Let's make Soy Milk

The first steps in soymilk production: from soybeans to okara and jun

Soy is a fairly simple plant to grow; it can thrive in a variety of climates and soils. Once harvested, soybeans are brought to the production plant, cleaned in a grain elevator and dehulled by steaming the hull.

The grain elevator also measures the moisture content of the soybeans, which is typically from 45% to 55%. The clean beans must be soaked or cooked in the enzyme invalidator using high pressure and temperature to eradicate a specific enzyme indigestible for humans.

Final production processes and soymilk processing equipment – Jun’s journey

Once okara is extracted from jun, the liquid is boiled in a soymilk cooking machine. The beverage-in-making is then stored in a soymilk storage tank, a mechanism ensuring production quality management. For commercial soymilk, the next step is the addition of sugars, flavors, and vitamins.

In order to disperse flavors properly, all the ingredients are blended, adding them from a smaller tank to raw soymilk in a larger tank. Once sterilized, jun is passed to a homogenizer to break down fat particles and prevent them from separating from the liquid. The temperature then must be decreased to room temperature in the cooling tanks. The final step is aseptic packaging without exposing the product to air.

Soy milk quality: food safety and foam reduction

Another critical characteristic of high-quality soy milk is the absence of foam. Namely, soy contains a substance called saponin, which tends to foam in addition to protein. A practical solution is the use of defoamers, chemical additives that curb the formation of foam. The most effective defoamers for soy products are based on glycerin fatty acid ester, although defoamers can also be silicone-, water- or oil-based, etc.

Zero waste production – what to do with okara?

As a soybean byproduct, okara is associated with environmental problems due to large quantities of insoluble fiber. However, the industry has found ways to use the waste. Namely, it is used in agriculture as food for cattle and manure. Okara can also be used as a non-gluten flour alternative in baking goods.

Methods for elimination of disagreeable soy odor

Soymilk has a specific “beany” odor resulting from the oxidation of specific unsaturated fatty acids by the enzyme lipoxygenase during the seed grinding process. This odor is repulsive for many consumers; therefore, manufacturers are trying to eliminate it as much as possible.

There are several ways to go about it, such as disabling the LOX enzyme with heat by boiling or blanching the beans in hot water. Nevertheless, it is possible to eliminate the odor without a heat treatment by blending soybeans in water free of dissolved oxygen. It is achieved by adding glucose and glucose oxidase to water to consume oxygen.