The influence of alkaline earth metal equilibria on the rheological, melting and textural properties of Cheddar cheese

Abstract

The total calcium content of cheese, along with changes in the equilibrium between soluble and casein (CN)-bound calcium during ripening can have a major impact on its rheological, functional and textural properties; however, little is known about the effect of other alkaline earth metals. NaCl was partially substituted with MgCl2 or SrCl2 (8·7 and 11·4 g/kg curd, respectively) at the salting stage of cheesemaking to study their effects on cheese. Three cheeses were produced: Mg supplemented (+Mg), Sr supplemented (+Sr) and a control Cheddar cheese. Ca, Mg and Sr contents of cheese and expressible serum obtained therefrom were determined by atomic absorption spectroscopy. Addition of Mg2+ or Sr2+ had no effect on % moisture, protein, fat and extent of proteolysis. A proportion of the added Mg2+ and Sr2+ became CN-bound. The level of CN-bound Mg was higher in the +Mg cheese than the control throughout ripening. The level of CN-bound Ca and Mg decreased during ripening in all cheeses, as did % CN-bound Sr in the +Sr cheese. The presence of Sr2+ increased % CN-bound Ca and Mg at a number of ripening times. Adding Mg2+ had no effect on % CN-bound Ca. The +Sr cheese exhibited a higher G' at 70 °C and a lower LTmax than the control and +Mg cheeses throughout ripening. The +Sr cheese had significantly lower meltability compared with the control and +Mg cheeses after 2 months of ripening. Hardness values of the +Sr cheese were higher at week 2 than the +Mg and control cheeses. Addition of Mg2+ did not influence the physical properties of cheese. Supplementing cheese with Sr appeared to have effects analogous to those previously reported for increasing Ca content. Sr2+ may form and/or modify nanocluster crosslinks causing an increase in the strength of the para-casein matrix.

The influence of alkaline earth metal equilibria on the rheological properties of rennet-induced skim milk gels

“…Ca addition to milk can lead to an increased strength of rennet gels (Sandra et al 2012;Udabage et al 2001;Zoon et al 1988). Cooke and McSweeney (2013) observed that the addition of SrCl 2 at the salting stage of Cheddar cheese manufacture caused significant alterations to its rheological properties, with Sr exhibiting a behavior similar to that previously reported for Ca addition. In the same study, the addition of MgCl 2 at salting had no effect on the rheological properties of cheese.…”

“…It is likely that Sr phosphate nanoclusters formed in the SrCl 2 milks. These Sr nanoclusters may have a different stoichiometric ratio of ions compared to conventional Ca-based CCP nanoclusters (Cooke and McSweeney 2013) and may have slightly different properties as a result. In the 10mmol.L −1 CaCl 2 milk gel, the level of CN-bound Ca remained constant between the gelation point and during aging, whereas the CN-bound Mg and Sr decreased in the 10mmol.L −1 MgCl 2 and SrCl 2 milks, respectively, during this time period (Figs.…”