Soluble Salts in Processed Cheese Prepared with Citrate- and Phosphate-Based Calcium Sequestering Salts

In this study, the protein and salts distribution (Ca, P, Na and Mg) in processed cheese (PC) samples prepared with 180 or 360 mEq/kg of the calcium sequestering salts (CSS) disodium phosphate (DSP), disodium pyrophosphate (DSPP), sodium hexametaphosphate (SHMP) and trisodium citrate (TSC) was studied. For this purpose, a water-soluble extract (WSE) of PC samples was prepared. All PC samples contained 45-46% moisture, 26-27% fat and 20-21% protein and had a pH of 5.2 or 5.7. Ultracentrifugation slightly reduced the protein content of the WSE of PC, indicating that most protein in the WSE was non-sedimentable. At equal concentration of CSS, the protein content of the WSE was higher for PC at pH 5.7 compared to PC at pH 5.2. Approximately 55-85% of the Ca and P in the WSE of samples was 10 kDa-permeable for PC prepared with DSPP and SHMP. This suggests that the formation of non-permeable Ca-polyphosphate-casein complexes. For PC prepared with TSC, >90% of Ca in the WSE was 10 kDa-permeable, indicating that micellar disruption arises from sequestration of micellar Ca. These results indicate that the WSE method is an appropriate method to understand how salts present in PC are distributed. However, the WSE and ultracentrifugal supernatant of the WSE can include both soluble and protein-associated salts. Therefore, determining levels of salts in 10 kDa permeate of ultracentrifugal supernatant of the WSE is most appropriate.

Changes of physicochemical and functional properties of processed cheese made with natural cheddar and mozzarella cheeses during refrigerated storage

The present study aimed to investigate changes of physicochemical and functional properties of the processed cheeses (PCs) made with Cheddar (PC1), Mozzarella (PC2) and both of them at a ratio of 1:1 (PC3) during storage at 4 °C for 4 months. The results showed that the type of natural cheese used affected the composition of PCs with lower fat content in PC2 due to the lower fat content of Mozzarella cheese used. PC2 with lower fat content showed decreased meltability and oil leakage compared with PC1 and PC3. The stretchability of all the samples significantly (P < 0.05) decreased during storage, and PC1 showed lower stretchability. This was confirmed by increased protein hydrolysis of all the samples during the storage with a higher level of proteolysis in PC1, leading to decreased stretchability of PCs. Further low-field nuclear magnetic resonance analysis indicated more entrapped water in cheese due to moisture migration into the cheese matrix that might squeeze the fat globules to aggregate, causing more fat leakage during later stages of storage. This was evidenced by microstructural analysis showing different extents of increase in fat particle sizes and decrease in free serum in all the PC samples over the storage time. Therefore, the present study provides further understanding of the mechanism of quality change of PC during refrigerated storage as affected by proteolytic properties and composition of natural cheese used.

A review on stringiness property of cheese and the measuring technique

This review paper provides a deep understanding of stringiness property in a cheese product. Stringiness is used to describe the extended continuous strand of a molten cheese, especially mozzarella cheese. Stringiness is often described quantitatively by stretch length, as well as qualitative definition which focuses on the dimension of strand and ease of extensibility. Very often, the scope of defining stringiness attributes is limited by the measuring techniques because a complete experimental setup is required to obtain information on both stretch quantity and stretch quality. Among the measuring methods, cheese extensibility rig stands out to be the best method to assess stringiness attribute of a cheese as it is an objective method. In addition, a detailed study on the molecular behavior and interactions among natural and imitation cheese components in delivering stringiness, and the challenges faced therein have been reviewed. Thus, the review provides a foundation for the development of vegan cheese or plant-based cheese with stringiness properties.

Seasonal variations in the functional performance of industrial low-moisture part-skim mozzarella over a 1.5-year period

Seventy-five blocks of low-moisture part-skim mozzarella cheese were procured from an industrial cheese plant, and the relationships between the physicochemical and functional properties were evaluated during refrigerated storage. In total, cheeses were obtained from 1 cheese vat on 7 different production dates, at 2 to 4 monthly intervals, over a 1.5-yr period; all cheeses were made using a standard recipe. The cheeses were held at 4°C for 0, 1, 2, 4, 8, 16, or 32 d and assayed for composition, primary proteolysis, serum distribution, texture profile analysis, heat-induced changes in viscoelastic behavior, cheese extensibility, and melt characteristics. The results demonstrated a substantial increase in serum uptake by the calcium-phosphate para-casein matrix between 1 and 16 d of storage with a concomitant improvement in the functional performance of the cheese. Extending the storage time to 32 d resulted in further changes in the functional quality, concurrent with ongoing increases in protein hydration and primary proteolysis. Differences in the measured characteristics between the cheeses obtained on different sampling occasions were evident. Principal component analysis separated the cheeses based on their variance in functional performance, which was found to be correlated mainly with the calcium content of the cheese. The results indicate that the manufacturing process should be tightly controlled to minimize variation in calcium content and enhance the quality consistency of the cheese.

