Get only one value from Arduino to Matlab using fscanf

Hello everyone, I want to send data from Arduino to Matlab and Matlab back to Arduino. Because I use interrupt so I have to use Serial seperately in Arduino and Matlab There are code I learn from the Internet to send data from Arduino to Matlab In Matlab:

arduino=serial('COM4','BaudRate',9600);
fopen(arduino);
y=fscanf(arduino,'%f');
fclose(arduino);

And in Arduino:

float temperature=9.100;
void setup() 
{
  Serial.begin(9600);
}

void loop() 
{
   Serial.print(temperature);
}

But when I run the program in Matlab, I saw that y had many different values, sometimes y was a char array. I just want to get one value, so how can I do that? Thank you very much!