Alteration of imitation cheese structure and melting behaviour with wheat starch

摘要

Imitation cheeses were manufactured with increasing levels (0-20%, w/w) of native wheat starch in partial or total replacement of rennet casein protein. With increased addition of native wheat starch up to 9% (w/w), irregular starch particles (sometimes horseshoe-shaped) became more numerous and disruptive of the protein structure. Differential scanning calorimetry showed the presence of a large endothermic peak at 42 pC, corresponding to the melting of the palm oil constituent, and a smaller second endotherm at 79-82 pC with the inclusion of starch at levels of up to 9% (w/w). This smaller endotherm was not present on heating imitation cheese containing 20% (w/w) starch, which had no meltability. Results indicated that the second smaller endotherm corresponded to a phase transition in the casein-continuous matrix facilitating flow behaviour in the imitation cheese network. At concentrations of 3-9% (w/w), wheat starch behaved like a filler material, with limited effects on the rheology of the casein matrix at temperatures below 50 pC, however its inclusion increased the processing time and reduced the meltability of the imitation cheese.