TASTE INTERACTION OF STYRENE ETHYLBENZENE MIXTURES IN AN OIL-IN-WATEREMULSION

Styrene and ethylbenzene are present in detectable amounts in polystyr ene packaging materials and migration of these compounds may cause a t aint of the packed food. The effect of mixtures of styrene and ethylbe nzene on the detection threshold concentration in a 5% oil-in-water em ulsion was investigated with the constant stimulus differences test. T he detection threshold concentrations of the individual compounds in t he emulsion were found to be 1.0 ppm for styrene and 3.0 ppm for ethyl benzene. Linear regression of the percentages of correct answers and t he logarithm of the sum of the concentrations of both compounds in the mixtures expressed as fractions of their threshold concentration gave the following relationship: % of correct answers = 42.5 X log (sum of threshold fractions) + 74.8 (r = 0.87). Calculation of the sum of thr eshold fractions at the 75% point of correct answers gave a value of 1 .0, which clearly indicates that the effect of mixing of styrene and e thylbenzene is additive at sub-threshold levels in a 5% oil-in-water e mulsion.