STUDY OF FOAM STABILITY BY VIDEO IMAGE-ANALYSIS - RELATIONSHIP WITH THE QUANTITY OF LIQUID IN THE FOAMS

Foaming properties of three different protein solutions [casein ca, soybean isolate si, deamidated gluten dg] were studied. A video image camera, coupled to an apparatus designed for the study of the formation and the stability of foams, made it possible to follow the evolution of the foam textures at the same time as physical characteristics, such as the foam volume and the liquid in the foam. The texture of the images was characterized by an original mathematical procedure derived from the two-dimensional Haar transform. A principal component analysis was then applied to the assessed texture characteristics, in order to emphasize the similarities and the differences between the foam textures. Video image analysis was found to be complementary to the physical characterization of the foams. According to the regularity and the stability of their foams, the proteins could be ranked in the following order Ui-om the more to the less stable foams): ca, dg, si.