Water solubility of the films was determined following the method of Romero-Bastida et al. (2005). Briefly, pieces of films
from each formulation were cut uniformly (2 3 cm) and were conditioned in a desiccators containing silica gel (0% RH) for 7 days. Prior to the test, samples were weighed to a nearest weight of 0.0001 g. Followed by this, samples were dispersed into test beakers containing deionized water (80 ml). The samples were tested at room temperature (25 C) and maintained under constant agitation for 1 h. After soaking, the remaining pieces of films were filtered through filter paper (Whatman No. 1). Next, the samples were dried in an oven at 60 C until constant weight was achieved. All the samples were measured in triplicates with the percentage of total soluble matter (% solubility) being calculated using the formula:
Pieces of film of 2×3 cm were cut from each film and were stored in a dessicator (o% HR) for 7 days. Samples were weighed to the nearest 0.0001 g and placed into test beakers with 80 ml of deonized water. The samples were maintained under constant agitation for 1 h at room temperature (approximately 25 °C) or at boiling temperature. The remained pieces of film after soaking were dried again in an oven at 60 °C to constant weight. The percentage of total soluble matter (% solubility) was calculated as follows: