Effect of chitosan and citric acid level on the physical properties of starch based edible films containing oregano essential oil

HERNANDEZ NUÑEZ, MAURY SABRINA ; FLORES SILVIA

Encuentro; II Encontro de Polímeros Naturais- EPNAT2020; 2020

Universidad de Sao Pablo, Universidad Paulista

The use of edible films and coatings containing antimicrobials has proven to be a useful tool to protect food against flora spoilage and decrease the risk of pathogen growth. The most commonly used antimicrobials are organic acids, chitosan, some plant extracts, and their essential oils. In turn, the use of starch films for food packaging has been restricted due to its hydrophilic characteristic, a poor barrier against moisture, and its high sensitivity to water. Hence, mixtures of starch with other bio-based polymers (cellulose acetate, chitosan, etc.) have been developed to form composite materials with improved physical properties. According to this, starch based edible films containing oregano essential oil were developed by casting method. Films formulation included citric acid and chitosan at different concentrations (0.07 ? 0.47 and 0.19 ? 0.41 % w/w respectively) were investigated in order to study the effect of such compounds on their mechanical properties, solubility in water and color parameters. Results showed that films with the lower amounts of citric acid (0.13 and 0.07 % w/w) generate higher values of stress at break and Young´s modulus, and percentages of elongation at break less than 6%. Solubility in water tends to increase as citric acid concentration was higher. The films were transparent and slightly yellow but with high L* values (84-87) and b* (9.8-16.9). The optimized formulation results 0.13 % w/w of citric acid and 0.38 % w/w of chitosan which show adequate stress at break and lowest solubility in water. Therefore, this formulation could be considered as a polysaccharide-based materials with improved properties, which have potential as bioactive packaging material for food application.