change text label after checkbox is checked angular

Using this tutorial dynamic checkbox angular, I have create dynamic checkboxes and I need to change the text label after the the checkbox was checked. But I can’t solve the problem where i need text label change on checked selected index only, for now it changes all the text. This is what i had tried so far: demo,

this is what I want to produce,

Before checked:

  • select (ticked checkbox)
  • select
  • select
  • select

After checked:

  • selected (change text label)
  • select
  • select
  • select

Source: New feed