Kishk - a dried fermented milk cereal mixture. 2. Assessment of a variety of protein analytical techniques for determining adulteration and proteolysis

A variety of protein assays were applied to the analysis of 25 commercial s amples of Lebanese Kishk to detect the adulteration of goat's milk with cow 's milk. Polyacrylamide gel electrophoretic (PAGE) methods could detect the degree of adulteration similar to 25 %. Using sodium dodecyl sulphate (SDS -PAGE), reverse phase high performance liquid chromatography (RP-HPLC) and anion-exchange fast protein liquid chromatography (FPLC) failed to detect t he degree of adulteration in Kishk due to a very extensive proteolysis that made the distinction of the original caseins very difficult. Moreover, the immunoassay technique (Cortecs method) had limited application for powder products and could not be used effectively to calculate the degree of adult eration of goat's milk Kishk with cow's milk. (C) Inra/Elsevier, Paris.