Capsaicin migration through maple sap collection tubing

Abstract Capsaicins, present in most hot sauces and salsas, are responsible for the “hot” sensation in many spicy foods. At high doses, capsaicins cause significant discomfort upon contact with the sensitive tissues of the mouth and throat of mammals. By applying a capsaicin containing paste to the outside of maple tree sap collection tubing, operators hope to minimize rodent (primarily red squirrel, Tamiasciurus hudsonicus ) gnawing damage to the tubing. However, some operators and sap processors have expressed concern regarding the potential migration of capsaicins through the tubing and into the tree sap, leading to contaminated maple syrup. To address these concerns, we filled a variety of new and used sap collection tubing with maple sap, plugged the ends, and coated the tubing with a commercially available capsaicin-based rodent repellent paste. Following storage, the contents of the tubes were carefully removed and subjected to a solid-phase extraction clean-up process. Capsaicins in the sap were then quantified by high performance liquid chromatography/fluorescence detection. Results indicate that polyethylene tubing was more resistant to capsaicins migration than was polyvinyl tubing. While capsaicins were detected in the sap, the predicted levels in syrup would be below the human taste threshold.