Strawberries are a quintessential summer fruit. But, have you ever taken a bite of a beautiful, red strawberry only to be disappointed with its bland and watery flavor? If so, you might want to take a closer look at the pesticides used on the crop.
In a recent study published in ACS’ Journal of Agricultural and Food Chemistry, researchers found that certain fungicides commonly used on strawberries can impact cellular mechanisms, resulting in berries with subdued flavor, sweetness, and lower nutritional value.
Flavor and nutrition in berries disrupted by pesticides
The flavor and nutritional value of fruits, including berries, are a result of their unique taste, smell, and composition. For instance, sweetness often arises from the amount of dissolved glucose or fructose present, while aroma comes from volatile compounds such as esters and terpenes. Additionally, many fruits are rich in essential nutrients, such as vitamin C, folic acid, and antioxidants.
However, fungicides are designed to disrupt the cellular processes of detrimental fungi, and they could inadvertently interfere with the production of these essential flavor and nutritional compounds. Therefore, a team led by Jinling Diao from China Agricultural University set out to investigate how two common fungicides used on strawberries, boscalid (BOS) and difenoconazole (DIF), affect molecular pathways in berries.
"Consumers have been complaining about the deterioration of the flavor of strawberries. The use of pesticides could have potential impacts on fruit flavor but the mechanisms are unclear," the researchers noted in their study.
The researchers grew three groups of strawberries (Fragaria x ananassa Duch) in identical conditions. They applied BOS or DIF to two of the groups when the berries were still green, while the third group received no treatment.
Even after treatment, the fully grown berries were identical in size and color to those grown without pesticides. However, when they analyzed the chemical makeup of each berry, a striking pattern emerged. Soluble sugars and nutrients, such as sucrose and Vitamin C, were reduced in the strawberries sprayed with pesticides. Additionally, some of the sugars were converted into acids in mature fruit, thereby making them even less sweet. Oxidative damage owing to the pesticide use also subdued taste and aroma. These negative effects were felt strongest using boscalid.
Moreover, upon closer inspection, the team discovered that boscalid had a direct impact on the regulation of genes involved in cellular pathways responsible for producing sugars, volatile compounds, nutrients, and amino acids. This assessment was also confirmed through perceived taste as in a blind taste test, people consistently preferred the untreated strawberries.
Implications for farmers and consumers
This work provides insight into the use of pesticides in crop production. While pesticides are necessary for protecting crops from harmful pests and fungi, they can have unintended consequences on the quality and nutritional value of the produce. By understanding the molecular pathways impacted by these chemicals, farmers can make informed decisions about the types of fungicides to use and when to apply them to minimize any negative effects on flavor and nutrition.
Pesticides not only impact the flavor profile of fruit and vegetables by altering molecular signaling but may also be harmful. According to data that the Department of Agriculture and the Food and Drug Administration in the United States released in 2022, over 70% of non-organic fresh produce sold in the U.S. contains residues of potentially harmful pesticides. Some of the most widely sprayed crops include strawberries, apples, cherries, spinach, nectarines, and grapes. Across the ocean in Europe, a study by the Pesticide Action Network (PAN) found that a third of apples and half of all blackberries surveyed had residues of the most toxic categories of pesticides, some of which have been linked to health conditions including cancer, heart disease, and birth deformities.