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Carbon Dioxide Induced Soybean Protein Precipitation: Protein Fractionation, Particle Aggregation, and Continuous Operation
Author(s) -
Thiering Russell,
Hofland Gerard,
Foster Neil,
Witkamp GeertJan,
van de Wielen Luuk
Publication year - 2001
Publication title -
biotechnology progress
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.572
H-Index - 129
eISSN - 1520-6033
pISSN - 8756-7938
DOI - 10.1021/bp010019l
Subject(s) - fractionation , carbon dioxide , precipitation , chemistry , particle (ecology) , particle size , chemical engineering , carbon fibers , chromatography , materials science , biology , organic chemistry , physics , ecology , meteorology , composite number , composite material , engineering
A novel protein fractionation technique using a volatile electrolyte has been developed. Carbon dioxide was used to isoelectrically precipitate 80% and 95% pure glycinin and β‐conglycinin fractions from soybean isolate. The protein fractions precipitated as primary particles 0.2−0.3 μm in diameter, which under optimum conditions may be recovered as aggregates up to 500 μm in diameter. The dependency of protein fractionation efficiency on aggregate settling rates has been demonstrated. The isoelectric points of the two main soybean fractions, glycinin and β‐conglycinin, were calculated to be pH 5.2 and 4.95, respectively. Solution pH was accurately controlled by pressure in the isoelectric pH range of the different soybean protein fractions, and a pH “overshoot” was eliminated. Volatile electrolyte technology was also applied to a continuous process in order to eliminate the particle recovery concerns associated with batch precipitation and to demonstrate the potential for scale‐up. Glycinin was effectively recovered on‐line (94% glycinin recovery) with a purity approaching that of the batch process (95%).