The effect of sodium dodecyl sulfate (SDS) and triethylene glycol (TEG) on secondary structure of decolored bloodmeal (DBM) during heating was examined via synchrotron-based Fourier transform infra-red spectroscopy (FT-IR) and wide angle X-ray scattering (WAXS). Both additives homogenize secondary structure distribution; SDS increases α-helices and decreases β-sheets and β-turns, while SDS–TEG reduces α-helices and β-sheets and increase random coils. Short heat cycles only change the composition of SDS-TEG treated DBM, implying TEG is responsible for chain mobility. Prolonged heating slowly increases β-sheets and suddenly increases α-helices at 55–75 °C in SDS-TEG treated DBM and 100 °C in SDS-treated DBM. Finally, WAXS shows that structural change due to heating is reversible for SDS-TEG treated DBM