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K. J. SIEBERT and Y. Tan. Food Science & Technology, Cornell Univ., New York State Agricultural Experiment Station, 630 W. North St., Geneva, NY 14456-1371 Binding of flavor compounds by food matrix ingredients can alter the aroma of a food and impact flavor release. Proteins are well known to bind various flavor compounds, but the molecular features that affect this interaction have not been well established. The object of this study was to construct mathematical models of binding of each of several flavor compound classes with beta-lactoglobulin as a function of their molecular properties. Single flavor compounds of each of three chemical classes (esters, aldehydes and ketones) were combined with various concentrations of beta-lactoglobulin in aqueous buffer in a sealed vial. After equilibration the headspace concentration of the flavor compound was assessed by SPME-GC. The proportion of flavor compound bound with each protein concentration was modeled for each compound class in terms of a small number of molecular features using partial least squares regression. Particular members of each compound class bound to a greater extent than others. For the esters the proportion bound was modeled in terms of the numbers of carbon atoms and hydrogen atoms in the molecule (R2=0.868). For aldehydes, binding was modeled by the molecular weight, numbers of carbon and hydrogen atoms, number of carbon-carbon double bonds and the extent of branching in the molecule (R2=0.894). Ketone binding was modeled by the numbers of carbon and hydrogen atoms, the asymmetry of the ketone function and the extent of branching in the molecule (R2=0.931). The binding of beta-lactoglobulin to all three classes of flavor compounds increased with increasing carbon number (molecular size); this indicates that the interaction is largely hydrophobic. An increased degree of branching of aldehydes or ketones led to weaker interactions. It should be possible to predict the degree of binding of other flavor compounds of the classes studied.
Session 79, Food Chemistry: Protein and enzyme chemistry
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