RELATIONSHIP BETWEEN SENSORY ASSESSMENT AND RHEOLOGICAL PROPERTIES OF COSMETIC CREAMS.

Area of Science:

• Cosmetic Science
• Rheology
• Consumer Science

Background:

• Understanding consumer perception of cosmetic product texture is crucial for product development.
• Rheological properties significantly influence sensory attributes of emulsions like O/W creams.
• Objective rheological measurements need correlation with subjective sensory evaluations.

Purpose of the Study:

• To correlate untrained judges' sensory rankings of O/W creams with their rheological characteristics.
• To investigate the relationship between consistency, spreadability, and stickiness with specific rheological parameters.
• To determine which rheological property drives consumer preference.

Main Methods:

• 144 untrained judges evaluated O/W creams based on consistency, spreadability, and stickiness.
• Rheological properties were measured using flow curves.
• Sensory rankings were statistically correlated with rheological data.

Main Results:

• Consistency ranking strongly correlated with shear stress (at shear rates ≤ 44 s⁻¹).
• Spreadability ranking showed a relationship with plastic viscosity within the 26-32°C range.
• Judges exhibited poor agreement on stickiness, with no clear rheological correlation found.
• Consumer preference was highest for the cream with the greatest consistency.

Conclusions:

• Consistency is a key sensory attribute in O/W creams, directly linked to measurable shear stress.
• Plastic viscosity is a relevant parameter for predicting spreadability of O/W creams.
• Stickiness (tackiness) is a complex sensory attribute with poor correlation to standard rheological parameters, requiring further investigation.
• Optimizing O/W cream consistency is vital for enhancing consumer acceptance.