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Abstract
The effects of a hydrophilic (HLB 15) sucrose ester (SE) emulsifier on native starches from maize, potato, tapioca and wheat (normal starches with approximately 20-25% amylose) and mutant waxy (100% amylopectin) and Hylon VII (high amylose) maize starches were studied.
The SE reduced iodine binding capacity (IBC) and glucoamylase digestibility of native, normal starches and high amylose maize starch, presumably due to starch-SE inclusion complex formation. A weak, limited interaction was observed between waxy maize starch (amylopectin) and the SE.
The SE reduced the enthalpy of gelatinization of the normal starches, but not waxy maize starch, as measured by differential scanning calorimetry (DSC), indicating that complex formation between the SE and amylose occurred during starch gelatinization. Complex formation was further confirmed by the presence of a complex melting endotherm during rescanning (reheating) of samples by DSC.
Starch fractions solubilized by boiling and sonication of normal, waxy and Hylon VII maize starches were evaluated by high performance size exclusion chromatography. Addition of the SE to presolubilized starch samples preferentially removed amylose from solution, presumably due to precipitation of insoluble starch-SE complex. Weak interactions between SE and amylopectin resulting in formation of soluble aggregates was suggested but not confirmed.
Unique cooking properties of each of the starches studied were demonstrated in Rapid Visco-Analyzer viscosity profiles. The SE increased time to peak for the normal starches and waxy maize starch, suggesting interaction between the starch and SE due to complex formation at the granule surface during gelatinization. Hot and cold viscosities of the normal starches were also affected by the SE but the direction and magnitude of the effect varied with starch type.
X-ray diffraction confirmed V-hydrate (inclusion) complex formation between the SE and normal maize but not waxy maize starch. Preliminary NMR data indicated some interaction between normal and waxy maize starches and the SE during starch gelatinization although the nature of the interaction could not be determined.
