Okara Washing Secondary Extraction Centrifuge Maximizing Soy Protein Recovery

Most soy milk plants lose between eight and fifteen percent of their soluble protein because the okara leaving the primary separation still carries extractable solids. The HD-DEC-380W is a dedicated second stage decanter that recovers this protein through counter current washing. After the first separation stage, the okara cake is re-slurried with a controlled quantity of hot water and fed into this machine, where the fresh water displaces the protein rich liquid trapped inside the pulp structure. The washed liquid, now carrying additional solids, returns to the front of the process, and the exhausted okara leaves with very low residual protein and low moisture.

The economic case for this machine is straightforward to calculate. A plant processing ten tonnes of soybeans per day typically produces four to five tonnes of okara, and every percentage point of protein left in that pulp represents a direct loss of product. Users who install a washing stage with the HD-DEC-380W report overall protein recovery climbing from about eighty five to above ninety five percent, which means additional finished soy milk from the same quantity of beans with almost no extra labour and only a modest increase in water and energy consumption. The payback period is usually measured in months rather than years, especially where soy protein prices are high.

• Counter Current Wash Design: The machine is engineered specifically for re-slurried okara rather than for primary separation, with a feed zone and bowl geometry optimised for dilute slurries that contain only a small amount of fine fibre at low solids concentration.
• Ratio Controlled Wash Water: A flow meter and modulating valve maintain the washing water to pulp ratio within plus or minus three percent of the recipe value, which is essential for repeatable extraction efficiency from one batch to the next.
• High Recovery Yield: Typical installations reach a total protein recovery above ninety five percent across both stages, and the residual protein in the discharged okara drops below two percent on a dry basis, which customers confirm through routine laboratory analysis.
• Gentle Low Shear Feeding: The inlet design avoids mechanical shear and air entrainment, so the recovered protein solution shows very little foaming and the globulin fraction retains its functional properties for tofu and beverage applications.
• Automatic Wash Water Compensation: When the feed flow drops, the controller automatically scales the washing water flow to maintain the ratio, which prevents over-dilution of the recovered extract and keeps the downstream evaporator load stable.
• Compact Two Stage Package: The unit can be supplied together with its own re-slurry tank, powder mixer and transfer pump as a matched package, so the washing stage is added to an existing line without redesigning the primary separation area.

This decanter is installed in the second extraction position of soy milk, tofu, soy protein concentrate and soy beverage plants, immediately after the primary separation and re-slurry stage. It is also used in plants producing yuba and dried tofu, where maximum solids recovery directly determines the economics of the operation, and in facilities that process other high protein slurries such as pea and mung bean milk. Because the design is compatible with CIP and with hot washing water, the washing stage can be integrated into an existing cleaning cycle without additional downtime, and the recovered extract can be routed either back to the primary tank or directly to formulation.

The machine is shipped assembled on a fumigated wooden base inside a seaworthy plywood case, with the bowl locked and the drive protected, and with all pipe connections capped and labelled. If the optional re-slurry package is ordered, the tank, mixer and pump are packed in a second crate together with the interconnecting sanitary piping and the instrumentation. The delivery includes the operation manual, the yield calculation worksheet, a spare gasket and screen set, material certificates and the factory test report. Warranty is twelve months from commissioning, and a process engineer can attend start-up to verify the wash water ratio and confirm the achieved recovery rate on site.