PHYSICAL-PROPERTIES AND MICROSTRUCTURE OF RENNET GELS FROM CASEIN MICELLES OF DIFFERENT SIZES

The influence of the amount of kappa-casein in casein micelles on the physical properties and the microstructure of rennn`et gels was invest igated. Casein micelles of different sizes were used containing differ ent amounts of kappa-casein, because smaller casein micelles contained more kappa-casein than larger ones. The storage modulus (G') of the r ennet gel was measured in real time. The saturated G'(G(sat)') depende d on the micellar size. The values of G(sat)' increased with decreasin g diameters of casein micelles. Therefore, rennet gels of smaller case in micelles contain more elastically active network chains and form a more elastic rennet gel. Electron microscopic observations showed that the rennet gels of smaller casein micelles had many smaller pores in the gel microstructure. Their para-casein micelles fused and clustered more extensively, in comparison to larger casein micelles.