Application Note | CoaguSens™ Flex

Testing natural cheese meltability and functionality

Natural cheese functionality

Natural cheese is valued not only for its distinctive flavor and nutritional benefits, but also for its functional properties during cooking and processing. Among these, meltability plays a central role in determining cheese performance in applications such as pizza, baked dishes, and ready-to-eat meals. Functional behavior is influenced by cheese composition, microstructure, ripening stage, and manufacturing parameters, which together determine how cheese responds to heat and mechanical handling during food preparation.

Meltability: a key quality attribute in natural cheese

Meltability describes the extent to which cheese flows and spreads upon heating. In natural cheese, it depends largely on protein network integrity, moisture content, and the balance between fat and protein. During ripening, proteolysis weakens the casein matrix, allowing greater flow under heat. However, excessive proteolysis can cause over-softening and oiling-off, reducing the desirable elastic melt. Variations in pH, calcium content, and salt levels also alter the protein–fat interactions that control melt behavior.

Firmness and texture

Firmness reflects the mechanical resistance of cheese to deformation. In natural cheeses, it is shaped by the arrangement of casein micelles, moisture levels, and fat distribution. Firmer cheeses tend to exhibit slower melt and retain shape longer during heating, while softer varieties spread more readily. Texture changes naturally during ripening as enzymatic activity alters the protein network, reducing firmness and enabling better flow under heat. Manufacturers adjust factors like moisture-to-protein ratio and cooking conditions to achieve the target meltability for specific applications.

Consistency

Consistency refers to the uniformity and cohesiveness of melted cheese. Ideal melted cheese should flow evenly without breaking into lumps or releasing excessive oil. Factors influencing consistency include fat emulsification, protein breakdown during ripening, and salt concentration. Inadequate control of these factors may cause irregular melt or textural defects like graininess. Standardizing milk composition and closely monitoring ripening progress are essential steps for maintaining consistent melt quality.

Viscosity

Viscosity describes the resistance of melted cheese to flow under applied force. It determines how cheese behaves during stretching, pouring, or string formation in hot applications. Viscosity is controlled by the extent of protein hydration, fat distribution, and the degree of proteolysis. Cheeses with high moisture and moderate proteolysis generally exhibit lower viscosity and greater stretch. In contrast, over-ripened or low-moisture cheeses can become overly fluid or fail to form desirable strands.

Understanding these core functional attributes is critical for predicting how a natural cheese will perform in industrial or culinary applications. In the next section, we present a detailed evaluation of meltability in different natural cheese types, using a standardized approach to compare their heat performance.

Case Study: Testing meltability in natural cheeses

Instrument: CoaguSens™ Flex - Precision measurement of cheese meltability

CoaguSens™ Flex is an advanced analytical instrument designed for the dairy industry to evaluate the rheological and viscoelastic properties of milk gels and cheeses. It enables real-time measurement of enzymatic and acid coagulation kinetics in milk, while accurately quantifying gel firmness and structural evolution under controlled temperature conditions. The platform further supports meltability assessments of cheeses (natural or processed) by capturing temperature-dependent viscoelastic behavior, providing reproducible and reliable functional performance data.

CoaguSens™ Flex empowers food scientists, technologists, and process engineers to refine formulations, optimize enzyme activity and ingredient dosing, and adapt processing conditions. These capabilities ensure the consistent attainment of critical product attributes, including desired texture, firmness, and melt characteristics. By delivering real-time, accurate data, CoaguSens™ Flex supports the fine-tuning of recipes, the control of ingredient quality, and the adjustment of process parameters—ensuring consistent meltability and texture across production batches. The instrument measures the following parameters as a function of temperature:

the shear elastic modulus (G′): measuring the firmness of the gel;
the shear loss modulus (G’’): measuring the viscous behavior of the gel;
the loss tangent [tan(δ)]: defined as the ratio G’’/G’ indicating the proportion of viscous behavior compared to the elastic behavior of the sample.

