Single quote marks on '(hd0,x)'

[Goh Lip]

The new version of grub, GNU GRUB 1.98-1ubuntu1, has its grub.cfg as 
follows...
set root='(hd0,5)'  instead of
set root=(hd0,5)

I noticed it will still work without the quote marks, ie.,
set root=(hd0,5)
also will work with or without quote marks on
configfile (hd0,5)/boot/grub/grub.cfg    or
linux '(hd0,5)'/vmlinuz root=/dev/sda5

What is the significance of the quote marks and why was it added to the new 
grub version?

Thanks and regards - Goh Lip