Determination of Recognition Threshold and Just Noticeable Difference in the Sensory Perception of Pungency of Zanthoxylum bangeanum

Zanthoxylum bungeanum, also called the Szechuan pepper, is a pungent-flavored spice. Together with the chili pepper, it constitutes the typical flavor of famous Chinese Szechuan cuisine. With the worldwide popularity of Sichuan cuisine and pungent food, the research on sensory perception of pungency of Z. bungeanum becomes more important and necessary. This article first determined the sensory recognition threshold and just noticeable difference of pungency of Z. bungeanum. The pungent extract, containing hydroxyl α-sanshool (63.6%), hydroxyl β-sanshool (22.8%), and hydroxyl γ-sanshool (7.4%) from Z. bungeanum was used as the tested sample prepared in ethanol–water solution. Ten selected assessors participated in three sessions of sensory tests in standard sensory evaluation booths established according to ISO 8589 by following two-alternative forced choice procedure. The data showed that the recognition threshold was 0.036 mg pungent extract per 1 mL ethanol–water solution and just noticeable difference exponentially increased with the increase of the concentration of pungent extract solution. The response of pungency among assessors followed Weber’s Law with a stable Weber fraction (0.118) from 0.0360 to 0.500 mg pungent extract per 1 mL. Nevertheless, the fraction changed when the concentration of pungent extract solution was above 0.500 mg per 1 mL.