I can see in the feed looking at the source that the itunes:summary is now different. (So don't use Feedburner, it is doing something).
iTunes will take 24-48 hours to pull new information, and sometimes that is not until you also release a new episode/media file. Give the ping 24-48 hours, then if it still doesn't update, release a new episode. If it doesn't update in 24-48 hours but the new episode appears in iTunes, then something else is wrong, and you will want to contact Apple.