Headspace sampling of the volatile fraction of vegetable matrices.
ABSTRACT The evolution of vapour phase sampling of the volatile fraction of vegetable matrices, or of products directly related to them, over the period 1996-2007 is reviewed. High concentration capacity headspace (HCC-HS) and dynamic headspace (D-HS) techniques, that is headspace sampling approaches where the analytes in the vapour phase are concentrated into a sorbent, an adsorbent or a solvent, are considered. Advantages, disadvantages and applications to the vegetable field of several successful techniques based on these approaches are critically presented, including in-tube sorptive extraction (INCAT, HS-SPDE), headspace sorptive extraction (HSSE), solid-phase aroma concentrate extraction (SPACE), large surface area HCC-HS sampling (MESI, MME, HS-STE), headspace liquid-phase microextraction (HS-LPME) and dynamic headspace samplings (D-HS). The developments necessary to overcome some of the limits of the above approaches and techniques are also discussed in view of their application to new fields.
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ABSTRACT: In-tube extraction (ITEX) is a novel technique that can be coupled with gas-chromatography mass-spectrometry (GC-MS) and used for the extraction and separation of volatile compounds from different matrices. In this study a simple and efficient ITEX/GC-MS method was developed and optimized for the extraction and analysis of volatile compounds from tomatoes. The analytes were extracted from sample headspace by dynamic extraction and trapped into the selected sorbent material (Tenax TA), followed by their thermal desorption into the GC injector. Different extraction parameters were tested (incubation time and temperature, amount of sample, number of pumping strokes) and the optimal ones selected. The best compromised between the extraction performance and analysis time was achieved when 1g of sample was incubated at 70 o C for 20 min. followed by 30 extraction strokes. Between the main odor-active volatiles found in the analyzed cherry variety tomato samples were: hexanal, trans-2-hexenal, cis-3-hexenol, hexanol, 6-methyl-5-hepten-2-one, 2-and 3-methylbutanal, methyl salicylate, 1-penten-3-one.Analele Universităţii din Oradea, Fascicula Protecţia Mediului. 11/2012;