Dominique Langlois

French National Institute for Agricultural Research, Lutetia Parisorum, Île-de-France, France

Are you Dominique Langlois?

Claim your profile

Publications (7)11.93 Total impact

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This paper describes the potential of evaluating odor intensities in a gas chromatographic effluent by cross-modality matching with the finger span (GC-O-FSCM). A simple prototype is described that allows the precise measurement and acquisition of the distance between the thumb and another finger during the analysis. The stimulation of panelists at the sniffing port with ethyl butyrate shows a log-log relation between peak height values obtained from finger span and stimulus concentrations. It also shows that all panelists are able to perform this task but with different precision, which is used to select them. A triplicate evaluation by GC-O-FSCM of the intensity of flavor constituents in synthetic solutions shows that a four-member panel is perfectly able to determine most of the characteristics of the solutions and to create a finger span multidimensional space highly correlated with the theoretical intensity space.
    Journal of Agricultural and Food Chemistry 05/1999; 47(4):1673-80. DOI:10.1021/jf980794p · 2.91 Impact Factor
  • Dominique Langlois · Patrick Xavier Etiévant · Patricia Pierron · Anne Jorrot ·
    [Show abstract] [Hide abstract]
    ABSTRACT: Ten tomato varieties, i.e. Cencara, Daniella, Elena, Ibiza, Lemon Boy, Lucy, Melody, Perfecto, Raf and Rondello, were studied over two consecutive years by GC and GC-sniffing for their differences in flavour composition. Precautions were taken to avoid differences due to the growth conditions and stage of matu-rity. The aroma profiles obtained from dilutions of the extracts confirm the importance of most compounds previously reported as being key flavour compounds in tomatoes. Moreover, they outline a greater number of other key compounds which had not been identified or reported as such in the literature. Among them, 2-methoxyphenol, eugenol, decanal and geranylacetone were identified. Among 39 compounds quantified, 27 were found to permit discrimination between varieties both in 1992 and 1993. Six varieties were characterised in both years by specific flavour compositions. The differences between varieties is due to particular relative amounts of volatile compounds arising from the metabolism of aliphatic amino acids and carotenoids. Volatile compounds arising from each metabolic processes were found to be highly correlated with each other.
    Zeitschrift für Lebensmittel-Untersuchung und -Forschung 10/1996; 203(6):534-540. DOI:10.1007/BF01193159
  • [Show abstract] [Hide abstract]
    ABSTRACT: The intensity perceived by sniffing after GC elution of six volatile compounds was measured by ten judges using two pieces of apparatus: a PC mouse which is moved on a 60-cm length scale and a rheostat apparatus which measures the finger span. The choice of the components mixed was influenced by purity, elution time, presence in food and known Steven's slopes. The histograms obtained by summing the responses (determined by measuring the areas under the peaks) of ten people show no significant differences between the two pieces of apparatus. Histograms realised in parallel by Charm analysis with three other judges showed great differences between subjects. However, the mean of the three Charm analysis histograms was very similar to those histograms obtained with the two previously described pieces of apparatus. The same concentrations of ethyl butyrate, 3-methyl butanoic acid and 2,3,5-trimethyl pyrazine had the greatest odour intensity and thiophene, 2,6-dimethyl pyrazine and acetophenone had the lowest odour intensity.
    Zeitschrift für Lebensmittel-Untersuchung und -Forschung 01/1995; 201(4):344-350. DOI:10.1007/BF01192730
  • Luigi Moid · Patrick Etievant · Dominique Langlois · Jocelyne Dekimpe · Francesco Addeo ·
    [Show abstract] [Hide abstract]
    ABSTRACT: The odour impact compounds of raw, pasteurized and UHT bovine milk were investigated using vacuum extraction and extract dilution sniffing analysis using CharmAnalysis™. Fifteen odour peaks with Charm values between 10 and 3443 were detected. Of these peaks, twelve were identified as hexanal, ethyl butanoate, 2-heptanone, heptanal, dimethyl sulphone, l-octen-3-ol, ethyl hexanoate, 2-nonanone, nonanal, benzothiazole, 2-undecanone, indole and one as a mixture of 2-tridecanone and δ-decalactone. Dimethyl sulphone, indole and one unknown compound (retention index 1154) were the only ones detected as odour impact compounds in all three types of milk. Ethyl butanoate and ethyl hexanoate were found as powerful odorants only in raw milk. A further predominant odorant for this milk was dimethyl sulphone, which was the most important odorant in pasteurized milk. 2-Hexanone and 2-nonanone were identified as the most intense volatile flavour compounds of UHT milk. The powerful odorants described can be used as indicators of the aroma quality of heated milk.(Received February 04 1993)(Accepted July 07 1993)
    Journal of Dairy Research 07/1994; 61(03):385 - 394. DOI:10.1017/S0022029900030806 · 1.60 Impact Factor
  • Nerida. Abbott · Patrick. Etievant · Sylvie. Issanchou · Dominique. Langlois ·
    [Show abstract] [Hide abstract]
    ABSTRACT: The data from the extract dilution sniffing analysis of beer samples have been treated by two methods of analysis to give either ''charm'' or ''FD'' values. The results obtained from these two methods were compared and demonstrated that the rank order of intensity of the odor-active regions was different for most panelists when the data were presented as charm rather than FD values. Points of uncertainty observed while using this method such as between- and within-individual reproducibility and gaps in the coincident response have also been discussed.
    Journal of Agricultural and Food Chemistry 10/1993; 41(10). DOI:10.1021/jf00034a034 · 2.91 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The importance of obtaining and proving that the odor of an extract is representative of the odor of the original product from which it was obtained, before analysis by GC-FID, GC-MS, or GC sniff, is discussed. The sensory methods, such as triangle tests, matching tests, and quantitative analysis, used to determine the representativeness of the odor of an extract are described. Beer extracts obtained by three methods were used to illustrate the interest of the sensory tests. A method using a mixture of XAD resins was proved by sensory analysis to give some extracts with sensory characteristics representative of the particular beers from which they were obtained. Such sensory evaluation of the quality of the aroma of extracts has to be systematically made when sniffing analysis is applied to new types of beer or to different types of products.
    Journal of Agricultural and Food Chemistry 05/1993; 41(5). DOI:10.1021/jf00029a019 · 2.91 Impact Factor
  • Luigi Moio · Dominique Langlois · Patrick Etievant · Francesco Addeo ·
    [Show abstract] [Hide abstract]
    ABSTRACT: The main compounds responsible for the aroma of bovine, ovine, caprine and water buffalo freshly secreted milk have been identified by means of a gas chromatography–olfactometry technique. Of the fourteen odour-active volatile compounds detected, eight were present in all milks studied. Ethylbutanoate and ethylhexanoate (fruit-like aroma), among the neutral odorants, were the major contributors to the odour of bovine, ovine and caprine milk. The aroma of water buffalo milk was less dependent on ethylhexanoate and was also due to l-octen-3-ol (aroma of raw mushrooms), nonanal (freshly cut grass), indole (stable, animals) and an unidentified constituent, characterized by a retention index of 828, with a typical odour of warm milk and/or smoked cheese. Other aroma components were specific for some types of milk, contributing to the complexity and richness of flavour.(Received June 22 1992)(Accepted October 29 1992)
    Journal of Dairy Research 04/1993; 60(02):215 - 222. DOI:10.1017/S0022029900027527 · 1.60 Impact Factor