Supervised Chemical Pattern Recognition in Almond (Prunus dulcis) Portuguese PDO Cultivars: PCA- and LDA-Based Triennial Study

• Published in: Journal of agricultural and food chemistry 2012-09, Vol.60 (38), p.9697-9704
• Main Authors: Barreira, João C. M, Casal, Susana, Ferreira, Isabel C. F. R, Peres, António M, Pereira, José Alberto, Oliveira, M. Beatriz P. P
• Format: Article
• Language: English
• Subjects: almonds; alpha-tocopherol; alpha-Tocopherol - analysis; Analysis of Variance; Biological and medical sciences; carbohydrates; cultivars; Discriminant Analysis; Fatty Acids - analysis; Food Analysis - methods; Food industries; Fruit and vegetable industries; Fundamental and applied biological sciences. Psychology; linoleic acid; Nutritive Value; Portugal; Principal Component Analysis; protected designation of origin; Prunus - chemistry; Prunus dulcis; Tocopherols - analysis; Tocotrienols; triacylglycerols; Triglycerides - analysis
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf301402t

Almonds harvested in three years in Trás-os-Montes (Portugal) were characterized to find differences among Protected Designation of Origin (PDO) Amêndoa Douro and commercial non-PDO cultivars. Nutritional parameters, fiber (neutral and acid detergent fibers, acid detergent lignin, and cellulose), fatty acids, triacylglycerols (TAG), and tocopherols were evaluated. Fat was the major component, followed by carbohydrates, protein, and moisture. Fatty acids were mostly detected as monounsaturated and polyunsaturated forms, with relevance of oleic and linoleic acids. Accordingly, 1,2,3-trioleoylglycerol and 1,2-dioleoyl-3-linoleoylglycerol were the major TAG. α-Tocopherol was the leading tocopherol. To verify statistical differences among PDO and non-PDO cultivars independent of the harvest year, data were analyzed through an analysis of variance, a principal component analysis, and a linear discriminant analysis (LDA). These differences identified classification parameters, providing an important tool for authenticity purposes. The best results were achieved with TAG analysis coupled with LDA, which proved its effectiveness to discriminate almond cultivars.