Impact of glyphosate management techniques on residue levels and chemical composition of Coffea arabica and Coffea canephora beans.

Glyphosate is the most extensively applied herbicide and can be absorbed by non-target plants potentially altering their chemical profile. Coffee, the second most consumed beverage worldwide, relies on glyphosate use to sustain productivity. However, limited evidence exists regarding absorption of soil-applied glyphosate, its possible translocation into coffee beans, and chemical changes. This study investigated the impact of different glyphosate application techniques on chemical composition and residue accumulation in Coffea arabica and Coffea canephora beans. Plants were subjected to seven treatments varying in spray nozzle types (flat-fan and cone) and application schedules (October and December; October and February; and October, December and February). Glyphosate residues were quantified by LC-MS/MS, while gravimetric analyses assessed moisture, ash, and soluble extract yield; chlorogenic acids and caffeine were determined by UHPLC-PDA. Results demonstrated that glyphosate is absorbed and translocated to beans, with residue levels ranging from 0.0 to 0.5 mg/kg. Nonetheless, applications performed in October and December resulted in lower residues levels compared to schedules performed until February, with no significant alterations related to the negative control. Contrary to expectations, chlorogenic acids levels were not affected by glyphosate application. Similarly, despite isolated differences, none of the evaluated parameters were significantly influenced by glyphosate use. These findings were supported by PCA and PERMANOVA, which revealed that sample discrimination was influenced exclusively by species and crop year. Further studies investigating additional coffee bean compounds, particularly from a food safety perspective, are needed to provide a more comprehensive understanding of the effects of glyphosate on coffee beans.