Modification of Sweet Potato (Ipomoea batatas) Starches by Anti-Solvent Precipitation Method and Their Application to Stabilize Pickering Emulsions

Abstract

Starch from unconventional sources can be an option to use as stabilizers in food emulsions. However, native starch properties do not have adequate properties for emulsion applications. In the current research, native starches isolated from three new sweet potato genotypes and modified by the precipitation method with ethanol were characterized as to morphology, structural, chemical, and physical properties, and they were tested as stabilizers in Pickering emulsions (oil-in-water emulsions). Native starches showed spherical shapes with some irregularities and agglomerations, particle size lower than 18 µm, and A- and C-type crystalline structures. Irregular shapes with particle sizes between 0.1–18 µm and V6h-type crystalline structure were observed after starch modification. Furthermore, native starches showed lower oil (<7.9%) and water absorption (<2.3%) capacities at 25°C, which increased to values between 9.77%–29.33% and 15.45%–20.52% for water and oil absorption capacities, respectively. The modified starches were used to stabilize oil-in-water emulsions, and these systems were stable for 30 days at 4°C and 25°C. The current research reports for the first time the characterization of residual starches isolated from new sweet potato genotypes, their modification, and emulsion application.