Potassium-based emulsifying salts in processed cheese: A rheological, textural, tribological and thermal approach

The aim of the study was to investigate the impact of potassium-based emulsifying salts (ES; 2% wt/wt concentration) with different phosphate chain lengths [dipotassium hydrogenphosphate (K2HPO4; DKP), tetrapotassium diphosphate (K4P2O7; KTPP), pentapotassium triphosphate (K5P3O10; TKPP)] on the physicochemical, viscoelastic, textural, tribological, thermal, and sensory properties of processed cheese (PC; 40% wt/wt dry matter, 50% wt/wt fat in dry matter) during a 60d storage period (6 ± 2°C). On the whole, the hardness of all PC samples increased with the increasing chain length of ES (DKP < TKPP < KTPP) and the prolonging storage period. Moreover, the hardness results were in accordance with those of the rheological analysis. All PC samples exhibited a more elastic character (G' > G"; tan δ < 1). The type of potassium-based ES affected the binding of water into the structure of the PC. Furthermore, the study confirmed that the manufactured PCs received optimal sensory scores, without any excessive bitterness. It could be concluded that the type of applied ES and storage length affected the functional properties of PC. Finally, the information provided in this study could serve as a tool for the dairy industry to help appropriately select potassium-based ES for PC manufacture with desired properties.

Microbiological, physicochemical and sensory changes throughout ripening of an experimental soft smear-ripened cheese in relation to salt concentrations

To evaluate the sodium chloride content effect on microbiological, biochemical, physicochemical and sensorial characteristics, Munster cheeses were prepared from pasteurized milk seeded with 3 yeasts (Kluyveromyces marxianus, Debaryomyces hansenii, Geotrichum candidum) and 5 ripening bacteria (Arthrobacter arilaitensis, Brevibacterium aurantiacum, Corynebacterium casei, Hafnia alvei, and Staphylococcus equorum). Experiments were performed under 1.0%, 1.7% and 2.4% NaCl levels in cheese in triplicate. Ripening (d2 - d27) was carried under 12°C and 96% RH. These kinetics were both reproducible and repeatable at 99% confidence level. For each microbial, biochemical and physicochemical parameter, 2 kinetic descriptors (maximal or minimal rate and its occurrence time) were defined. On d2 the physicochemical variables (water activity, dry matter, water content) were strongly dependent on the salting level. From d2 to d27 K. lactis was insensitive to salt while D. hansenii was stimulated. G. candidum growth appeared very sensitive to salt in cheese: at 1.0% NaCl G. candidum exhibited overgrowth, negatively impacting rind appearance, underrind consistency and thickness and off-flavor flaws. Salt concentration of 2.4% induced death of G. candidum. Four bacteria (A. arilaitensis, B. aurantiacum, C. casei, and H. alvei) were moderately sensitive to salt while S. equorum was insensitive to it. Salt level in cheese had a significant effect on carbon substrate consumption rates. Lactate consumption rate in 1.0% salted cheeses was approximately twice higher than under 2.4% NaCl. Data analysis of microorganism, biochemical, and physicochemical kinetics and sensory analysis showed that the best salt level in Munster-type cheeses to achieve an optimum balance between cheese characteristics, sensory qualities and marketability was 1.7% NaCl.

Determination of Minerals in Soft and Hard Cheese Varieties by ICP-OES: A Comparison of Digestion Methods

For sample preparation prior to mineral analysis, microwave digestion (~2 h) is quicker and requires lower acid volume as compared to dry (6-8 h) and wet digestion (4-5 h). However, microwave digestion had not yet been compared systematically with dry and wet digestion for different cheese matrices. In this work, the three digestion methods were compared for measuring major (Ca, K, Mg, Na and P) and trace minerals (Cu, Fe, Mn and Zn) in cheese samples using inductively coupled plasma optical emission spectrometry (ICP-OES). The study involved nine different cheese samples with moisture content varying from 32 to 81% and a standard reference material (skim milk powder). For the standard reference material, the relative standard deviation was lowest for microwave digestion (0.2-3.7%) followed by dry (0.2-6.7%) and wet digestion (0.4-7.6%). Overall, for major minerals in cheese, strong correlation was observed between the microwave and the dry and wet digestion methods (R² = 0.971-0.999), and Bland-Altman plots showed best method agreement (lowest bias), indicating the comparability of all three digestion methods. A lower correlation coefficient, higher limits of agreement and higher bias of minor minerals indicate possibilities of measurement error.

