Arduino and MatLab with OWI Robotic Arm Edge -- Issue with I2C
The documentation in MATLAB for scanI2CBus() notes that the return is a cell array of character vectors

They even give the example:

a = arduino('COM9');
scanI2CBus(a,1)


with result:

ans = 
            '0x48'


It appears you will need to parse the cell array into the numeric value or otherwise convert it to a number, perhaps using the MATLAB function hex2dec('hex_value')