FI72147C - FOERFARANDE FOER FRAMSTAELLNING AV SOETNINGSMEDEL. - Google Patents

Description

72147 1 Method for the preparation of sweetening air, Förfarande för framställning av sötningsmedel 5

The present invention comprises a process for preparing a sweetener.

Lactose can be separated from any of its tallow dairy products, such as e.g. whole milk, skimmed milk, buttermilk, whey », curd. Of particular interest is the recovery of lactose from whey, which is often considered a useless by-product.

Lactose has a weakly sweet taste and when lactose is used as a sweetener it must be converted to sweeter sugars Glu-15 and galactose. It is known to carry out such conversion by hydrolysis with an acid, an ion exchanger or an enzyme. Such a process is described, among others, in a hydrolysis process, for example, in the Journal of Dairy Science, Vol. 64 pp. 1759-1771, "Beta-Galactosidase: A Review of Recent Research," M L 20 Richmond, J J Gray, and C M Stine.

However, such previously known methods for converting lactose to glucose and galactose have taken place with a relatively low dry matter content (KA content) and / or a relatively low degree of hydrolysis, and the rate of conversion in the hydrolysis has been low. It has been found that it was not possible to hydrolyze lactose at a dry matter content of more than 20-40%, which is why the degree of hydrolysis or the rate of change in hydrolysis has been unsatisfactorily low. Due to the low degree of hydrolysis, the sugar solution obtained by the known methods contains, in addition to glucose and galactose, also a certain amount of residual lactose, which, especially during long storage and at low temperatures, is at risk of crystallization. The low concentration of KA or the low degree of hydrolysis makes the methods economically disadvantageous and causes the final product to become very dilute or to have a composition that needs to be further processed to become useful for many purposes.

2,724,7 1 A process for hydrolyzing lactose is also known from U.S. Patent 4,067,748. According to this method, lactose is hydrolyzed by means of a strongly acidic cation exchanger, preferably by means of a strongly acidic polystyrene ion exchange resin. In the patented process, the hydrolysis can take place at a dry matter content of 20-40%, e.g. 30%, and the hydrolysis takes place by means of an ion exchange resin having a very low degree of crosslinking, preferably a degree of crosslinking of between 0.5 and 5%.

The above-mentioned patented process also uses lactose, the dry matter content of which is so low that it is not directly usable for many purposes, but must be further processed, such as by evaporation. Further, an ion exchange resin with a very low degree of crosslinking is used, which is possible and which may be suitable at the prevailing low dry matter content, but which on the contrary would not be practically possible at a higher dry matter content due to the osmotic pressure at a higher dry matter content. that the ion exchange resin beads are in danger of breaking and thus damaged.

20

According to the patent, the conversion of lactose takes place by further mixing the lactose together with the ion exchange resin, which causes the ion exchange beads to break and wear, alternatively it is shown that the lactose to the top of the column.

The known methods are thus disadvantageous partly because it is necessary to work with a relatively low dry matter content of lactose, partly also because it has proved necessary or necessary to carry out hydrolysis with an ion exchange resin having a very low degree of crosslinking, i.e. one with a high dry matter content. tends to break down and because process 35 is run with mixing lactose and ion exchange resin, which measures together result in apparently long conversion times of lactose to glucose and galactose.

It 3 721 47 1 It could be assumed that the use of an ion exchange resin with a higher degree of crosslinking than mentioned in previously known publications or the conversion of lactose with a higher dry matter content or the conversion of lactose by passing it through a solid ion-5 exchange pulp bed would lead to longer conversion times from lactose to glucose or galactose or alternatively to lower degrees of hydrolysis while maintaining the same running time, but it has surprisingly proved that this is not the case, but that higher dry matter concentrations and higher ion exchange masses with a higher degree of crosslinking can be used according to the invention. by carrying out the conversion in a solid ion exchange bed and nevertheless obtain surprisingly short conversion times and a very high degree of hydrolysis.