Functionality of Mozzarella cheese analogues prepared using varying protein sources as influenced by refrigerated storage

The functional properties (shredability, meltability, fat leakage, stretchability) of Mozzarella Cheese Analogue (MCA) prepared using acid casein (ACMCA), rennet casein (RCMCA) and their admixture (ARCMCA) were monitored with those of Natural Mozzarella Cheese (NMC) during refrigerated storage. The shredability of analogues was superior over such attribute of NMC. The MCAs had good shredability up to 28 days, while that of NMC started deteriorating from 21 days onwards. The meltability of both NMC and MCAs improved with advancement of storage; the extent of increase in meltability during span of 35 days period was 2.65, 2.85, 2.78 and 2.63 for NMC, ACMCA, RCMCA and ARCMCA respectively. The stretch value of the MCAs exhibited an increase up to 21 days of refrigerated storage followed by decline up to 35 days, whereas NMC exhibited a linear increase in stretch value with advancement of storage till 35 days. There was a steady decline in the fat leakage in case of any of the MCAs with advancement in storage period; the difference in the values of fat leakage up to 35 days was to the tune of 1.50 cm2, 1.39 cm2 and 1.43 cm2 for ACMCA, RCMCA and ARCMCA respectively. Conversely, NMC exhibited linear increase in fat leakage with progressive storage up to 35 days. It is concluded that MCAs had better functional stability as compared to NMC during refrigerated storage. Amongst MCAs, ARCMCA performed better in terms of baking qualities than those prepared using AC or RC alone. MCAs had better storage stability as compared to NMC.

Impact of heating on sensory properties of French Protected Designation of Origin (PDO) blue cheeses. Relationships with physicochemical parameters

The aim of this study was to measure the impact of heating on the sensory properties of blue-veined cheeses in order to characterise their sensory properties and to identify their specific sensory typology associated with physicochemical parameters. Sensory profiles were performed on a selection of Protected Designation of Origin (PDO) cheeses representing the four blue-veined cheese categories produced in the Massif Central (Fourme d’Ambert, Fourme de Montbrison, Bleu d’Auvergne and Bleu des Causses). At the same time, physicochemical parameters were measured in these cheeses. The relationship between these two sets of data was investigated. Four types of blue-veined cheeses displayed significantly different behaviour after heating and it is possible to discriminate these cheese categories through specific sensory attributes. Fourme d’Ambert and Bleu d’Auvergne exhibited useful culinary properties: they presented good meltability, stretchability and a weak oiling-off. However, basic tastes (salty, bitter and sour) are also sensory attributes which can distinguish heated blue cheeses. The relationship between the sensory and physicochemical data indicated a correlation suggesting that some of these sensory properties may be explained by certain physicochemical parameters of heated cheeses.

Changes in quality of nonaged pasta filata Mexican cheese during refrigerated vacuum storage

Six batches of Oaxaca cheese (a Mexican pasta filata cheese) from 3 dairy plants were sampled and vacuum-packaged at 8°C up to 24d. Counts of principal microbial groups, pH, levels of sugars, organic acids, lipolytic and proteolytic indices, and texture, color, and meltability values of cheeses were studied at d 1, 8, 16 and 24 of storage. A descriptive sensory analysis of selected taste, odor, and texture characteristics was also carried out. The main changes in the cheeses during the storage were decreases in pH, hardness, elasticity, and whiteness, and an increase in meltability. Neither lipolytic nor proteolytic activities were evident during the storage of cheeses. Storage time resulted in a gradual quality loss of unmelted cheeses. This loss of quality might be related to the decrease of hardness and the appearance off-flavors.

Chemical changes that predispose smoked Cheddar cheese to calcium lactate crystallization

We have observed a high incidence of calcium lactate surface crystals on naturally smoked Cheddar cheese in the retail marketplace. The objective of this study was to identify chemical changes that may occur during natural smoking that render Cheddar cheese more susceptible to calcium lactate crystal formation. Nine random-weight (approximately 300 g) retail-packaged samples of smoked Cheddar cheese were obtained from a commercial manufacturer immediately after the samples were smoked for about 6 h at 20 degrees C in a commercial smokehouse. Three similarly sized samples that originated from the same 19.1-kg block of cheese and that were not smoked were also obtained. Within 2 d after smoking, 3 smoked and 3 control (not smoked) samples were sectioned into 5 subsamples at different depths representing 0 to 2, 2 to 4, 4 to 6, 6 to 8, and 8 to 10 mm from the cheese surface. Six additional smoked cheese samples were similarly sectioned at 4 wk and again at 10 wk of storage at 5 degrees C. Sample sections were analyzed for moisture, L(+) and D(-) lactate, pH, and water-soluble calcium. The effects of treatment (smoked, control), depth from cheese surface, and their interactions were analyzed by ANOVA according to a repeated measures design with 2 within-subject variables. Smoked samples contained significantly lower moisture and lower pH, and higher total lactate-in-moisture (TLIM) and water-soluble calcium-in-moisture (WSCIM) than control cheeses. Smoked samples also contained significant gradients of moisture, pH, TLIM, and WSCIM, with lower moisture and pH, and higher TLIM and WSCIM, occurring at the cheese surface. Gradients of moisture were still present in smoked samples at 4 and 10 wk of storage. In contrast, the pH, TLIM, and WSCIM equilibrated and showed no gradients at 4 and 10 wk. The results indicate that calcium and lactate in the serum phase of the cheese were elevated because of smoking, especially at the cheese surface immediately after smoking treatment, which presumably predisposes the smoked cheeses to increased susceptibility to calcium lactate surface crystallization.

