Unit Operations in Food Processing - PTP
Unit Operations in Food Processing - PTP
Unit Operations in Food Processing - PTP
Food Processing
Raw Materials
Meat, Eggs, Milk Cereal & Legumes Fruits & Vegetables Seafood Etc.
Food Processing
Products
These unit operations can stand alone & depend upon logical physical principles Examples ?
Materials Handling
Including : The variety of operations from harvesting Transportation Conveying the product from truck to bin
Concerning: Sanitary conditions Losses minimized Quality mantained Bacterial growth minimized All transfer and deliveries of materials must be on time
Materials Handling
Examples : Refrigerated trucking of perishable produce Conveying product from truck to storage All transfers & deliveries must be on time & that time kept to a minimum for efficiency & quality
Cleaning
Removal of dirt and bacteria from the food to maintain the quality of the product Using : brushes, high velocity air, steam, water, magnets, filtration The floors and walls of the processing facility must also be cleaned
Spray Washer
Shape Sorting
Separating
Basis: density, size, shape Cream separator - milk cream & skim ; based on the density difference between fat and nonfat solids of milk ; using a disc type centrifuge Clarification remove sediment and microorganisms centrifugally in a clarifier (a disc type centrifuge); example : recover yeast cells from the fermentation broth
Size Reduction
Using high shear forces, graters, cutters, slicers, example : emulsions with very small fat globule droplets are made in a homogenizer Equipments : grinder, slicer, chopper. Size increase : aggregation, agglomeration, gelation
Membrane Processes
Reverse osmosis -uses membrane with the smallest pore -separate water from other solutes -uses the highest pressure pump Ultrafiltration -larger pores -retain protein, salts and sugar -allowing smaller molecules to pass (permeate) Microfiltration -pores less than 0.1 micron -separate fat from protein, reduce microorganism from fluid systems
Size Reduction
Slicing Dicing Cutting Etc.
Mixing
Heat Transfer
Heating & cooling Pasteurization Sterilization Refrigeration Freezing Etc.
Thermal processing
Sterilization complete destruction of microorganisms, at least 121oC, 15 to destroy all spores Commercial sterility products may contain viable spores, but they will not grow under normal conditions Pasteurization comparatively low-energy thermal process; decreasing number of spoilage organisms present; shelf-life extension; product is not sterile & will be subject to spoilage
DRYING
Sun drying Cabinet drying (placed in trays and dried in a current of hot air), ex: raisins from grapes. Spray drying - applied to fluid products Freeze drying - for heat sensitive food - the moisture is removed by sublimation, ex: instant coffee
Drying
Forming
Some foods often need to be formed into specific shapes, for example: confectionary, snack foods, cereals, cheeses, variety breads and sausages.
Processes can include : Compacting, extrusion, molding with the application of binding agents, heat and pressure
Forming
Packaging
Used for : - protection from microbial contamination, dirt, insects, light, moisture, flavor changes and physical alteration - shipping - improving the usefulness of the product - helps with marketing of food product The kind of packages : - metal cans, glass/plastic bottle, paper, cardboard, plastic and metallic films.
Packaging
pressure, temperature, fluid flow, acidity, weight, viscosity, humidity, time, etc.
Overlapping Operations
A combination of unit operations to achieve the total proces. Production of :
Dried fruit :
Reference :