Applied Biochemistry and Biotechnology

, Volume 43, Issue 3, pp 199–209 | Cite as

Predigestion of soybean proteins with immobilized trypsin for infant formula

  • Shi-Jun Ge
  • Long-Xiang Zhang


Soybean protein isolates of low soybean trypsin inhibitor (STI) residue were prepared by acidic precipitation of soybean flour water extracts (0.8–1.2%) at pH 5.0, followed by acidic washing at this pH and affinity adsorption of residual STI with immobilized trypsin on polystyrene anion-exchange resin GM 201. After heat treatment, soybean protein isolates were subjected to controlled hydrolysis with the immobilized trypsin. Then, the predigested soybean protein was prepared. The predigested soybean protein was free of STI activity, and its solubility at acidic pH range was greatly increased. Sedimentation test showed that it formed a much finer clot at pH 4.5 than that of untreated soybean protein. The pepsin digestibility index at pH 4.0 and chymotrypsin digestibility index at pH 8.0 were obviously improved. These results suggested that the predigested soybean protein prepared by this method may be used in infant formulas.

Index Entries

Soybean protein immobilized trypsin protein digestibility protein enzymatic modification infant formula 


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Copyright information

© Humana Press Inc. 1993

Authors and Affiliations

  • Shi-Jun Ge
    • 1
  • Long-Xiang Zhang
    • 1
  1. 1.Department of BiologyPeking UniversityBeijingChina

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