This document discusses cheese texture, the factors that affect it, and methods for measuring texture. The major points are: - Texture is a primary quality attribute of cheeses and can vary between cheese types (e.g. mozzarella is stretchy, parmesan is crumbly). The casein matrix and entrapped fat globules are the major structural components. - Various factors influence cheese texture, including scalding temperature, curd fineness, stirring duration, acidity, pH, fat and water content. Lower pH and higher acidity result in harder texture. - Texture changes during storage due to proteolysis. Initially, cheese softens quickly then more gradually as peptides are cleaved

1. Cheese Texture
Muhammad Saad Haleem

2. Introduction
• Texture is the primary quality attribute of cheeses
• Cheeses offer a variety of textures For each cheese type.
“For example, Mozzarella cheese is “stretchy” or “stringy” and
Parmesan cheese is "crumbly,” etc.”
Major structure-forming constituent in cheese
• The casein matrix in which fat globules are entrapped.
• Water or serum is both bound to casein and fills interstices of the
matrix.
Factors contributing in cheese texture
• Scalding temperature
• Fineness of the curd
• Duration of stirring
• Acidity
• pH

3. Factors affecting cheese texture
• Lower pH of milk at the time of enzyme addition or that of the curd at milling
results in harder cheese.(shown in fig a).
• Low acidity weakens the protein bonds through charge repulsion, as the
negative charges on casein molecules increase with pH in the cheese
structure.
• Higher fat and water content tends to weaken the protein structure in the
cheese and vice versa.
• Increase in fat content results in smoother and softer cheese and increase in
casein content results in firmer cheese.

4. Effect of pH on cheese texture (figure A)

5. DifferentTerms: Describe CheeseTexture
SensoryTerm Definition
Adhesiveness Stickiness of sample in the mouth throughout mastication
Brittleness Breakability of the sample at the first bite
Creaminess The extent to which the cheese has a velvety mouthfeel
Crumbliness The ease of fragmenting cheese into small particles
Chewiness Number of chews required to swallow a certain amount of sample
Cohesiveness Amount of deformation undergone by a material before rupture when biting
completely through the sample using molars
Firmness The force required to compress the cheese with the
Finger.

6. DifferentTerms: Describe CheeseTexture
SensoryTerm Definition
Graininess The extent to which the cheese is bitty towards the end
of chewing
Hardness Force required to penetrate the sample with the molar
teeth
Long/Longness Tendency to fracture only after a relatively large
deformation
Smoothness The smoothness of the cheese against the palate as it
breaks down during mastication
Thickness In-mouth consistency assessed as the force developed by the tongue during the
compression of the food between the roof of the mouth and the tongue

7. Textural Changes during Storage
Texture of many cheeses change almost continuously after it is manufactured
due to the proteolytic action of the residual enzyme. Lawrence et al. (1987) list
the following three factors as having an effect on cheese texture during ripening:
• (a) pH at which whey is drained from the curd. This determines the
proportions of chymosin and plasmin in the cheese
• (b) Salt-in-moisture ratio that controls, along with temperature, the activity
of residual rennet and plasmin in cheese
• (c) pH of cheese after salting

8. • The textural changes in cheese during storage may be considered to
occur in 2 phases;
PHASE 1 (the first two weeks after manufacture)
There is a rapid change during which the casein network is greatly weakened when
only a single bond in about 20% of the αs1-casein is hydrolyzed. The resulting peptide
αs1-I causes the initial softening of the cheese. This peptide is present in all types of
cheeses, at least during the early stages of ripening.
PHASE 2 (the period subsequent to the first two weeks)
The proteolytic changes are fairly gradual. The extent of textural change during this
phase is based on the rate of proteolysis and increase in pH. As each peptide is
cleaved, two new ionic groups are generated. This reduces the amount of free water in
the matrix by increasing the solvation of the protein chains. Thus, as the Cheddar-type
cheese ages, it hardens, and the protein matrix becomes less cohesive.

9. •The most notable change with age, due to proteolytic
breakdown of the protein matrix, is;
 Decrease in fracture strain and springiness.
 Increase in creaminess.
•Texture development of cheese is affected by;
 pH (cheese pH has been described as the single most important factor that
influences the texture).
 Storage temperature.
 Humidity conditions of Storage.

