Effect of mechanical contrast on sensory perception of heterogeneous liquid and semi-solid foods

This study investigated the influence of size and fracture stress (sigma(F)) of dispersed particles embedded in liquid and semi-solid model food matrices on sensory perception and hedonic response. kappa-carrageenan particles varying in size (0.8, 2.4, 4.2 mm) and fracture stress (sigma(F): 25, 100, 250 kPa) were added (15% w/w) to liquid starch-based model soups and semi-solid protein-based model gels. Sensory profiles were quantified by untrained panellists (n = 54) using the Rate-All-That-Apply (RATA) method. Particle size mainly affected the type of sensory descriptors selected by the subjects, whereas fracture stress of particles determined mainly the perceived intensity of selected descriptors. Soups and gels with small particles (0.8 mm) were mainly perceived as gritty, whereas soups and gels with medium-sized particles (2.4 mm) were mainly perceived as beady. Increasing particle size to 4.2 mm caused lumpy and heterogeneous sensations in soups and gels. With variations of particle fracture stress, the perceived intensity of the selected attributes increased or decreased significantly for all particle sizes. Mouthfeel heterogeneity and chewiness increased significantly when increasing the fracture stress from 20 to 100 or 250 kPa. Mechanical contrast did not enhance liking of model soups and gels probably because kappa-carrageenan particles were perceived as artificial and provided texture contrast without flavour contrast. We conclude that size and fracture stress of dispersed particles embedded in liquid and semisolid model food matrices affect differently sensory perception with particle size determining type of sensory descriptors selected and particle fracture stress determining intensity of selected sensory attributes. (C) 2018 Elsevier Ltd. All rights reserved.