Measurements meet perceptions: rheology–texture–sensory relations when using green, bio‐derived emollients in cosmetic emulsions

Abstract

ObjectiveProduct aesthetics and sensory performance can strongly influence a cosmetic product’s acceptance by consumers. However, classic sensory analysis is time‐consuming, expensive and does not provide information on the target group’s preference. In the previous phase of this project, we had untrained consumers evaluate six cosmetic emulsions based on their aesthetics using a check‐all‐that‐apply (CATA) survey. In this project, our goals were to quantitatively characterize the rheology and textural properties of the six cosmetic emulsions containing green, bio‐derived emollients and identify statistical relationships between the consumers’ description of products and the instrumental measurements.MethodsSix emulsions were prepared—three with olive oil and three with heptyl undecylenate as an emollient. Four sensory‐like attributes, namely firmness, work of shear, stickiness and adhesiveness, were tested using a texture analyser. Rheological characterization included continuous flow testing and oscillatory measurements. Droplet size and stability were also evaluated. Statistical relationships were quantified between measurements in this study and sensory survey results published previously.ResultsThe textural and rheological results indicated that the emulsions were different—as designed. The texture and rheology measurements had analogous grouping outcomes to the consumers’ discrimination. Emulsions 1 and 2 were the firmest, hardest to spread, stickiest and had the highest viscosity, while Emulsions 5 and 6 were the least firm, easiest to spread, less sticky than Emulsions 1 and 2, and had the lowest viscosity. Emulsions 3 and 4 fell in between the other two groups. Using olive oil instead of heptyl undecylenate as an emollient increased firmness, spreading, stickiness, viscosity and droplet size of the emulsions in every case—when comparing emulsions within each pair. All six emulsions had a shear‐thinning behaviour. Viscosity and firmness directly correlated for the emulsions. Emulsions were visually stable at room temperature over the course of 6 months and viscosity remained relatively constant over this period also.ConclusionCertain sensory attributes can be reliably predicted with instrumental measurements. Identifying and quantifying sensory–texture–rheology relationships can contribute to achieving appropriate product characteristics tailored to suit market needs.

Relationship between sensorial and physical characteristics of topical creams: A comparative study on effects of excipients

“…Several authors have in fact made successful attempts to connect physical characteristics of topical formulations to certain sensory attributes. Some of the methods that have been linked to sensory attributes are rheology (Greenaway, 2010;Huynh et al, 2021;Lee et al, 2021;Lukic et al, 2012;Savary et al, 2019;Vergilio et al, 2021), frictional analysis (Lee et al, 2021;Savary et al, 2019;Skedung et al, 2016;Timm et al, 2012) and texture analysis (Huynh et al, 2021;Lee et al, 2021;Savary et al, 2019;Vergilio et al, 2021). Rheology was found to be a useful tool to predict sensory attributes related to the application phase of cosmetic emulsions (Lee et al, 2021;Savary et al, 2019), while texture analysis was found to be a good predictor of textural attributes comprising stickiness and firmness (Lee et al, 2021;Savary et al, 2019).…”

Chemical and mechanical accelerated and long‐term stability evaluation of sunscreen formulation containing grape seed extract

“…Lukic et al 34 have found a direct correlation between textural parameters of consistency and cohesiveness with maximal and minimal viscosity and G′/G″ obtained from the rheological analysis. Another study confirmed the direct correlation of firmness with viscosity and G′ and the negative correlation between adhesiveness with firmness, G′, and a viscosity 35 . Nevertheless, despite the correlations found between certain textural and rheological parameters, the accuracy of the latter is well documented, especially when studying structural changes over time 36 .…”

“…Another study confirmed the direct correlation of firmness with viscosity and G′ and the negative correlation between adhesiveness with firmness, G′, and a viscosity. 35 Nevertheless, despite the correlations found between certain textural and rheological parameters, the accuracy of the latter is well documented, especially when studying structural changes over time. 36 Therefore, the examined rheological behavior in this study could provide a better understanding of the thermal stability of sunscreen formulation with GSE.…”

Chemical Profile and Biological Effects of an Herbal Mixture for the Development of an Oil-in-Water Cream

“…In this sense, specific tests have been developed for the complete assessment of those products. Thus, specific sensorial characteristics can be predicted by interpretation of the physical-mechanical parameters recorded through rheological and texture analysis measurements [ 14 , 54 , 55 ].…”