Effects of high pressure homogenization on faba bean protein aggregation in relation to solubility and interfacial properties

摘要

High pressure homogenization profoundly impacted the globular protein aggregation, and subsequently also its solubility and interfacial properties, using faba bean protein as model. The aggregate size and apparent molecular weight were studied by dynamic laser scattering and size exclusion chromatography before and after high pressure homogenization. High pressure homogenization dissociated large insoluble protein aggregates ( 1 mu m), leading to soluble supramolecular aggregates. Accordingly, 15 kpsi homogenization dramatically improved faba bean protein solubility (10 mg/ml) from 35 to 99% at neutral pH. High pressure homogenization resulted in certain level of protein unfolding with increased surface hydrophobicity. High pressure homogenized proteins adsorbed at the air-water interface faster than the untreated ones as a result of their higher surface hydrophobicity and the dissociation of insoluble protein aggregates. However, the supramolecular aggregates may compete with protein molecules at the interface, which then impaired the viscoelasticity of the interfacial network. This phenomenon observed may be related to the slower rate of rearrangement for supramolecular aggregates at interface due to a more complex structure. Consequently, the foaming capacity of 30 kpsi treated faba bean protein improved from 91 to 260% with 95% retention for 30 min. However, high pressure homogenization had negative effects on protein emulsifying property. This research revealed that plant globular protein aggregation status can determine both protein solubility and functionality. It has also provided insight how high pressure homogenization can be used strategically to modify protein functionality by modulating protein aggregation.