SE508748C2 - Methods to prepare and prepare a calcium-enriched soy drink for distribution - Google Patents

Abstract

A method of producing and preparing for distribution soya milk comprising mixing together shelled and finely-divided soya beans with water at a temperature between 60 DEG C and 90 DEG C. The mixture of finely-divided beans and water is ground and subjected to heating and cooling in order to encourage spore germination. This is followed by a sterilising heat treatment to kill any germinating spores. The heating also deactivates trypsin inhibitor and reduces tainting flavours. Trisodium citrate and tripotassium phosphate are added to the water beforehand so that calcium lactate can be added without the formation of a precipitate. After a sterilising heat treatment the milk is homogenised and then packaged under aseptic conditions into aseptic packing containers. The milk has a superior flavour and storage properties.

Description

508 748 There is thus a need for a rational, industrial way of producing soy beverages without disadvantages and problems of the kind associated with conventional process techniques.

An object of the present invention is therefore to fulfill these wishes and to provide a way to, without requiring high investment costs and complicated process equipment, easily produce soy beverages on a rational industrial scale and at the same time obtain a product with good taste and storage properties.

This and other objects are achieved by the present invention by the method initially described using peeled finely divided beans. By using the whole bean after peeling, in addition to the already mentioned benefits, a higher protein yield is achieved. About 90% of the total protein content, compared to a maximum of 70% for methods where said okara is removed.

The invention will be explained in more detail in the following with reference to the accompanying drawings in which Figure 1 shows a flow chart for producing soy beverage (according to the invention) based on soy powder, Figure 2 is a flow chart for making soy powder from soybeans.

Figure 1 shows six different consecutive steps (10-15) in the method according to the invention. Some of these steps may be combined with each other, but are shown and explained here separately.

In step 10, the soy powder is mixed with water. The purpose is to allow the soy particles to swell so that they are then easier to grind. The proportion between water and soy powder may vary, but is assumed in this example to be 1/3 soy powder and 2/3 water.

The proportions are weight based. The mixing time depends on the temperature, which is suitably 60-70 ° C but not more than 90 ° C. Under these conditions a mixing time of 10-15 minutes is sufficient.

LN C C * J GO The mixture is then passed through a grinder (preferably a colloid mill). The purpose here is to ensure good baling and to grind the soy particles to a suitable grain size for further grinding in a homogenizer.

In step 12, the mixture is heated to and maintained at 85-90 ° C for 30 minutes. The mixture can be diluted with water to facilitate pumping, etc. The heat treatment serves three purposes, namely to destroy or inactivate the heat-sensitive trypsin inhibitor, to reduce off-taste and a microbiological purpose. Through heat treatment, spores from the raw soybeans are prepared so that they can begin to grow when the temperature is lowered. Later, these growing spores are killed during a UHT treatment.

At step 13, the mixture is filled to 10-15 ° C and milk and other ingredients are added. The mixture must be kept at this low temperature for at least 2 hours. During this residence time, the mentioned growth of the spores takes place.

At step 14, homogenization and UHT treatment are performed.

The homogenization is necessary for a uniform distribution of the raw materials and as a final grinding of the soy powder.

The UHT treatment kills all bacteria and growing spores.

The UHT-treated product is finally filled under aseptic conditions into consumer packages made from sterilized packaging material.

The aseptic consumer packages are preferably made of a laminated packaging material of the type having a paper backing layer, outer waterproof thermoplastic coatings (preferably polyethylene) and an aluminum foil arranged between the inner plastic coating and the backing layer which gives the package good tightness to light and oxygen. Although the soy product at the time of packaging may have some off-taste, it decreases after a relatively short storage (10 days) in packages made from this packaging material. Accordingly, the packages are advantageous for producing a soy product without off-taste but with good storage properties in the manner according to the invention.

The soy powder (peeled finely divided soybeans) is prepared in the manner illustrated in Figure 2. Raw soybeans are sorted at step 20 and bad beans, stones, etc. are sorted out. After sorting, the beans are heated in warm air to reduce the moisture content to 5-7%.

At step 23, the beans are peeled and ground.

At step 24, the soy powder is packaged in plastic bags and stored in the plastic bags until the soy beverage is prepared.

In some cases, it may be of interest to fortify the soy drink with calcium. It has previously been considered impossible or possible only at pH values of 4-4.5 to fortify soy beverages with calcium before heat treatment. In experiments, the result has been precipitation of the product and small particles that give a sandy oroganoleptic feeling. In order to achieve a stable homogeneous calcium-enriched soy drink, it has furthermore been necessary to use expensive stabilizer in high concentration, which has increased the costs and thereby made these products economically unattractive.

In accordance with the present invention, the soy beverage can be fortified with calcium, without the aforementioned problems, by adding salts to the water to be mixed with the soy powder. Some trisodium citrate and tricalium phosphate are added to the water.

The proportions depend on the concentration of soy protein and calcium reinforcement and the heat treatment. For a beverage consisting of about 50% milk, 1.5% soy protein and calcium boost of 3.0-3.5%, the concentration of trisodium citrate should be 1.5% and of tricalium phosphate (K3PO4) 1%. Before packaging (when other ingredients such as milk and vitamins are also added) the calcium lactate is added.

Using this method, a mixture of 50% pure milk and 50% soy protein drink (or soy and other vegetable proteins) gives a calcium concentration of about or over 100mg of calcium per liter, which is comparable to milk. 508 748 From the description above it thus appears that the invention effectively solves problems and disadvantages previously associated with conventional technology. In particular, the invention makes it possible to produce calcium-enriched soy drink with good taste and storage capacity on a rational and industrial scale without the use of expensive complicated process equipment and without expensive additives which were previously necessary.

Claims (6)

508 748 PATENT CLAIMS 1. Methods of preparing and preparing for distribution a calcium-enriched soy beverage with good taste and shelf life properties by swelling peeled, finely divided soybeans in water to form an aqueous slurry which is then added for calcium enrichment and other additives selected for the manufacture of the soy beverage, sterilized by a heat treatment and packaged under aseptic conditions in distribution packages, characterized in that stabilizing salts are added to the water in order to prevent precipitation of the later added calcium-enriching additives. 2. A method according to claim 1, characterized in that calcium lactate is selected as the calcium-enriching additive. 3. A method according to claim 1 or 2, characterized in that said stabilizing salts consist of trisodium citrate and tricalium phosphate. 4. A method according to any one of the preceding claims, characterized in that the formed aqueous slurry is also added to milk and vitamins in connection with the addition of the calcium-enriching additive. 5. A method according to any one of the preceding claims, characterized in that the sterilizing heat treatment is a UHT treatment. 6. A method according to any one of the preceding claims, characterized in that the aqueous slurry is heated before the addition of said additives in order to activate spores present in the slurry.