Prouducts prossing Technology

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What are normal stresses in relation to a material's surface?

Stresses that act parallel to the surface

Stresses that can only compress the material

Stresses that act perpendicular to the surface (correct)

Stresses that affect the thermal properties of the material

Which of the following factors primarily influences thermal conductivity in foods?

Size of food particles only

Color and texture of the food

Moisture content and temperature (correct)

Chemical composition only

What is the typical thermal conductivity range for most foodstuffs?

0.6 - 0.7 J m-1 s-1°C-1 (correct)

0.5 - 0.6 J m-1 s-1°C-1

1.0 - 1.1 J m-1 s-1°C-1

0.8 - 0.9 J m-1 s-1°C-1

What does specific heat capacity indicate about a material?

The amount of heat required to change temperature of a unit mass by one degree (A) Signup and view all the answers

How is thermal resistance defined in relation to heat flow?

The temperature difference divided by the rate of heat flow per unit area (C) Signup and view all the answers

Which type of stress acts parallel to a material's surface?

Shear stress (D) Signup and view all the answers

What role does thermal conductivity play in food freezing processes?

It ensures uniform freezing to prevent spoilage (D) Signup and view all the answers

What is the unit for measuring specific heat capacity?

kJ/kg.°K (C) Signup and view all the answers

What is specific heat capacity mainly useful for?

Determining the energy needed for heating or cooling (A) Signup and view all the answers

How do electrical properties of foods influence food technology?

They affect microwave and ohmic heating methods. (C) Signup and view all the answers

What best describes the structure of most foods?

They consist of distinct physical phases in close contact. (A) Signup and view all the answers

What is a characteristic of gels in food?

They consist of large molecules coagulated in a solvent. (C) Signup and view all the answers

What does viscosity measure in fluids?

The resistance to flow when force is applied (B) Signup and view all the answers

Which structure is specifically created in meat analog development?

Fibrous structures (A) Signup and view all the answers

Which property does higher viscosity characteristic liquid exhibit?

It has more resistance to flow. (C) Signup and view all the answers

What generally characterizes powders in food?

They consist of fine, dry particles. (B) Signup and view all the answers

What is the primary purpose of size reduction in pharmaceutical applications?

To increase the surface area (A) Signup and view all the answers

Which of the following methods involves particles scraping against one another?

Attrition (C) Signup and view all the answers

Which law states that energy required to reduce size is constant for the same reduction ratio, regardless of the original size?

Kick's law (B) Signup and view all the answers

What is the effect of reducing particle size in suspensions within pharmaceuticals?

Reduces rate of sedimentation (C) Signup and view all the answers

Which size reduction process utilizes mechanical means like a hammer or bar?

Impact (B) Signup and view all the answers

Which factor primarily affects the ease of size reduction of a material?

Hardness of the material (A) Signup and view all the answers

What is the term for size reduction processes involving a sharp blade?

Cutting (A) Signup and view all the answers

Which law states that the energy expended for size reduction is proportional to the square root of the diameter of the particle produced?

Bond's law (C) Signup and view all the answers

What is the primary outcome of the spray-drying process?

Transforming liquid substances into fine powder (C) Signup and view all the answers

Which is a key characteristic of the freeze-drying process?

It lowers pressure to facilitate sublimation (C) Signup and view all the answers

In which industry is spray-drying commonly used to produce powdered ingredients?

Pharmaceuticals (D) Signup and view all the answers

What is the first step in the freeze-drying process?

Freezing the product to a temperature of -40ºC (D) Signup and view all the answers

Which of the following best describes the characteristics of the final product obtained from freeze-drying?

It retains its shape, texture, and nutrients (C) Signup and view all the answers

What role does the atomization stage play in spray drying?

It creates optimum conditions for evaporation (B) Signup and view all the answers

Which of the following materials can be produced using spray-drying technology?

Powdered metals (A) Signup and view all the answers

What happens during the sublimation stage of freeze-drying?

The solid ice turns directly into vapor (D) Signup and view all the answers

What does the equation γ = ΔρgR0/β represent?

The relationship of surface tension to various parameters (A) Signup and view all the answers

Which method is mentioned as more efficient than rotor/stator systems for emulsification?

