Sulfur compounds identification and quantification from Allium spp. fresh leaves

J Food Drug Anal. 2014 Dec;22(4):425-430. doi: 10.1016/j.jfda.2014.04.002. Epub 2014 May 20.

Abstract

Pyruvic acid concentration is a critical factor in determining Allium spp. pungency. This study was initiated to accurately measure the background pyruvic acid levels in Romanian Allium spp. From the pungency point of view, all analyzed plant varieties in this study are considered low pungent cultivars based on the enzymatically produced pyruvate level (between 42 μmol/g and 222 μmol/g fresh wt). Chromatographic analysis was carried out for the different varieties of the most popular fresh leaves (Allium cepa var. "Diamant", Allium cepa var. "Rubiniu", and Allium ursinum L.) in order to identify the sulfur compounds. The thin layer chromatography analysis led to the identification of allicin, with Rf = 0.377-0.47, as an important sulfur compound. The gas chromatography-mass spectrometry analysis of the leaves' extracts detected disulfides as the major sulfur compounds. Principal component analysis was performed to establish the differences in plant composition. These studies suggest the potential good uses of the fresh leaves of Romanian Allium spp. as condiment, ingredient, or preservative in the food industry.

Keywords: Allium cepa; Allium ursinum L.; Bioactive compounds; Leaves; Thin layer chromatography.

Grants and funding

This work has benefited from the financial and technical support of the project RE-SPIA (695/09.04.2010, SMIS code 11377), financed by REGIO (Regional Operational Programme 2007–2013) and implemented by the Faculty of Food Science and Engineering, “Dunarea de Jos” University of Galati, Galat ‚i, Romania.