Comparison of two systems for sample preparation and injection by dynamic headspace GC analysis

Imhof, R.; Bosset, J. O.

doi:10.1002/jhrc.1240140913

Cited by 19 publications

(6 citation statements)

References 12 publications

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“…The mean value for the coefficients of variation for all the chemical families obtained by method A was 45.2%, whereas 26.5 and 21.8% were the mean values obtained by methods B and C, respectively. These results confirmed better repeatability for the DHS methods which used automatic P&T-RH than for the DHS method which used semi-automatic P&T-MWH [23].…”

Section: Resultssupporting

confidence: 63%

Comparison of dynamic headspace methods used for the analysis of the volatile composition of Spanish PDO ewe’s raw milk cheeses

Barrón

Redondo

Ortigosa

et al. 2005

Lait

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-Different dynamic headspace (DHS) methods used for determination of volatile compounds in cheeses were compared. Three different laboratories using gas chromatography coupled to mass spectrometry carried out the analyses of volatile compounds of Spanish Protected Designation of Origin ewe's raw milk cheeses. One laboratory used "purge and trap" (P&T) with thermal desorption of the trap by ultrafast microwave heating (MWH) and the other two laboratories used P&T with thermal desorption of the trap by resistive heating (RH). Each method detected around 78-85 different individual compounds which belonged to different chemical groups, namely, acids, alcohols, ketones, esters, aldehydes, sulphur compounds, hydrocarbons and terpenes. Using the P&T-MHW method, larger percentages of acids and aldehydes in the cheeses were found compared with the P&T-RH methods, whereas the contrary occurred for the percentages of alcohols and ketones. Differences in the percentages of some volatile compounds such as ketones, alcohols and acids between the laboratories using P&T-RH under different analytical conditions were also recorded. The results pointed out differences in the selectivity for the extraction of various volatile compounds from cheese samples according to the DHS methods used, particularly when using tenax or graphitised carbon as trap absorbents. In spite of these differences, both P&T-MWH and P&T-RH methods were equally satisfactory for the comparison of the different cheese varieties. However, each of the DHS methods was more suitable for the characterisation of the volatile compounds of a particular cheese type. De plus, des différences dans les pourcentages de certains composés volatils, tels que cétones, alcools et acides ont également été observées entre les laboratoires utilisant le système de P&T-CR dans des conditions différentes. Les résultats soulignent des différences en termes de sélectivité d'extraction des volatils à partir des échantillons de fromage selon la technique d'extraction employée, et en particulier selon la nature de l'absorbant du piège (tenax ou charbon). Malgré ces différences, les deux méthodes P&T-CMO et P&T-CR se sont révélées également satisfaisantes pour comparer différentes variétés de fromages. Cependant, chacune des méthodes d'extraction était plus appropriée pour caractériser les composés volatils pour un type de fromage en particulier.fromage / composé volatil / espace de tête dynamique / étude inter-laboratoire

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Section: Resultssupporting

confidence: 63%

Comparison of dynamic headspace methods used for the analysis of the volatile composition of Spanish PDO ewe’s raw milk cheeses

Barrón

Redondo

Ortigosa

et al. 2005

Lait

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“…This procedure, prior to headspace analysis, allowed for the same conditions of volatile suspension as recommended by Mariaca & Bosset (1997). Therefore, the sample mainly contained the neutral and alkaline components (Imhof & Bosset, 1991). To limit the negative effect of temperature, the whole homogenization procedure was carried out at 4 8C, just before headspace analysis.…”

Section: Dynamic Headspace Extraction and Gas Chromatography (Gc)-masmentioning

confidence: 99%

Controlled production of Camembert-type cheeses. Part II. Changes in the concentration of the more volatile compounds

Leclercq-Perlat

Latrille

Corrieu

et al. 2004

Journal of Dairy Research

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Flavour generation in cheese is a major aspect of ripening. In order to enhance aromatic qualities it is necessary to better understand the chemical and microbiological changes. Experimental Camembert-type cheeses were prepared in duplicate from pasteurized milk inoculated with Kluyveromyces lactis, Geotrichum candidum, Penicillium camemberti and Brevibacterium linens under aseptic conditions. Two replicates performed under controlled conditions of temperature (12 °C), relative humidity (95±2%), and atmosphere showed similar ripening characteristics. The evolutions of metabolite concentrations were studied during ripening. The volatile components were extracted by dynamic headspace extraction, separated and quantified by gas chromatography and identified by mass spectrometry. For each cheese the volatile concentrations varied with the part considered (rind or core). Except for ethyl acetate and 2-pentanone, the volatile quantities observed were higher than their perception thresholds. The flavour component production was best correlated with the starter strains. During the first 10 days the ester formations (ethyl, butyl and isoamyl acetates) were associated with the concentrations of K. lactis and G. candidum. The rind quantity of esters was lower than that observed in core probably due to (1) a diffusion from the core to the surface and (2) evaporation from the surface to the chamber atmosphere. G. candidum and Brev. linens association produced 3 methyl butanol and methyl 3-butanal from leucine, respectively. DMDS came from the methionine catabolism due to Brev. linens. Styrene production was attributed to Pen. camemberti. 2-Pentanone evolution was associated with Pen. camemberti spores and G. candidum. 2-Heptanone changes were not directly related to flora activities while 2-octanone production was essentially due to G. candidum. This study also demonstrates the determining role of volatile component diffusion.

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“…The system was developed and described by the inventor (Rektorik, 1985). This system is however less reproducible, less sensitive and more subject to artifacts than the others (Imhof and Bosset, 1991). The latter allow many different materials to be used for the trap thus making it possible to combine two or more different trapping materials as described above.…”

Section: Adsorption On Solid Sorbentsmentioning

confidence: 99%

Rapid Preconcentration and Enrichment Techniques for the Analysis of Food Volatile. A Review

Pillonel

Bosset

Tabacchi

2002

LWT - Food Science and Technology

117

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Comparison of two systems for sample preparation and injection by dynamic headspace GC analysis

Cited by 19 publications

References 12 publications

Comparison of dynamic headspace methods used for the analysis of the volatile composition of Spanish PDO ewe’s raw milk cheeses

Comparison of dynamic headspace methods used for the analysis of the volatile composition of Spanish PDO ewe’s raw milk cheeses

Controlled production of Camembert-type cheeses. Part II. Changes in the concentration of the more volatile compounds

Rapid Preconcentration and Enrichment Techniques for the Analysis of Food Volatile. A Review

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