MEASURING AROMA TRANSPORT IN POLYMER-FILMS

A new method to measure aroma transport through polymeric films is int roduced This recirculating constant-volume method minimizes localized concentration gradients, allows for the evaluation of high barrier fil ms, and provides a humidity generation scheme which is simple, accurat e, and easy to implement. Vinylidene chloride copolymer co-VDC, and et hylene vinyl alcohol copolymer; EVOH, were tested under identical cond itions to evaluate the efficacy of the methodology. Additionally, edib le, hydrophilic whey protein isolate (WPI) films were tested at identi cal temperature and permeant concentration levels with three different levels of relative humidity. The permeability coefficient measured fo r d-limonene in co-VDC (55 degrees C) was 18,000 MZU (+/-5000) [1 MZU = 10(-20) kg-m/(m(2)-s-Pa)], while the measured value of d-limonene pe rmeability coefficient in EVOH (55 degrees C, 50% RH) was 0.9 MZU (+/- 0.3). These values are within the range of reported literature values for co-VDC and EVOH. An exponential relationship between d-limonene pe rmeability and relative humidity in the WPI films (40 degrees C) was s uggested, with the permeability coefficients increasing from 1.2 to 3. 2 to 8.8 MZU as the relative humidity increased from 40% to 60% to 80% RH, respectively The preliminary data for WPI films indicated they we re comparable to EVOH, the industry standard for hydrophilic barrier f ilms.