Investigation of Pregelatinized Sago Starch-Decanoic Acid Complex by Ultrasonication and its Potential to Stabilize Oil-In-Water Emulsion

Starch-lipid complexes resulting from inclusions between amylose and fatty acid molecules form helical structures with hydrophilic groups on the outer surface and hydrophobic cavities expected to be applied as stabilizers in emulsion systems. Enhancing the inclusion requires pretreatment to promote the development of starch-lipid complexes. Addition pregelatinization of sago starch at several degrees of gelatinization is expected to increase the complexing index (CI) value. The main objective of this research is to investigate the impact of pregelatinization temperature on the establishment of starch-lipid inclusion complexes between sago starch and decanoic acid (DA) using the ultrasonication method and to examine the function of the produced complexes in enhancing the stability of oil-in-water emulsions. Pregelatinization of sago was performed at 65, 70, and 75 °C. The results showed that starch gelatinization at 65 °C (degree of gelatinization (DG) = 26.62 %), 70 °C (DG = 70.21 %), and 75 °C (DG = 100 %) resulted in CI values of 64.18, 61.87, and 49.34 %, respectively, when complexed with DA. The properties of the formed starch-lipid complexes were characterized by increased crystallinity, thermal stability, and decreased viscosity. Using starch-lipid complexes from pregelatinized sago starch (PSS) and DA as emulsion stabilizers can reduce the increase in emulsion viscosity, improve emulsion cream formation, and maintain emulsion stability during 28 days of storage. HIGHLIGHTS Partial gelatinization of sago starch is more efficient than native and fully gelatinization starch in creating complexes between starch and lipids. Pregelatinization of sago starch at 65 °C resulted in the highest starch-lipid CI. The formation of a starch-lipid complex from PSS and DA increases crystallinity and thermal properties and decreases viscosity. The use of PSS-DA complexes in emulsions can enhance cream formation and maintain emulsion stability. GRAPHICAL ABSTRACT