  Chocolate is known to undergo solid-liquid transition upon an increase in
temperature as well as under application of deformation field. Upon sudden
reduction in temperature from a molten state (or thermal rejuvenation),
rheological properties of chocolate undergo evolution as a function of time
under isothermal conditions, a behavior reminiscent of physical aging in
polymeric glasses. Then again, subsequent to cessation of shear flow (or
mechanical rejuvenation), chocolate shows temporal evolution of the rheological
properties, a behavior similar to physical aging in soft glassy materials. In
this work, we evaluate three rheological properties, namely, dynamic moduli,
relaxation time spectrum and characteristic relaxation time of chocolate, and
compare their evolution after thermal as well as mechanical rejuvenation. We
observe that the evolution of the rheological properties subsequent to
mechanical rejuvenation is distinctly different from that of thermal
rejuvenation, wherein the evolution is more gradual in the former case. On the
one hand, this work provides unique insights into how shear affects the
rheological behavior of chocolate. On the other hand, this work clearly
suggests that chocolate explores different sections of the energy landscape
after mechanical rejuvenation compared to that of thermal rejuvenation.
