How to change the default user and group of automounted SD card with Debian?

I’m going to use the SD card as a data storage on my BeagleBone Black. The SD card is perfectly mounted on /media/PARTITON_NAME with user debian and group admin as the owner.
I’d like to change this default owner to my custom user of the linux system.

Where can I change the user and group with which the SD card is mounted?
I thought it would be a udev rule, but I couldn’t find one.

I’m using the following Debian system:
BeagleBoard.org BeagleBone Debian Image 2014-05-14
Linux beaglebone 3.8.13-bone50 #1 SMP Tue May 13 13:24:52 UTC 2014 armv7l GNU/Linux

Regards,
Stefan.

I'm going to use the SD card as a data storage on my BeagleBone Black. The
SD card is perfectly mounted on /media/PARTITON_NAME with user debian and
group admin as the owner.
I'd like to change this default owner to my custom user of the linux
system.

Where can I change the user and group with which the SD card is mounted?
I thought it would be a udev rule, but I couldn't find one.

Your question is very Debian generic and not Beagle-specific.

I think a udev rule would allow you to provide specific mount arguments
fairly easily.

However, are you sure you simply aren't looking for 'chown'? Assuming
you've created an ext2/ext3/ext4 type of format on your SD card, then there
will simply be user ID numbers associated with ownership of all the files,
including the root directory on the card. A simple 'sudo chown -R
newuser.newuser /media/PARTITON_NAME' (copied your spelling), should
resolve that pretty quickly.