2.2. Saliva sample collection and treatment

Saliva was collected at the start and end of the 3 different sessions. Saliva collection and saliva sample treatment and storage procedures were performed as described previously (Wang et al., 2022). Flow rates were expressed as grams of saliva per minute (g/min). Saliva samples were dried with a SpeedVac device, and each dried saliva sample was then dissolved in 20 μL of buffer (Laemmli 2x, Bio-Rad) without a denaturing agent. Then, the Eppendorf tubes with the reconstituted saliva samples were heated in boiled water for 3 min before western blot analysis.