Oil chemical variation in walnut (Juglans regia L.) genotypes grown in Argentina

MARCELA MARTÍNEZ; DAMIÁN MAESTRI

EUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY

Wiley-VCH

Lugar: Weinheim, Germany; Año: 2008 vol. 110 p. 1183 - 1189

1438-7697

Walnut (Juglans regia L.) oil (WO) from the varieties Chandler, Franquette, Hartley, Lara, Mayette, Serr, Sorrento and Tulare were studied in order to evaluate genotypical variations in fatty acid (FA) and volatile compositions, tocopherol content and oxidative parameters. Oil content was found to range between 71.4 - 73.9 %. Oils obtained by pressing presented low acid (0.05-0.22 % oleic acid), peroxide (0.05-0.47 meq O2/kg oil), K232, and K270 values, and moderate (247-365 mg/g oil) total tocopherol contents. Variations in unsaturated fatty acid contents were between 16.1 - 25.4 % (oleic acid), 52.5 - 58.9 % (linoleic acid), and 11.4 - 16.5 % (linolenic acid). Oxidative stability (OS), as measured by the Rancimat method, was poor (2.64 - 3.44 hs) and it correlated positively with oleic and negatively with linolenic acid contents. In contrast with their low OS, the antioxidant capacity evaluated through the 2,2-diphenyl-1-picrylhydrazyl radical assay showed that WOs analyzed here have good radical scavenging activity. Tocopherols appear to be the most important contributors to this biochemical property. Findings connected with volatile composition showed a similar qualitative pattern where aldehydes were present at higher concentration. Most of them seem to come from unsaturated FAs mainly through a chemical pathway.