The object of the invention is thus to provide a new process for the preparation of a sweetener from lactose, which process enables the practical and economical preparation of the desired sweetener.

Another object of the invention is to provide a process in which the dry matter content of the lactose solution can be kept substantially higher than hitherto possible, and in which the dry matter content of the final product remains correspondingly higher than previously proved possible without evaporation or further hydrolysed product treatment.

25

It is a further object of the invention to provide a process for preparing a sweetener from lactose which maintains a substantially higher dry matter content than has previously been the case, obtains a higher degree of hydrolysis than previously common and in which the process can be run so that the rotation speed is substantially faster than before. .

The process for preparing a sweetener according to the invention is mainly characterized in that lactose with a pH of less than 7.35 is dissolved in water at a temperature of 80-150 ° C or preferably 90-120 ° C.

at a temperature to a dry matter content of 40-80% or preferably 50-60%, or a lactose permeate having the same dry matter content is heated to the same temperature of 4 72147 "L, after which the resulting lactose solution is hydrolyzed by co-pressing the lactose solution through an ion exchange bed formed with a degree of crosslinking of the cathicine exchange bed of 5.5-10%, thereby causing the conversion of lactose to glucose and galactose, and that the hydrolysis is carried out to a degree of hydrolysis of 40-100% or preferably 70-90% at a flow rate of 2.0-0 , 5 petit volumes per hour, corresponding to a conversion time of 0.5-2 hours from lactose to glucose and galactose, after which the resulting glucose-galactose product is cooled to 10-20 ° C and taken for immediate use, interim storage or further processing.

The process according to the invention starts from an aqueous solution of lactose with a dry matter content of 40-80%. Preferably, the dry matter content of the lactose solution 15 is between 50-60%. If the lactose is dissolved in water, the temperature is raised between 80 and 15 ° C or preferably between 9 ° C and 120 ° C. At high temperatures, lactose dissolves more completely and thus a higher ΚΛ content is obtained than at lower temperatures. The high KA content of the lactose solution has the advantage of obtaining a concentrated solution which does not need to be evaporated and which gives the process a higher capacity. Depending on the starting conditions under which the lactose is prepared, the pH of the lactose solution may vary, but normally the pH is less than 7 and preferably 5-6.

25 The lactose solution may be filtered to clarify the solution, but this is not absolutely necessary, but the lactose solution can be further processed immediately after dissolution in water to break down the lactose into glucose and galactose.

This further treatment of the lactose solution takes place with an acidic heterogeneous catalyst, in this case hydrolysis, in which the lactose solution is treated with a strongly acidic cation exchanger, e.g. polystyrene sulfonic acid or some other polymer-based ion exchanger. In order to work with said high dry matter concentrations and at the same time to maintain high rotational speeds in the hydrolysis of lactose to glucose and galactose, a suitable cation exchanger for this purpose must have a relatively low degree of crosslinking, for example 5.5-10% or preferably 5, 5-6%. The cation exchanger acts here as a heterogeneous catalyst in which hydrogen ions cleave lactose into glucose and galactose. The heterogeneous acid catalysis is carried out at a temperature of 80-150 or preferably 90-120 ° C. Depending on how long the lactose solution is kept in contact with the cation exchanger, the process can be run at a degree of hydrolysis of between 40% and practically 100%. For commercial use, in order to maintain the greatest possible sweetness and best taste, the catalysis is suitably run to a degree of hydrolysis of about 70-90%. With a degree of hydrolysis of less than 70-80%, there is a risk that lactose and / or galactose will crystallize out during long storage and at low temperatures. If it is further desired to increase the sweetness of the hydrolyzed lactose solution, some additional lactose may be added to enhance the sweetness of glucose and galactose. When the lactose solution is combined with a strongly acidic cation exchanger, the acidity of the lactose solution increases accordingly and the effluent glucose-galactose product may have a pH of 1.5-2.5. It can be considered an advantage that the glucose-galactose solution has a relatively low pH, whereby microbial stability is improved at low pH.

