Comparison of the fatty acid composition of pecan and walnuts from various regions and the development of a rapid analytical method

Abstract

The study determined the fatty acid profiles of pecan and walnut samples from various regions of Türkiye and proposed a rapid method for profiling fatty acids. Twenty walnut samples (Ahırlı, İncesu-Seydişehir and Derbent-Konya, Yenişarbademli and Yalvaç-Isparta, Burdur, Göksun and Çağlayancerit-Kahramanmaraş, Ezine-Çanakkale, Belen-Hatay, Denizli, Mut-Mersin, Ermenek-Karaman and Osmaniye) and one pecan sample (Narlıca-Hatay) were analysed. Fatty acid methyl esters (FAME) were prepared using direct methylation of 0.1-gram samples, and compositions were determined via gas chromatography. The study compared direct methylation to other extraction methods (ASE and Bligh & Dyer) using the “Maraş-18” cultivar. Results showed that linoleic acid levels in walnuts ranged from 48.5 to 64.1%, with an average of 57.16%. Oleic acid content ranged from 13.6 to 33.4%, with a mean of 20.5%. Alpha-linolenic acid varied between 7.6 and 17.1%, with the highest levels in the “Native” cultivar from Yenişarbademli. The pecan sample had high oleic acid (59.6%) but low α-linolenic acid (1.14%). While the “Maraş-18” cultivar showed consistent fatty acid profiles across methods, minor statistical differences in individual fatty acid percentages were observed. Due to its speed, efficiency, and alignment with green chemistry, the direct methylation method may be recommended for fatty acid analysis in walnut kernels.

Keywords

• Walnut
• Juglans regia. L
• Fatty acid
• Gas chromatography

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