Title : Whey protein sodium alginate complexes to make edible films
Edible films are an alternative to petroleum based plastics and contributes to reduce the pollution. This films can be prepared using natural polymers like proteins, carbohydrates, lipids or a mix of them. Whey proteins (WP) can interact with sodium alginate (ALG) through the formation of complexes between positively charged proteins and anionic polysaccharides. To evaluate the best ratio between WP and ALG potentiometric and turbidity titration were made using a spectrophotometer at ?=400nm. Once the ratio was determinated, the stability and particle size of the WP-ALG complexes was measured with a micro-electrophoresis/electrophoretic light scattering technique using a Zetasizer nano ZS90. Finally, edible films were prepared using the casting technique, samples were let dry for 48h at 45°C and 30%RH. The best ratio among WP-ALG was determinated at 4:1 (Protein:Carbohydrate), so the successive samples were prepared using this ratio. The zeta-potential of WP and ALG and the WP-ALG complexes showed good stability (below -30mV). The particle size of the complexes (410.7?m) were lower than the size of the ALG, showing the interaction between the two components. The edible films obtained were flexible, transparent with a thickness of 223 ?m. In conclusion, the formation of WP-ALG complexes helps to improve the solution stability and are good alternative to produce edible films.
Audience take away:
Feasibility to create edible films from natural polymers.
? Different characteristics between a filming solution made by singular polymers and made with protein-carbohydrate complexes.
? Importance of protein-carbohydrate ratio for the design of edible films.
? An alternative to reduce the pollution