Over the past three decades, electronic nose devices have gained popularity in various fields due to their great potential for detecting volatile organic compounds (VOCs). To improve the performance of such devices, proteins from the olfactory system are very attractive sensing materials. Nevertheless, conserving their biological properties when exposed to gaseous VOCs is quite challenging. Indeed, the absence of an aqueous environment can largely affect the activity of the proteins. Water molecules play a crucial role in the stabilization of the protein structure. Consequently, the hydration degree of the working milieu has a large impact on the function of the biosensors. In this study we investigated the performance of an optoelectronic nose based on odorant binding proteins and emphasized the role of humidity on the activity of the system.