Evaluation of SDS‐PAGE Method for Estimating Protein Digestibility

In a new technique digestibility of unheated and autoclaved soy protein concentrate (SPC) samples was determined in vitro by SDS‐PAGE. Results were compared with those determined by the pH drop method and with apparent in vivo digestibility in rats. Results of the pH drop method correlated more highly (r = 0.95) with apparent in vivo digestibility than SDS‐PAGE results (r=0.92). However, the SDS‐PAGE technique had two advantages: it allowed estimation of the molecular weight(s) of polypeptides/peptides remaining in protein hydrolyzates and from densitometric analysis, visualization of the process of protein digestion.