Evaluation of Correlation Between Rheological Characteristics and Consumer Sensorial Perception

Objectives: The purpose of this study was to seek correlation between toothpaste’s rheological characteristics and consumer sensorial perception during and after brushing, which might serve as a potential guidance for future toothpaste formulation design.
Methods: Six commercial toothpastes were evaluated in this study. For rheology evaluations, full and 1:1 and 2:1 dilutions of toothpastes were characterized using dynamic oscillatory flow, steady torsional flow, continuous shear rate ramp, and compression / extension tests without suppressing wall slip. Diluted formulations were centrifuged and their supernatants’ static surface tension values measured. Shear and extensional viscosity indexes were also characterized by a microcapillary rheometer. For sensory evaluation, 25 panelists were recruited and asked to brush their teeth with the commercial toothpastes. Sensory parameters covering both during brushing and after brushing perceptions were scored by panelists on a 1 to 5 scale. All results were correlated using principle component analysis (PCA) to map out the relationships between toothpaste’s rheological characteristics and consumer sensorial perception.
Results: Positive correlation was found between toothpaste HB consistency index and Chalkiness feeling during brushing. PowerLaw consistency index were found to be inversely correlated to foaming sensation of the toothpaste. Both cohesive work and HB consistency index were found to be positively correlated to the slippery feel in the mouth.
Conclusions: The results indicated that certain toothpaste rheological characteristics could be used to predict consumer sensorial perception, which might provide guidance to toothpaste formulation design in the future.