Starting from a lactose solution with a KA content as high as 40-80 or preferably 50-60%, a high capacity and a flow rate of 0.2-2.0 petit volumes per hour are obtained for the process, as far as possible keeping the degree of hydrolysis above 80%. This flow rate is substantially higher than previously possible.

Despite the high temperature prevailing throughout the process, the risk of caramelization is low due to the high flow rate and rapid reaction, and the finished hydrolyzed product contains very small and negligible amounts of caramelized products.

To further improve the taste of the finished hydrolyzed glucose-galactose product and to remove any caramelized substances, the sugar product can be clarified, for example, by filtration through activated carbon. However, such clarification is only necessary for certain products, i.e. when a clear and colorless product is desired.

6 72147 1 If necessary, the finished sugar product can also be evaporated, but since the KA content is as high as 4U-80% or preferably 50-60%, evaporation is usually not necessary. The finished hydrolyzed product normally has a pH of 1.5-2.5. When applying the sugar product 5 to its future range of use, the pH can be raised if necessary.

The prepared sugar product is well suited for many different purposes, for example for use in foods such as various pastries, beverages such as beer, soft drinks, all kinds of canned food for which a certain sweetness is desired, cheese products such as cheese sauces, spreadable cheeses, cream cheeses, confectionery and in dairy products such as condensed milk, sour milk products, sour curd, yoghurt, dry mixes such as baking mixes, pancake mixes, salad dressings, sausages, burgers, soups or ice cream sweeteners.

In addition to this, many other areas of use are possible. The product produced thus has a high KA content and a high conversion rate, and it is possible to run the process according to the invention in such a way that a very high degree of hydrolysis is obtained for the product.

20

It can be shown that in cm it is very possible to control the degree of hydrolysis to a couple of percent by varying the petit volumes, to. the conversion time of lactose to glucose and galactose.

The following are some examples of the method according to the invention. In all examples, equipment has been used to handle 100 kg of lactose solution, and since the following examples only give the weight of the finished product, it is required that in all cases 100 kg of lactose solution be introduced and treated.

30

Example 1 40 kg of whey powder made from whey was added to 65 kg of 80 ° C water. This temperature was maintained until most of the lactose was dissolved, after which the lactose solution was treated vigorously with a hnp base with a polystyrene-sulfonic acid-based cation exchanger having a degree of crosslinking of 8%. The hydrolysis was run to a degree of hydrolysis of 40%, 722147 L, after which the finished hydrolyzed product was taken out and analyzed. The reaction rate corresponded to 0.5 petit volume. The product had a brownish-yellow color and a faint caramel taste. After filtration through activated carbon, the tan color and virtually 5 caramel flavors disappeared completely and the final product was somewhat sweet. After storage in a refrigerated state at a temperature below 10 degrees, the product became cloudy afterwards as the unmodified lactose crystallized and thus gradually sank to the bottom.

Example 2 65 kg of whey made from whey was dissolved in 35 kg of water at 97 ° C. After all the lactose was dissolved in water, the pH was measured to be 5.51. At a maintained temperature of 97 degrees, the lactose solution was treated with an ion exchange pulp having a degree of crosslinking of 5.5%, which was a strongly acidic cation exchanger. The hydrolysis was run to a degree of hydrolysis of 96%. Immediately after hydrolysis, the pH was measured to be 1.82. The finished product had a clean, sweet taste without a clear off-flavor. The color was slightly yellowish. After clarification with activated carbon-20, the product was clear and completely free of off-flavors. The conversion rate according to this example corresponded to one petit volume per hour. Due to the high degree of hydrolysis, no crystallization could be observed even during long-term storage at low temperature.

