A research team led by a plant scientist at the University of California at Davis claims that they have solved the mystery behind bland tasting tomatoes. Their finding will be detailed in the June 29 issue of the journal Science.
When shoppers look for tomatoes at the grocery store, they are often trying to spot the best looking tomato. While a picture perfect tomato may be pleasing to the eye, it’s likely that it won’t be pleasing to the taste buds. However, older shoppers may be looking for something a bit tastier than what you can usually find in the produce aisle.
Scientists say that the discovery will have a major impact on the U.S. tomato industry, especially the Golden State. According to a recent report by the USDA, California makes up a significant portion of the U.S. processing tomato output. The University of California at Davis notes that the U.S. tomato industry harvests more than 15 million tons of tomatoes a year for processing and fresh-market sales.
A California League of Food Processors report from the month of June states that as of the beginning of this month inventories of U.S. processed tomato products were approximately 5.6 million tons. Current inventory is 10 percent below the prior year level.
Despite a industry-wide practice of breeding tomatoes for their appearance more so than taste, scientists believe that their discovery will help breeders reverse current practices, leading to better tasting tomatoes in the near future.
“This information about the gene responsible for the trait in wild and traditional varieties provides a strategy to recapture quality characteristics that had been unknowingly bred out of modern cultivated tomatoes,” said Ann Powell, a biochemist in the university’s Department of Plant Sciences and one of the lead authors of the study, in a statement.
“Now that we know that some of the qualities that people value in heirloom tomatoes can be made available in other types of tomatoes, farmers can have access to more varieties of tomatoes that produce well and also have desirable color and flavor traits,” she added.
Tomato breeding is an all-important practice for the U.S. tomato industry. The University of Florida has a Tomato Breeding Program that tries to develop and disseminate new scientific knowledge and technology when it comes to tomato breeding that will help the Sunshine State’s producers to be successful in the global economy. A history of the UF’s Tomato Breeding Program suggests that developing disease and heat-tolerant tomatoes is more important to Florida’s tomato researchers than improving the taste of the fruit.
The UC-Davis research team found that plant breeders are unintentionally compromising the flavor of tomatoes. Plant breeders will select tomato varieties that are light green so that the fruit can be harvested at the same time.
“Modern tomato (Solanum lycopersicum) varieties are bred for uniform ripening (u) light green fruit phenotypes to facilitate harvests of evenly ripened fruit,” the scientists write in the report.
Selecting light green tomato varieties breeds a gene mutation into the tomatoes that changes the flavor of the tomatoes and their attractiveness for processing.
This practice “is one piece of the puzzle about why the modern tomato stinks,” said Harry Klee, a tomato researcher at the University of Florida, according to The New York Times. “That mutation has been introduced into almost all modern tomatoes. Now we can say that in trying to make the fruit prettier, they reduced some of the important compounds that are linked to flavor.”
The research team started examining the genes that play a role in tomato fruit development and ripening. The team spent several summers looking for transcription factors (or proteins) that regulate genes. They concentrated on finding the proteins that contribute to color and quality. During their search for transcription factors, the researchers concentrated on tomatoes that were dark green before they ripened.
The scientists identified two transcription factors, called GLK1 and GLK2, that control the advancement of chloroplasts. Chloroplasts help plants to photosynthesize, turning the energy of the sun into sugars and other substances that factor into flavor and color.
To determine how to improve the flavor of tomatoes researchers went all the way back to the 1950s, the time at which the late Professor Charles Rick started collecting mutant and wild species of tomatoes. The researchers found that dark green tomatoes, which have GLK2, are tastier because they have higher levels of sugars and increased levels of lycopene.
“Nature presents numerous important genes and their variants, like uniform ripening, that breeders employ to facilitate the needs of growers, processors and consumers,” said Jim Giovannoni, a USDA plant molecular biologist with the Boyce Thompson Institute at Cornell University, in a statement. “Understanding the genes responsible for these characteristics facilitates the challenging process of breeding crops that meet the needs of all components of the food-supply chain.”
However, if growers continue to breed tasteless tomatoes the only solution will be to arm oneself with as much information about tomato varieties as possible. During a 2009 interview on KPBS, entitled “Seeking Out The Tastiest Tomato: From The Garden To The Plate,” environmental reporter Ed Joyce discussed the problem of breeding for shelf-live as opposed to flavor.
Joyce recommended that, besides the health benefits of eating organic food, listeners should try organic tomatoes to compare their taste to the taste of non-organic tomatoes.
“There’s studies that are ongoing, not conclusive, that say the potential of not using pesticides, synthetic pesticides that is, and synthetic fertilizers when you grow organic tomatoes, produces a better tomato in terms of flavor, in terms of taste, and maybe nutrients as well,” Joyce said.
The study was funded by the University of California Discovery program, the U.S. Department of Agriculture-Agricultural Research Service, the National Science Foundation, the Viet Nam Education Foundation, the Fundación Genoma España, and the Ministerio de Ciencia y Tecnología and the Instituto Tecnólogico de Costa Rica.