10. Chadder Cheese
• As the Cheddar-type cheese ages, it hardens, and the protein matrix becomes less
cohesive.
• The changing texture of Cheddar cheese might be divided into three distinct stages
corresponding to the commercial classification of mild, medium, and mature Cheddar
cheese. (Hort and Grys, 2001)
• In fact, after 64 weeks the Cheddar cheese is very soft, having lost its structural integrity
due to extensive proteolysis (Hort and Grys, 2001)
Mozzarella Cheese:
• Mozzarella cheese is regarded as unripened cheese, it does undergo changes during
storage;
• Due to the proteolytic breakdown of αs1- casein in Mozzarella cheese, the protein matrix
is both reorganized and weakened, resulting in a softer, less elastic, and more meltable
cheese.
• Insufficient proteolysis due to high salt content can cause “Curdy” texture in Mozzarella
cheese (Olson, 1982).

11. Feta Cheese:
During Feta cheesemaking, a relatively high concentration of
rennet is used. This leads to high aggregation rate and a coarse
casein network that is responsible for the firm gel and cheese.
• In the Young Feta cheese, this firming effect is greater than the
softening effect of proteolysis.
• As storage time is prolonged, the proteolytic effect increases to an
extent that the cheese becomes softer and shorter

12. Measurement ofTexture
• Instrumental measurements of “mechanical” characteristics, those that are
manifested by the reaction of the foods to applied stress have been correlated with
sensory attributes fairly well.
• The ten most frequently used texture terms in the United States are:
 Crisp
 Dry
 Juicy
 Soft
 Creamy
 Crunchy
 Chewy
 Smooth
 Stringy, and hard.

13. • Texture measurement techniques can be grouped into
Subjective technique
Instrumental technique
Subjective Measurements:
• Subjective measurements or sensory evaluation are made by the trained taste panel.
Instrumental methods can be broadly grouped under the following three categories
i. Empirical
ii. Imitative
iii. Fundamental.
Empirical measurements
• Those tests that tend to relate a measured variable to a material property without a rigorous
scientific basis.
• Example: Penetrometer, Puncture test, and Ball-compressor tests.

14. Imitative Methods
• The method in which may also be called semi-fundamental methods, include
measurement systems that are used to make mechanical measurements with little
control of experimental variables.
• Example:- Probe type and size, Product shape.
• The imitative methods are perhaps the largest group of instrumented texture-
measurement methods.
Fundamental methods
• These methods are employ valid rheological test techniques, and the data are
analyzed using well-defined rheological, structural, and molecular theories.
• The fundamental test methods also yield results that are independent of test
instrument.
• Some fundamental tests that are popularly used for texture evaluation include
(Uniaxial compression, bending, and torsion tests) .

15. • Texture evaluation of cheese depend upon
i. Physical texture
ii. Sensory texture
Physical texture evaluation classified
i. liquid foods and Soft Cheeses
ii. Solid foods and Soft Cheeses
liquid foods and Soft Cheese
• Successful correlations of fundamental measurement of rheological properties and sensory
perception of viscosity or thickness, smoothness.
Solid foods and Solid cheese
• Present an additional challenge because they require work of mastication before their
texture can be perceived and even worse, the texture of solid foods changes during
mastication.
• Mouthfeel of cheeses and fracture stress and toughness is influenced by the lubricating
properties of the fats.

16. SensoryTexture Evaluation
• Involves an interaction between the food and the soft body tissues of fingers
and mouth.
• In instrumented measurements, only the food material is deformed.
Instrumented and other techniques are of restricted value in predicting the
product characteristics as perceived by the consumers

17. Texture Profile Analysis
The TPA test was performed using the General Foods Texturometer (GFT) that compressed
the food sample in two successive deformations.
1. by a flat plunger, to imitate the grinding action of the jaw, the plunger was driven.
2. by an eccentric at constant speed; but the plunger traveled with a sinusoidally varying
speed, coming to a momentary stop at both ends of the stroke. (Friedman et al.,1963).
There are three textural characteristics of foods
i. Mechanical
ii. Geometrical
iii. others
The mechanical properties were further grouped as
• primary properties (hardness, cohesiveness, viscosity, elasticity, and adhesiveness)
• secondary properties (brittleness,chewiness, and gumminess).

18. • The geometrical properties are those related to size and shape.
• the other properties are those pertaining to moisture content and fat content
(e.g., oiliness and greasiness) of the product

21. TPA testing of cheese