Example 3 80 kg of lactose made from whey was dissolved in 20 liters of 140 degree water at a pressure of 3.10 bar. The pH of the lactose solution was measured to be 5.0. While maintaining the temperature at 140 degrees, the lactose solution was treated with a strongly acidic polystyrene-sulfonic acid-based cation exchanger having a degree of crosslinking (DVB content) of 6% and hydrolysis was carried out to a degree of hydrolysis of 92%. The reaction rate corresponded to a bed volume of 1.1 hours. The finished product was brownish and had a faint caramel taste. The product appeared to be suitable for 35 bakery purposes without clarification. A certain tendency to crack was observed in the polystyrene sulfonic acid beads, which is presumed to be due to the high osmotic pressure generated at the high dry matter content in this example.

8 72147

1 Example A

50 kg of lactose made from cottage cheese whey was mixed with 50 kg of 100 degree water. The pH of the lactose solution was measured to be 5 ^> 5. Maintaining the same temperature, the lactose solution was treated with an acidic cation exchanger having a degree of crosslinking of 10% and hydrolysis was run to a degree of hydrolysis of 95%. The conversion corresponded to a flow rate of 0.72 petit volumes per hour. The finished product was slightly yellowish and had good sweetness without off-flavors. After clarification with activated carbon, a clear colorless product was obtained without any noticeable off-flavor. The product was considered to be well suited as a sweetener for beverages, for example beverages in the brewing industry such as beer or soft drinks e.g. Despite the relatively high degree of crosslinking of the cation exchanger, the hydrolysis could be driven to a degree of hydrolysis at a flow rate of 95% at 0.7 petit volumes per hour, corresponding to a reaction rate of less than 1.5 hours from lactose to glucose and galactose.

Example 5 71 kg of lactose powder made from whey were dissolved in 29 kg of water and mixed at a temperature of 119 degrees and a pressure of 1.9 bar. The pH of the lactose solution was measured to be 1.8. At this temperature, the lactose solution was treated with a cation exchanger having a degree of crosslinking of 5.5% and hydrolysis was run to a degree of hydrolysis of 93%. The reaction corresponded to a flow-25 rate of 1.9 petit volumes per hour. The finished product was slightly yellowish and had a pure sweet taste with no significant off-flavor.

Despite the high dry matter content, high degree of hydrolysis, and relatively low degree of crosslinking, hydrolysis could be performed at a flow rate of 1.9 petit volumes per hour, corresponding to a reaction rate of lactose of only about one hour, no visible cracking or other damage was observed in the ion exchange resin.

Example 6 60 kg of whey powder made from whey was dissolved in 40 liters of water at a temperature of 100 degrees. The lactose solution was treated vigorously

II

35 9,721 47 l of an acidic cation exchanger consisting of a mixture of 50% of a cation exchanger having a degree of crosslinking (DVE content) of 5.5% and the remainder of a cation exchanger having a degree of crosslinking of 8%. The hydrolysis was run to a degree of hydrolysis of 98% at a reaction rate of 1.5 petit volumes per hour. The product made was practically completely clear and colorless and had a strongly sweet taste.

Example 7 10 50 kg of lactose powder was dissolved in 50 liters of 97 degree water. The lactose solution was hydrolyzed to 96% with a strongly acidic cation exchanger with a degree of crosslinking of 5.5%. The lactose hydrolyzate had a relatively strong sweet taste. 15% pure lactose was then added to the lactose hydrolyzate, with the taste panel estimating that the sweetness was noticeably higher than that of the freshly hydrolyzed lactose.

In addition to these, a large number of experiments were performed, which are explained in the tables below: 20 Table 1

Pre-flow Temperature Pressure Concentration Sign obtained petiti- ° C bar degree of hydrolysis volume / h% 25 8 0.2 60 36 29 (34) 9 1 75 42 33 10 0.4 83 50 45 11 1 96 59 89 12 0.7 97 65 95 30 13 1 120 2.0 72 96 14 1 141 3.8 81 96 15 1.5 60 35 30 16 1.5 74 41 36 17 1.5 86 50 45 35 18 1.5 95 60 82 19 2.0 97 66 97 20 1.9 119 1.9 71 93 7 214 7 10 I \ Ύ!

