Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/4/2002
Publication Date: 12/19/2002
Citation: Bezman, Y., Mayer, F., Takeoka, G.R., Buttery, R.G., Ben-Oliel, G.,Rabinowitch, H.D., Naim, M. 2002. Differential effects of tomato (Lycopersicon esculentum Mill) matrix on the volatility of important aroma compounds. Journal of Agricultural and Food Chemistry. Vol 51, p. 722-726. Interpretive Summary: Flavor is a major determinant of food acceptance. Flavor perception in foods is influenced by interactions between flavor compounds and a variety of non-flavor matrix components such as lipids, proteins and carbohydrates. This study was conducted to determine the influence of tomato matrix on the volatility of important fresh tomato odorants. Significant tomato matrix effects on the volatility of certain odorants were found using quantitative determination using solid phase microextraction (SPME) and direct static headspace techniques. In most cases, the tomato matrix significantly retained the odorants relative to a water solution, meaning that the actual concentration of odorants in the headspace would be underestimated if one calibrated the concentrations using a water solution rather than a tomato matrix calibration curve. It is suggested that selected interactions of each odorant with the matrix components determine volatility. This study has important implications in flavor research since if a matrix effect is found, analysis of the odorant concentration in the headspace rather than in the food itself is recommended since this is closer to what is actually perceived by the consumer.
Technical Abstract: Significant tomato matrix effects on the volatility of certain fresh tomato odorants were found during quantitative determination using solid phase micro extraction (SPME) and direct static headspace techniques. The concentrations of some odorants, such as (E,E)-2,4-decadienal, beta-damascenone and B-ionone, in disrupted fresh tomato fruit in the presence of saturated calcium chloride using SPME employing a tomato matrix calibration curve, were 5.5-, 2- and 12-fold higher, respectively, than those calculated by calibration against buffer solutions. Static headspace analyses clearly indicated that in most cases, the tomato matrix significantly retains the odorants relative to the buffer solution, suggesting that the actual concentration of odorants in the headspace of tomato is lower than expected using a simple matrix such as buffer. The differential pattern of various odorants between the matrix and the buffer media could not be explained by inferior mass transfer from the green tomato matrix. Rather, it is the selected interactions of each odorant with the matrix components that determine volatility. Saturated calcium chloride, although needed in disrupted fruit tissue to block enzymatic activity, was found to interact specifically with 2-isobutylthiazole, reducing its content in the headspace by at least six fold. Other divalent cationic salts such as those of magnesium and zinc also interacted with this odorant. It may be concluded that if a matrix effect is found, analysis of the odorant molecule contents in the headspace rather than in the food itself is recommended in order to better evaluate their access to the olfactory receptors.