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

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. (C) 2017 Elsevier B.V. All rights reserved.