31285 - Unit Operations

Learning outcomes

The aim of this course is to provide the students with the knowledge of the main unit operations in food technology applied to raw materials, semi-finished and final foods. In particular, large space to the conservation and stabilization operations will be dedicated.

Course contents

Module 1:

Filtration: Darcy's equation; surface and depth filtration; filtration's parameters. Filtration operations: on membrane (microfiltration, reverse osmosis, ultrafiltration, nanofiltration), with deposit, depth filtration, cross-flow filtration. Physical principles and types of systems (pressure, vacuum, centrifugation), by type of operation, by type of filter medium. Filtration adjuvants. Polarization phenomena. Introduction to industrial applications. Tyndall effect; turbidimeters and nephelometers. Static and dynamic sedimentation: decantation, flotation, centrifugation (vertical and horizontal axis). Pressing: factors influencing extraction yield. Continuous (screw, belt) and discontinuous (pneumatic, piston) presses; pressing diagrams and cycles of positive and vacuum pressure. Unit operations based on thermodynamic transitions and equilibria: Distillation (Raoult's and Henry's law; liquid / vapor equilibrium curves in a closed and open system; simple and fractional distillation; still and distillation columns; solubility coefficient; azeotropism; hybrid products), solvent extraction. Use of low temperatures: refrigeration (refrigeration cycle, technical parameters, use of refrigerant gases) cryoconcentration, crystallization.

 

Module 2:

Stability factors in preserved food of plant and animal origin: Water activity and mobility of food systems. Polymeric approach and glass transition. Adsorption and desorption isotherms. Dependence of reaction kinetics on temperature (Arrhenius and WLF law). State diagrams. Unit operations based on the transfer of thermal energy (cooking, blanching, pasteurization, sterilization, freezing, deep freezing and IQF). Use of microwave, radio frequency and ohmic heating. Unit operations based on the transfer of thermal energy and matter (evaporation and dehydration); water removal technologies (drying, freeze-drying, spray-drying, drum drying, direct osmosis).

Readings/Bibliography

Singh, P.R., Heldman, D.R. Introduction to Food Engineering, Editor: Academic Press, 2014. https://nzifst.org.nz/resources/unitoperations/index.htm

Teaching methods

Frontal teaching, individual and group exercises which will allow the students to practice, use of spreadsheet, visits to food industries, seminars. Students with learning disorders and\or temporary or permanent disabilities: please, contact the office responsible (https://site.unibo.it/studenti-con-disabilita-e-dsa/en/for-students ) as soon as possible so that they can propose acceptable adjustments. The request for adaptation must be submitted in advance (15 days before the exam date) to the lecturer, who will assess the appropriateness of the adjustments, taking into account the teaching objectives.

Assessment methods

The final evaluation for "Operation Units" (6 CFU) for Viticulture and Enology or Food Technology BSc courses will be carried out as follows: a unique written test including topics from both modules (Module1/prof. Parpinello + Module 2/prof. Dalla Rosa) with 12 multiple choices and 6 open answers. For module 2 the open answers will include drawing and description of a flow diagram of a food / beverage preparation and a simple exercise on mass transfer.
The duration of the test will be 50 minutes. This modality will be available in all scheduted dates reported in ALMAESAMI for the session of January-February, June-July,September). The teacher in charge for the finale grade recording for Food Technology is Prof. Alessandra Bendini whereas for Viticulture and Enology is Prof. Giuseppina P. Parpinello. For grading purposes: for multiple-choice questions, 2 points for each correct answer, and for open-ended questions, a maximum of 1.5 points will be awarded. No points will be deducted for missing or incorrect answers. The use of support materials such as textbooks, notes, or computer media is not permitted during the exam. Calculators are permitted. The maximum score achievable for providing all correct and complete answers is 30 cum laude. A minimum score of 18/30 is required for a pass. This type of assessment is scheduled for all scheduled exam dates (January-February, June-July, September), wich are posted on ALMAESAMI. Registrations will not be accepted after the deadline. Students are encouraged to register for their preferred date and, in the event of a cancellation, to remove themselves from the list by the exam date. Failure to book on ALMAESAMI will result in the exam being taken on the desired date. Students with learning disorders and\or temporary or permanent disabilities: please, contact the office responsible (https://site.unibo.it/studenti-con-disabilita-e-dsa/en/for-students ) as soon as possible so that they can propose acceptable adjustments. The request for adaptation must be submitted in advance (15 days before the exam date) to the lecturer, who will assess the appropriateness of the adjustments, taking into account the teaching objectives.

Teaching tools

Projector, PC, videos, internet, visits to industries (when possible). Power point slides of the lectures will be available through the website https://virtuale.unibo.it 

Office hours

See the website of Giuseppina Paola Parpinello

See the website of Marco Dalla Rosa