Pilot-plant fractionation of soybean glycinin and beta-conglycinin

A laboratory process for separating glycinin and beta-conglycinin from soyb ean flakes was successfully scaled up to the pilot-plant scale (15 kg soy f lakes). Average yields of the glycinin and beta-conglycinin fractions were both 9.4% on a dry basis (db). The protein contents of glycinin and beta-co nglycinin fractions were 92.8 and 97.7% db, respectively. The glycinin and beta-conglycinin purities were 90.4 and 72.7% of the protein content, respe ctively, which were very comparable to those of the laboratory-scale proces s. 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 beta-conglycinin fraction. The native glycinin structure loss in the glycinin fraction was n egligible. The native beta-conglycinin loss in the beta-conglycinin fractio n was 10%, as estimated by rocket immunoelectrophoresis analysis. Hydrophob icity index value showed that hydrophobic properties of the pilot-plant pro tein fraction were ordered, from high to low: beta-conglycinin fraction > g lycinin fraction > intermediate mixture fraction.