Fatty Acids of Italian Blood Orange Juices

Abstract

This paper reports the composition of fatty acids in two types of Italian blood orange juices: one is a not-from-concentrate (NFC) juice and the other is a reconstituted-from-concentrate (RFC) juice. Both juices have been purposely processed from the same stock of blood oranges. Fatty acids have been separated and identified as methyl esters by GC/MS, and 11 of them have been determined by GC-FID. Four acids (linoleic, palmitic, linolenic, and vaccenic) constitute ∼88% of total acids. Unsaturated acids predominate (77%) over saturated (23%). Mean concentration of fatty acids is ∼680 mg/L in both juices. Separation and quantification of the lipid classes point out that neutral acylglycerols and polar phosphatides are much more abundant than glycolipids. Significant differences of fatty acid distribution have been found in the isolated fractions, but each class exhibits similar profiles both in NFC and in RFC juices, indicating that no selective degradation of any acid occurs during the process of thermal evaporation. Linear discriminant analysis of fatty acid concentrations, relative to 90 Italian orange juices taken from the literature, allows blood and blond juices to be differentiated and oleic, palmitoleic, and linolenic acids to be selected as the most predictive variables. Moreover, palmitoleic, palmitic, and linolenic acids differentiate the blood juices (Tarocco, Sanguinello, and Moro) and linoleic, oleic, and palmitoleic acids the blond juices (Naveline, Ovale, and Valencia).