Color is not a property of the font (even though some UI may show selection of the text color under the "font" property; this is done just for convenience). Color is the attribute of the element of structure of the structured document or a style of such document, such as whole document, paragraph or spreadsheet cell.
You can control this property in Microsoft office document separately, the font separately. See for more information: http://msdn.microsoft.com/en-us/library/bb726434(v=office.12).aspx
]. You should understand that font or color information is not the attribute of any file, but can only be the attribute of the document (but more likely of the structure elements of a document).
Text files containing unstructured text (I mean the text not formed as XML, HTML or something like that) contain no information of fonts, colors or any other formatting/presentation properties.