is this a default outlook behavior folders do not show up in recover deleted item folder in outlook however this is not a case with emails . I checked with exchange server 2010 . Please sugge

Folders are not retained in the Recoverable Items folder within Exchange which is what the Recover Deleted Items from server is looking at.  So the only tiem folders are preserved is IF the folder is deleted normally and sitting with the the Deleted items Folder.  Once that the deleted items folder is emptied all folder related information is gone/not retained within the recoverable items folders