Vitamin E Composition of Walnuts (Juglans regia L.):  A 3-Year Comparative Study of Different Cultivars

Joana S. Amaral,†# M. Rui Alves,‡§ Rosa M. Seabra,*† and Beatriz P. P. Oliveira‡
REQUITE, Servios de Farmacognosia and Bromatologia, Faculdade de Farmcia, Universidade do Porto, R. Anbal Cunha 164, 4050-047 Porto, Portugal; Escola Superior de Tecnologia e de Gesto, Instituto Politcnico de Bragana, Quinta de Sta. Apolnia, Apartado 1134, 5301-857 Bragana, Portugal; and ESTG, Instituto Politcnico de Viana do Castelo, Av. do Atlntico, 4900 Viana do Castelo, Portugal
J. Agric. Food Chem., 2005, 53 (13), pp 5467–5472
DOI: 10.1021/jf050342u
Publication Date (Web): May 26, 2005
Copyright © 2005 American Chemical Society
†

 Serviço de Farmacognosia.

,
#

 Present adress:  Escola Superior de Tecnologia e de Gestão.

,
‡

 Serviço de Bromatologia.

,
§

 Instituto Politécnico de Viana do Castelo.

,
*

 Corresponding author (telephone 351.222078934; fax 351.222003977; e-mail rseabra@ff.up.pt).

Abstract

The tocopherol and tocotrienol composition of walnuts (Juglans regia L.) was determined for nine cultivars (cvs. Arco, Franquette, Hartley, Lara, Marbot, Mayette, Mellanaise, Parisienne, and Rego). Walnuts were harvested over three consecutive years from two different geographical origins (Bragança and Coimbra, Portugal), for a total of 26 samples. The methodology employed was a normal-phase high-performance liquid chromatography coupled to a series arrangement of a diode array detector followed by a fluorescence detector, allowing the simultaneous analysis of all tocopherols and tocotrienols. The analyses showed that all samples presented a similar qualitative profile composed of five compounds:  α-tocopherol, β-tocopherol, γ-tocopherol, δ-tocopherol, and γ-tocotrienol. γ-Tocopherol was the major compound in all samples, ranging from 172.6 to 262.0 mg/kg, followed by α- and δ-tocopherols, ranging from 8.7 to 16.6 mg/kg and from 8.2 to 16.9 mg/kg, respectively. Multivariate analysis of the data obtained showed the existence of significant differences in composition among cultivars. These differences were also significant when cultivars were grouped by year of production, showing that besides genetic factors, the vitamin E composition was influenced by environmental factors.

Keywords: Vitamin E; tocopherols; tocotrienols; Juglans regia L.; walnuts, chemometrics; multivariate analysis; predictive biplots

View: Full Text HTML | Hi-Res PDF

Tools

History

  • Published In Issue June 29, 2005
  • Received for review February 15, 2005. Revised manuscript received April 12, 2005. Accepted April 19, 2005. J.S.A. and M.R.A. are grateful to Programa para o Desenvolvimento Educativo para Portugal (PRODEP III) for financial support.

Recommend & Share

Related Content

Other ACS content by these authors: