Development of wet media milled purple sweet potato particle-stabilized pickering emulsions: The synergistic role of bioactives, starch and cellulose

Most food-grade Pickering particles nowadays are prepared using purified single-compound substances as starting materials. Fabrication of sustainable and multifunctional particles directly from raw biomass materials could avoid complexed isolation procedure, avoid use of harmful chemicals and maintain the bioactives in raw materials. Purple sweet potatoes, rich in bioactives, were used to produce purple sweet potato particles (PSPPs) via wet media milling, which effectively decreased the particle size of PSPPs from 3371 ± 109 nm to 312 ± 18 nm after 240 min of milling. And significant amounts of bioactives and their antioxidative activity were retained. Pickering emulsions (PSPP-Es) were successfully formed using PSPPs as Pickering stabilizers. These PSPP-Es exhibited good freeze-thaw and heating stability. Low pH (3–6) and strong ionic strength (150 mM–600 mM) conditions contributed to smaller droplet size (10–12 μm) and better storage stability of PSPP-Es. Besides, PSPP-Es possessed better lipid oxidative stability than Tween 80 (a low molecular weight surfactant) stabilized emulsion due to presence of intrinsic antioxidants. This work would facilitate the development of Pickering stabilizers with outstanding emulsifying ability, high food safety, and functional properties directly from whole grain materials, and widen the application of whole grain particle-stabilized Pickering emulsions in food, cosmetics and pharmaceutical industry.