MQTT binding strip unit from message

Hi there,

I have a binding set up to retrieve measurements through MQTT. Here’s an example of what comes in:

nefas/DSMR1/power_returned 855 W

Now I would like to strip the unit when receiving the MQTT updates for persistence purposes. With this I mean removing the " W", so I am left over with just a number. Otherwise I can’t feed it into my influxdb+grafana setup for graphs.
Is there a way to configure this in the mqtt binding or openhab itself?

Transformation ?