Identification of kafirin film casting solvents

The sorghum prolamin protein, kafirin can be used for making edible films. Several food compatible solvents were examined to identify novel kafirin film casting solvents to replace aqueous ethanol, commonly used for prolamin film casting. Glacial acetic acid and lactic acid were identified as the best primary solvents and 55% (w/w) aqueous isopropanol as a good binary solvent. However, the low volatility of the latter two prevents their use as casting solvents. Films could be cast from glacial acetic acid at 25 °C, a much lower temperature than the 70 °C required with aqueous ethanol. The sensory, tensile, and water barrier properties of the films cast from glacial acetic acid at 25 °C and aqueous ethanol at 70 °C were almost the same. However, the use of glacial acetic acid at 25 °C for casting kafirin films is advantageous as it gave films of more consistent quality.