Comparison of Functional Properties of Soybean Protein Isolates Prepared by Different Methods

Abstract

Abstract: Several soybean protein isolates (SPI) were prepared by acid precipitation, Samoto method and calcium-precipitation method, respectively. The characteristics including protein yield, total lipid content, solubility and emulsification of these SPIs were investigated. Our results showed that the yield of calcium-precipitation protein (Less-LP SPI) was lower than that of acid precipitation protein (APP), but higher than 7S, 11S extracted by Samoto fractionation procedure. The lipid content of Less-LP SPI was decreased by 45% when compared with that of APP. The lipid content of lipophilic protein (LP) obtained from Samoto fractionation was 7.48%, but the lipid contents in 7S and 11S were 1.45% and 2.36%, respectively. The Samoto LP-rich fraction had inferior solubility and emulsifying properties. Less-LP SPI had lower solubility (pH ≤ 10) and emulsifying activity than APP, while Less-LP SPI had superior emulsion stability. In summary, Less-LP SPI has lower lipid and better emulsion stability and therefore can improve the shelf life of foods.

Key words: soy protein isolate, solubility, emulsification, lipid content

CLC Number:

References

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