From Composition to Perception: Venus Flytrap Domain Biosensors of the Human Sweet Taste Receptor for Quantifying Sweetness

Sweetness is still judged by sensory panels throughout food manufacturing, because no validated function maps composition onto sweetness: relative sweetness varies with reference concentration, sweetener interactions change with the matrix, and composition and perception diverge even in unblended raw materials. Instrumental methods all return composition or a bulk property, and lipid-membrane taste sensors recognize solute charge rather than sweetness. This review examines the Venus flytrap (VFT) domain of the human sweet taste receptor as the recognition element for closing that gap. It maps sweet ligands onto primary and secondary binding sites, which fixes the sweeteners a construct can cover; compares routes based on cells, membrane-mimetic carriers and isolated domains; and finds performance reporting concentrated on limits of detection far below use levels. Most isolated-domain engineering has used the umami receptor T1R1, whose immobilization chemistry, protection strategies and multi-week stability have not been tested on TAS1R2-VFT. Two TAS1R2-VFT transducers have been reported, and no receptor-based method has yet been calibrated or validated against a sucrose equivalent scale. Calibration to sucrose equivalent concentration, constructs covering more than one domain, formulations not requiring ultra-low-temperature storage, and attribution of responses in real matrices remain the tasks.