In the above examples, a cation exchanger with a low degree of crosslinking was used. The divinylbenzene content in this cation exchanger is about 5.5%.

5 Table 2

In the following examples, a cation exchanger with a DVB content of about 6% was used.

Pre-flow Temperature Pressure Concentration Sign obtained petit- ° C bar KA degree of hydrolysis / h% 21 1 60 35 29 22 1 74 42 33 23 1 85 50 47 24 1 95 59 93 25 1 99 65 98 26 1 119 2.0 73 97 27 1 141 3.8 82 96 28 1.5 61 0.21 35 28 29 1.5 73 41 40 30 1.5 85 51 45 31 1.5 96 60 89 32 1.5 98 65 96 33 1 , 5 121 2.0 73 97 34 1.5 141 3.8 82 96 721 47 11

Table 3

In the following examples, a cation exchanger with a DVB content of 8% was used.

Pre-flow Temperature Pressure Concentration Sign obtained petitila- ° C bar KA degree of hydrolysis / h% 35 0.4 60 35 35 36 1.2 74 41 34 37 1.5 85 50 46 38 1.5 96 59 90 39 1, 5 99 66 97 40 1.7 119 2.0 73 96 41 1.9 141 3.8 79 96

Table 4

Pre-flow Temperature Pressure Concentration Sign obtained petitila- ° C bar KA degree of hydrolysis / h% 42 0.8 61 35 34 43 1.2 73 42 35 44 1.5 85 50 42 45 1.5 97 60 98 46 1, 5 99 65 98 47 1.8 120 2.0 71 97 48 2.0 141 3.8 81 97 In these examples, a mixed cation exchanger with 50% cation exchanger with a degree of crosslinking of 8% and another 50% cation exchanger with a degree of crosslinking of 5%. With a combined degree of crosslinking (DVB content) of 6.75%.

12,721 47

It had to be shown that a cation exchanger with a low degree of crosslinking in a given range facilitates hydrolysis so that a higher flow rate can be maintained without lowering the degree of hydrolysis. With a degree of hydrolysis of more than 80%, the product becomes so stable that practically no crystallization occurs, even during long storage. However, cation exchangers with a low degree of crosslinking become quite pressure sensitive or easily broken, and at a high dry matter content, as mentioned above, the osmotic pressure becomes so strong that damage to the cation exchanger is at risk. Therefore, in the high dry matter content, it is often necessary to use cation exchangers with a higher degree of crosslinking in the range of 5.5-10% than would otherwise be desirable for driving reasons.

In all the above examples, the apparatus shown in Figure 1 below has been used, and lactose and permeate, respectively, have been treated mainly at the temperatures in terms of dry matter shown in the attached curve in Figure 2, where the dry matter content is shown on the vertical axis and the temperature ° C on the horizontal axis.

20

The device shown in Figure 1 consists of a closed container 1 with an upper dome 2 and a lower dome 3 and a midsole 4 up to the inside of the lower dome. The intermediate base 4 and the vessel up to about halfway are filled with a cation exchanger bed 5, and in a plane somewhat above the upper surface 6 of the cation exchanger bed 25 there is an inflow of lactose 7. The inlet 7 communicates with a spreader 8 provided with several nozzles (not shown). which spread lactose evenly on the surface of the ion exchange bed. A number of separator nozzles 9 are mounted on the midsole 4 to discharge hydrolysed lactose into the space 10 between the midsole 4 and the lower dome 30 3, and the hydrolysed lactose is taken out of the outlet pipe 11. Some lactose in the plane above the inlet 7 the inflow 12 is also provided with a spreader 13 for evenly distributing the regenerating acid on the surface of the ion exchange bed. In the plane above the surface 35 6 of the ion exchange bed there is another inflow 14 for compressed air or other gas.

