back to top
This article is not yet available in the language you selected
Soy milk
Article index
 | Production soy milk | |
| Cleaning | |
| Dehulling | |
| Blanching | |
| Grinding | |
| Filtering | |
| Mixing | |
| Sterilizing | |
| Homogenizing | |
| Cooling | |
| Packaging |
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.
companias
