NumberForm with fixed width and exponent in the form "e + 00" or "e-02"

I want to export a matrix of real numbers outside in a txt file in which the entries have the form MatLab:

7.568627450980391913e-01
1.000000000000000000e + 00
3.176470588235293935e-01

Code Export["out.txt", ScientificForm[out,19,NumberFormat->(Row[{#1,"e",#3}]&)], "Table"]; do not do what I want. How can I remedy this?