Food processing can be very complex. Even the process of baking that may seem so straightforward involves many different steps that the food processor must consider in order to create high quality predictable outcomes. For example, steps may include flour blending, formulation and dough mixing, fermentation, dividing, rounding, proofing, molding, panning, baking, de-panning, cooling, packaging, stacking, storage and distribution. Each of these steps are considered as a unit operation. Food manufacturers must understand the scientific principles behind what’s happening at each unit operation to help them identify and solve problems that may arise. Some common unit operations and their purpose in food processing are listed below:
- Materials Handling: Safely harvesting and efficiently transporting the raw material to the processing plant with minimal injury
- Cleaning: Preparing the raw material for processing by removing hazards and unwanted materials that could lead to spoilage or food safety risks.
- Separating: Sorting and segregating foods based on physical properties. Separating allows for uniformity and enables utilization of components that have unique functional properties.
- Size Reduction: Reduction of food to small particles sizes such as cutting, chopping, grinding, milling and homogenizing of liquids
- Mixing: Uniformly combining food components to ensure uniformity.
- Heat Exchange: Use of heat or cold to control microorganisms or/and to change food properties e.g. pasteurization and freezing.
- Concentration: Removal of water from liquids to produce a thick concentrate that can later be reconstituted by adding back water
- Drying: Removal of water from foods, usually to produce a product of very low moisture e.g. production of onion powder from fresh onions
- Forming: Converting food product to various shapes using dies and molds e.g. during pasta making
- Packaging: Placing product in a container to facilitate handling and shipping, provide protection, to inform consumers, and to market the product
- Controlling: Utilization of manual and remote systems to control the food processing operation. Example of factors that can be controlled include time, temperature, pressure, and speed of material flow
In general, food processors take a step-wise approach in creating products that meet their specifications. It helps them to answer the question of “why”, whenever problems are encountered. Once the why is answered, it becomes easier to find a solution. You can practice to take this approach my making a product at home that you have probably made before without thinking too much about the science behind it. For example, this could be baking a cake, cooking a jam or jelly, or making homemade ice-cream. Prepare one of these products again, but before you do so, study the science behind each of the different steps that are required. This is the science-based approach that food scientists take to their jobs every day.
Reference: Potter, N. N. & Hotchkiss, J. H. (1998). Food Science, 5th edition. New York, NY: Springer Science+Business Media LLC.
