The relationship between breaking force and hydrophobic interactions or disulfide bonds involved in heat‐induced soy protein gels as affected by heating time and temperature

Abstract

SummaryHydrophobic interactions and disulfide bonds involved in heat‐induced soy protein gels were characterised by determining the dissolution kinetics of gels. Reducing SDS‐PAGE results revealed that all proteins in gel network could be dissolved simultaneously by 1% (w/v) SDS solution, while a majority of glycinin (11S) A polypeptide and a moderate amount of 11S‐B polypeptides, 7S‐α′, α, γ, and β subunits were found in 2% (w/v) DTT dissolving samples. Stronger interaction force between proteins in gel network would result in lower dissolution constant rate. The breaking force of soy gels increased from 543 to 2171 gforce with increasing heating temperature from 85 to 100 °C, and denaturation of 11S globulins played an important role in the development of gel network. As increasing heating time from 30 to 120 min, the breaking force of gels increased from 1687 to 2175 gforce, then decreased to 1253 gforce when the time was prolonged to 240 min. Negative correlations were observed between breaking force and dissolution constant rate kSDS or Δk, which suggested that the strengthening of both hydrophobic interactions and disulfide bonds.