Rice flour films prepared in the present work have similar
mechanical properties to those of starch based films. However,
their water vapor permeabilities are two times higher than those of
starch based films, when both are prepared with glycerol. Films
with sorbitol are less permeable to water and more rigid, while
films with glycerol are more plasticized and have poorer water
vapor barrier properties. The selection of the plasticizer depends on
the specific application. The presence of lipids in the rice flour does
not cause important changes in film hygroscopicity (similar water
sorption isotherms). From the results presented in this work, it is
clear that the permeabilities are controlled mainly by plasticizer
concentration. In fact, both starch and flour films present poor
water vapor barrier and are not indicated for packaging low
moisture food, for example. In other words, the higher permeability
of flour films is not a big problem, and flour is a good raw material
to prepare edible films. On the other hand, preparing edible films
from rice flour is a new alternative for using this raw material,
which is sometimes much cheaper than commercial starches.