Flaking is the process of using mechanical pressure to turn granular oilseeds into flakes. The purpose of flaking is to break the cell structure of the oilseeds, increase their surface area, and shorten the path for oil to flow out, facilitating oil extraction and improving the steaming and frying effect. The requirements for flaking are thin and uniform flakes with minimal powder and no oil leakage.

Why Flake Oilseeds?

Oilseeds consist of numerous cells, with a tough cell wall made of cellulose and hemicellulose. Oil and other substances are contained within these cell walls. To extract oil from the cells, the cell walls must be broken. Flaking uses mechanical pressure to break the cell structure and some cell walls. The thinner the flakes, the more cell structure is broken, and the better the oil extraction.

Factors Affecting Flaking Effectiveness

The main factors affecting flaking effectiveness include the properties of the oilseeds, such as oil content, moisture content, shell content, impurity content, particle size, temperature, and plasticity. Equipment type and operator skill are also important factors.

Oilseeds entering the flaking machine must be thoroughly cleaned of impurities, especially hard impurities like metal, to prevent damage to the rollers. Oilseeds must meet size requirements and have a uniform particle size to ensure even flaking. Large oilseeds should be crushed and softened before flaking to meet mechanical requirements.

During flaking, oilseeds deform under the pressure of the rollers. The resistance to pressure varies with moisture content. Dry seeds are brittle and crack easily, while moist seeds are more plastic and form flakes easily. High moisture content can cause oil to separate and make the flakes sticky, while very high moisture can reduce friction and stop the flaking process.

Temperature also affects the resistance to pressure. Lower temperatures increase elasticity and reduce plasticity, while higher temperatures increase plasticity and reduce oil viscosity, making oil extraction easier.

Oil content significantly affects flaking quality. High oil content and thin flakes can cause excessive oil to lubricate the rollers, reducing machine output or stopping operation.

High shell content in oilseeds increases resistance to pressure, widening the gap between rollers and reducing flaking quality. Impurities can cause roller collisions, increasing flake thickness and powder content.

Rollers wear over time and need to be ground. Grinding requires skill and should be done by trained professionals. Operators should regularly inspect production, especially flake thickness and material leakage, and adjust roller pressure as needed to meet production requirements.