Novel approach for the determination of volatile compounds in processed onion by headspace gas chromatography–mass spectrometry (HS GC–MS)

• Published in: Talanta (Oxford) 2013-01, Vol.103, p.137-144
• Main Authors: Colina-Coca, Clara, González-Peña, Diana, Vega, Estela, de Ancos, Begoña, Sánchez-Moreno, Concepción
• Format: Article
• Language: English
• Subjects: Dimethyl; Gas chromatography; Gas Chromatography-Mass Spectrometry; Headspace GC–MS; High-pressure processing; Mass spectrometry; Monitoring; Onion; Onions; Onions - chemistry; Pressure; Pulverized; Scan mode; SIM; SIM mode; Sulfides; Sulfur Compounds - analysis; Volatile compounds; Volatile Organic Compounds - analysis
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2012.10.022

A novel headspace gas chromatography–mass spectrometry (HS GC–MS) method was developed for analysis of volatile compounds in onion (Allium cepa L. var. cepa, ‘Recas’). MS was operated using full scan mode and selective ion monitoring (SIM) mode in order to quantify some specific compounds with increased sensitivity relative to full scan mode. The limits of detection and quantitation ranged from 0.01 to 0.10μg/g and from 0.02 to 3.83μg/g fresh weight, respectively, for studied compounds. The procedure allowed the identification of eighteen compounds and quantitation of nine compounds in the volatile fraction of onion, belonging mainly to di-, and trisulfides and aldehydes. These methods were applied to evaluate how high-pressure (HP) as a processing technology affects onion volatile compounds, responsible in part of the onion biological activity. Onion samples were treated at T1: 200MPa/25°C/5min, T2: 400MPa/25°C/5min and T3: 600MPa/25°C/5min (treatments). In addition, the difference among diced, freeze-dried and pulverized onions (groups) was studied, in order to select the process more adequate for better preserving volatile compounds. The results obtained in full scan mode showed that both main factors (group and treatment) had a significant effect (P