Development of processed low-sodium Maasdam cheese

ABSTRACT The article assesses the effect of different potassium emulsifying salts concentrations on physicochemical, colorimetric, and texture characteristics of processed cheese manufactured using Maasdam. Except for pH, physicochemical parameters remained unchanged, but the gradual substitution of sodium emulsifying salts with potassium-based salts influenced color and texture. Treatments with at least 50% potassium salts showed a reduction of at least 30% of sodium. The sodium decrease allows the product's classification as processed cheese with low-sodium content (<140mg per 56.7g serving). The data obtained present substantial information that can help the dairy industries develop newly reduced-sodium products.

Using microwave-accelerated digestion instead of dry ashing during sodium analysis of low-moisture, part-skim mozzarella

Mineral analysis of cheese products is a labor- and time-intensive process. Pretreatment using dry or atmospheric wet ashing to decompose organic matter before measurement on a spectrometer can take more than 24 h to complete. Samples of low-moisture, part-skim mozzarella (LMPS) cheese were digested using microwave-accelerated digestion (MAD) and conventional dry ashing. A comparison of 23 samples, in duplicate, was performed to determine equivalency. A two one-sided test (TOST) analysis showed that the confidence intervals were within acceptable differences for standard method variation (less than 70 mg/100 g per International Dairy Federation method 119:2007). Bias was observed for the quantification of sodium in microwave-digested samples, averaging 14 mg/100 g higher. Based on the TOST criteria, we concluded that the methods are equivalent.

Reduced-sodium cheeses: Implications of reducing sodium chloride on cheese quality and safety

Sodium chloride (NaCl) universally well-known as table salt is an ancient food additive, which is broadly used to increase the storage stability and the palatability of foods. Though, in recent decades, use of table salt in foods is a major concern among the health agencies of the world owing to ill effects of sodium (Na) that are mostly linked to hypertension and cardiovascular diseases. As a result, food scientists are working to decrease the sodium content in food either by decreasing the rate of NaCl addition or by partial or full replacement of NaCl with other suitable salts like potassium chloride (KCl), calcium chloride (CaCl₂ ), or magnesium chloride (MgCl₂ ). However, in cheese, salt reduction is difficult to accomplish owing to its multifaceted role in cheese making. Considering the significant contribution in dietary salt intake (DSI) from cheese, researchers across the globe are exploring various technical interventions to develop reduced-sodium cheeses (RSCs) without jeopardizing the quality and safety of cheeses. Thus, the purpose of this study is to provide an insight of NaCl reduction on sensory, physicochemical, and technofunctional attributes of RSCs with an aim to explore various strategies for salt reduction without affecting the cheese quality and safety. The relationship between salt reduction and survival of pathogenic and spoilage-causing microorganisms and growth of RSCs microflora is also discussed. Based on the understanding of conceptual and applied information on the complex changes that occur in the development of RSCs, the quality and safety of RSCs can be accomplished effectively in order to reduce the DSI from cheese.

Sodium Content of Foods Contributing to Sodium Intake: Comparison between Selected Foods from the CDC Packaged Food Database and the USDA National Nutrient Database for Standard Reference

The sodium concentration (mg/100g) for 23 of 125 Sentinel Foods (e.g. white bread) were identified in the 2009 CDC Packaged Food Database (PFD) and compared with data in the USDA's 2013 National Nutrient Database for Standard Reference(SR 26). Sentinel Foods are foods identified by USDA to be monitored as primary indicators to assess the changes in the sodium content of commercially processed foods from stores and restaurants. Overall, 937 products were evaluated in the CDC PFD, and between 3 (one brand of ready-to-eat cereal) and 126 products (white bread) were evaluated per selected food. The mean sodium concentrations of 17 of the 23 (74%) selected foods in the CDC PFD were 90%-110% of the mean sodium concentrations in SR 26 and differences in sodium concentration were statistically significant for 6 Sentinel Foods. The sodium concentration of most of the Sentinel Foods, as selected in the PFD, appeared to represent the sodium concentrations of the corresponding food category. The results of our study help improve the understanding of how nutrition information compares between national analytic values and the label and whether the selected Sentinel Foods represent their corresponding food category as indicators for assessment of change of the sodium content in the food supply.

