Development of Biodegradable Alginate-Based Films with Bioactive Properties and Optimal Structural Characteristics with Incorporation of Protein Hydrolysates

Alginate is widely used in the food industry due to its biodegradability, biocompatibility, and non-toxicity. Protein hydrolysates possess properties important for forming the mechanical characteristics, protective, and barrier properties of the films. The aim of the research was to develop biodegradable alginate-based films with bioactive properties and the optimal structural characteristics when protein hydrolysates were incorporated. The microstructure of the cross-sections of films with 0.5 and 1.0% protein hydrolysates was characterized by smoother and homogeneous surfaces, which indicated the compatibility of sodium alginate and protein hydrolysate. The addition of protein hydrolysate significantly increased the thickness of the film by 0.06 mm and reduced the solubility by 49.4% ( p < 0.05). The results showed the high biodegradability of alginate-based films after 2 weeks of storage. With the introduction of protein hydrolysate, changes occurred in the FTIR patterns due to the interaction between the hydroxyl groups of peptides and the alginate, and, consequently, the thermal stability of the alginate films increased. The alginate films with PH positively affected the storage capacity of sweet cherry berries, both at room temperature and under refrigeration conditions. The alginate-based films with protein hydrolysate have improved properties and can serve as an alternative to polypropylene packaging materials.