Sustainable Packaging Films Composed of Sodium Alginate and Hydrolyzed Collagen: Preparation and Characterization

Hydrolyzed collagen (HC) has been extensively explored in the food sector because of its functional properties and broad availability as a low-cost byproduct. However, its widespread use as a component of edible films lacks detailed information. In this study, sodium alginate/hydrolyzed collagen (SA/HC) films with distinct loadings of HC (10, 20, and 30%) were prepared. FT-IR results suggested the formation of intermolecular chemical bonds between SA and HC. When the control sample was compared with the highest concentration of HC evaluated, it was confirmed that incorporating HC increased the maximum degradation rate temperature from 226.51 to 232.89 degrees C (second thermal event). The thickness of all the SA/HC films increased as a function of the HC load, and a reduction of the water vapor transmission rate (WVTR) from 1215.7 +/- 71.0 to 592.4 +/- 52.2 g m(-2) day(-1) was observed. Although SEM images showed the addition of hydrolyzed collagen led to a discontinuity in the film polymeric matrix, there was no statistically significant influence on the tensile strength. However, the elongation at break experienced a significant reduction (from 11.1 +/- 7.4 to 4.0 +/- 2.4%), by comparing the control sample and a 30% HC loading. In general, SA/HC films with a 10% HC loading resulted in a superior general performance, so this formulation is recommended for future food packaging studies.

Automated summary

This study prepared SA/HC films with different HC loadings, showing that incorporating HC increased the maximum degradation temperature and thickness of the films, while reducing the water vapor transmission rate. Although tensile strength was not significantly affected, elongation at break experienced a significant reduction.