721 47 13 1 During the hybridization of lactose, the acid flow 12 and the air flow 14 are closed, and a certain amount of lactose solution is pumped per unit time, preferably by means of a positive pump, into the tank 1 and spread evenly over the surface 6 of the ion exchange bed. Lactose gradually passes down through the bed at a certain rate, but if lactose is pumped in at a higher rate than that which can pass through the ion exchange bed, a layer of lactose solution 15 is formed above the bed. The lactose solution layer 15, which is about 5 cm above the ion exchange bed, is considered suitable the level 16 tends to rise to allow compressed air to be pushed into the adjacent pressure space 17. The hydrolyzed lactose can be taken out in batches or continuously through an outlet pipe 11 from the bottom of the tank. Due to the solid ion exchange bed, there is no wear of the ion exchange resin beads, and the lactose solution pumped in through the supply pipe 7 comes after using the ion exchange resin acid 15 to an increasingly strong acidity in the effluent or thereafter, which is disadvantageous to obtain the maximum possible hydrolysis.

The acidity of the ion exchange resin decreases during the hydrolysis process, and at some point the ion exchange resin must be regenerated. This is done 20 by rinsing the lactose supply pipe 7, the applicator 8 and the ion exchange bed 5 with water, after which the water is pumped from below through the outlet pipe 11 to the ion exchange bed so that the bed rises and fluffs. By means of the air coming through the air supply 14, the ion exchange bed 5 is pressed down to its original level, acid, preferably 5% hydrochloric acid, is pumped in through the acid supply pipe and spreader 13 and passes through the ion exchange bed from above until the mass is saturated with acid. Excess acid is removed by rinsing with water, after which the equipment is ready for re-use to hydrolyze lactose to glucose and galactose.

30

Figure 2 shows a graph of suitable processing temperatures. The vertical axis gives the percentage dry matter content, and the horizontal axis gives the dissolution temperatures of lactose and permeate in water, respectively. It appears that the temperature for complete dissolution of lactose in 35 water at a dry matter content of 40% is about 92 degrees, and that the temperature rises as the dry matter content increases to about 140 degrees to a dry matter content of 80%. The corresponding temperature is about 55 ° C for 40% of the dry matter content of 72147 centimeters and about 100 ° C for the 80% dry matter content.

Claims (7)

A process for the preparation of a sweetener, characterized in that lactose having a pH of less than 7 is dissolved in water at a temperature of 80-150 ° C or preferably 90-120 ° C to a dry matter content of between 40 ° C. and 80% or preferably between 50 and 60%, or lactose permeate with the same dry matter content is heated to the same temperature, after which the lactose solution formed is hydrolyzed by pressing the lactose solution in parallel through a solid bed of a strongly acidic cation exchanger having a 5 10% obtaining a conversion of lactose to glucose and galactose, and of hydrolysis to a degree of hydrolysis of 40-100% or preferably 70-90% at a flow rate of 2.0-0.5 bed volumes per hour corresponding to a conversion time for lactose to glucose and galactose in 0.5-2 hours, after which the obtained glucose-galactose product is cooled to a temperature of 10-20 ° C and withdrawn for direct use, for intermediate storage or for dare treatment. 1 Patent claim Process according to claim 1, characterized in that the hydrolysis is carried out without changing the temperature at which the lactose is dissolved in water or to which the lactose permeate is heated. Process according to claim 1 or 2, characterized in that the lactose solution is clarified before the hydrolysis treatment. 25 Process according to any one of claims 1-3, characterized in that the highly acidic cation exchanger has a crosslinking degree of preferably 5.5-6%. 30 Process according to any of the preceding claims, characterized in that the glucose-galactose product obtained by the hydrolysis is filtered through active koi after the hydrolysis for clarification of the product and to remove any caramel flavor. 35 Process according to any of the preceding claims, characterized in that the finished hydrolyzed product is subjected to one or more of the following treatments: Filtration by active koi, evaporation