A food that's subtly sweet to one person may be very sweet to another, so how can food and beverage companies objectively determine just how sweet something actually is? Well, an experimental new "bioelectronic tongue" may one day do the job.
Currently, panels of human taste-testers are used to assess the sweetness – and other qualities – of food and drink products. While such groups may reach an overall consensus on whether or not something is either too sweet or not sweet enough, the assessment still ends up being largely subjective.
That's where the bioelectronic tongue comes in.
On an actual human tongue, most sugars and other sweet compounds interact primarily with a single section of one of two sweetness-sensitive areas. That section is known as the Venus flytrap domain, as its molecular structure resembles the folding leaves of the namesake carnivorous plant.
Led by Tai Hyun Park and Seunghun Hong, scientists from Korea's Seoul National University started by using bacteria to produce copies of the Venus flytrap domain. Those copies were deposited in a thin layer on multiple gold electrodes, which were linked together via carbon nanotubes. The resulting device is known as a field-effect transistor.
When solutions containing sucrose sugar or the artificial sweetener saccharin were applied to that device, an electrical current running through it decreased in a consistent and easily readable fashion – the greater the concentration of sucrose or saccharin, the greater the drop in current. Additionally, the field-effect transistor did not react when exposed to cellobiose, which is tasteless sugar.
The prototype bioelectronic tongue has already been used to assess the sweetness of drinks such as apple juice and sucrose-sweetened chamomile tea, exhibiting what is claimed to be 10 times the sensitivity of previously developed bioelectronic systems.
A paper on the research was recently published in the journal ACS Applied Materials & Interfaces.
Source: American Chemical Society