Set default font name,size to syncfusion richtext editor's source code

In Angular 6, I have used a sync-fusion rich text editor(RTE). I have set font name and size to it as follows.

e.g. my RTE contains text/data as "This is testing template". If I click on source code button of RTE then it shows like

Means, though I have set font name and size to RTE , it does not reflect in source code. What I want is like it should show me source code as,

To show like above source code, I have to do "select All" content of RTE and then set font and size explicitly by clicking on font and font size buttons on RTE. Then only I get style tag attached. So, I have to always select all contents of RTE and then set font and size which is very hectic. So, how can I set the same by default in source code of RTE. Thank you in advance.