Hi MD,
There is no setting for this. We have removed the setting in ES2.0 as some users may set this to a high value causing issues with their server performance when the large number of emails are processed.
Currently the default amount is set to 20. If you really want to modify it, you can do so in this file: JoomlaFolder/administrator/components/com_easysocial/includes/cron/hooks/email.php