Effect of Addition of Antioxidant Flaxseed Polypeptide on the Rheological Properties of Native Maize Starch

Abstract

Abstract Effects of adding antioxidant flaxseed peptides (FP) on rheological properties of native maize starch (NMS) were investigated using temperature sweep and frequency sweep tests. The NMS concentration of 15 % (w/w) and FP concentrations of 0.2–1.0 % (w/w) were used. The FP samples were prepared by controlled hydrolysis flaxseed protein isolate with pepsin. The highest DPPH radical scavenging activity (53.25 %) was achieved at 22 % of hydrolysis. The onset gelatinization temperature (Tonset ) increased from 67°C to 76°C when the 1 % FP was present in the NMS–FP mixture. The storage modulus (G′) decreased significantly in the presence and increased in concentration of FP. The variation of G′ and loss modulus (G″) of NMS–FP mixtures with angular frequency was fitted well (R 2>0.97) Power law type models. The consistency coefficient (K′ and K″) decreased in the presence and increased in the concentration of FP. While the n′ increased with the presence FP, the n″ decreased. The NMS–FP mixtures produced physical gels (G′>G″). NMS-FP mixtures showed non-Newtonian shear thinning behavior in steady shear flow.