Text animations do not have these extra formatting options.
A text animation in Captivate 5 is actually a special kind of widget that manipulates the text as a whole to animate it. You have to think of a text caption as just a string of text that you can only format as a single unit, not individual words within the line of text (character level formatting) as you can do with normal text captions.
Because the animated text must be able to be subjected to all manner of fancy effects using ActionScript, (including breaking it apart and putting it back together a gain) this tends to limit your options for formatting.