SORPTION BEHAVIOR OF FLAVOR COMPOUNDS INTO PACKAGING FILMS FROM ETHANOL SOLUTION

The sorption of flavor compounds into low-density polyethylene (LDPE) and ethylene-vinyl alcohol copolymer (EVOH) films was greatly influenc ed by ethanol concentration, and maximal sorptions were observed at 5- 10% (v/v) ethanol for LDPE and 10-20% (v/v) ethanol for EVOH. The sorp tions of ethyl hexanoate, octanal, and octanol into LDPE film were sim ilar to 1.7, 16.5, and 2.5 times higher than those in the 0% (v/v) eth anol solution, respectively (for EVOH film, the sorption increments of these compounds were similar to 6.2, 3.5, and 4.1 times, respectively ). To better understand this phenomenon, the solvent properties of eth anol solutions were investigated. The dielectric constants were roughl y unchanged in the range 5-15% (v/v) ethanol. According to the results obtained by H-1 NMR measurement, in which the difference in proton ch emical shift from water-d (HDO) and ethyl alcohol-d (EtOD) became maxi mum at 23% (v/v) ethanol solution, the structural change of water indu ced by the addition of ethanol would be great up to 23% (v/v) ethanol. These results accurately reflected the sorption behavior. Therefore, the specific sorption behavior of flavor compounds from an ethanol sol ution would be brought about by the heterogeneous water-ethanol struct ure.