Changes of SDS-PAGE patterns of soymilk protein and trypsin inhibitor activity induced by heating

H.H. Huang, K.C. Kwok, Hanhua Liang, K.R. Gao

Research output: Journal article publicationJournal articleAcademic research


Objective: To evaluate the heating effects on SDS PAGE patterns of soymilk protein, trypsin inhibitor activity and sulfhydryl bond content in soymilkMethods: Soymilk samples were heated at 95 ℃,120 ℃ and 140 ℃.SDS PAGE was adopted to detect the pattern changes of soymilk proteins after heating and β mercaptoethanol pretreatment. Trypsin activities were analyzed to detect the changes of trypsin inhibitor activities. Ellman method was used to detect sulfhydryl bond.Results: The protein bands of 7,8,11,12,13,14,15,16 disappeared and one new band(band 17)with Mr of 104 620 appeared in the SDS PAGE pattern of soymilk proteins after heated at 95 ℃,120 ℃ and 140 ℃. The sulfhydryl bond content decreased after heating and this change contributed to the pattern change of soymilk protein by β mercaptoethanol pretreatment and by determining the sulfhydryl bond content. The holding time to inactivate 90% of soy bean inhibitor activity at 95 ℃ ,120 ℃ and 140 ℃ were 35 min, 7 min and 60 s respectively.Conclusion: Heating treatment may change the sulfhydryl bond and SDS PAGE pattern of soymilk proteins. The TDT curve indicates that the holding time required to inactivate 90% of soybean trypsin inhibitor could be reduced ten folds by raising 30 ℃ within the temperature range of 95 140 ℃.
Original languageChinese (Simplified)
Pages (from-to)140-144
Number of pages5
Journal營養學報 (Acta nutrimenta sinica)
Issue number2
Publication statusPublished - 2001


  • Soymilk
  • Thermal treatment
  • Trypsin inhibitor
  • Sulfhydryl bond

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