Abstract:

The effects of different emulsifying salts on the structure of processed Mozzarella cheese was analyzed by
using FTIR and scanning electron microscopy (SEM). The results showed that there were four types of secondary structures
including α-helix, β-sheet, random coil and β-turn in processed cheese, but they were in different proportions due to the
type of emulsifying salt. β-sheet accounted for major proportion of the secondary structure in processed cheese made with
different emulsifying salts. The processed cheeses made with DSP and SHMP were special and neither possessed α-helix;
while random coil accounted for a smaller proportion in the processed cheeses made with each of three other salts. Based
on scanning electron micrographs, the interactions between proteins were different and the structure was uniform in the
processed cheese made with 2% sodium citrate, 0.37% sodium pyrophosphate and 0.2% sodium polyphosphate (calculated
by weight relative to the raw Mozzarella cheese). Moreover, fat globules were nearly coated by hydrated paracaseinate.

Key words: processed cheese, emulsifying salt, FTIR, protein secondary structure