AsianScientist (Mar. 3, 2016) – Snack lovers around the world, rejoice. Researchers in Japan have found a way to make thaumatin, one of the sweetest plant-derived sugar substitutes on the market, even sweeter. Their work was published in Scientific Reports.
Thaumatin, a protein derived from the fruit of an African tropical plant (Thaumatococcus daniellii Benth), is the sweetener of choice when it comes to diet beverages and gummy and jelly candies boasting natural ingredients. Only humans and primates taste sweetness from thaumatin. It also masks bitterness and helps enhance flavor.
“Making natural sweeteners stronger could be a huge plus to the food industry, especially as there are concerns regarding the consumption of low-calorie sugar substitutes to prevent lifestyle-related diseases,” said lead author Tetsuya Masuda, an assistant professor at Kyoto University.
Masuda and colleagues analyzed the structure of thaumatin with X-rays to determine which parts of the protein make it taste sweet to us. From these studies, they found that the basic amino acids in thaumatin play a crucial role in eliciting sweetness, implying that substituting acidic amino acids with basic ones could make it sweeter.
When aspartic acid was replaced with asparagine, thaumatin was made 1.7 times sweeter than before.
These findings also confirm the complex interaction between thaumatin and the tongue’s sweetness receptors. It was discovered in the early 2000s that sweetness is detected when positively-charged molecules on the protein go near negatively-charged molecules on the sweetness receptor.
“For a long time, the mechanism with which we taste sweetness from thaumatin was a mystery, and for that reason it took very long to ‘sweeten’ it up,” Masuda explains.
“Now that we’ve taken steps in the right direction, I’m excited about developing applications for a stronger form of thaumatin.”
The article can be found at: Masuda et al. (2016) A Hypersweet Protein: Removal of The Specific Negative Charge at Asp21 Enhances Thaumatin Sweetness.
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Source: Kyoto University; Photo: Eiri Ono/Kyoto University.
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