# The Effect of Edible Coatings on Selected Physicochemical Properties of Cassava Chips
## 3 Results  
### Water Vapor Permeability, Solubility and Thickness of Edible Coatings  
The pectin films showed higher solubility and lower water vapor permeability and thickness than the whey protein films. Analyzing the 2 and 3% pectin films showed that they were 45.6% more permeable to water vapor than films produced with 1% pectin. Additionally, the pectin films were 68.9% less permeable to water vapor than the whey protein films. The 1% pectin films had the lowest water vapor permeability and thickness, as compared to the 2% and 3% films. In addition, the 9% whey protein films had the lowest permeation and thickness, as compared to the 11 and 13% films. The pectin coatings were totally soluble in water since, after 24 h of immersion, the films were completely solubilized (Table 2). Similar results were reported by [PERSON] et al. [22], who also demonstrated that pectin films were completely solubilized in water. Pectin is a highly hydrophilic polysaccharide, which rapidly disintegrates in water. [PERSON] et al. [33] similarly stated that all coatings from fatty acids and pectin were completely soluble.  
The solubility of polysaccharide coatings in water is advantageous in situations where the film is consumed with the product, causing low alterations in the sensory properties  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Coating**} & \multirow{2}{*}{**(\%)**} & **Water Vapor Permeability** & **Water** & \multirow{2}{*}{**Thickness (mm)**} \\  & & **(g mm/m\({}^{2}\) day kPa)** & & & \\ \hline \multirow{4}{*}{Pectin} & 1 & 1.95 \(\pm\) 0.03 \({}^{\text{e}}\) & 100 \({}^{\text{a}}\) & 0.025 \(\pm\) 0.001 \({}^{\text{e}}\) \\  & 2 & 2.74 \(\pm\) 0.06 \({}^{\text{d}}\) & 100 \({}^{\text{a}}\) & 0.052 \(\pm\) 0.003 \({}^{\text{d}}\) \\  & 3 & 2.94 \(\pm\) 0.04 \({}^{\text{d}}\) & 100 \({}^{\text{a}}\) & 0.068 \(\pm\) 0.008 \({}^{\text{c}}\) \\  & 9 & 6.98 \(\pm\) 0.12 \({}^{\text{c}}\) & 30.66 \(\pm\) 2.65 \({}^{\text{c}}\) & 0.103 \(\pm\) 0.001 \({}^{\text{b}}\) \\ \multirow{2}{*}{Whey protein} & 11 & 7.67 \(\pm\) 0.27 \({}^{\text{b}}\) & 32.54 \(\pm\) 2.93 \({}^{\text{c}}\) & 0.118 \(\pm\) 0.002 \({}^{\text{a}}\) \\  & 13 & 9.88 \(\pm\) 0.24 \({}^{\text{a}}\) & 36.32 \(\pm\) 3.14 \({}^{\text{b}}\) & 0.113 \(\pm\) 0.001 \({}^{\text{a}}\) \\ \hline \hline \end{tabular} Different letters in the same column indicate significant statistical differences (\(p<0.05\)).  
\end{table}
Table 2: Water permeability, solubility, and thickness of edible coatings obtained from pectin and whey protein.  
of the food. The coatings obtained from pectin showed less permeation than with whey, which was not very resistant to water vapor, mainly because of the material's porosity, that is, coatings obtained from whey protein were more porous than those from pectin; this difference was statistically significant and could be related to the thickness of the coatings.  
The lower water vapor permeability of the pectin-based coatings could be explained by the lower thickness of the coatings, as compared to the whey protein coatings [34]. Matching results were obtained by [PERSON] et al. [22], who used pectin and whey protein coatings. A possible explanation for the increased permeability of edible coatings made from whey in this study could be the denaturation of the proteins under the temperature conditions used for their processing, i.e., when the protein was disrupted, it was denatured; the polar amino acids were possibly exposed, which increased the absorption of water.