RHEOLOGICAL AND FUNCTIONAL PROPERTIES OF CHEESE

T.A.MADUWAGE

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INTRODUCTION

•Cheese is nutritious food•Made mostlly from cow’s milk•Curded by lactic acid bacteria•A great source of protein and calcium•Contains additional nutrients

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TYPES OF CHEESE

•Asiago cheese •Bleu cheese •Cheddar cheese•Cream cheese •Feta cheese •Goat cheese •Swiss cheese •Vegetarian cheese 

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FUNCTIONAL PROPERTIES OF CHEESE

•Color- varies from orange to white•Meltability- depends on the casien network •Free oil formation- gives at greasy appearance•Browning- occurs at high temperature

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RHEOLOGICAL PROPERTIES OF CHEESE

Definition of texture “ all the rheological and structural attributes of the product perceptible by means of mechanical tactile and where appropriate visual and auditory receptors”

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DETERMINING MOLECULAR MECHANISM FOR TEXTURE

  

 

Rheological Properties(small – strain, non – linear

and fracture)   

Sensory tests

Materials & polymer models Chemical 

mechanism(Fillid gel,composite material,particle gel,polymer gel)

(Molecular changes &intermolecular bonding)

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ASSESSMENT OF PHYSICAL PROPOERTIES IN TEXTURE

•Rheological methods are employed•Rheology is the study of the deformation and flow of materials

σ = F /A ε = ΔL / L0

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• Perfectly fluid materials obey Newton’s postulate σ = μγ• Ideally solid materials obey Hooke’s law σ = Gγ• Cheese is a viscoelastic material • It exhibits both solid like and fluid like behavior

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Rheological tests• Three categories empirical- supply basic single point information imitative-try to imitate the forces and deformations

associated with a specific process fundamental- gives information as to the element

properties of a material

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Small strain rheological methods

•Used to define both the elastic and the viscous nature of cheese. •Cheese is a time dependent material• useful in understanding mechanisms of some endues functions. •used to determine changes caused by processing and storage parameters of cheeses

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LARGE STRAIN METHOD

• Used to determine cheese texture• These measurements occur outside of linear

viscoelastic region• Characterize the non linear and fracture properties of

the material• Relate well to sensory properties since mastication is

a large strain action

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SENSORY ANALTSIS FOR CHEESE TEXTURE

• Both tactile and kinesthetic properties• Two categories of sensory tests• Analytical tests include a powerful tool: descriptive

analysis• Descriptive analysis-differentiate cheeses

qualitatively and quantitatively• Descriptive analysis of cheese texture requires

descriptive technique and a texture language

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ANALYSIS OF CHEESE TEXTURE• Used to differentiate many cheese varieties • Considered by the consumer as a determinant of

overall quality and preference • Instrumental mechanical measurements have

correlated with the mechanical sensory perceptions• But lack in correlations with other terms

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FACTORS AFFECTING RHEOLOGICAL AND FUNCTIONAL PROPERTIES

• Can be categorized as belowProperties of milkCheese compositionCheese making proceduresPostmanufacturing processes

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