Sweet success: UF researchers find key to sweeter, healthier strawberries

6 Apr
Paige Levin is a freshman journalism and political science student at the University of Florida. She enjoys writing opinion pieces and in-depth feature articles, and loves to discover people’s stories. Levin hopes to one day combine her passions for writing, government and politics to work in the nation’s capitol and bring the political information needed back to the people. Paige has been writing for about five years now, she is currently an intern for the Pledge 5 Foundation, and was previously the editor-in-chief of her high school newspaper.

Paige Levin is a freshman journalism and political science student at the University of Florida. She enjoys writing opinion pieces and in-depth feature articles, and loves to discover people’s stories. Levin hopes to one day combine her passions for writing, government and politics to work in the nation’s capitol and bring the political information needed back to the people. Paige has been writing for about five years now, she is currently an intern for the Pledge 5 Foundation, and was previously the editor-in-chief of her high school newspaper.

Editor’s note: This is part of a series of contributing bloggers beginning their careers as journalists/public relations professionals at the University of Florida. Please see my earlier post about getting journalists excited about science writing early on.

By Paige Levin

Whether they are tucked into a shortcake, whipped into a smoothie or sitting atop a yogurt parfait, there is nothing more enticing than a scoopful of juicy, red strawberries. But how many times have you bitten into a berry-laden treat, only to be left grimacing by a less than satisfying bitter burst?

You might be tempted to reach for the sugar to help sweeten your snack, which while tasty, isn’t beneficial to the waistline. Now, researchers at the University of Florida say they have found the compounds that promise a sweeter and healthier berry.

The study, conducted by the University of Florida’s Plant Innovation Program entitled “Strawberry Flavor: Diverse Chemical Compositions, a Seasonal Influence, and Effects on Sensory Perception,” identifies the 30 compounds in strawberries that give the fruit its distinctive flavor. This allows breeders to now create better tasting and possibly healthier varieties of strawberries.

One of the team members, Thomas Colquhoun said in the long term, six of the compounds discovered by Michael Schwieterman and his colleagues may allow scientists to create processed foods that taste sweeter while using less sugar, making the foods healthier.

“Our idea is to make our crops more flavorful and healthy for consumers so that our consumers eat healthier and eat more of it,” Colquhoun said.

Colquhoun, an assistant professor in floriculture biotechnology and genetics, said the study is unique because it uses a very sophisticated type of psychophysics. Psychophysics looks at the relationship between certain physical stimuli, in this case strawberry variety, and the sensations they affect or cause.

For the study,  166 consumers between 18 and 71 years old  were recruited and asked to taste between three and five different varieties of strawberries. After chewing and swallowing a whole strawberry, panelists were asked to rate it based on overall taste, texture  and perceived intensity of sweetness and sourness.download (2)

Linda Bartoshuk, director of human research at UF’s Center for Smell and Taste, was in charge of the consumer taste panel. Bartoshuk compared consumer opinions using a method called cross-modality matching. This method combines the pleasure and sensory scales, making it possible to compare opinions fairly.

“It doesn’t matter what your scale is or what my scale is,” Colquhoun said. “We can compare those two things because they can be mixed and matched and weighted.”

By comparing the psychophysics data from consumer panels with biochemical data, Colquhoun said they identified 30 volatile compounds associated with flavors consumers enjoy. Within that, the study showed a group of six volatiles associated with perceived sweetness intensity, without the contribution of sugar.

“You’re actually sensing this volatile, and there is some sort of signal that is telling your brain what you taste is actually sweet, even though you’re not registering sugar,” Colquhoun said. “So what that indicates is that we may be able to reduce the level of sugar, increase the level of these volatiles, and the strawberry should be perceived as approximately the same sweetness.”

Eventually, those six volatiles may be used to lower sugar content in products like strawberry jam and yogurt, but for now, Colquhoun said this information is passed along to the UF strawberry breeder so that he can grow more flavorful strawberries. He added that more varieties with richer flavor and better health benefits should be hitting the markets within the next two years.

Paul Lyrene, professor emeritus of horticultural sciences, said he thinks the new information will only have minimal effects on improving the strawberry in the short term.

“I think all the information is good and worthwhile and sometimes helpful, but I do not believe that the studies are going to lead to any great breakthroughs in flavors of strawberries because the problem is really not at the molecular level, its at some other level,” Lyrene said.

The reason we currently have such poor-flavored fruit is not because of the chemistry, Lyrene said, but because flavor is given low priority in the marketing system.

“I, as a plant breeder, know exactly how to make my fruit taste better without really knowing any of the molecular biology of what happens,” he said. “I have, for example, varieties of blueberries that everybody says are better than what is being grown, but the growers will not plant them because they yield only half as much.”

Lyrene said other issues come from the fact that a crop has to have a lot of different features to be successful.

“It has to be resistant to various diseases. It has to yield well.  It has to be attractive in appearance for the consumer, and it has to be compatible with the modern packing and shipping methods,” Lyrene said.

The team’s research, which began with tomatoes, and is now expanding to include blueberries, peaches, citrus and culinary herbs.

“UF is a unique place because we have a huge team of very, very highly skilled breeders,” Colquhoun said. “What we can do is just go right down the line and help our breeders with our basic science and applied consumer science.”

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