Preparation and characterization of octenyl succinic anhydride modified waxy maize starch hydrolyzate/chitosan complexes with enhanced interfacial properties

Adsorption and Assembly of Octenyl Succinic Anhydride Starch/Chitosan Electrostatic Complexes at Oil–Water Interface

“…In this case, moderate complexation strength favored the surface activity of the complexes. Their relatively small size may also account for their accelerated adsorption by reducing the energy barrier …”

“…OSA-G (3.4% amylose content, d 4,3 = 15.32 μm) and OSA-D ( M w = 2.25 × 10 5 g mol –1 , 15 mPa·s viscosity, d 4,3 = 139.81 nm) with the same substitution degree of 0.0309 were prepared as previously described. , 86.8% deacetylated CS with a weight-average molecular weight of 2.4 × 10 5 g mol –1 and a viscosity of 200 mPa·s was supplied by Haidebei Co., Ltd. (Shandong, China). Caprylic/capric triglycerides (99% purity) used as model oil were purchased from Croda Co., Ltd. (East Yorkshire, UK).…”

“…To obtain complexes with different structures, different OSA-D/CS mass ratios (r = 3:1, 6:1 and 9:1) and different pH values (pH = 5.5, 6.0 and 6.5) were used at a fixed OSA-D concentration (1% w/v) according to our previous study. 17 The desired pH values examined at pH 6.5, 6.0, and 5.5 represented the insoluble complexes undergoing association, dissociation, and termination, respectively, 17 and were adjusted with 0.5 M HCl or NaOH. Homogeneous pure OSA-D, OSA-G, and CS (1% w/v) dispersions were used as controls.…”

“…Their stronger rigidity and large size (3.5–25 μm) also limit their adsorption and expansion at the interface. − Dissolved OSA starch (OSA-D) is usually obtained by the enzymatic hydrolysis of OSA-G. Due to a decrease in molecular weight and size as well as an increase in water solubility, OSA-D has great potential for interfacial design. It can interact electrostatically or hydrophobically with other macromolecules in aqueous solution, resulting in surface-active complexes. − CS, obtained via deacetylation of chitin, is the only positively charged polysaccharide in nature . The amino groups carried by CS make it soluble in dilute acid solutions, but at pH > 6.5, self-aggregation occurs owing to their deprotonation (p K ≈ 6.5). , Because of the low surface activity of dissolved CS molecules, their ability to stabilize oil–water interface is limited. , Yet, the cationic nature of CS allows for electrostatic complexation with negatively charged biopolymers, resulting in the formation of complexes with enhanced interfacial properties .…”

“…23 In our previous studies, we described the complexation behavior between OSA-D and CS and obtained OSA-D/CS complexes with different structures and wettabilities. 13,17 However, the adsorption kinetics of these complexes at oil−water interface and the properties of interfacial films are not fully understood. Different complex structures will inevitably lead to changes in particle packing, thickness, and viscoelasticity of interfacial films, thus affecting performance of Pickering emulsions.…”