Iodine binding property of a ternary complex consisting of starch, protein, and free fatty acids

A ternary complex consisting of amylose, whey protein, and free fatty acids (FFA) has been identified in our previous investigations, and its iodine binding properties were investigated. After reaction with iodine solution, an absorption peak (λmax) at 620 nm was shown for pure amylose whereas the λmax decreased to 510 nm when amylose was first complexed with FFA. Interestingly, a λmax of 550 nm with an intermediate absorbance was observed for the ternary complex indicating its intermediate spectrophotometric property. Consistently, the amount of iodine bound by the ternary complex was between free amylose and typical amylose–FFA complex from potentiometric titration indicating the amylose–FFA complex within the ternary complex is less compact and more space is left for iodine binding. This in-between property of the ternary complex suggests it can be used as a molecular carrier to accommodate a forth component in addition to its functional lipids carrying capability in food product development.