The thermal degradation of control films (TPS) followed the
pattern described in the literature typical of glycerol-plasticized
starch-films (García et al., 2009). A small step of weight loss (c.a.
10%) between 50 and 150 C was attributed to water loss. The mass
loss event between 200 and 255 C could be attributed to the
decomposition of the glycerol-rich phase. At temperatures higher
than 255 C occurs the oxidation of the partially decomposed starch. In the films carrying RE, the degradation temperatures
showed a shift towards lower values, respect to the TPS films.
Moreover, a higher shift was observed for the samples TPS-RE20%,
i.e. with greater added extract amount. These results agree with
FTIR studies showing that extract weaken the starch-glycerol
interactions.
The chars amount at temperatures higher than 250 C increased
in the following order: TPS-RE20%> TPS-RE10%> TPS-RE5%> TPS.
This behavior was attributed to the high thermal stability of the
extract