Water AbsorptionThe water-absorption capacity of coated paper, controlled by the type of cellulosic substrate and the nature of coating materials, reflects the paper resistance to water. The water resistance of the biopolymer-coated papers was measured through direct contact with the surface of the papers with water. Figure 3 shows water absorption of the HPMC-paper films without and with various plasticizers and plasticizer contents at different coating weights. An ANOVA reveals that coating weight and coating composition significantly affected (p < 0.05) water absorption values. Water absorption of HPMC-coated papers increased with increasing coating weight from 3 to 9 g/m2. A similar effect of coating weight also has been reported for pulp papers coated with whey protein isolate (Han and Krochta 1999). The water absorption of uncoated papers was 25.44 ± 0.42 g/m2. So, HPMC coatings formulated without plasticizers reduced water absorption by 25% for 3 g/m2. This water-absorption reduction obtained in this study was comparable to that obtained by Reis et al. (2011) after chitosan coating with a coat weight of 3.5 g/m2.