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Hydrophilic Edible Films: Modified Procedure for Water Vapor Permeability and Explanation of Thickness Effects
Author(s) -
McHUGH T. HABIG,
AVENABUSTILLOS R.,
KROCHTA J.M.
Publication year - 1993
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.1993.tb09387.x
Subject(s) - water vapor , relative humidity , materials science , composite material , permeability (electromagnetism) , humidity , vapor pressure , chemistry , meteorology , organic chemistry , biochemistry , physics , membrane
The ASTM E96 Standard Method for determining water vapor permeability (WVP) was modified for hydrophilic edible films. Accurate measurement of relative humidity conditions and maintenance of 152 m/min air speeds were essential outside the test cups. The WVP Correction Method was developed to account for the water vapor partial pressure gradient in stagnant air layer of the test cup. Errors were as high as 35% without this correction. Applying these guidelines explained commonly observed thickness effects on WVP values of hydrophilic films. Relative humidity was the cause of observed thickness effects.