Salt Soaking Research Articles

Hard-to-cook defect in black beans: the contribution of proteins to salt soaking effects

Softening effects of chelating and ion-exchange agents in bean soaking solutions have been attributed to improved solubilization of pectates. The present results indicate a mechanism based on protein destabilization also contributes to softening. Solubility and calorimetric data established softening to be correlated with increased protein denaturation of isolated protein bodies and not with pectin solubilization during cooking, although pH 10, but not pH 7, carbonate buffer did extract significant ( p ≤ 0·05) quantities of both pectin and protein. Carbonate ions reduced onset temperature of protein body denaturation by > 10°C. Rates of protein and pectin solubilization in hardened beans were faster then softening rates, suggesting that softening was not totally attributable to thermal degradation of macromolecular components or middle lamella dissolution.