Evaluation of X-ray fluorescence spectroscopy as a method for the rapid and direct determination of sodium in cheese

Cheese manufacturers indirectly determine Na in cheese by analysis of Cl using the Volhard method, assuming that all Cl came from NaCl. This method overestimates the actual Na content in cheeses when Na replacers (e.g., KCl) are used. A direct and rapid method for Na detection is needed. X-ray fluorescence spectroscopy (XRF), a mineral analysis technique used in the mining industry, was investigated as an alternative method of Na detection in cheese. An XRF method for the detection of Na in cheese was developed and compared with inductively coupled plasma optical emission spectroscopy (ICP-OES; the reference method for Na in cheese) and Cl analyzer. Sodium quantification was performed by multi-point calibration with cheese standards spiked with NaCl ranging from 0 to 4% Na (wt/wt). The Na concentration of each of the cheese standards (discs: 30mm×7mm) was quantified by the 3 methods. A single laboratory method validation was performed; linearity, precision, limit of detection, and limit of quantification were determined. An additional calibration graph was created using cheese standards made from natural or process cheeses manufactured with different ratios of Na:K. Both Na and K calibration curves were linear for the cheese standards. Sodium was quantified in a variety of commercial cheese samples. The Na data obtained by XRF were in agreement with those from ICP-OES and Cl analyzer for most commercial natural cheeses. The XRF method did not accurately determine Na concentration for several process cheese samples, compared with ICP-OES, likely due to the use of unknown types of Na-based emulsifying salts (ES). When a calibration curve was created for process cheese with the specific types of ES used for this cheese, Na content was successfully predicted in the samples. For natural cheeses, the limit of detection and limit of quantification for Na that can be determined with an acceptable level of repeatability, precision, and trueness was 82 and 246mg/100g of cheese, respectively. Calibration graphs should be created with standards that reflect the concentration range, ratio, and salt type present in the cheeses. This XRF method can be successfully used for the rapid and direct measurement of Na content in a wide variety of natural cheeses. Commercial process cheese manufacturers use proprietary blends of ES. We did find that the XRF technique worked for process cheese when the calibration graphs were created with the specific types of ES actually used.

Cross-sectional survey of salt content in cheese: a major contributor to salt intake in the UK

OBJECTIVE

To investigate the salt (sodium chloride) content in cheese sold in UK supermarkets.

STUDY DESIGN

We carried out a cross-sectional survey in 2012, including 612 cheeses available in UK supermarkets.

METHODS

The salt content (g/100 g) was collected from product packaging and nutrient information panels of cheeses available in the top seven retailers.

RESULTS

Salt content in cheese was high with a mean (±SD) of 1.7±0.58 g/100 g. There was a large variation in salt content between different types of cheeses and within the same type of cheese. On average, halloumi (2.71±0.34 g/100 g) and imported blue cheese (2.71±0.83 g/100 g) contained the highest amounts of salt and cottage cheese (0.55±0.14 g/100 g) contained the lowest amount of salt. Overall, among the 394 cheeses that had salt reduction targets, 84.5% have already met their respective Department of Health 2012 salt targets. Cheddar and cheddar-style cheese is the most popular/biggest selling cheese in the UK and has the highest number of products in the analysis (N=250). On average, salt level was higher in branded compared with supermarket own brand cheddar and cheddar-style products (1.78±0.13 vs 1.72±0.14 g/100 g, p<0.01). Ninety per cent of supermarket own brand products met the 2012 target for cheddar and cheddar-style cheese compared with 73% of branded products (p=0.001).

CONCLUSIONS

Salt content in cheese in the UK is high. There is a wide variation in the salt content of different types of cheeses and even within the same type of cheese. Despite this, 84.5% of cheeses have already met their respective 2012 targets. These findings demonstrate that much larger reductions in the amount of salt added to cheese could be made and more challenging targets need to be set, so that the UK can continue to lead the world in salt reduction.

