Potential application of phenolic compounds with different structural complexity in maize starch-based film

Abstract

Effects of phenolic compounds with different structural complexity (including protocatechuic acid, naringin and tannic acid) on the properties and functions of maize starch-based film were determined, and the intermolecular force between starch and different phenolic compounds was further analyzed. Different phenolic compounds exhibited varying effects on the thickness (0.101–0.141 mm), moisture content (8.32–9.53 %), color (ΔE value: 1.70–5.01), light transmittance (50–63 %), crystalline structure, thermal resistance characteristics, intermolecular force, microstructure, surface morphology, mechanical properties (tensile strength: 3.2–8.8 MPa; elongation at break: 18–38 %), moisture barrier (6.44–10.12 ×10⁻¹¹ g m⁻¹ s⁻¹ Pa⁻¹) and antioxidant activity of film, owing to the differences in the amount of phenolic hydroxyl groups, molecular size and steric hindrance of phenolic compounds. The present results showed that the proper increase of phenolic hydroxyl number, molecular size and addition dose could improve the binding affinity between phenolic compounds and polysaccharides, so as to promote phenolic compounds to aggregate polysaccharide molecules with themselves as the core, resulting in the change of aggregation and disorder degrees among components in film matrix. Meanwhile, the differences on the interactions between phenolic compounds and polysaccharides could lead to the variation of the dispersion and compatibility of film matrix, as well as the crystallinity, spatial structure, hydrophilic domains of film. Furthermore, phenolic compounds with high amount of hydroxyl groups could enhance the antioxidant activities of film. All present results suggested that phenolic compounds had potential value to enhance the properties and function of maize starch-based film.