In vitro glycation and antigenicity of soy proteins

Soy protein isolate (SPI) was glycated with fructose or fructooligosaccharides (FOS) through the Maillard reaction in powder and liquid systems. A reduction in primary free amino groups of SPI up to 85% and 96% was observed in the powder and liquid system, respectively. Following heating at 95 °C for 1 h under liquid conditions, the electrophoretic behavior of allergenic 7S (β-conglycinin) and 11S (glycinin) fractions of SPI was modified when glycated with FOS (molar ratio primary amino groups to FOS of 1:74) as shown by SDS-PAGE analysis. The antigenicity of this glycated protein was also largely reduced (up to ∼90%) compared with that of the unglycated form. Glycation reactions with fructose in a powder and liquid system also reduced the antigenicity of the glycated proteins.