Barrier properties of whey protein isolate films to carbon dioxide and ethylene at various water activities

A cell designed and constructed in the Laboratory of Surface Chemistry (LAF IDESU) of the Faculty of Chemistry, Uruguay, is used to determine permeabil ities of whey protein isolate films to Carbon Dioxide and Ethylene at vario us water activities. As usual in hydrophilic films, permeabilities increase considerably when water activities increase. In a sorption electrobalance, sorption isotherms of CO2 and C2H4 (5 % in N-2) are performed on films at various contents of water. The amounts of gases sorbed increase with higher water activities.