WATER-VAPOR BARRIER AND RHEOLOGICAL PROPERTIES OF SIMULATED AND INDUSTRIAL MILKFAT FRACTIONS

The applicability of anhydrous milkfat fractions in edible films and c oatings was determined through moisture barrier penetrometer and stres s-relaxation testing. Industrial milkfat fractions were compared along with tripalmitin:anhydrous milkfat blends which simulated milkfat fra ctions having different melting points. The water vapor permeability ( WVP) was determined gravimetrically using a modified ASTM E96-92 metho d, while rheological properties were determined via cone penetration a nd stress-relaxation tests. The WVP of the lipid films, at 27.5 degree s C and 0 to 100% RH difference, ranged from 0.0093 g.mm/kPa.h.m(2) fo r pure tripalmitin to 0.5993 g.mm/kPa.h.m(2) for anhydrous milkfat. in dustrial milkfat fraction WVPs were intermediate to these extremes, wi th the higher-melting-point fraction having the lower WVP.