Pilot‐plant fractionation of soybean glycinin and β‐conglycinin

A laboratory process for separating glycinin and β‐conglycinin from soybean flakes was successfully scaled up to the pilot‐plant scale (15 kg soy flakes). Average yields of the glycinin and β‐conglycinin fractions were both 9.4% on a dry basis (db). The protein contents of glycinin and β‐conglycinin fractions were 92.8 and 97.7% db, respectively. The glycinin and β‐conglycinin purities were 90.4 and 72.7% of the protein content, respectively, which were very comparable to those of the laboratory‐scale process. The total sulfhydryl plus half cystine content of the glycinin fraction was 37.8 mol/mol protein and 14.8 mol/mol protein for the β‐conglycinin fraction. The native glycinin structure loss in the glycinin fraction was negligible. The native β‐conglycinin loss in the β‐conglycinin fraction was 10%, as estimated by rocket immunoelectrophoresis analysis. Hydrophobicity index value showed that hydrophobic properties of the pilot‐plant protein fraction were ordered, from high to low: β‐conglycinin fraction > glycinin fraction > intermediate mixture fraction.