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Soy milk

Article index
 Production soy milk
 Cleaning
 Dehulling
 Blanching
 Grinding
 Filtering
 Mixing
 Sterilizing
 Homogenizing
 Cooling
 Packaging
Soy milk is an alternative for cow’s milk, made of ground soybeans mixed with water
The milk is very nutritive. It is rich in proteins and isoflavones, low in fat and cholesterol-free. Isoflavones, certain organic chemicals, are in several ways beneficial to one’s health.
Soy milk doesn’t contain lactose, which makes it safe for people with lactose intolerance. Because soy milk contains less calcium than cow’s milk, it is often fortified with calcium. Fortification with vitamin D and some vitamin B is also commonly done.

By using appropriate processing techniques the beany taste of soy milk can be reduced or eliminated. Nevertheless often flavourings, sugar and salt are added to make the milk more attractive for consumers.

In many recipes soy milk can be used as substitute for milk.

Production soy milk

In general, for the production of soy milk soybeans are used with less taste, which are slightly creamy, so the beany taste is avoided and a better texture is obtained.
Large soy beans with clear hilum are preferred. The producers often work directly with farmers, so a soybean that produces the best soy milk is grown.

Cleaning

First the soybeans are cleaned. Undesirable parts are removed using a destoner, gravity and sieves. After that the soybeans are polished and sorted by colour.

Dehulling

The cleaned soybeans are steamed and mechanically split in half. By this the bean looses its hull. These hulls are sucked off and processed in animal feed. In this way only the cotyledons are left, which contain all the nutritient elements for the soy milk.
An additional benefit of this process is the change in lecithin composition of the soybean, through which the emulsion stability of the soy milk increases.

Blanching

Next the soybeans are blanched in water of 85 to 90°C during 15 to 20 minutes. Because of this the soybean becomes digestible and lipoxygenase is inactivated. In this way oxidation of the present polyunsaturated fatty acids is prevented. By absorbing water the bean swells, becomes softer and therefore better processable.

Grinding

The hydrated soybeans are grinded with soft and cleared water in two steps. The weight proportion between water and beans has to be around 10:1. This ends in a white slurry with minuscule particles. Due to the grinding all the valuable nutrients are released into the water, which leads to a milky oil-in-water emulsion. By homogenisation the release of nutrients is increased, because of the extension of the product surface.

Filtering

The insoluble particles of the soybean are removed with a decanter. These insoluble parts are pressed against the surface by centrifugal acceleration and are carried out of the decanter with an internal screw. The thick soy pulp of fibers that is removed is called okara and has to contain as less water as possible.
After addition of water it is possible to pass the removed okara through a second decanter. The so produced wash-water can be returned and used for grinding the soybeans with water. In this way the yield might increase with approximately 10%. The protein content increase even from 4 to 5% in weight. After drying, okara is mainly used in animal feed.

Mixing

In a large tank the other ingredients are added to the soy milk and the total is mixed well.

Sterilizing

It is possible to extend the shelf life of soy milk by pasteurization or sterilization.
After pasteurization, combined with cold storage, soy milk can be stored during 8 weeks. But often UHT-sterilization is applied. The soy milk is heated by using steam injection during 5 seconds at 145°C, after which flash cooling occurs. This flash cooling at the same time removes off-flavours.

Homogenizing

To prevent creaming of fat particles, the hot soy milk is homogenized after sterilization.

Cooling

Using a plate heat exchanger the hot, homogenized milk is cooled down to room temperature.

Packaging

Soy milk is often packed through aseptic filling. The cooled soy milk is transported to the packaging machine, where it is wrapped in a cardboard packaging and immediately sealed. From here the packs are automatically packed in boxes and placed on a pallet.

User comments

2007-05-01 13:07:54

Name: editor
A relation in Nigeria wants to improve the quality of their soy milk in terms of shelf life and texture and would like to get recommendation on sources of quality emulsifier, stabilizer and preservatives.
Please contact the editor at info@hyfoma.com

Eine Relation in Nigeria möchte die Qualität ihrer Sojabohnenölmilch in Lagerbeständigkeit und Struktur ausgedrückt verbessern und möchte Empfehlung erhalten über Quellen des Qualitätsemulsionsmittels, des Stabilistors und der Konservierungsmittel.
Treten Sie bitte in Verbindung mit dem Herausgeber an info@hyfoma.com.

Een relatie in Nigeria wil de kwaliteit van hun sojamelk betreffende houdbaarheid en textuur verbeteren en zou graag aanbeveling ontvangen over een kwaliteitsemulgator,
stabilisator en conserveermiddelen.
Voor contact: info@hyfoma.com

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process description

soy milk

Soy milk is an alternative for cow’s milk, made of ground soybeans mixed with water The milk is very nutritive. It is rich in proteins and isoflavones, low in fat and cholesterol-free. Isoflavones, certain organic chemicals, are in... read full description