To see whether a bean has been changed:
$bean->getMeta('tainted');
Note that certain properties, like lists (see chapter lists) also cause a bean to get marked as tainted. In RedBeanPHP version 3.4 there is a shorthand method: isTainted().
In RedBeanPHP 3.4+ you can check whether a certain property has changed and you can retrieve the previous value.
$post->hasChanged('title'); //has title been changed?
$oldTitle = $post->old('title');
RedBeanPHP Easy ORM for PHP © 2013 Gabor de Mooij and the RedBeanPHP community - Licensed New BSD/GPLv2