The effect of sodium reduction with and without potassium chloride on the survival of Listeria monocytogenes in Cheddar cheese

Sodium chloride (NaCl) in cheese contributes to flavor and texture directly and by its effect on microbial and enzymatic activity. The salt-to-moisture ratio (S/M) is used to gauge if conditions for producing good-quality cheese have been met. Reductions in salt that deviate from the ideal S/M range could result in changing culture acidification profiles during cheese making. Lactococcus lactis ssp. lactis or Lc. lactis ssp. cremoris are both used as cultures in Cheddar cheese manufacture, but Lc. lactis ssp. lactis has a higher salt and pH tolerance than Lc. lactis ssp. cremoris. Both salt and pH are used to control growth and survival of Listeria monocytogenes and salts such as KCl are commonly used to replace the effects of NaCl in food when NaCl is reduced. The objectives of this project were to determine the effects of sodium reduction, KCl use, and the subspecies of Lc. lactis used on L. monocytogenes survival in stirred-curd Cheddar cheese. Cheese was manufactured with either Lc. lactis ssp. lactis or Lc. lactis ssp. cremoris. At the salting step, curd was divided and salted with a concentration targeted to produce a final cheese with 600 mg of sodium/100 g (control), 25% reduced sodium (450 mg of sodium/100 g; both with and without KCl), and low sodium (53% sodium reduction or 280 mg of sodium/100 g; both with and without KCl). Potassium chloride was added on a molar equivalent to the NaCl it replaced to maintain an equivalent S/M. Cheese was inoculated with a 5-strain cocktail of L. monocytogenes at different times during aging to simulate postprocessing contamination, and counts were monitored over 27 or 50 d, depending on incubation temperature (12 or 5 °C, respectively). In cheese inoculated with 4 log₁₀ cfu of L. monocytogenes/g 2 wk after manufacture, viable counts declined by more than 3 log₁₀ cfu/g in all treatments over 60 d. When inoculated with 5 log₁₀ cfu/g at 3mo of cheese age, L. monocytogenes counts in Cheddar cheese were also reduced during storage, but by less than 1.5 log10 cfu/g after 50 d. However, cheese with a 50% reduction in sodium without KCl had higher counts than full-sodium cheese at the end of 50 d of incubation at 4 °C when inoculated at 3 mo. When inoculated at 8 mo postmanufacture, this trend was only observed in 50% reduced sodium with KCl, for cheese manufactured with both cultures. This enhanced survival for 50% reduced-sodium cheese was not seen when a higher incubation temperature (12 °C) was used when cheese was inoculated at 3 mo of age and monitored for 27 d (no difference in treatments was observed at this incubation temperature). In the event of postprocessing contamination during later stages of ripening, L. monocytogenes was capable of survival in Cheddar cheese regardless of which culture was used, whether or not sodium had been reduced by as much as 50% from standard concentrations, or if KCl had been added to maintain the effective S/M of full-sodium Cheddar cheese.

Determining salt concentrations for equivalent water activity in reduced-sodium cheese by use of a model system

The range of sodium chloride (salt)-to-moisture ratio is critical in producing high-quality cheese products. The salt-to-moisture ratio has numerous effects on cheese quality, including controlling water activity (a(w)). Therefore, when attempting to decrease the sodium content of natural cheese it is important to calculate the amount of replacement salts necessary to create the same a(w) as the full-sodium target (when using the same cheese making procedure). Most attempts to decrease sodium using replacement salts have used concentrations too low to create the equivalent a(w) due to the differences in the molecular weight of the replacers compared with salt. This could be because of the desire to minimize off-flavors inherent in the replacement salts, but it complicates the ability to conclude that the replacement salts are the cause of off-flavors such as bitter. The objective of this study was to develop a model system that could be used to measure a(w) directly, without manufacturing cheese, to allow cheese makers to determine the salt and salt replacer concentrations needed to achieve the equivalent a(w) for their existing full-sodium control formulas. All-purpose flour, salt, and salt replacers (potassium chloride, modified potassium chloride, magnesium chloride, and calcium chloride) were blended with butter and water at concentrations that approximated the solids, fat, and moisture contents of typical Cheddar cheese. Salt and salt replacers were applied to the model systems at concentrations predicted by Raoult's law. The a(w) of the model samples was measured on a water activity meter, and concentrations were adjusted using Raoult's law if they differed from those of the full-sodium model. Based on the results determined using the model system, stirred-curd pilot-scale batches of reduced- and full-sodium Cheddar cheese were manufactured in duplicate. Water activity, pH, and gross composition were measured and evaluated statistically by linear mixed model. The model system method accurately determined the concentrations of salt and salt replacer necessary to achieve the same a(w) as the full-sodium control in pilot-scale cheese using different replacement salts.