Emulsified Milkfat Effects on Rheology of Acid-Induced Milk Gels

Reconstituted skim milk formed by a gel by acidification to < pH 5.2 and heating to 60°C. The gel compressive stress (σ_c) was influenced by the heating process, increased with milk-nonfat-solids (MNFS) and reached a maximum at pH 4.0. The addition of emulsified fat facilitated gelation, increase gel σ_c and shear modulus, and decreased gel deformability. At an equal fat concentration, emulsions containing small-sized fat globules (i.e., more globules) reinforced the gels more markedly than emulsions comprised of large globules reflecting the importance of number of globules in the gels. Electron micrographs revealed crosslinkages between fat globules and casein particles in the gel network, which may have caused reinforcement of milk gels by milkfat.