A new sensory sweetness definition and sweetness conversion method of five natural sugars, based on the Weber-Fechner Law.

This study's aim is to establish a new sensory sweetness definition and conversion method for five sugars. A "closed-type" question based on triangle test and paired comparison was used for sensory evaluation. The absolute threshold and nine sensory difference threshold values were determined and used to generate a sweet sensory difference strength curve. Defining absolute threshold of sucrose sweetness as 1, the sucrose sweetness at any concentration could be calculated via the curve. After taking the logarithm of each curve, sweetness index was calculated as 1, 1.12, 0.94, 1.29, and 1.25 for sucrose, glucose, fructose, lactose and maltose, respectively. Based on this, each sugar concentration and sweetness could be converted and calculated. Single sugar and mixed-sugars sweetness comparison experiments verified the new sweetness index and sweetness values were more accurate (83.3-100%) than those reported in previous studies. Therefore, this new definition and conversion method established more reliable references for sweet taste sensory applications.