Desenvolvimento e caracterização de películas compósitas de quitosano, lipidos e tripolifosfato

Mestrado em Engenharia Alimentar - Instituto Superior de AgronomiaIn this work the effect of a lipid and a crosslinking agent, sodium tripolyphosphate (TPP) on the development of chitosan based films were evaluated. Different contents of oleic acid or beeswax (0 to 40%), and TPP (0 to 5%), were simultaneously used to study their effect on the properties of the films obtained. The water vapour permeability of the films with oleic acid was influenced by the amount of this compound. Low permeability values were observed using oleic acid concentrations between 25-35% and TPP concentrations between 1-5%. Regarding the mechanical properties, almost all films with good permeability results showed good mechanical properties. Beeswax films’ water vapour permeability was influenced by the amount of beeswax and TPP. This study showed lower values when 35-40% of beeswax and 4-5% of TPP were applied. Although the films produced with beeswax and TPP ranges referred didn´t show the highest Young’s modulus, it can be considered that they have an acceptable stiffness. The oil based films are advantageous regarding to the beeswax ones. To obtain a minimum on the permeability values, less amounts of lipid and TPP are required in the acid oleic formulations. In addition, these formulations allow the formation of more homogeneous film