Rheological properties and microstructure of model processed cheese containing low molecular weight emulsifiers

Abstract

AbstractThe influence of low molecular weight emulsifiers (SDS, CTAB, lecithin, mono‐diglycerides) on rheological properties and the microstructure of model processed cheese, made using rennet casein, at three different pH values was investigated. Interactions between the low molecular weight emulsifiers and rennet caseins in model processed cheese are consistent with those found in model food emulsions of liquid continuous phase. Compared with the control, the addition of CTAB (cationic) resulted in the hardest and most elastic processed cheese, while the incorporation of SDS (anionic) produced the softest and least elastic cheese. Processed cheese with added lecithin or mono‐diglycerides behaved much like the controls, but with an increase in syneresis level. No syneresis was observed with the SDS cheeses. In general, low pH cheeses (pH 5.45) were harder than high pH cheeses (pH 6.05). Rheologically, all the processed cheese samples can be described as [weak gels]. The protein matrix of the high pH processed cheese containing CTAB consisted mainly of protein particles linked into a chain‐like form, while those containing lecithin and SDS showed a mixture of individual as well as short chained protein aggregates, and the control had protein aggregates of intermediate size. The added low molecular weight emulsifiers resulted in a finer dispersion of the fat in the protein matrix. Protein‐emulsifier charge interactions seem to be the prime determinant of the rheological properties of these model processed cheeses.