The TG–DTA curves supplied information about the thermal
stability and thermal decomposition of propyl gallate. This food
additive was thermally stable up to 200 °C in an air and nitro-
gen atmosphere and decomposed in two steps. The DSC curve
showed an endothermic peak beginning at 145 °C with a max-
imum at 150 °C, which was related to the melting of the sam-
ple, followed by its crystallization, with a peak found at 135 °C.
XRD and SEM confirmed that PG recrystallized in a different
form after the melt. The information provided by the coupled
TG-FTIR techniques suggests that n-propanol was released dur-
ing the first step of thermal decomposition of this compound. In
the UV region, PG had two main absorption bands. The first
band was assigned to a p ? p⁄ transition and the second to a
n ? p⁄ transition. In the visible region, PG did not absorb. The
bands presents in the NIR and MIR regions provided us with
information about the functional groups present in the molecule
and showed a strong hydrogen bonding in the PG molecule,
probably between the oxygen atom of the ester group and
the OH groups of the aromatic ring.