Linseed Mucilage and Chitosan composite films - 11th International ...

addition of less polymer (FC), these findings suggest a net increase in yellow-brown color due to incorporation of
water level. Negative values of a* suggest the films had a green tint.
Color
20.00
18.00
16.00
14.00
b*
12.00
10.00
8.00
FA
FB
FC
Control
6.00
4.00
2.00
0.00
-3.00 -2.00 -1.00 0.00
a*
Figure 2. Color parameters of FA, FB and FC films.
The color index (∆E*) (Table 2) is influenced by L*, a* and b* values and could describe how far apart two
colors are in the color space. It was seen that ∆E* values changed upon addition of linseed mucilage polymer due
to alterations in b* and a* values of film.
Table 2. Color parameters of FA, FB and FC films
Film sample L* a* b* ∆E
FA 97.01±1.02 (-)1.54±0.49 10.55±3.22 5.06±1.64
FB 97.52±0.93 (-)1.71±0.28 9.88±2.33 5.06±0.81
FC 96.08±1.26 (-)2.20±0.51 15.18±3.89 7.53±2.47
The water vapor transmission rate of films plays an important role in deteriorative reactions of food; therefore, it
is the most extensively studied property of films. Water vapor permeability is assumed to be independent of the
water vapor pressure gradient applied across the films. However, hydrophilic materials, such as polysaccharide
films, deviate from this ideal behavior due to interactions of permeating water molecules with polar groups in the
film’s structure [14]. The WVTR values showed in Table 3. change significantly with varying concentrations of
linseed mucilage polymer. In order hand the chitosan films have relatively poor water vapor barrier
characteristics, which result from their hydrophilicity. Glycerol, through its plasticizing action, changes the
polymer network creating mobile regions with larger interchain distances, promoting water clustering
by competing with water at active sites of the polymer matrix and the formation of micro cavities in the polymer
network structure. Water sorption by biopolymers often results in swelling and conformational changes. The
absorbed water plasticizes the film matrix, leading to a less dense structure where chain ends are more mobile,
thus increasing transmission rate [15].
Table 3. WVT of films
Film WVT (g Pa -1 s -1 m -1 ) x 10 -10