Relationship between flavor dilution values and odor unit values in hydroalcoholic solutions:: Role of volatility and a practical rule for its estimation

The gas-liquid partition coefficients (GLPC) of a series of compounds in hydroalcoholic solutions have been determined experimentally in order to show that it is possible to establish a direct relationship between the odor unit values (actual concentration/odor threshold) and the flavor dilution values from an aroma extract dilution analysis (AEDA). GLPCs depend primarily on the chemical functionality of the compound and secondarily on its intrinsic volatility, and it is shown that GLPCs can be estimated from GC retention data. The GLPC of a compound is directly proportional to I(ap)boolean AND 1.32 and inversely proportional to Delta I boolean AND 4.61, Delta I being the difference between the retention indexes of the compound in a Carbowax 20M column and in a BP-5 column, while I-ap is the RI of the compound in the latter column. The function has been applied to the determination of the odor spectrum of Grenache red wine from FD values and has yielded satisfactory results.