Effects of high hydrostatic pressure treatment on the soybean proteins-mineral interaction.

MANASSERO CARLOS; AÑON MARÍA CRISTINA; VAUDAGNA SERGIO R.; SPERONI FRANCISCO

Florianopolis

Workshop; 2013 International Nonthermal Food Processing Workshop; 2013

The enrichment of a diet consisting of non-conventional proteins with high biological value and micronutrients such as iron, calcium and magnesium represents an issue of current interest. Generally the divalent ions of these minerals form insoluble species with soybean protein damaging its important functional properties, limiting its use in certain kinds of food like liquid stuffs. High hydrostatic pressure (HHP) is an emerging technology able to inactivate microorganisms and enzymes that also may modify macromolecular structure. The aim of this work was to study the effect of HHP on soybean protein-ions interaction and their precipitation, in order to incorporate soybean proteins, supplemented with minerals, as food ingredients. Soybean protein isolate (SPI) was prepared by isoelectric precipitation. Dispersions of SPI were prepared at 10 g/L in distilled water. CaCl2, FeSO4 or MgCl2 were added in various concentrations between 1.5 and 7.5 mmol/L and pH was adjusted to different values. Protein dispersions were subjected to HHP at 600 ± 5 MPa during 5 min. at room temperature. After HHP treatment protein solubility, stability of dispersions and association between soybean proteins and calcium were determined. Our results showed that HHP treatment improves the solubility of SPI dispersions enriched in minerals, the magnitude of this effect was greater. The solubilizing effect of HHP was greater for calcium than for magnesium and iron, and was greater at the highest assayed pHs, and at the lowest assayed ion concentrations. The velocity of sedimentation of insoluble proteins in calcium-enriched SPI decreased markedly after HHP treatment. These findings suggest that HHP might be useful to formulate soybean based beverages enriched with minerals improving their solubility and stability.