You would be well advised to look at the Reference section to read up on Serial. As well, have a look at Nick Gammon's excellent tutorial, http://gammon.com.au/serial
Can't help with the MatLab stuff, except to say that you don't need a delay in sending unless you find that the Serial buffer (64 bytes) in the Arduino starts overrunning. No idea why MatLab might be sending zeros when it isn't supposed to.