Quantitative Analysis, Aroma Values

Analysis of the vacuum volatile constituents of fresh tomatoes was carried out using capillary GLC-MS and packed column GLC separation with Infrared, NMR and CI-MS analysis. Evidence was obtained for the presence of the unusual components 3-damascenone, 1-nltro-2--phenylethane, 1-nltro-3-methylbutane, 3-cyclocltral and epoxy-3-1onone. A method for the quantitative analysis of the volatile aroma components In fresh tomato has been Improved and applied to fresh tomato samples. The quantitative data obtained have been combined with odor threshold data to calculate odor unit values (ratio of concentration / threshold) for 30 major tomato components. These calculations Indicate that the major contributors to fresh tomato aroma Include (Z)-3-hexenal, 3-lonone, hexanal, 3-damascenone, 1-penten-3-one, 3-methylbutanal, (E)-2-hexenal, 2-lso-butylthlazole, 1-nltrophenylethane and (E)-2-heptenal. 

The quantitative analysis of aroma substances using conventional methods often gives incorrect values. The high vapor pressure, the poor ex-tractability especially of polar aroma substances from hydrous foods and the instability of important aroma substances, e. g., thiols, can cause unforeseeable losses in the purification of the samples and in gas chromatography. 

Figure 1 Quantitative descriptive analysis configuration of the aroma in orange juice samples. The average intensities for the various attributes are graphed on lines radiation outward from a value of 0 at the center point to a value of 9 at the outward perimeter.

The area of flavor and aroma barrier is receiving growing attention in the field of plastics packaging. The permeation of flavors is difficult to measure quantitatively because they contain many components. Many times, only a simple component of a flavor is measured if a quantitative value must be determined. Gas chromatography and mass spectrophotometric (GC/MS) techniques have been developed that allow the analysis of complex flavors. However, in most cases, the use of organoleptic testing provides reliable and pertinent data at a greatly reduced cost. 

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