Pickering Water‐in‐Oil Emulsions Stabilized Solely by Fat Crystals

Abstract

Abstract Water‐in‐oil (W/O) emulsions have attracted heightened attention because of the ever‐increasing interest in using non‐calorific water to replace calorie‐dense fat in food. However, designing clean‐label and ultra‐stable W/O emulsions is a longstanding challenge in colloid science. Herein, a novel, facile approach is introduced to designing cocoa butter (CB)‐based crystals to stabilize Pickering W/O emulsions. Results using a combination of small‐ and wide‐angle X‐ray scattering and microscopy across length scales reveal that the fat crystals formed in an oleogel of CB with vegetable oil offer high stability to water droplets (up to 60% (v/v)) against coalescence and phase inversion, over storage for 7 months. Such extraordinary stability is attributed to the nanoplatelet‐like CB crystals of βV polymorph located at the water–oil interface and to the inter‐droplet fat crystal network formation, interlocking the water droplets. The increment in water volume fraction endows gel‐like properties with the water droplets acting as “active fillers.” These newly designed Pickering W/O emulsions stabilized solely by fat crystals with unusual rigidity offer great promise for fabricating advanced functional materials in food, pharmaceutics, and cosmetic applications, where long‐term stabilization of water droplets using sustainable particles is a necessity.

Keywords

• cocoa butter crystals
• scattering
• oleogels
• Pickering particles
• rheology
• storage