
Lucia
L
Ansanelli
Giuliana
G
Calcagni
Cristina
C
Segre
Annalaura
A
D000704:Analysis of Variance; D002849:Chromatography, Gas; D005227:Fatty Acids / Q000032:analysis*; D005990:Glycerol / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D031658:Olea / Q000737:chemistry / Q000145:classification; D000069463:Olive Oil; D010938:Plant Oils / Q000737:chemistry* / Q000145:classification*; D012680:Sensitivity and Specificity; D012802:Sicily
D005227:Fatty Acids; D000069463:Olive Oil; D010938:Plant Oils; D005990:Glycerol