Perceptual mapping of citrus juices using projective mapping and profiling data from culinary professionals and consumers

Projective mapping, also known as the nappe map technique is a method proposed for gathering similarity data in which panelists are directed to place products on a two dimensional surface. Two groups of participants, experienced chefs and consumers, performed this task and traditional attribute scaling. Ten fresh squeezed citrus juices and one commercial juice were judged along with two duplicates for a total of 13 products. Nappe map data were analyzed using multifactor analysis (MFA) and generalized procrustes analysis (GPA). Scaling data were analyzed using MFA, GPA, and principle components analysis (PCA). Configurations were generally similar, with juices differentiated by an axis opposing sweet, orange, floral and fruity characteristics against grapefruit, bitter and sour notes. A textural (pith vs. smooth) axis was also evident in some plots. Nappe configurations were similar, especially comparing GPA and MFA analyses within a group. Comparisons of configurations between groups were less similar, as shown by lower Rv coefficients. Configurations showed a good correspondence of scaled attribute results to nappe results for the consumers, but less so for the chefs, suggesting different criteria for the chefs in the nappe and scaling tasks. The nappe method may uncover perceptions not captured by traditional scaling and PCA especially for groups such as chefs, who may have more idiosyncratic perceptions of the critical sensory attributes.