DEVELOPMENT OF ANTIOXIDANT STARCH FILMS INCORPORATED WITH AGROINDUSTRIAL RESIDUES

The non-biodegradable materials increasing and the difficulty in recycling most of the packaging have pushed the development of biodegradable packaging. However, their utilization will only be feasible if they are competitive in terms of cost and functionality. An alternative to make them economically competitive is employing cheaper materials, like agroindustrial residues. This study aimed to develop biodegradable films added with brans from jaboticaba peel (JP), mango peel (MP) and broccoli stalk; products rich in antioxidants. The cassava starch films have been produced by casting process with glycerol as plasticizer. The influence of the concentration and type of waste on the mechanical and antioxidant properties of the films has been evaluated by a central composite design. The results have been statistically analyzed by the response surface methodology and desirability function. Through these results, the optimal formulation for film production was determined. Except for elongation at break and solubility, the fitted equations showed predictive for all the studied properties. The absence of MP bran produced films with higher Young’s modulus (58.67 MPa) and tensile strength (1.01 MPa). The percent inhibition and EC50 results ranged from 10.70 – 46.91% and 5.84 – 5.81mg/mL, respectively. Higher concentrations of agroindustrial residues (mainly MP) resulted in films with larger antioxidant capacity, while smaller concentrations produced less antioxidant films. Evaluating the results, it was defined the optimal formulation of the desired film (2.8% of JP bran and 20.0% of MP bran) and their predicted response variables (0.8 MPa for the tensile strength, 40.0 MPa for Young´s modulus, 4.5mg/ml for EC50, and 41.6% for percentage inhibition). Based on the relative deviation values obtained for each response variable it was proved that the optimization was satisfactory. Furthermore, it was concluded that the optimized film can be used as packaging for liquid products, since it contained linseed oil without leaking.