Researchers from Kyoto University, Japan, have found a way to make thaumatin, one of the sweetest natural sugar substitutes on the market, even sweeter. “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 life style-related diseases,” said Tetsuya Masuda, at Kyoto University.
Thaumatin, a protein derived from the fruit of an African tropical plant, is the sweetener of choice when it comes to “diet” beverages and gummy and jelly candies boasting natural ingredients. Thaumatin also masks bitterness and helps enhance flavor. Only humans and primates taste sweetness from thaumatin. Masuda and colleagues have analyzed its structure 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. In this study, Masuda replaced aspartic acid with asparagine, making thaumatin 1.7 times sweeter than before. This also confirms the complex interaction between thaumatin and the sweetness receptor of the tongue, which was discovered in the early 2000s after long speculation by scientists.
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Plant-derived sweetener Thaumatin
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