Comparison of pH stat and O-phthalaldehyde method for degree of hydrolysis measurement of alcalase and flavourzyme digested casein

Abstract

Casein hydrolysates produced using commercial proteases alcalase (endopeptidase) and flavourzyme (endo- and exopeptidase) were analysed for degree of hydrolysis through two methods; the pH stat and O-phthalaldehyde method. The pH stat method is useful for measurement of DH for the casein hydrolysed using enzyme with endoprotease activity up to 20% degree of hydrolysis, with identical values compared to OPA method while it is unsuitable for the measurement of sodium caseinate digest with enzymatic preparation having exopeptidase activity.