If you look closely at your antialiased text samples, you'll notice that the edges contain a lot of red and blue:
This suggests that the antialiasing is taking place inside your computer, which has used subpixel rendering to optimise the results for your LCD monitor.
If so, it should be quite easy to extract the text at a higher resolution. For example, you can use ImageMagick to extract images from PDF files at 300 dpi by using a command line like the following:
convert -density 300 source.pdf output.png
You could even try loading the PDF in your favourite viewer and copying the text directly to the clipboard.
Addendum:
I tried converting your sample text back into its original pixels and applying the scaling technique mentioned in the comments. Here are the results:
Original image:
After scaling 300% and applying simple threshold:
After smart scaling and thresholding:
As you can see, some of the letters are still a bit malformed, but I think there's a better chance of reading this with Tesseract.