Cashew Processing
Cashew nuts require meticulous handling during processing due to the presence of cashew nut shell liquid (CNSL)—a highly caustic substance that can cause serious skin burns. The entire processing sequence ensures the safe extraction of the edible kernel while preserving its quality and flavor. Here’s a comprehensive breakdown of each step:
Drying
Objective: Reduce the moisture content of freshly harvested cashew nuts.
Method: Nuts are spread out and sun-dried for 2–3 days.
Outcome: Lowered moisture levels enhance shelf life and prepare the nuts for subsequent processing stages.
Roasting or Steaming
Objective: Soften the outer shell and deactivate CNSL.
Methods:
Drum Roasting: Nuts are tumbled in a rotating drum over an open flame.
Steam Cooking: Nuts are exposed to high-pressure steam in closed chambers.
Shelling
- Objective: Extract the cashew kernel from its hard outer shell.
- Method: Shelling is done either manually by skilled workers or mechanically using automated equipment.
- Note: Care is taken to minimize kernel breakage, as whole nuts fetch a higher market price.
Drying the Kernel
Objective: Further reduce the moisture in the extracted kernels.
Method: Kernels are dried in hot air chambers at approximately 70°C for 6–12 hours.
Outcome: This ensures a crunchy texture and prevents microbial growth during storage.
Peeling
Objective: Remove the thin, brown testa (skin) that covers the kernel.
Methods:
Manual Peeling: Done by hand using specialized tools.
Mechanical Peeling: Air jets or machines may be used in large-scale operations.
Post-Peeling Process: Kernels are sorted and classified based on size, color, and appearance.
Grading
Objective: Categorize cashew kernels according to industry standards.
Types of Grades:
Whole Nuts: W180, W210, W240, W320, W450 (lower number = larger size).
Broken Pieces: Baby bits, splits, and other broken grades.
Scorched or Dessert Kernels: For use in cooking or value-added products.
Quality Control
Checks Involved:
Visual Inspection: Identifies discolored, moldy, or damaged nuts.
Moisture Testing: Ensures optimal dryness for long-term storage.
Aflatoxin Testing: Detects harmful mold toxins that can affect food safety.
Packaging
Objective: Preserve the freshness and quality of the final product.
Methods:
Vacuum Packing: Removes air to slow oxidation.
Nitrogen Flushing: Replaces oxygen with nitrogen to prolong shelf life.
Storage: Finished products are kept in cool, dry environments to maintain their flavor and safety.
Processing cashew nuts is a labor-intensive and technically sensitive operation that requires careful handling at every stage—from drying and roasting to shelling, grading, and packaging. The presence of caustic cashew nut shell liquid (CNSL) adds to the complexity, demanding safety measures and skilled labor. Each step plays a crucial role in ensuring the kernels are safe to eat, visually appealing, and long-lasting. With proper processing, cashews not only retain their rich flavor and crunch but also meet the stringent quality standards demanded by global markets. Ultimately, the precision and care involved in this process reflect in the premium quality of the final product enjoyed worldwide.