Effects of ±2 °C cup rim temperature variations relative to beverage temperature on flavor perception

Food temperature and temperature stimulation of areas around the tongue and nose can influence flavor perception. However, during mastication, the lower lip makes contact with cutlery and tableware, and temperature sensation in the lower lip is thought to play a significant role in flavor perception. In this study, a tumbler-type device that can apply a specific temperature to the lower lip without altering the beverage is utilized to investigate changes in flavor perception, including in-mouth aroma, aftertaste, intensity of taste, throat feeling, deliciousness, comfort, sweetness, saltiness, sourness, bitterness, and umami. The evaluation experiment revealed that cooling the cup rim by 2 °C relative to the beverage temperature led to a stronger perception of coldness, improved throat feeling, and significant increases in perceived deliciousness and comfort (p < 0.05). In addition, warming the cup rim for warmed green tea tended to enhance the perception of in-mouth aroma (p = 0.055). This study demonstrated that the temperature of the lower lip during drinking influences human flavor perception.