Modified properties of a glycated and cross-linked soy protein isolate by transglutaminase and an oligochitosan of 5 kDa

• Autores: Miao Fu, Xin-Huai Zhao
• Localización: Journal of the science of food and agriculture, ISSN 0022-5142, Vol. 97, Nº 1, 2017, págs. 58-64
• Idioma: inglés
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• Resumen

  • Soy protein is an important protein ingredient for the food industry; however, its properties can be improved by enzymatic and chemical modifications. This study applied a new enzymatic glycation and cross-linking to modify soy protein isolate (SPI), using an oligochitosan of 5 kDa and transglutaminase. Properties of the obtained glycated and cross-linked SPI (GC-SPI) were unknown and thus assessed. RESULTS GC-SPI contained glucosamine of 13.6?g?kg?1 protein, but less reactable NH2 than SPI (0.42 vs. 0.50?mol?kg?1 protein). Infrared spectra and circular dichroism results showed that GC-SPI other than SPI and cross-linked SPI had more OH in molecules, and was more disordered in secondary structure. In comparison with SPI, GC-SPI showed enhanced water-binding capacity, could form aggregates with enlarged hydrodynamic radius (180.2 vs. 82.9?nm) and negative zeta-potential (?31.2 vs. ?27.7 mV) in dispersion, but exhibited lower thermal stability (e.g. greater mass loss) upon heating at a temperature above 288?°C. GC-SPI also had lower in vitro proteolytic digestibility than SPI due to the protein cross-linking. CONCLUSION Oligochitosan of 5 kDa and transglutaminase can be used to glycate and cross-link SPI. This approach is applicable to generate potential protein ingredient with good hydration and dispersive stabilisation. ? 2016 Society of Chemical Industry