Evaluation of antioxidant and physicochemical properties of microalgae/ whey protein- based edible films

In the last decades, edible films based on whey proteins have become promising eco-friendly materials that can be used as carriers for some bioactive substances such as nutrients and antioxidant agents. Spirulina, one of the best-known cyanobacteria, is a rich source of nutritional compounds with beneficial health effects. Edible films from whey protein concentrates (WPC) were developed applying different treatments, such as water-bath heating for 30 minutes at 75^o C and ultrasound treatment for 15 minutes at 70^o C with the addition of a commercial spirulina powder. WPC-based edible films were prepared with the addition of spirulina in different concentrations (1; 2; 4; 6 and 8 % w/w). Other edible microalgae such as commercial chlorella and ulva have also been examined for the production of edible films. After production, the films were characterized according to their physicochemical properties (thickness, moisture content, solubility in water, degree of swelling), optical parameters (Fourier transform infrared spectrum), tensile properties, and antioxidant activity. Results showed that the ultrasound treatment increased the homogenous distribution of spirulina during the denaturation process and enabled its entrapment within the film matrix. Furthermore, the incorporation of other microalgae in WPC films needs further research as it was difficult to homogenously distribute them in the film matrix because of their poor solubility, and they were not further investigated.