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.