The FOP group has been working on a joint project on chili perception with Dr. Ian Fisk and Dr. Nicole Yang in the University of Nottingham. In their study, the amount of saliva stimulated by capsaicin (5 ppm) was examined to assess if there is any physiological change on the saliva secretion level. The group used a square of cotton gauze (35×35×10 mm) to measure the amount of saliva secretion. 10 μL of pure water was used as the control (CTR) to compare with 10 μL of capsaicin solution (5 ppm) placed at the cotton gauze (CAP). Each cotton gauze was weighed before putting into mouth and after placing 2 min on the top of tongue with mouth closed, so the weight difference was regarded as the amount of saliva secreted. The amount of saliva collected exposed to either a blank control (water) or capsaicin was evaluated and shown in figure 3.

The result suggested that saliva secretion was enhanced when capsaicin was exposed in the mouth (p<0.05). An additional 74% saliva was generated from capsaicin-containing cotton gauze compared with control. The work has now been submitted for publication in Food Chemistry. In parallel to the Nottingham study, Mr. Cong Lv, a master student is working on the oral temperature change after capsaicin consumption and its impact on the sensory perception.