Fat taste detection with odorant-binding proteins (OBPs) on screen-printed electrodes modified by reduced graphene oxide

Abstract

Except for the widely accepted taste primaries—sour, sweet, bitter, salty, and umami, increasing evidence indicated that the existence of a taste modality responsive to fat. Based on the hydrophobic nature of dietary fats, a new kind of gustatory biosensor with odorant-binding proteins (OBPs) modified screen-printed electrodes was designed for sensing the “fat taste”. Through electrochemical reduction, graphene oxide was modified on the carbon electrodes to form a sheet that comprised graphene domains with residual oxygen-containing functional groups, which could increase the electrode conductivity and be used for protein immobilization. For fat taste sensing, taste substances of medium- and long-chain fatty acids, such as lauric acid, linoleic acid, and docosahexaenoic acid, were detected through cyclic voltammetry. Moreover, the sensor showed high affinities to medium- and long-chain fatty acids comparing to the tastants of other five primaries tastes. The gustatory biosensor offered a powerful analytic technique for detecting fat taste substances, which seem to be an alternative to labor-intensive and time-consuming cell-based assays or animal experiments. Furthermore, it could be treated as the sensory evaluation panels for food and beverage industry, and even for disease managements.