The presented paper investigated the influence of brewers’ spent grain (BSG) extrusion
parameters on the photo-oxidative resistance of poly(ε-caprolactone)-based wood polymer composites.
Filler samples characterized by the higher melanoidin content were more efficient in hindering of polymer
degradation, inhibiting the decomposition of the polymer amorphous phase. As a result, deterioration
of mechanical performance was limited, which was expressed by the higher values of aging factor
for samples containing BSG extruded at higher temperatures.