Understanding mechanisms behind the oily mouthcoating perception of pure vegetable oils using tribology.

Tribology is the science of measuring friction between surfaces. While it has been widely used to investigate texture sensations of food applications, it is seldom applied in pure edible oil systems. In this research, we measured friction, viscosity, and solid fat content (SFC) of nine vegetable oils at 30 and 60°C. Polarized static microscopy was used to assess crystal formation between 60 and 30°C. Descriptive sensory analysis and quantification of oral oil coatings were performed on the oils at 60°C. Expressing the friction factor of oil over the Hersey number (calculated using high sheer-viscosity values) showed no differences in friction between 30 and 60°C, except for shea stearin. Static microscopy revealed crystallization occurred at 30°C for shea stearin, whereas no or few crystals were present for other oils. At 30°C, friction at 1 × 10-2 m/s showed an inverse correlation with SFC (R = -0.95) and with high shear rate viscosity (R = -0.84), as well as an inverse correlation (R = -0.73) with "oily mouthcoating" perception. These results suggest that friction could be a predictor of fat-related perceptions of simple oil systems. Additionally, we hypothesize that the presence of crystals in oils could lower friction via a ball-bearing lubrication mechanism.

Comparison of RATA, CATA, sorting and Napping® as rapid alternatives to sensory profiling in a food industry environment.

Today, there is a need to accelerate new product development to deliver faster innovations which are expected by consumers. This requires identifying rapid descriptive methodologies requiring less training than conventional sensory profiling (SP) still providing good quality data allowing to identify food sensory drivers of consumer liking. A set of nine samples covering a large sensory space has been designed systematically combining at three different ratio three commercial almond, rice, and oat-based milks. Ten expert panellists familiar with sensory profiling and naïve with the plant-based milk category performed sorting, Napping®, CATA, RATA tasks and then SP. Overall liking of each sample was rated by 80 plant-based milk consumers. Among the four alternative methodologies, RATA provided both an overall product configuration and description the closest to SP (RV = 0.93) and allowed to identify the sensory drivers of plant-based milk acceptance similarly to SP. CATA is relevant to build a product landscape and to highlight product clusters with major sensory differences whereas Sorting and Napping® are alternatives to CATA, as product mappings were close, when no previous glossary or knowledge exits on product attributes.