Influência da torrefação na degradação térmica do glifosato em grãos de café

Abstract

Glyphosate is a widely used herbicide in the management of weeds across several agricultural crops, including coffee, due to its high effectiveness. However, its application can lead to residue accumulation in coffee beans, making it essential to understand how processing steps—particularly roasting—affect its thermal degradation. In this context, the present study aimed to evaluate the behavior of glyphosate during coffee roasting under different heating profiles, comparing an industrial roaster with a bench-scale roaster. Different coffee batches, originating from cultivation systems with distinct agronomic conditions, were analyzed, allowing the observation of natural variations in initial glyphosate concentrations. The results showed that dark roasting achieved the highest degradation levels, reaching up to 90%, whereas light roasting resulted in approximately 78% reduction, highlighting the strong influence of time and temperature on the compound’s thermal stability. When comparing roasting equipment, the initial drying step present in the industrial roaster significantly improved heat transfer efficiency, enhancing subsequent chemical reactions and promoting greater glyphosate degradation compared to the bench-scale roasting process. This study reinforces the importance of understanding the thermal dynamics of coffee roasting to ensure compliance with residue limits, while also demonstrating how process adjustments can maximize glyphosate reduction in the final product.