Ultrasound (C) Signup and view all the answers

What is one of the primary benefits of ultrasound technology in food processing?

Improving nutritional value and safety (D) Signup and view all the answers

What is a primary mechanism by which larger drops become smaller in the ultrasound emulsification process?

Acoustic cavitation (A) Signup and view all the answers

In high-pressure homogenization, what does the premix consist of?

Combined nutrients and other ingredients in specific ratios (C) Signup and view all the answers

Which of the following is NOT a mentioned application of ultrasound technology?

Desalination (D) Signup and view all the answers

What is the primary role of ultrasound-assisted extraction in cosmetics?

To extract bioactive molecules from plant ingredients (C) Signup and view all the answers

The term 'microfluidization' in high-pressure homogenization refers to what?

The forced passage of a liquid through a narrow orifice (D) Signup and view all the answers

What is the primary function of high-pressure homogenizers?

To create a stable emulsion by breaking down particles (C) Signup and view all the answers

Which of the following industries commonly uses high shear emulsifiers?

Pharmaceuticals and cosmetics (A) Signup and view all the answers

What is a significant advantage of membrane emulsification over conventional emulsification processes?

It results in very fine emulsions with controlled droplet sizes (A) Signup and view all the answers

How do high-shear mixers create shear forces?

By rotating a stationary rotor and stator against each other (A) Signup and view all the answers

Which of the following processes is commonly NOT performed by high shear emulsifiers?

Freezing and refrigeration of products (B) Signup and view all the answers

What mechanism does membrane emulsification utilize to form emulsified droplets?

Drop-by-drop detachment from membrane pores (D) Signup and view all the answers

What pressure can high-pressure homogenizers exert during the emulsification process?

Up to 3,000 bar (C) Signup and view all the answers

Which of the following best describes the outcome of using high-pressure homogenizers?

A stable emulsion with increased surface area (C) Signup and view all the answers

Study Notes

Master Degree - Food & Cosmetic Products Engineering - Products Processing Technologies

Course Instructor: Pr. Abdelilah El Abbasi
Course Level: Master IPAC (S1)
Course Objective: To understand food and cosmetic product processing technologies, analyze production stages, and understand the impact of technological choices on product quality. Improve efficiency, sustainability, and competitiveness of associated industries.

What is a Process?

A process is a set of actions in a specific sequence, leading to a specific end (products and by-products).
The number of possible processes in any manufacturing industry is enormous.
Processes can be grouped into unit operations with similar purposes.
Unit operations were categorized early in the 20th century.

Process Flow Diagrams

Flow diagrams, also known as flow charts or flow sheets, are the standard graphical representations of processes.
They show the sequence of operations, raw materials, products, and by-products.
Additional information like flow rates, temperatures, pressures can be added.
These are also called block diagrams due to their use of rectangular blocks (operations).

Example: Potato Chips Process Flow Diagram

The example illustrates a potato chip production process with steps from storage to cooking.
Key stages include washing, peeling, sorting, slicing, washing, cooking, and conveying to the final product.

Standard Symbols in Process Flow Diagrams

Standardized symbols are used for frequently occurring equipment elements (pumps, vessels, conveyors, centrifuges, filters, etc).
Specific symbols represent different types of equipment, facilitating process visualization (e.g., reactor, distillation column, heat exchangers, plate heat exchangers, filters/membranes, centrifugal pumps, pumps, centrifuges).

Engineering Flow Diagram

The next stage in process development is the creation of an engineering flow diagram.
This diagram includes secondary equipment (measurement and control systems, utility lines, piping, etc), and details of measurement and control systems.
Used as a starting point for listing, calculating, and selecting all physical elements of a production line.
Provides a basis for plant layout development

Plant Layout

Plant layout (factory layout) is the most effective physical arrangement of industrial facilities, including machines and processing and service departments.
Crucial for achieving the greatest coordination and efficiency of materials, machines, methods, and manpower in the plant.

Table of Contents of Processing Technologies

The table lists various food and cosmetic production technologies (e.g., physical properties of materials, size reduction, filtration, centrifugation, extraction, frying, baking, roasting, crystallization, dissolution, mixing, extrusion, dehydration).
It also covers concentration, preservation, emulsification, and structure processes, emphasizing different aspects of food/cosmetic product processing techniques.

