If you’ve ever bitten into a juicy, red strawberry only to find that it was watery and somewhat flavorless, certain pesticides could be to blame.
In a recent study, scientists found that two common fungicides used on strawberries — boscalid (BOS) and difenoconazole (DIF) — can affect the fruit’s cellular mechanisms and mute its sweetness and overall flavor while lowering the berry’s nutritional value.
The study, “Insights into the Mechanism of Flavor Loss in Strawberries Induced by Two Fungicides Integrating Transcriptome and Metabolome Analysis,” was published in the American Chemical Society’s (ACS) Journal of Agricultural and Food Chemistry.
Each year, the Environmental Working Group (EWG) — a nonprofit activist group specializing in research and advocacy in areas like toxic chemicals and agricultural subsidies — puts out a list of fruits and vegetables with the highest amounts of pesticides after washing, called the “Dirty Dozen.”
Last year and in other previous years, strawberries topped the list, along with leafy greens like spinach, kale and mustard greens. Before testing, EWG prepares the produce as a consumer would.
“EWG recommends that, whenever possible, consumers purchase organic versions of Dirty Dozen produce,” said EWG science analyst Sydney Swanson in an EWG press release. “Most pesticides can’t legally be applied to produce that is grown organically.”
Almost 70 percent of produce in the U.S. that is not grown organically has been found to have pesticide residue, according to the press release. Levels were usually within legal limits, but that doesn’t guarantee that the produce is safe. According to one study, more than one-fourth of pesticides used in this country contain chemicals that have been banned in Europe due to health risks.
Pesticides are aimed at fungi and insects, but they are toxic, and many of them have been linked to health problems in humans, such as cancer and toxicity in the nervous system and brain, the EWG press release said.
The sweetness you taste when biting into a plump, juicy strawberry comes from the levels of dissolved fructose or glucose, while its distinct smell is produced by volatile compounds like terpenes and esters, an ACS press release said.
Fungicides are designed to interfere with the cellular processes of fungi, so when they’re applied to berries, they can also disrupt the processes of the fruits themselves, which impacts their nutritional compounds, as well as their flavor.
In the ACS study, the researchers examined how BOS and DIF affected particular molecular pathways in strawberries.
The team cultivated three types of strawberries using the same growing conditions and applied BOS and DIF to two of the groups. When fully grown, the berries in all three groups were the same color and size. However, the researchers found that chemical changes had occurred in both groups exposed to the fungicides.
The research team found that there was a reduction in vitamin C, sucrose and other nutrients and soluble sugars; that the fruits’ sugars had been converted into acids, affecting their level of sweetness; and that the levels of their volatile compounds had changed, muting their aroma and taste.
The team also found that the cellular pathway gene regulation related to the production of volatile compounds, nutrients, amino acids and sugars had been directly affected by BOS.
Perhaps most telling was that, when subjected to a blind taste test, people consistently preferred the strawberries that hadn’t been treated with pesticides.
The researchers said their study may give guidance to farmers in future pesticide use. “Everyone should eat plenty of fresh fruit and vegetables, no matter how they’re grown,” said EWG toxicologist Dr. Alexis Temkin in the EWG press release. “But shoppers have the right to know what potentially toxic substances are found on these foods, so they can make the best choices for their families, given budgetary and other concerns.”
Article adapted from EcoWatch.