Changes in the proportions of soluble and insoluble calcium during the ripening of cheddar cheese

In cheese, the concentration and form of residual Ca greatly influences texture. Two methods were used to determine the proportions of soluble (SOL) and insoluble (INSOL) Ca in Cheddar cheese during 4 mo of ripening. The first method was based on the acid-base buffering curves of cheese and the second was based on the extraction of the aqueous phase ("juice") of cheese under high pressure and determining the concentration of SOL Ca in the juice using atomic absorption spectroscopy. When cheese was acidified there was a strong buffering peak at pH approximately 4.8, which was due to the solubilization of residual colloidal calcium phosphate (CCP) of milk that remained in cheese as INSOL Ca phosphate. The area of this buffering peak in cheese was expressed as a percentage of the original area of this peak in milk and was used to estimate the concentration of residual INSOL Ca phosphate in cheese. There were no significant differences between the 2 methods. The proportions of INSOL Ca in cheese decreased from approximately 73 to approximately 58% between d 1 and 4 mo. These methods will be useful techniques to study the role of Ca in cheese texture and functionality.

Effect of pH and calcium concentration on proteolysis in mozzarella cheese

Low-moisture Mozzarella cheeses (LMMC), varying in calcium content and pH, were made using a starter culture (control; CL) or direct acidification (DA) with lactic acid or lactic acid and glucono-delta-lactone. The pH and calcium concentration significantly affected the type and extent of proteolysis in Mozzarella cheese during the 70-d storage period at 4 degrees C. For cheeses with a similar pH, reducing the calcium-to-casein ratio from -29 to 22 mg/g of protein resulted in marked increases in moisture content and in primary and secondary proteolysis, as indicated by polyacrylamide gel electrophoresis and higher levels of pH 4.6- and 5%-PTA-soluble N. Increasing the pH of DA cheeses of similar moisture content, from approximately 5.5 to 5.9, while maintaining the calcium-to-casein ratio almost constant at approximately 29 mg/g, resulted in a decrease in primary proteolysis but had no effect on secondary proteolysis. Comparison of CL and DA cheeses with a similar composition showed that the CL cheese had higher levels of alpha(s1)-CN degradation, pH 4.6- and 5%-PTA-soluble N. Analysis of pH 4.6-soluble N extracts by reverse-phase HPLC showed that the CL cheese had higher concentrations of compounds with low retention times, suggesting higher concentrations of low molecular mass peptides and free amino acids.

Effect of pH and calcium concentration on some textural and functional properties of mozzarella cheese

The effects of Ca concentration and pH on the composition, microstructural, and functional properties of Mozzarella cheese were studied. Cheeses were made using a starter culture (control) or by direct acidification of the milk with lactic acid or lactic acid and glucono-delta-lactone. In each of three trials, four cheeses were produced: a control, CL, and three directly-acidified cheeses, DA1, DA2, and DA3. The cheeses were stored at 4 degrees C for 70 d. The Ca content and pH were varied by altering the pH at setting, pitching, and plasticization. The mean pH at 1 d and the Ca content (mg/g of protein) of the various cheeses were: CL, 5.42 and 27.7; DA1, 5.96 and 21.8; DA2, 5.93 and 29.6; DA3, 5.58 and 28.7. For cheeses with a high pH (i.e., approximately 5.9), reducing the Ca content from 29.6 to 21.8 mg/g of protein resulted in a significant decrease in the protein level and increases in the moisture content and mean level of nonexpressible serum (g/g of protein). Reducing the Ca concentration also resulted in a more swollen, hydrated para-casein matrix at 1 d. The decrease in Ca content in the high-pH cheeses coincided with increases in the mean stretchability and flowability of the melted cheese over the 70-d storage period. The fluidity of the melted cheese also increased when the Ca content was reduced, as reflected by a lower elastic shear modulus and a higher value for the phase angle, delta, of the melted cheese, especially after storage for <12 d. The melt time, flowability, and stretchability of the low-Ca, high-pH DA1 cheese at 1 d were similar to those for the CL cheese after storage for > or = 12 d. In contrast, the mean values for flowability and stretchability of the high-pH, high-Ca DA2 cheese over the 70-d period were significantly lower than those of the CL cheese. Reducing the pH of high-Ca cheese (27.7 to 29.6 mg/g of protein) from -5.95 to 5.58 resulted in higher flowability, stretchability, and fluidity of the melted cheese. For cheeses with similar pH and Ca concentration, the method of acidification had little effect on composition, microstructure, flowability, stretchability, and fluidity of the melted cheese.