Proteolysis in reduced sodium Feta cheese made by partial substitution of NaCl by KCl

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.

Investigation on the Intrinsic Potential of Using Potassium Chloride for Partially Replacing NaCl in Kimchi and the Effect of Information on Consumer Acceptance of Sodium-Reduced Kimchi According to Age

The high sodium content of kimchi is a contradicting factor from its fame as a healthy food. With the aim of reducing the sodium content of kimchi, the objective of this study was to understand the effect of providing "sodium-reduced" information on the acceptance of kimchi according to the age of consumption. Six sodium-reduced kimchi samples, prepared with different percentages of sodium reduction (25% and 50%) and potassium chloride concentration (none, 0.47%, and 0.93%), were compared to control kimchi (2.0% w/v NaCl). Sensory characterization of the samples was obtained using descriptive analysis. A total of 167 kimchi consumers with balanced proportion of the young (below 40) and the old (above 40) evaluated seven kimchi samples in either of the two conditions: blind testing condition or informed testing condition where each of the samples was provided with a label that informed about "sodium reduction percentage" and "whether a salt replacer was used or not." The results showed that in terms of healthiness perception, Korean female consumers believed that kimchi with a high sodium reduction rate would contribute to health in general, though an unfavorable notion of using a salt replacer was also observed. Also, the results suggested that promoting information about sodium reduction in kimchi would generally increase consumer acceptance. However, this phenomenon was influenced not only by the sample for which the information was provided, but also by the age of consumers with different health interests and kimchi experience. PRACTICAL APPLICATION: The findings of this study showed simply reducing sodium and promoting it with a health claim showed limitation in achieving a high level of sodium reduction, such as a 50% reduction rate, which implied the importance of using supplementary material such as potassium chloride that can fulfill the missing saltiness and flavors of the original product. Promotion of "sodium-reduced" claims in kimchi generally results in increased consumer acceptance. However, the effectiveness of the information was dependent on which sample was provided and the age of the consumers, among whom health interests and kimchi experience differ.

Development of Reduced-Fat, Reduced-Sodium Semi-Hard Sheep Milk Cheese

This paper examines the effects of the incorporation of denatured whey proteins along with salting in NaCl/KCl brine on the characteristics and ripening of sheep milk reduced-fat (RF), semi-hard cheese. Incorporation of denatured whey proteins was carried out by: i. adding commercial microparticulated whey protein (MWP) in reduced-fat cheese milk (RFM), or ii. by ‘in situ’ heat-induced partial denaturation of whey proteins of reduced-fat cheese milk (RFD). The implemented cheesemaking conditions included curd washing, moderate clotting, scalding temperatures, and ripening of cheeses packed in plastic bags under vacuum at 10 °C. Full-fat cheeses (FF) were manufactured in parallel. Physicochemical composition, textural profile, and proteolysis were assessed throughout 60 days of ripening. The mean moisture, fat on dry matter (FDM), moisture on non-fat substances (MNFS), protein on dry matter (PDM), salt, and salt-in-moisture (S/M) content of the RF cheeses were 47.4%, 32.8%, 57.3%, 54.3%, 1.63%, and 3.36%, respectively; pH ≈ 5.0, a_w ≈ 0.977, Ca ≈ 1000 mg/100 g cheese. The MNFS of FF and RF cheeses were similar. Proteolysis indices were not affected by any of the treatments, and they were similar to the FF counterparts. The applied cheesemaking technology was adequate for the production of semi-hard reduced-fat and reduced-sodium cheeses. Ripening under packaging hindered moisture loss without impairing the evolution of proteolysis and textural parameters. The same holds true for salting in NaCl/KCl brine. The high pasteurization of cheese milk was more effective for the increase of moisture and MNFS than the addition of MWP, without exhibiting any adverse effects.

Optimization of physicochemical and textural properties of pizza cheese fortified with soybean oil and carrot extract

Response surface methodology (RSM) was used to optimize pizza cheese containing carrot extract. The effects of two important independent variables including soybean oil (5%–20%) and carrot extract (5%–20%) were studied on physicochemical and textural properties of pizza cheese containing carrot extract. According to the results, RSM was successfully used for optimizing formulation of pizza cheese containing carrot juice. Results of this study revealed that oil (A), carrot (B), AB, square term of carrot (B²), B, AB, square term of oil (A²), B², AB, AB, A²B, A², A², A, A², A², AB, and AB² had the most effect on moisture, acidity, stretch, L*, a*, b*, hardness, meltability, springiness, peroxide value (PV), cohesiveness, chewiness, gumminess, fracture force, adhesiveness force, stiffness, flavor, and overall acceptability, respectively. A formulation upon 20% oil and 10.88% carrot extract was found as the optimal formulation for pizza cheese containing carrot extract. At the optimal formulation, PV, L*, a*, b*, meltability, stretch, cohesiveness, springiness, gumminess, chewiness, adhesive force, flavor, texture, and overall acceptability at the optimum formulation were measured 2.23, 82.51, −3.69, 18.05, 17.86, 85.61, 0.41, 7.874, 23.7, 0.27, 0.61, 3.50, 3.95, and 3.65, respectively.

Effect of partial NaCl substitution with KCl on the texture profile, microstructure, and sensory properties of low-moisture mozzarella cheese

The effect of partial substitution of NaCl with KCl on texture profile, soluble Ca, K, Na, and P, and microstructure of low-moisture mozzarella cheese (LMMC) was investigated. LMMC batches were prepared using four combinations of NaCl and KCl salt viz., NaCl only, NaCl:KCl, 3:1, 1:1 and 1:3 (w/w); all used at of 46 g/kg curd and plasticised in 4% brine containing the above salt mixtures. Texture profile, microstructure, and percentages of soluble Ca, K, Na, and P were determined. There were no significant differences in hardness, cohesiveness, adhesiveness, and gumminess among the experimental LMMC batches. Environmental scanning electron microscopy images showed compact and homogeneous structure of LMMC at day 27 of storage; however, no significant difference was observed among the experimental LMMC batches. Hardness increased significantly in all experimental LMMC during storage. LMMC salted with NaCl/KCl mixtures had almost similar sensory properties compared with the control. There was no significant difference in creaminess, bitterness, saltiness, sour-acid, and vinegary taste among the experimental LMMC at the same storage period.

