Novel strategies for fabricating reduced fat foods: Heteroaggregation of lipid droplets with polysaccharides

This study describes the formation of emulsion-based materials with novel textural characteristics by controlled heteroaggregation of food-grade colloidal particles and polymers. Heteroaggregation was induced by mixing a suspension of colloidal particles (β-lactoglobulin-coated lipid droplets) with a solution of polymer molecules (pectin) under conditions where the particles and polymers had similar charges (pH 7) or opposite charges (pH 4). The mean particle size, microstructure, flow behavior, and shear modulus of the mixtures formed depended on particle-to-polymer ratio and solution pH. At pH 4, negatively charged pectin molecules were attracted to the surfaces of positively charged protein-coated droplets leading to particle aggregation, increased viscosity, and gel formation, which were attributed to bridging flocculation. At pH 7, pectin molecules were not attracted to the droplet surfaces, but there was still an increase in emulsion viscosity and gel strength above a critical pectin concentration due to depletion flocculation. Bridging flocculation (pH 4) led to more extensive particle aggregation, higher viscosities, and stronger gels than depletion flocculation (pH 7). The presence of pectin in the emulsions had little impact on their microstructure or lipid digestion rate in a simulated gastrointestinal model. This study has important implications for the creation of reduced fat foods, and the development of foods, cosmetics, personal care, and other products with novel properties.

► Novel textures can be created through controlled lipid droplet-polymer interactions. ► Bridging flocculation occurs at pH 4 (positive droplets: negative polymers). ► Depletion flocculation occurs at pH 7 (negative droplets: negative polymers). ► Droplet aggregation did not change lipid digestion.