Buffering capacity of saliva influences the perception of acid-related sensory properties

Sufficient evidence had shown that the secretion and functional properties of saliva affect retronasal smell, taste and texture perception during food oral processing. A less noticed but important functional indicator of saliva is its buffering capacity and its influence on sensory perception. This study hypothesized that salivary buffering capacity differs among individuals due to possibly varied salivary compositions, and salivary buffering capacity could be the main cause of individual’s perception variation of acid-related sensory properties. To test this hypothesis, salivary buffering capacity was assessed both ex vivo and with oral samples, then correlated with sour taste perception. Ex vivo acid titration experiment of saliva samples found that the titration curve could be divided into three distinct sections and sectional buffer values had very good indication of corresponding function of different saliva buffer systems: at lower pH (pH < 5), ex vivo buffer value was positively correlated with salivary α-amylase activity and total protein content, suggesting an important role of salivary protein in acidic environment. A salivary buffering capacity evaluation of orally processed samples was proposed then validated. Sensory analysis showed that participants with higher salivary buffering capacity perceived less sour taste with increased concentration of citric acid stimulants, proving our initial hypothesis.