Principles of Food Engineering

A.Y. 2019/2020
Overall hours
Learning objectives
The course aims at providing students with the knowledge necessary for the interpretation and measurement of the phenomena on which the fundamental physical operations for the treatment of agricultural and food products are based. The course provides knowledge on the main unitary operations of food technology in terms of phenomenology, material and energy balances, kinetics, functional schemes of the main plants and optimization criteria. The course also aims to provide knowledge on mathematical relationships and models useful for solving numerical design and control problems.
Expected learning outcomes
At the end of the course the students will be able to evaluate and interpret physical phenomena and apply the related laws. Students will be able to tackle and solve numerical exercises in order to design and monitor heat transport operations, thermodynamics applied to gas-vapor mixtures, fluid transport, concentration by evaporation, pasteurization and thermal sterilization, drying, centrifugation, filtration and membrane separation, solid-liquid extraction. At the end of the course the students will know how to assess the suitability of plants and of the operating conditions of the treatments, define the conditions for optimization, and use proper technical language and terminology.
Course syllabus and organization

Single session

Lesson period
Prerequisites for admission
Students must have a sufficient knowledge of the subjects covered in Physics courses of High School, of Elementary Algebra and of Trigonometry; students must be familiar with physical properties and fundamental physical and mechanical laws related to the unit operations considered in the course; they must be familiar with the use of the scientific calculator.
It is highly recommended to have passed the exams of Calculation elements and Physics.
Assessment methods and Criteria
The exam consists of a written test, which includes the solution of exercises similar to those faced during course practice, and the answer to open questions on phenomena, theoretical aspects, plants and operating conditions of operations covered in the course. The exam will assess: knowledge of physical phenomena and of operations studied in the course, of relevant physical laws, of schemes and characterisitcs of the main plants; the ability to solve numerical problems related to the operations covered in the program; the acquisition of proper terminology and language. A test for each module will be held; students must pass the exam related to the first module to take the second part of the exam. Regirstration for the exam is through Unimia. The vote, expressed by a mark out of thirty, is obtained as the mathematical average of the two parts and is communicated through Unimia.
During the Covid emergency the exam will be held remotely, according to insctructions provided by the teachers.
Applied physics
Course syllabus
The structure of matter. Quantities and units of measurement. Communication of measurement results and errors. Dimensional analysis.
Heat flux. Temperature definition. Heat transport: definition of internal energy and heat. Conduction: Fourier law, thermal conductivity, steady and transient conduction, conduction through simple and composite walls. Convection: forced convection; natural convection; the calculation of convective conductance by dimensional analysis; the numbers of Reynolds, Nusselt, Prandtl and Grashoff and the correlations between them. Combined heat exchange for convection and conduction. Heat exchangers: types and energy balances; basic design of a heat exchanger. Radiation: the electromagnetic spectrum, the properties of waves; the main laws of emission (Plank's, Stefan-Boltzmann's and Wien's laws), heat exchange by radiation between objects of simple geometry.
The laws of perfect gases ( reminders). Mixtures of gases and vapours ( moist air). Physical quantities characteristic of humid air. Psychrometric diagrams. Main transformations of humid air. Air conditioning principles.
Definition of fluid. Gases and liquids. Ideal fluids and real fluids. Density. Pressure.
Static of fluids: Pascal's principle, Stevino's law, Archimedes' thrust, Torricelli's experience. Pressure gauges and barometers.
Dynamics of ideal and real fluids: flow rate, continuity equation, Bernoulli's equation. Continuous and localized pressure drop. Pumps: description, head, power.
Rheology essentials.
Teaching methods
The teaching form will be classroom lectures and classroom calculation exercises in the presence of the teacher.
Teaching Resources
Materials provided by the teacher available in Ariel site.
Suggested textbooks: R.P. Singh , D.R. Heldman, Principi di Tecnologia Alimentare, Casa Editrice Ambrosiana; Termodinamica e trasmissione del calore, Y.A. Cengel, McGraw-Hill; Elementi di fisica tecnica, Y. A. Cengel, J. M. Cimbala, R.H. Turner, McGraw-Hill; Heat Transfer. A practical approach, Y. A. Cengel, McGraw-Hill;
Meccanica dei fluidi, Y. A. Cengel, J. M. Cimbala, R.H. Turner, McGraw-Hill.
Unit operations
Course syllabus
Mass balances; solution of numerical problems. Energy balances in cooling and heating operations; properties of saturated steam; solution of numerical problems. Evaporation: mass and energy balances; evaporators; solution of numerical problems. Pasteurization and sterilization; death rate of microorganisms (I and II Bigelow's laws); kinetics of heat damage reactions, Arrhenius equation; evaluation of the sterilization effect of thermal treatments; optimization of thermal treatments; sterilizers and pasteurizers; solution of numerical problems. Equilibrium moisture content and water activity. Air drying: transformations of air-vapour mixtures; use of the psychrometric diagram; heat and material balances in air drying; dryers; solution of numerical problems; principles of freeze-drying. Sedimentation and centrifugal separation; centrifuges. Filtration: mechanisms of solid retention; filtering materials and aids; filters. Membrane separation (microfiltration, ultrafiltration, reverse osmosis). Solid-liquid extraction: single and multistage concurrent extraction, continuous countercurrent extraction; extractors.
Teaching methods
The teaching form will be lectures and calculation exercises held by the teacher by videoconference and by commented (audio) presentations.
Teaching Resources
Textbook: R.P. Singh , D.R. Heldman, Principi di Tecnologia Alimentare, Casa Editrice Ambrosiana. Suggested textbook: C. Pompei - Operazioni unitarie delle tecnologie alimentari, Casa Editrice Ambrosiana. Materials provided by the teacher available in Ariel site (
Applied physics
Practicals: 32 hours
Lessons: 32 hours
Professor: Ferrari Enrico
Unit operations
AGR/15 - FOOD SCIENCE AND TECHNOLOGY - University credits: 6
Practicals: 16 hours
Lessons: 40 hours