Thermal analysis of gelatin-chitosan edible film mixed with plant ethanolic extracts

Films based on blends with different gelatin (GEL) and chitosan (CH) (GEL100, GEL75:CH25, GEL50:CH50 and CH100) ratios, with and without ethanolic extracts (boldo of Chile, guarana, cinnamon and rosemary), were prepared by casting technique. The thermal behavior of all films was studied by DSC analysis, and glass transition (T (g)) temperature, melting temperature (T (m)) and melting enthalpy (Delta H (m)) were determined. In addition, crystallinity (X) was calculated. In the first scan, GEL100 presented higher T (m) (81.9 +/- 0.5 A degrees C), Delta H (m) (22.6 +/- 0.2 J g(-1)) and X (36.4 +/- 0.3%) values than CH100 (p ae<yen> 0.05). In the second scan, the T (g) of GEL100 films dislocated a lower temperature (28.2 +/- 1.1 A degrees C). Films based on blends (GEL75:CH25 and GEL50:CH50) without extracts exhibited a T (g) of around 50 A degrees C and intermediate T (m) and X values in the first scan, which significantly decreased as CH increased (GEL50:CH50: T (m) = 74.3 +/- 1.0 A degrees C, Delta H (m) = 16.6 +/- 0.1 J g(-1) and X = 15.7 +/- 0.1%) (p ae<yen> 0.05), showing good compatibility among these biopolymers. Furthermore, ethanolic extracts addition decreased significantly the Delta H (m) and X of films based on blends with 50% of chitosan polymer in the formulation (p ae<yen> 0.05), showing intermediate values between pure biopolymers. (AU)