Physical Properties of Materials

The physical properties of foods and cosmetics are essential for product quality and stability.
Key qualities are texture, structure, appearance, and stability (e.g., water activity).
Quantitative knowledge of properties (thermal conductivity, density, viscosity, specific heat, enthalpy, etc) is essential for rational process design.

Mechanical Properties

Mechanical properties determine the behavior of food materials when subjected to forces.
Includes elastic, plastic, and viscous deformations.
Elastic deformation is momentary, plastic is permanent, while viscous is permanent flow.
Relevant for processing operations like conveying and size reduction alongside consumption aspects like texture.

Types of Stress

Normal stresses (compressive or tensile) act perpendicular to the material's surface.
Shear stresses act parallel to the material's surface.
Classification based on force direction and material relationships for processing understanding.

Thermal Properties

The thermal properties (thermal conductivity, specific heat, latent heat, diffusivity, phase transition and emissivity) are crucial for process engineering in the food and cosmetic industries.
Thermal properties influence how heat transfer occurs (conduction, convection, radiation) during heating, cooling, and phase transitions.

Thermal Conductivity and Thermal Resistance

Thermal conductivity (λ) determines the rate of heat transfer through a food material. It's influenced by moisture levels, temperature, and material structure.
Thermal resistance (R) is the ratio of temperature difference to heat flow rate. A lower resistance indicates better heat conduction and vice versa.
Essential for predicting heat transfer speed and product qualities while optimizing procedures.

Specific Heat Capacity

Specific heat (cp) is the amount of heat that must be transferred to change the temperature of a material by one degree at constant pressure.
Foods with higher specific heat require more energy to change temperatures. This is essential for process design.

Electrical Properties

Electrical properties of foods/cosmetics are relevant to microwave and ohmic heating methods.
These properties influence electrostatic force effects (especially in powders).
The primary electrical properties are electrical conductivity and dielectric properties.

Structure of Foods

Most foods are heterogeneous mixtures of different physical phases.
Structures are visualized through microscopy (microstructure/nanostructure).
Various structures include cellular, fibrous, gel, emulsion, foam, or powder types.

Food Structures (types):

Cellular structures (veggies, fruits, muscle).
Fibrous structures (meat).
Gels (jelly-like).
Emulsions (minute liquid droplets dispersed in another).
Foams (small bubbles in liquid).
Powders (fine solid particles).

Viscosity

Viscosity is the internal friction or resistance to flow in a fluid, affected by different layers of the fluid flowing over one another.
Higher viscosity fluids deform less easily compared to lower-viscosity fluids.
Viscosity differences (water versus honey) are important for food characteristics and manufacturing. Various materials have distinct degrees of viscosity.

Size Reduction

Size reduction involves reducing large solid units into smaller units/particles (coarse/fine).
This is widely used in pharmaceuticals, cosmetics, and food processing industries (e.g., comminution, grinding, milling, micronization).
Solid-state size reduction is called milling, while emulsification/atomization deals with liquids.

Objectives of Size Reduction

Increased surface area to enhance the therapeutic effectiveness of drugs.
Narrow size-range particles for easier and uniform mixing of powders.
Enhanced texture, flavor, and stability (e.g., improved shelf life) due to reduced sedimentation rates.

Mechanism of Size Reduction

Impacts (e.g., hammer mills).
Compression (e.g., roller mills).
Cutting (e.g., cutter mills).
Attrition (e.g., fluid-energy mills, jet mills).
Various mechanisms (impact, compression, cutting, attrition) cause the reduction or grinding of the material.

Laws of Size Reduction

Griffith theory: Force application depends on crack length.
Kick's law: Energy required for size reduction is constant for the same reduction ratio, regardless of the original size.
Rittinger's law: Energy for size reduction is directly proportional to new surface created.
Bond’s law: Energy for size reduction is proportional to the square root of the diameter of the particle produced.
Size reduction laws establish relationships between force and energy used depending on the material's structure, size, and properties for effective process engineering.