Influence of Starters on Chemical, Biochemical, and Sensory Changes in Turkish White-Brined Cheese During Ripening

Turkish White-brined cheese was manufactured using Lactococcus strains (Lactococcus lactis ssp. lactis NCDO763 plus L. lactis ssp. cremoris SK11 and L. lactis ssp. lactis UC317 plus L. lactis ssp. cremoris HP) or without a starter culture, and ripened for 90 d. It was found that the use of starters significantly influenced the physical, chemical, biochemical, and sensory properties of the cheeses. Chemical composition, pH, and sensory properties of cheeses made with starter were not affected by the different starter bacteria. The levels of soluble nitrogen fractions and urea-PAGE of the pH 4.6-insoluble fractions were found to be significantly different at various stages of ripening. Urea-PAGE patterns of the pH 4.6-insoluble fractions of the cheeses showed that considerable degradation of alpha(s1)-casein occurred and that beta-casein was more resistant to hydrolysis. The use of a starter culture significantly influenced the levels of 12% trichloroacetic acid-soluble nitrogen, 5% phosphotungstic acid-soluble nitrogen, free amino acids, total free fatty acids, and the peptide profiles (reverse phase-HPLC) of 70% (vol/vol) ethanol-soluble and insoluble fractions of the pH 4.6-soluble fraction of the cheeses. The levels of peptides in the cheeses increased during the ripening period. Principal component and hierarchical cluster analyses of electrophoretic and chromatographic results indicated that the cheeses were significantly different in terms of their peptide profiles and they were grouped based on the use and type of starter and stage of ripening. Levels of free amino acid in the cheeses differed; Leu, Glu, Phe, Lys, and Val were the most abundant amino acids. Nitrogen fractions, total free amino acids, total free fatty acids, and the levels of peptides resolved by reverse phase-HPLC increased during ripening. No significant differences were found between the sensory properties of cheeses made using a starter, but the cheese made without starter received lower scores than the cheeses made using a starter. It was found that the cheese made with strains NCDO763 plus SK11 had the best quality during ripening. It was concluded that the use of different starter bacteria caused significant differences in the quality of the cheese, and that each starter culture contributed to proteolysis to a different degree.

Rheology, Microstructure, and Functionality of Low-Fat Iranian White Cheese Made with Different Concentrations of Rennet

A batch of full-fat (23% target fat) and 3 batches of low-fat (6% target fat) Iranian white cheese with different rennet concentrations (1-, 2-, and 3-fold the normal usage) were produced to study the effect of fat content reduction and promoted proteolysis on the textural and functional properties of the product. Cheese samples were analyzed with respect to their rheological parameters (uniaxial compression and small amplitude oscillatory shear), meltability, microstructure, and sensory characteristics. Reduction of fat content from 23 to 6% had adverse effects on the texture, functionality, cheese-making yield, and sensory characteristics of Iranian white cheese. Fat reduction increased the instrumental hardness parameters (storage modulus, stress at fracture, and Young's modulus of elasticity), decreased the cheese meltability and yield, and made the microstructure more compact. Doubling the rennet concentration reduced values of instrumental hardness parameters, increased the meltability, and improved the sensory impression of texture. Although increasing the rennet concentration to 2-fold the normal usage resembled somewhat the low-fat cheese to its full-fat counterpart, it appeared to cause more reduction in yield. Increasing the rennet concentration 3-fold the normal usage produced a product slightly more elastic than the low-fat cheese with normal concentration of rennet. Increasing the rennet concentration to 2-fold the normal usage was useful for improving the textural, functional, and sensory properties of low-fat Iranian white cheese.

Effect of Enterococcus faecium on microbiological, physicochemical and sensory characteristics of Greek Feta cheese

Greek Feta cheese was prepared using as adjunct starter cultures Enterococcus faecium FAIR-E 198, E. faecium FAIR-E 243, and their combination. Numbers of enterococci in the control and in the batches containing E. faecium strains as adjunct starters rapidly increased until day 15 of ripening, and then remained constant. Both E. faecium strains positively affected the counts of non-starter lactic acid bacteria (NSLAB), micrococci and coliforms, while thermophilic cocci were not influenced. Moreover. E. faecium FAIR-E 243 enhanced the growth of mesophilic cocci and thermophilic bacilli. Physicochemical characteristics, such as pH, moisture, ash, salt in moisture and fat in dry matter (FDM) were not influenced by the addition of the E. faecium strains. The most pronounced effect was observed in the case of proteolysis. Both E. faecium strains, either as sole adjunct starter or in combination, increased the proteolytic index and the free amino groups concentration, and enhanced degradation of alpha(s1)- and beta-caseins in comparison to the control. Furthermore, the reverse-phase (RP)-HPLC peptide profiles of the water-soluble nitrogen (WSN) fractions were significantly affected by the addition of enterococci. The main volatile compounds produced were ethanol, acetate, acetone, acetaldehyde, acetoin and diacetyl, with highest amounts determined for ethanol, followed by acetate. Both E. faecium strains positively affected taste, aroma, colour and structure of the full-ripened cheeses, as well as the overall sensory profile. The present work emphasizes the technological significance of E. faecium strains and supports their use as adjunct cultures in the manufacture of Feta cheese.