Purpose and Impact of Cooking on Oil Extraction

Cooking transforms raw oilseeds into cooked seeds through moistening, steaming, and frying. This crucial step in oil pressing aims to alter the seeds' microstructure, chemical composition, and physical state using heat and moisture. The goal is to increase oil yield and improve the quality of the oil and meal. Cooking breaks down oil cells, denatures proteins, aggregates oils, reduces oil viscosity and surface tension, adjusts seed elasticity and plasticity, and deactivates enzymes

1. Dry Cooking: 

Common in small workshops for producing strong-flavored oils like rapeseed, peanut, and sesame oil. Seeds are heated directly to around 200°C, enhancing flavor through Maillard reactions.

2. Moist Cooking: 

Used in large oil mills with vertical or horizontal steam cookers. It handles large volumes but produces less aromatic oil due to lower temperatures (around 100°C). Pre-treatment like rolling seeds is necessary for uniform moisture and temperature distribution.

Cooking effectiveness directly affects oil yield and quality. For example, dry cooking at higher temperatures can enhance flavor and yield, while moist cooking is more efficient for large-scale production but may require careful control of temperature and moisture to avoid issues like low oil yield or high residue.