Results

Figure 1: Natural cheese samples

Figure 2: Fresh Mozzarella cheese after 70 °C

Figure 3: Comparison of the melting profiles (time evolution of the elastic modulus or firmness) of Swiss, Cheddar, Mozzarella, Pizza Mozzarella and Fresh Mozzarella cheeses between 4 °C and 70 °C.

Figure 4: Comparison of the elastic modulus (firmness) of Swiss, Cheddar, Mozzarella, Pizza Mozzarella and Fresh Mozzarella cheeses at 4 °C and 70 °C.

Figure 5: Loss tangent [tan(δ)] and viscous behavior of Swiss, Cheddar, Mozzarella, Pizza Mozzarella and Fresh Mozzarella cheeses at 4 °C

Figure 6: Loss tangent [tan(δ)] and viscous behavior of Swiss, Cheddar, Mozzarella, Pizza Mozzarella and Fresh Mozzarella cheeses at 70 °C

Mozzarella

Fresh, soft, and mild-flavored, mozzarella is known for its smooth texture and excellent melting properties. Traditionally made from cow’s or buffalo’s milk, it is widely used in salads, baked dishes, and fresh preparations.

Mozzarella exhibits a pronounced sensitivity to temperature. The shear elastic modulus (G′), reflecting gel firmness, decreases markedly from approximately 150 kPa to 6 kPa as the temperature rises from 4 °C to 70 °C, indicating a substantial softening of the protein matrix. In contrast, the viscous-to-elastic ratio remains relatively stable during melting, with the loss tangent [tan(δ)] showing only a slight reduction from 0.6 to 0.5, suggesting that the balance between viscous and elastic behavior is largely preserved despite the loss of firmness.

Swiss cheese

Famous for its characteristic holes and nutty, sweet flavor, Swiss cheese is a firm, cooked-curd variety. It offers good melting ability and is popular in sandwiches, fondues, and baked recipes.

In Swiss cheese, the shear elastic modulus (G′) decreases markedly from approximately 150 kPa to 6 kPa as the temperature increases from 4 °C to 70 °C, reflecting a pronounced loss of firmness with heating. Unlike mozzarella, however, the loss tangent [tan(δ)] exhibits a substantial change, decreasing from 0.9 at 4 °C to 0.55 at 70 °C. This indicates that, in addition to softening, the relative contribution of viscous behavior diminishes with temperature, resulting in a more elastic-dominated response at elevated temperatures.

Cheddar cheese

A firm, aged cheese with a range of flavors from mild to sharp, cheddar is versatile in cooking. Its uniform texture and balanced melt make it a staple for sauces, snacks, and baked dishes.

Cheddar displays a pronounced temperature-dependent softening, with the shear elastic modulus (G′) dropping sharply from approximately 150 kPa to 3 kPa as the temperature increases. In contrast, the loss tangent [tan(δ)] remains relatively stable, decreasing only slightly from 0.6 to 0.5, indicating that the balance between viscous and elastic contributions is largely maintained despite the significant reduction in firmness.

Natural mozzarella

Crafted from fresh milk without processing into imitation forms, natural mozzarella has a clean, milky flavor and elastic texture. It delivers authentic melt and stretch ideal for artisanal and premium recipes.

Fresh mozzarella exhibits a marked reduction in firmness with heating, as the shear elastic modulus (G′) decreases from approximately 45 kPa to 3 kPa over the tested temperature range. Unlike aged cheeses, however, the loss tangent [tan(δ)] increases substantially, rising from 0.55 to 0.9, indicating a clear shift toward viscous-dominated behavior as the product softens and transitions into a molten state.

Pizza mozzarella

Formulated for consistent melt, stretch, and browning, pizza mozzarella is a natural cheese optimized for high-temperature baking, ensuring a perfect texture and flavor for pizza applications.

