73G-9 Influence of volume fraction and droplet size distribution of food emulsions on their sensory perception

M. UEBERALL¹, J. Weiss², M. P. Penfield², and B. Kunz¹. (1) Department of Food Technology, The University of Bonn, Roemerstrasse 164, Bonn, 53117, Germany, (2) Department of Food Science and Technology, The University of Tennessee, 2605 River Road, Knoxville, TN 37996-1071

Emulsions such as milk and mayonnaise play a significant role in the food industry. Oil concentration and droplet size strongly affect appearance, texture and color thus influencing their appeal to consumers. Currently there is insufficient information about the impact of these physicochemical parameters on sensory characteristics of emulsions.

The objective of this study was to investigate the relationship between sensory properties (“consistency”, “smoothness”, “oiliness”, “creaminess”, and “color”) of oil-in-water emulsions and their volume fraction, particle size distribution and rheology.

Emulsions were produced by homogenizing sunflower oil with 5wt% milk protein solution to obtain final particle sizes ranging from 0.5 to 50mm and volume fractions ranging from 0 to 70vol%. Particle size distributions were measured using a light scattering technique (LS230, Beckman-Coulter). Flow properties were determined using a rotational rheometer (MCR300, Paar Physica). Color was measured using a colorimeter (CM501d, Minolta). Sensory panels consisted of 10 trained sensory panelists. Statistical analysis (ANOVA) was employed to determine significant differences in sensory perception using a 150-point computerized scale.

Perception of all sensory parameters but “smoothness” increased with increasing oil concentration. There were no significant differences in “consistency”, “creaminess”, and “oiliness” for emulsions with oil concentrations below 5vol%. Emulsions with particle sizes of 0.5 and 1mm did not differ significantly, but panelists were able to perceive differences in emulsions having droplet sizes larger than 10mm. Higher ratings in “creaminess” were related to an increase in viscosity and viscoelasticity. Unimodal particle size distributions resulted in a higher perception of oiliness when compared to bimodal distributions. The color of emulsions with small droplet sizes (< 1mm) and oil concentrations below 5vol% was perceived as “lighter”.

The study has important implications for the food industry as it enables food manufacturers to directly relate emulsion composition to their sensory perception and thus design emulsions with increased consumer acceptance.