Oil-filled hydrogel particles for reduced-fat food applications: Fabrication, characterization, and properties

• Oil-filled hydrogel particles suitable for use in foods were formed.
• These particles consisted of fat droplets embedded in casein-rich hydrogel beads.
• Oil-filled hydrogel particles increased product lightness and viscosity.
• Oil-filled hydrogel particles may be suitable as fat or starch replacers.

The food industry needs effective strategies to develop reduced calorie products with desirable sensory attributes. This study utilizes controlled phase separation of biopolymer mixtures to form oil-filled hydrogel particles suitable for use in food products. Filled hydrogel particles were fabricated from fat droplets (0 to 1%), sodium caseinate (1.5 to 3%) and high-methoxy pectin (1.5 to 3%) mixtures (pH 5) using two different approaches: multistep and simple methods. The multistep method involved inducing segregative phase separation of the mixed biopolymers at pH 7 (due to electrostatic repulsion), and then reducing to pH 5 to promote aggregative phase separation (due to electrostatic attraction). The simple method involved mixing all the components together at pH 7 and then adjusting to pH 5. The oil-filled hydrogel particles were spheroid in shape, with mean particle diameters (d43) around 10 μm. They consisted of fat droplets trapped within caseinate-rich hydrogel particles that were dispersed within a pectin-rich phase. The hydrogel particles increased the lightness and viscosity of aqueous solutions, and may therefore be suitable to replace fat droplets or starch granules in reduced calorie products.Industrial relevanceThe food industry needs effective strategies to develop reduced calorie products with desirable sensory attributes. This study utilizes controlled phase separation of biopolymer mixtures to form oil-filled hydrogel particles suitable for use in food products. They consisted of fat droplets trapped within caseinate-rich hydrogel particles dispersed within a pectin-rich phase. The hydrogel particles increased the lightness and viscosity of aqueous solutions, and may be suitable to replace fat droplets or starch granules within reduced calorie products.