no bound states capture. It can be seen from the table that there is no appreciable change in the $\beta^{+}$-decay rates as the core stiffens from low density to high density region. However the rates increase considerably with increasing stellar temperature due to a considerable increase in the available phase space. At the later stages of the collapse, $\beta^{+}$-decay becomes unimportant as an increased electron chemical potential, which grows like $\rho ^{{1\mathord{\left/
{\vphantom {1 3}} \right. \kern-\nulldelimiterspace} 3} } $ during in fall, drastically reduces the phase space. These results in increased electron capture rates during the collapse phase. Electron capture rates on $^{57}$Zn hence become important during the very late phases of stellar evolution of massive stars (prior to collapse) and at high stellar temperatures. At $\rho Y_{e}
[gcm^{-3}] = 10^{11}$ the calculated electron capture rates are bigger than the competing $\beta^{+}$-decay rates by more than four orders of magnitude. For the relevant peak rp-process conditions (T$_{9} [K] \sim 3$ and $\rho \sim 10^{7}$ gcm$^{-3}$), the pn-QRPA calculated $\beta^{+}$-decay rates are around a factor seven bigger than the corresponding electron capture rates. Therefore we present our results for both $\beta^{+}$-decay rates of $^{57}$Zn and electron capture rates on $^{57}$Zn 