Abstract:
Polysaccharide from Aureobasidium pullulans YTP6-14 is a homopolysaccharide, contains solely glucose as constituent. The reaction with pullulanase which hydrolyses α-(1,6) glycosidic bond produces maltotriose as final product. This polysaccharide is well dissolved in water the solution of which is heat stable with thick solution appearance and able to form film. Film solution was mixed with cinnamaldehyde (CH) as an antimicrobial additive. CH exhibited good growth inhibition both of tested fungi and bacteria at low concentration. Film forming solutions with CH 24 and 30 mg/ml were chosen to form the films. The film without CH was thin, smooth, homogeneously in texture, colorless and odorless while the CH incorporated film showed more yellowness, less transparent with cinnamon smell. The small CH droplets were found in the matrix of the modified film under scanning electron microscope. The addition of CH caused film to be inhomogeneous, more color different and thicker film. Moreover, the modified polysaccharide film with CH at 30 mg/ml increased water vapor permeability of the film. In the process of film preparation, the use of hot air to evaporate solvent (water) away caused CH loss by 70%. At room temperature CH was gradual decrease every week nevertheless, remained higher than MIC value even at 5 weeks of standing. The antimicrobial activity of the films incorporated with CH were observed on food model and agar plate. The polysaccharide film with CH 30 mg/ml showed the highest inhibiting activity on the tested microorganism.