Factors Affecting Size Reduction

Selection of mills (considerations of feed, safety, economics, products).
Hardness of materials.
Fibrous nature of the material (difficulty in processing).
Elastic/sticky nature of the material (e.g., waxes, synthetic gums, resins).
Slipperiness (inverse of stickiness).

Melting Point and Hygroscopic Nature of Materials

Waxy substances, fats, and oils soften during size reduction (heat generation) requiring cooling.
Hygroscopic materials absorb moisture, hindering the milling operation and requiring closed systems.
Abrasive materials produce significant resultant powder with metal wear, often requiring closed-system or inert grinding mills.

Hammer Mill

Principle: Rapidly moving hammers on a rotor against a stationary material.
Parts: Casing, rotor with hammers, screen, hopper, screw feeder, and receiver.
Advantages: Rapid action, continuous operation, easy installation, and control of particle size.
Disadvantages: High heat buildup, unsuitable for processing sticky or hard materials, loud and continuous noises, potential screen clogging.

Roller Mill (Edge Runner Mill)

Principle: Crushing effect due to heavy rollers.
Construction: Two heavy rollers resting on a stone bed.
Advantages: Suitable for applications where continuous operation is required, minimal attention during operation.
Disadvantages: More operation space required compared to some other mills.

Fluid-energy Mill

Principle: Impact and attrition by a high-pressure flow of air or inert gas in a looped pipe, with nozzles; creating high turbulence causing grinding.
Parts: Loop pipe, nozzles for gas, classifier, and inlet for feed.
Working: High pressure flow grinds particles to a fine level.
Advantages: Useful for grinding temperature-sensitive materials (vitamins) and powders for food products (antibiotics), and high energy efficiency, preventing contamination.
Disadvantages: Tendency for agglomeration, high energy consumption.

Cutter Mill

Principle: Using sharp blades for chopping material.
Advantage: Suitable for brittle or fibrous materials; commonly for dry granulation.
Disadvantage: High-speed operation and likely heat generation.

Micronization

Micronization is a process reducing the particle size of materials to the micron range for improved characteristics (e.g., bioavailability, solubility, and functionality).
Relevant in improving the quality and functionality of products in food and cosmetics industries.
Improved texture, skin penetration, anti-aging, and sun protection are notable benefits.

Size Reduction from Liquids: Atomization

A process breaking down liquids into smaller particles (droplets) often using high pressure or high-temperature methods.
Important for food processing, pharmaceuticals, chemical manufacturing for increased surface area.

Spray Drying

A process converting liquid substances into fine powders efficiently via atomization of feedstock and contacting it with hot air.
Used for various product creation (instant coffee, milk powder, flavorings, and medicines).
Conditions are optimized for proper drying and product characteristic retention.

Freeze-drying (Lyophilization)

Preserves products by freezing, reducing pressure for sublimation, and then using heat to dry them.
Maintains the product's shape, preventing damage to texture, flavor and nutritional content.
Used for various foods such as fruits, coffee, and also for pharmaceutical products.
Follows several steps including freezing, vacuuming, then heating.

Emulsification

An emulsion is a liquid dispersed in another liquid, different from the other liquids present.
Emulsions can contain various phases with different densities.
Stabilized by solid particles or emulsifiers for better consistency.

Emulsification Techniques

Techniques include: ultrasound, high-pressure homogenization, high-shear mixing, and membrane emulsification.
Choice of technique is contingent on material properties, required emulsion stability, and potential for heat and shear sensitivity.

Particles as Stabilizers - Pickering Emulsions

Pickering emulsions are stabilized by solid particles (e.g., inorganic/organic) rather than surfactants.
The particles adsorb onto the oil-water interface, reducing interfacial tension and maintaining stability.
This prevents coalescence (joining) of droplets. Applicable in various sectors (food, cosmetics, pharmaceuticals).

Microfibrillated Cellulose as Emulsion Stabilizer

A natural material derived from cellulose fibrils.
Offers advantages such as biocompatibility, biodegradability, excellent properties, and various applications ranging from food products (texture modifier, stabilizer, emulsifier) to cosmetics (thickening, stability, and moisture barrier).

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge on the physics of food and material properties with this quiz. Explore topics such as thermal conductivity, specific heat capacity, and the unique characteristics of food structures. Perfect for students in food technology or materials science.