Physical properties of food systems

Course Description

COURSE CONTENT

Rheological properties of food

Lecture (L): Introduction to rheological properties of food. Elasticity and plasticity.

Lab work (LW): Determination of elasticitical and plasticitical properties.

L: Rheological properties of liquid food. Factors Affecting Rheological Properties of

food. Rheological properties of the suspension. Viscoelasticity. Rheological properties of dough. Equipment for determining rheological properties.

Seminar (S): The Viscosity of Newtonian and non-Newtonian Systems. Rotational rheometer. Capillary rheometer. Transport of liquid food through pipelines. Darcys’ equation. Pump power calculations.

LW: Determination of rheological properties of food, application of rotational rheometer, application of a rheometer with a falling sphere. Application of capillary rheometer.

Texture and methods of determining the texture of solid food

L: Texture. Physical Properties of Powdered Materials.

LW: Determination of Physical Properties of Powdered Materials. Determination of Solubility parameters of powdered materials.

Thermophysical properties of food

L: Temperature change phases. Food properties at low temperatures. Changes of thermophysical properties below freezing point. The glass transition, Irruptive recrystallization, ante-melting.

S: Determination of freezing point using mathematical models. Assessment of latent heat, density, apparent specific heat, enthalpy and coefficient of thermal conductivity at phase change.

LW: Differential thermal analysis. Food Properties at Low temperatures.

Water in foods

L: The state of water in food. Relative and absolute humidity of food. Monolayer. Isotherm food sorption. Water activity.

S: Mathematical interpretation of water activity and sorption isotherms.

LW: Determination of food sorption isotherm at different humidity conditions in environment.

Coloid systems

L: Coloid systems. Surface activity. Foaming. Emulsification. HLB number of emulsifiers.

LW: Determination of foaming properties. Determination of emulsion stability.

Dielectric properties of food

L: Dielectric and Microwave Part of Electromagnetic Spectrum - Application at food. Effect of electromagnetic spectrum of a certain wavelength on properties food.

S: Determination of dielectric properties of food.

LEARNING OUTCOMES

• explain the difference between Newtonian and non-Newtonian liquids; changes in thermophysical properties of food at phase change; mathematical models that can determine the thermophysical properties of food at low temperatures; the terms of relative humidity, absolute humidity, monolayer and water activity in foods; the difference in the types of colloid systems most commonly represented in foods; the effect of processing on the stability of colloid systems; dielectric properties of food; heat transfer phenomena during food processing by heating
• define and explain the rheological properties of the dough
• select and apply a device for determining the rheological properties of the fluid
• measure and mathematically interpret the rheological properties of liquid, semi-liquids and suspension; dielectric parameters
• calculate the parameters for transporting liquid food through the pipelines
• determine power parameters of the pump for fluid transport; Physical Properties of Powder Materials; freezing and defrosting point using differential thermal analysis; the value of monolayer in the isotherm of sorption (experimentally); the stability of colloid systems
• enumerate textural properties of food
• mathematically interpret the textural properties of food; to interpret the values of monolayer
• identify equipment for determining the phase change temperature

To enrol in this course, the following courses must be completed:

• Physical Chemistry
• Principles of Engineering