36 Questions
What is the principle of conservation of mass stated by Antoine Laurent Lavoisier?
Mass can be neither created nor destroyed.
What happens to the mass of a reactant and product in a chemical reaction?
The mass of the reactant and product remains the same.
What is the equation that represents the conservation of mass principle?
Rate of mass entering - Rate of mass exiting = Rate of mass accumulation
What is the characteristics of a closed system?
The composition of the system as well as its mass remains the same.
What is the main function of the Feed Mill SCADA?
To control the flow of energy in the system.
What is the category of processing operations that involves the conservation of mass?
Category I
What is the result of the conservation of mass principle in a chemical reaction?
The mass of the reactant and product remains the same.
What is the main idea behind the conservation of mass principle?
Mass can be neither created nor destroyed.
What is the period when losses in leafy vegetables are higher?
June to November
What is considered a loss if it is not used at all?
Any commodity
What type of loss is caused by disease organisms and insects?
Biological loss
What is the main reason for physico-chemical loss?
Faster rate of inherent processes
What is the purpose of the course for AB engineers?
To understand the engineering principles involved in food processing
What will AB engineers be able to do with an understanding of process engineering?
Develop new food processes and modify existing ones
What is the main focus of the Unit Operations course?
The engineering principles involved in food processing
What is the source of the information about postharvest losses?
Dela Cruz & Calica, 2016
What is a process defined as?
A set of actions in a specific sequence, to a specific end
Which category of operations involves minimal mass transfer and may require heat transfer?
Category II: Preservation of packaged material
What is the primary goal of food process engineering?
To combine all forms of physical processing into a small number of basic operations
What are the 'actions' in a process grouped into?
A relatively small number of operations
What is an example of a Category I operation?
Emulsification
Which category of operations requires actual testing to confirm assumptions and computations?
Category IV: Simultaneous heat, mass transfer
What is the term for a manufacturing process that starts with raw materials and ends with products and by-products?
A process
What is an example of a Category III operation?
Sorting by size or quality
How can a food engineering process be viewed?
Overall or as a series of units
Which category of operations involves minimal mass transfer and leaching?
Category III: Convert raw materials to product ingredients
What is a unit operation in food engineering?
Each unit in a food engineering process
What is an example of a Category IV operation?
Baking
What is the primary purpose of a batch type dryer in the food processing industry?
To remove moisture from food
Which unit operation involves the separation of food particles based on their size?
Mechanical Separations
What is the purpose of a semi-batch type dryer in the food processing industry?
To remove moisture from food
Which unit operation involves the transfer of heat from one food ingredient to another?
Heat Transfer
What is the primary purpose of a village type rice mill?
To mill rice grains
Which unit operation involves the reduction of food particle size?
Size Reduction
Which unit operation involves the absorption of gases by food ingredients?
Contact Equilibrium
Which unit operation involves the mixing of food ingredients?
Mixing
Study Notes
Losses in Leafy Vegetables
- Losses in leafy vegetables are higher during the hot wet period (June to November) compared to the dry cool months (December to March).
- A loss is only considered if it is not used at all.
Nature of Losses
- Mechanical losses occur due to unintentional damage sustained by the commodity (e.g., abrasion, punctures).
- Biological losses result from disease organisms and insects.
- Physico-chemical losses occur due to a faster rate of inherent processes in the produce or abnormalities in such processes (e.g., weight loss).
Unit Operations
- Unit operations are a set of actions in a specific sequence, to a specific end, in food processing.
- These operations are governed by the same basic principles and serve essentially similar purposes.
- The study of food process engineering aims to combine all forms of physical processing into a small number of basic operations, called unit operations.
Conservation of Mass
- The principle of conservation of mass states that mass can be neither created nor destroyed, but its composition can be altered from one form to another.
- The mass of a system remains unaltered, even in chemical reactions, but the composition may change.
Categories of Processing Operations
- Category I: Consolidation, mixing to produce a formulated product, with minimal mass transfer and possible heat transfer.
- Category II: Preservation of packaged material, with minimal mass transfer and some heat transfer.
- Category III: Conversion of raw materials to product ingredients, with minimal mass transfer (e.g., leaching).
- Category IV: Simultaneous heat and mass transfer, with actual testing required to confirm assumptions and computations (e.g., blanching, baking, drying, evaporation).
Classifications of Operations
- Batch operations: a fixed quantity of material is processed at a time.
- Semi-batch operations: a combination of batch and continuous operations.
- Continuous operations: a continuous flow of material is processed.
Important Unit Operations in Food Industry
- Fluid flow
- Heat transfer
- Drying
- Evaporation
- Contact equilibrium processes (e.g., distillation, extraction, gas absorption, crystallization, membrane processes)
- Mechanical separations (e.g., filtration, centrifugation, sedimentation, sieving)
- Size reduction
- Mixing
Explore the different types of losses that occur in leafy vegetables, including mechanical, biological, and physico-chemical losses, and how they vary by season.
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