Physicochemical interactions between ferulic acid and maize starch

Abstract

Polyphenols have great potential health benefits to humans. Polyphenols incorporated in starch based foods to produce functional foods and nutraceuticals is scarce. One of the common polyphenols available is ferulic acid. This study was mainly designed to study the effect of ferulic acid in physicochemical, rheological properties, and enzymatic hydrolysis of maize starch. Addition of ferulic acid caused very little changes in the gelatinisation of starch. The addition of ferulic acid caused the uniformity of the gelatinisation to decrease. Retrogradation also was hindered by a very small margin when ferulic acid was added. Pasting properties such as peak time, pasting viscosity, peak temperature, hot paste viscosity, breakdown viscosity, final viscosity and setback viscosity were greatly affected by the addition of ferulic acid but pasting temperature was not affected. Flow behaviours were modelled by the Herschel-Bulkley equation and ferulic acid presence have an effect on the consistency, flow index and the yield stress of starch. Dynamic oscillation analysis indicated that the addition of ferulic acid also showed significant alteration of the viscoelasticity of the starch. Ferulic acid did not show any influence on the enzymatic hydrolysis of starch. The water solubility index and the swelling power of starch demonstrated an increase with the addition of ferulic acid. Hardness, adhesiveness, cohesiveness, gumminess, springiness and chewiness of starch-ferulic acid gels were affected with the increase of the concentration of the ferulic acid. Another objective of this study was to probe the nature of the inclusion complex formation between ferulic acid and high amylose starch. Two methods were used and both methods failed to produce starch-ferulic acid inclusion complexes. It is believed that the results of this study may inspire further studies on the use of polyphenols to produce functional foods and nutraceuticals.