Pizza mozzarella shows a slower meltability over time. It exhibited a substantial decrease in firmness with heating, as the shear elastic modulus (G′) declines from approximately 100 kPa to 15 kPa between 4 °C and 70 °C. The loss tangent [tan(δ)], however, remains relatively stable, decreasing only slightly from 0.85 to 0.80, suggesting that while the cheese softens considerably, the balance between viscous and elastic contributions is largely preserved ensuring the functionality of this cheese.

Using precise measurement to improve natural cheese functionality

Conclusion

This study demonstrates the role of rheological testing in understanding and controlling the meltability and functionality of natural cheeses. Meltability, firmness, consistency, and viscosity were assessed as key determinants of cheese performance in culinary and industrial applications, with particular focus on how different varieties respond to heating. Using the CoaguSens™ Flex, we quantified the shear elastic modulus (G′), loss modulus (G″), and loss tangent [tan(δ)] to capture the balance between firmness, elasticity, and viscous behavior under thermal stress.

Across all tested cheeses, heating from 4 °C to 70 °C produced a marked reduction in G′, confirming the universal softening of protein networks with rising temperature. However, differences between cheese types were significant. Mozzarella and Cheddar showed strong decreases in firmness while maintaining relatively stable tan(δ) values, indicating that although they softened, the elastic–viscous balance remained consistent. In contrast, Swiss cheese not only softened but also shifted toward a more elastic-dominated response, with tan(δ) decreasing substantially. Fresh mozzarella behaved differently, showing both reduced firmness and a sharp increase in tan(δ), reflecting a transition toward viscous-dominated behavior during melting. Pizza mozzarella, designed for consistent functionality, displayed an intermediate profile: substantial softening with only slight change in tan(δ), ensuring stable performance under baking conditions.

These findings highlight that cheese functionality during melting is highly variety-dependent, governed by microstructure, moisture, proteolysis, and formulation. Importantly, the study illustrates that objective rheological measurements can accurately predict sensory and functional performance, bridging laboratory data with real-world culinary outcomes.

By incorporating precision tools such as CoaguSens™ Flex into R&D and quality control workflows, manufacturers can optimize formulations, ensure consistency across batches, and deliver cheeses tailored to specific applications. This approach strengthens both product quality and consumer satisfaction, supporting innovation and competitiveness in the dairy industry.

Testing processed cheese meltability and functionality

The viscoelastic properties of yogurt significantly influences the overall sensory experience of the consumer. A smooth, creamy consistency enhances mouthfeel and consumer satisfaction, serving as a key differentiator among brands. Viscoelasticity affects flavor perception, with variations in thickness and creaminess potentially altering the taste experience, making texture crucial for yogurt appeal and enjoyment.

Yield optimization journey – Phase 3 : Optimizing cheese yield for maximum ROI

Cheese is obtained from coagulating milk by separating the milk gel into solid curds and liquid whey. The milk gel is cut into small cubes to increase curds surface/volume ratio and allow whey expelling from curds, a phenomenon called syneresis. The objective of any cheesemaker is to optimize the retention of fat and proteins in cheese while the level of moisture is maintained at a controlled level.

Yield optimization journey – Phase 2: How to stabilize cheese yield

Cheese is obtained by coagulation of milk and subsequent separation of the milk gel into liquid (whey) and solid (curd) phases. An essential step of the cheesemaking process involves cutting the formed milk gel into small cubes to allow whey separation by increasing curd surface/volume ratio. Cutting time selection greatly affects the yield, moisture and quality of cheese. Cutting the gel too soon when the curd is not firm enough leads to lower cheese yield through increased curd fines and fat loss, whereas delayed cutting results in higher cheese moisture content due to reduced collapse of the gel.

Yield optimization journey – Phase 1: Measuring the impact of recipe changes on milk coagulation

Parameters such as temperature, pH, coagulant dosage, protein content and calcium chloride influence the way milk coagulates. Real time data provided by CoaguSens™ Flex help understanding and controlling the influence of technological parameters on coagulation kinetics and consequently on yield.