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How sweet can you get? Plant-derived sweetener thaumatin becomes 1.7 times sweeter after amino acid swap

Date:
February 23, 2016
Source:
Kyoto University
Summary:
Researchers have made a sweeter version of thaumatin, a natural sweetener commonly used in 'diet' beverages, gummy, and jelly candies. 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.
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Japanese researchers have made a sweeter version of thaumatin, a natural sweetener widely used in "diet" beverages, gummies, and jelly candies.
Credit: Eiri Ono/Kyoto University

A sweeter version of a widely used plant-derived sweetener is on the way. Researchers 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," says lead author Tetsuya Masuda of 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. Sweetness is detected when positively charged molecules on the protein come in the vicinity of negatively charged molecules on the sweetness receptor.

"For a long time the mechanism in 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."


Story Source:

The above post is reprinted from materials provided by Kyoto University. Note: Content may be edited for style and length.


Journal Reference:

  1. Tetsuya Masuda, Keisuke Ohta, Naoko Ojiro, Kazuki Murata, Bunzo Mikami, Fumito Tani, Piero Andrea Temussi, Naofumi Kitabatake. A Hypersweet Protein: Removal of The Specific Negative Charge at Asp21 Enhances Thaumatin Sweetness. Scientific Reports, 2016; 6: 20255 DOI: 10.1038/srep20255

Cite This Page:

Kyoto University. "How sweet can you get? Plant-derived sweetener thaumatin becomes 1.7 times sweeter after amino acid swap." ScienceDaily. ScienceDaily, 23 February 2016. <www.sciencedaily.com/releases/2016/02/160223102845.htm>.
Kyoto University. (2016, February 23). How sweet can you get? Plant-derived sweetener thaumatin becomes 1.7 times sweeter after amino acid swap. ScienceDaily. Retrieved August 26, 2016 from www.sciencedaily.com/releases/2016/02/160223102845.htm
Kyoto University. "How sweet can you get? Plant-derived sweetener thaumatin becomes 1.7 times sweeter after amino acid swap." ScienceDaily. www.sciencedaily.com/releases/2016/02/160223102845.htm (accessed August 26, 2016).