Expert response from Community Manager
Moderator for GMOAnswers.com
Friday, 22/05/2015 12:32
Kevin Folta, professor and chairman of the horticultural sciences department at the University of Florida, Gainesville, answered a similar question posted on GMO Answers. The question inquires whether GMOs are responsible for the reduction of the flavor of tomatoes grown in the United States. Dr. Folta responds as follows:
“First, there are no GMO tomatoes on the market. The famous Flavr Savr GM tomato of the ’90s was gone before Y2K.
“There, question answered! But let’s look at this a little more deeply. Why do tomatoes taste boring?
“New varieties of tomatoes are developed through traditional breeding. A breeder has to evaluate thousands of lines from a genetic cross to find one winner, so you can imagine the huge expense and resources used.
“That said, tomatoes in breeding programs are not selected by breeders based on sensory traits like aroma and flavor; at least, they haven’t been. Breeders now have to prioritize how well they ship and store. They are interested in uniform size, shape and color. Breeders are highly interested in disease resistance, both on the plant and the fruit. In short, there are a lot of traits a good tomato has to have long before flavor is even considered.
“The production system for bulk tomatoes does not help either. Most are picked green and then ripened using ethylene gas, a compound usually produced naturally by the ripened fruit. Ripening is artificially induced, so you don’t get the usual balance of sugars, acids and volatiles you get when you grow one at home.
“At this point, I’ve blamed unremarkable tomato flavor on genetics and production. What’s up next for tomato flavor?
“Researchers here at the University of Florida, led by Dr. Harry Klee, have identified the natural compounds in tomatoes that consumers like. This information can help breeders make better decisions about what plants to use in crosses to select the best genetics to improve taste: http://www.cell.com/current-biology/abstract/S0960-9822(12)00408-3.
“These findings will pave the way for faster breeding of better tomatoes. Learn more from this New York Times article.
“GMO will eventually help the process. A tomato line carrying a gene from pepper (a tomato cousin) is resistant to bacterial wilt. This disease requires substantial application of copper sulfate to manage it. Keeping copper (a heavy metal) out of the environment would be a nice benefit of this GMO technology.”
“First off, 80 percent of what is perceived as taste is actually dependent upon smell. So you could rephrase your question to ask about how GMOs smell. There are many components in food that give each particular food its distinctive taste. For some tastes, like sweet, it is the presence of sugars that elicits a specific taste. Other tastes, like savory, are determined by levels of the amino acid glutamate. But often it is a complex mixture of components that results in a particular distinctive flavor of a food or food ingredient. While chemical composition impacts how foods taste, significant variation in taste occurs from season to season, across varieties and, most notably, in how fresh the food is.
“As part of the safety evaluation process, every GM product is analyzed extensively for the key compositional components (carbohydrates, fats, amino acids, minerals, bitter components that may be antinutrients) in the edible portions of the crop and compared with the composition of conventional lines grown in the same trials. There are many, many peer-reviewed articles that show that GM crops are compositionally equivalent to their conventional counterparts. Although not every component responsible for determining taste is evaluated in these studies, the components that determine nutritional value are assessed.
“Because scientists tend to be curious, there has been the occasional study to look at the sensory properties (or taste) of some GMO crops, even when there was not a particular reason to believe that the introduced GM trait would have any impact on taste or quality. A sensory evaluation conducted relatively recently looked at GMO (Bt) sweet corn relative to similar hybrids grown in the same location. In these studies, trained assessors at the National Food Lab participated in a blind sensory analysis to evaluate Seminis Performance Series sweet corn (see https://www.earlmay.com/bulk_seed__custom_packaging/seminis_performance_series_sweet_corn/). The evaluators found that the GMO sweet corn had the same great taste and eating quality of its conventional counterparts. There are numerous blogs out there (for example, this one) that attest to the findings of the expert tasters.
“Even one of the most widely grown GM crops, Roundup-ready soybeans, was put to the test early on to see how it performed in taste tests. Samples of soy oil and flour from the GM soy and a similar conventional variety were evaluated by USDA expert assessors to look for key flavor attributes. The assessors found the same range and intensity of flavors in the oils and flours from the GM and non-GM lines.
“So next time you get some food that tastes ‘bad,’ send it back to the kitchen, but don’t blame GMOs.”
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