Piezoelectric quartz crystal sensor for sensing taste-causing compounds in food

To meet the need for a fast and sensitive method in determining taste-causing compounds in beverage, piezoelectric quartz crystal (PQC) sensor array based on molecularly imprinted polymer (MIP) coating is developed for sensing quinine and saccharine in bitter drinks. The MIP-PQC sensor produces a satisfactory repeatability (R.S.D. below 5%, n = 3), high sensitivity (2.04 mg/L and 32.8 mg/L) and wide working range (10–1080 mg/L and 51–3420 mg/L) for sensing quinine and saccharine, respectively, with no significant interference from most substances commonly found in drinks except sucrose. The MIP-PQC was applied for sensing commercially available tonic water with results compared to taste assessment from a human taste panel. In addition to reducing cost and providing 24 h service, the MIP-PQC sensor array is shown to give a fast sample throughput of 17–19 analysis per hour, satisfactory repeatability, a high sensitivity to detect change in bitter taste in tonic water and negligible suppressing effect by saccharine as compared to the human taste panel. This technology provides a promising methodology for taste application in flavour estimation and quality control of experimental, intermediate and final product for drinks and beverages.