Abstract: The properties of composite gels of myofibrillar protein (MP) with native potato starch (NPS), oxidized potato starch (OPS) with 0.2% and 2% oxidant, heat moisture treated potato starch (HMTPS), and heat pressure treated potato starch (HPTPS), designated as NPS-MP, 0.2% OPS-MP, 2.0% OPS-MP, HMTPS-MP and HPTPS-MP, respectively were investigated. The results of rheological properties and low field nuclear magnetic resonance (LF-NMR) demonstrated that 0.2% OPS-MP had the highest storage modulus (G’) and the most stable water distribution, followed by NPS-MP, HMTPS-MP, 2.0% OPS-MP, and HPTPS-MP. The maximum values of gel strength and water holding capacity were recorded for 0.2% OPS-MP (P < 0.05), while the gel strength and water holding capacity of 2.0% OPS-MP and HPTPS-MP were determined to be relatively lower. The main intermolecular forces within the composite gels were hydrogen bonds and hydrophobic interactions, while disulfide bonds played a minor role. These intermolecular interactions were significantly enhanced with increasing starch content, and hydrogen bonds in 0.2% OPS-MP were significantly higher than in NPS-MP (P < 0.05). Microstructure observation showed that 0.2% OPS-MP were more compact and smooth and had a more uniform gel network structure as compared tothe other composite gels.

Key words: modified potato starch, myofibrillar protein, gel properties