SOLUBILIZATION MECHANISM OF CIS-3-HEXENOL AND MENTHYL ACETATE INTO SODIUM DODECYL-SULFATE MICELLES, AND THE VAPOR-PRESSURE OF THESE ODORANTS

The solubilization mechanism of cis-3-hexenol and menthyl acetate into sodium dodecyl sulfate (SDS) micelles, and the vapor pressure of thes e odorants were examined. Also, the electric conductivity and osmotic pressure of the SDS micelle dispersed system containing odorants were measured to determine the number of micelles and reveal the micelle fo rmation condition. Lots of cis-3-hexenol molecules are solubilized int o the palisade layer of SDS micelles to form composite micelles with t he surfactant resulting in an increase in the number of micelles. In o ur examination, it was revealed that a little quantity of the odorant enters into the; hydrophobic layer of the micelles after the solubilit y limit in the palisade layer is reached, but the solubilization mecha nism is different from those of hydrophobic alcohol such as geraniol a nd citronellol. Menthyl acetate proved to be solubilized into SDS mice lle hydrophobic layer only. By using a sweeping method with nitrogen g as, the aroma of the dispersed system samples were collected and the p artial vapor pressure of each odorants in the dispersed systems were d etermined through calculation on the quantity of collected aroma. The partial vapor pressure of cis-3-hexenol solubilized in palisade layer of the composite micelle with SDS indicated great negative deviation a nd the aroma of the dispersed system very much decreased in this solub ilization area. The partial vapor pressure of menthyl acetate solubili zed in the hydrophobic layer of SDS micelle extremely increases to be significantly larger than that based on the vapor pressure of pure liq uid, because the intermolecular force of menthyl acetate is weakened i n the hydrophobic layer. This accounts for an significant increase in the aroma strength of menthyl acetate solubilized in micelles.