The Core Classification: Protein and Fiber Content
Soybean meal is a valuable by-product created after extracting oil from soybeans. The fundamental basis for its classification in the commercial market is its crude protein content. This nutritional value is primarily influenced by one key factor: the inclusion or removal of the soybean hulls during processing. The hulls are the fibrous outer covering of the soybean seed and, when included, lower the overall protein percentage while increasing the fiber. Conversely, dehulling the beans before oil extraction results in a higher-protein, lower-fiber meal. This distinction is critical because it determines the suitability of the meal for different types of livestock. High-protein, dehulled meal is preferred for monogastric animals like swine and poultry, while lower-protein meal containing hulls is often suitable for ruminants.
Processing Methods and Their Impact
Another significant factor in how soybean meal is classified is the method used for oil extraction. The two main methods are solvent extraction and mechanical pressing.
- Solvent Extraction: This is the most common and efficient method, especially in the United States. It uses a solvent, typically hexane, to extract the oil, leaving less than 2% residual oil in the meal. This process, which involves cracking, dehulling (optional), and heating, is highly efficient and yields a consistent, high-protein meal.
- Mechanical Extraction (Expeller or Screw Pressing): This method involves heating and pressing the beans to physically squeeze out the oil. It is a less efficient process, resulting in a meal with a higher residual oil content, typically over 3%. The higher oil content provides more energy and makes the meal more palatable, which can be beneficial for certain animal rations, such as for dairy cattle. This is sometimes referred to as 'high oil' soybean meal.
Nutritional Quality and Standardization
Beyond basic protein and fiber percentages, the nutritional quality of soybean meal is also a key classification criterion. Adequate heat treatment during processing is vital to destroy naturally occurring anti-nutritional factors, such as trypsin inhibitors, that would otherwise hinder animal growth. Both under- and over-processing can negatively impact the meal's nutritional value. To ensure quality, the industry uses specific tests.
Some important quality indicators include:
- Urease Activity: A test that measures residual urease, which is an indirect indicator of active trypsin inhibitors. A high urease index suggests under-processing.
- Protein Solubility (KOH): Assesses potential overheating, which can make essential amino acids less available to the animal. Low protein solubility can indicate heat damage.
- Protein Dispersibility Index (PDI): Measures the amount of water-soluble protein in the meal, providing another reliable measure of proper heat treatment.
Manufacturers use these tests to ensure their products meet the established standards for quality, ensuring a consistent and reliable feed ingredient for their customers.
International Trade and Regulatory Classifications
For international trade and regulatory purposes, a more formal classification system is used, such as the Harmonized System (HS) code. This provides a universal standard for customs and tariffs. A recent European Union court ruling reaffirmed that soybean meal, as a residue from oil extraction, falls under HS code heading 2304. This distinguishes it from other animal feed preparations, which might fall under different, more restrictive headings, highlighting the importance of proper classification for economic reasons. Market segmentation can also classify soybean meal based on nature (organic vs. conventional), application (animal feed vs. food industry), and sales channel.
Comparison of Common Soybean Meal Types
| Feature | High-Protein Soybean Meal (Dehulled) | Lower-Protein Soybean Meal (With Hulls) | Full-Fat Soybean Meal |
|---|---|---|---|
| Processing | Solvent-extracted from dehulled beans | Solvent-extracted, hulls added back | Mechanically pressed from whole soybeans |
| Crude Protein (approx.) | 47-49% (as fed basis) | 44-46% (as fed basis) | Around 38% (as fed basis) |
| Crude Fiber (approx.) | Less than 3% | More than 6% | Depends on processing, generally higher than dehulled |
| Residual Oil | Typically below 2% | Typically below 2% | Often over 5% |
| Primary Use | Swine, poultry, aquaculture | Ruminants (cattle) | Specialized livestock, higher energy needs |
Conclusion
What is soybean meal classified as can be answered in several layers, each relevant to a different aspect of the supply chain. At its most basic, it is categorized by crude protein and fiber content, which is a result of whether the hulls were included during processing. Furthermore, the oil extraction method (solvent vs. mechanical) adds another dimension to its classification by affecting residual oil levels. Finally, for international trade, regulatory bodies apply specific tariff codes like the Harmonized System (HS) code 2304. These multi-faceted classification systems ensure that buyers and sellers worldwide can accurately identify, value, and regulate this crucial animal feed ingredient, standardizing a product that varies depending on its manufacturing details. For further information, detailed data sheets are available from industry-specific resources like Feedipedia.
