Taste sensing with cellophane phosphate membrane Original Research Article

There are reports of taste sensor fabrication by incorporation of lipids in a PVC membrane. Such lipid-based sensors were used to evaluate the senses of tastes such as sourness, saltiness, sweetness, bitterness and umami by measuring the membrane potential using Ag/AgCl electrodes. We have measured the senses of above five basic tastes with a functionalized polymer membrane without using any lipid. Commercial cellophane membrane was reacted with POCl3 for conversion to cellophane phosphate. FT-IR spectroscopy and XRD analysis were done to get an idea about the structure and the morphology of the membranes. The sensor characteristics like temporal stability, response stability, response to different taste substances, and reproducibility of sensing performance were studied using both cellophane and cellophane phosphate membranes. The sensor devices prepared with these membranes showed distinct response patterns in terms of membrane potentials for different taste substances. Both the membranes showed reproducible response patterns with a temporal stability of 30 min in 1 mM KCl solution and a stable response for 5 min in 1 mM solution of each of the taste substances such as HCl for sourness, NaCl for saltiness, sucrose for sweetness, quinine hydrochloride (Q-HCl) for bitterness and monosodium glutamate (MSG) for umami. The concentration threshold values of these membranes were compared with the human threshold values for the above taste substances. Both the membranes responded to lower threshold concentrations than the human detection limits. The membranes also showed characteristic response patterns for organic and mineral acids. Sensor device prepared with cellophane phosphate membrane has excellent shelf life.