Cheese pH, Protein Concentration, and Formation of Calcium Lactate Crystals

Abstract

The occurrence of calcium lactate crystals (CLC) in hard cheeses is a continual expense to the cheese industry, as consumers fail to purchase cheeses with this quality defect. This research investigates the effects of the protein concentration of cheese milk and the pH of cheese on the occurrence of CLC. Atomic absorption spectroscopy was used to determine total and soluble calcium concentrations in skim milk (SM1, 8.7% total solids), and skim milk supplemented with nonfat dry milk (CSM1, 13.5% total solids). Calcium, phosphorus, lactic acid, and citrate were determined in cheeses made with skim milk (SM2, 3.14% protein), skim milk supplemented with ultrafiltered milk (CSM2, 6.80% protein), and nonfat dry milk (CSM3, 6.80% protein). Supplementation with nonfat dry milk increased the initial total calcium in CSM1 (210 mg/100 g of milk) by 52% compared with the total calcium in SM1 (138 mg/100 g of milk). At pH 5.4, soluble calcium concentrations in CSM1 were 68% greater than soluble calcium in SM1. In cheeses made from CSM2 and CSM3, total calcium was 26% greater than in cheeses made from SM2. As the pH of cheeses made from SM2 decreased from 5.4 to 5.1, the concentration of soluble calcium increased by 61.6%. In cheeses made from CSM2 and CSM3, the concentrations of soluble calcium increased by 41.4 and 45.5%, respectively. Calcium lactate crystals were observed in cheeses made from SM2 at and below pH 5.1, whereas CLC were observed in cheeses from CSM2 and CSM3 at and below pH 5.3. The increased presence of soluble calcium can potentially cause CLC to occur in cheese manufactured with increased concentrations of milk solids, particularly at and below pH 5.1.

The effect of varying fat content on the microstructure of Oaxaca cheese, a typical pasta filata cheese

“…Chemical elementary analysis of crystals through an X‐ray detector coupled to SEM showed that they are formed of oxygen, carbon, calcium and phosphate. Agarwal et al. (2006) stated that the soluble form of calcium (in cheese) can readily combine with lactate (from lactose fermentation) to form calcium lactate, and as the calcium lactate concentration exceeds saturation; microcrystals of calcium lactate (or more specifically, calcium lactate pentahydrate) are formed.…”

“…On the basis of chemical elementary composition and appearance (bright white areas), crystals formed in dehydrated samples of Oaxaca cheese could be calcium lactate crystals. According to Agarwal et al. (2006), some calcium monohydrogen phosphate is also formed.…”

“…(2006), some calcium monohydrogen phosphate is also formed. In Cheddar cheese, they form on the exterior surface during storage (Agarwal et al. 2006; Rajbhandari and Kindstedt 2008) and one factor promoting their formation is acidic pH (<5.1).…”

New insight on crystal and spot development in hard and extra-hard cheeses: Association of spots with incomplete aggregation of curd granules

“…The increasing solute (salt, ions, FAA) concentration in the cheese water phase may give rise to aggregation and crystallization phenomena that result in the different types of structures in the interior and on the surface of different cheese varieties observed by some authors (Bianchi et al, 1974;Agarwal et al, 2006a;Tansman et al, 2015). Although the earliest studies date back to the 1900s (Babcock et al, 1903;Tuckey et al, 1938), a clear and unambiguous characterization of these structures has not yet been achieved.…”

Nucleation of amino acid‐rich crystals on the surface of dried scallop (Chlamys farreri) during storage: formation mechanism and influence of environmental relative humidity

“…Short time from catch to chemical treatment and short storage time, appropriate chemical treatment, and low storage temperature could slow down the formation and growth of white spots (Mikkelsen et al, 1997). The crystallisation of calcium lactate in hard cheeses during storage was also perceived as a quality defect (Agarwal et al, 2006). Besides, free amino acids such as tyrosine (Tyr) and phenylalanine (Phe) were also found to cause white spots, which resulted from the proteolysis of proteins by moulds on the soybean substrate (Chiou et al, 1997).…”