Résumé:
The objective of this work is the hydrolysis of casein bovine by the clarified extract of ficin and the crude extract of thistle flowers in order to study the impact of these on the allergenicity of bovine caseins.
The first part of this work is dedicated to the extraction and characterization of the enzyme content system in each plant (Ficus carica and Cynara cardunculus); the characterization aimed mainly determining the physicochemical characteristics, coagulant activity, proteolytic activity and the determination of the electrophoretic profiles of the studied enzymes. The main results showed
that, in terms of enzymatic activities, the clarified extract of ficin has a coagulant activity of 201.56 UP, and a proteolytic activity of19391.67 µg / ml / h, the cardoon flower extract has coagulant activity of 1.25 U.P and a proteolytic activity of 142.5 µg/ml/h. A second part which aims, the achievement of kinetic hydrolysis of bovine casein by extracts previously prepared and followed by the O-phthaldialdehyde method (OPA) to determine the degree of hydrolysis at each sampling time then a characterization of hydrolysates obtained was conducted
by a method électrophoritique SDS-PAGE. The extract of ficin shows a maximum degree of hydrolysis after 24 hours of58.3 % and 32.91 % for both ratios E / S = 1/100 and 1/1000 respectively, while that of the extract of the flowers of cardoon shows a DH maximum of 24.12 % and 32.42 % for both ratios E/S= 1/100 and 1/50 respectively. From the profiles électrophoritiques we can say that the extract of ficin differs from that of cardoon flowers by a speed faster degradation of caseins and
resulting in their disappearance after 30min ofreaction unlike the extract crude cardoon where caseins persist to 6 hours of hydrolysis.
Finally, the evaluation of immunoreactivity proteolysates after the enzyme treatment was performed by determination of the immuno-electrophoretic profiles by the Western blotting and the result was not sufficient to interpret, and consequently this test necessitate to be repeated and confirmed by other methods. On the other hand, the study of the impact of enzyme extracts on the allergenicity of proteins should be extended to other milk proteins such as whey proteins and other allergenic food proteins.
