DK155489B - PROCEDURE FOR ENZYMATIC DIVISION OF LACTOSE IN DAIRY PRODUCTS - Google Patents

Description

DK 155489 B

The invention relates to a method for enzymatic digestion of lactose in milk-containing products for use in the preparation of pleasure products, especially eating ice cream, or animal feed.

The process of the invention is characterized by treating the lactose-containing material with β-galactocidase incorporated into a fiber.

The enzyme can be recovered at the end of the enzymatic treatment. It is very advantageous to obtain milk and milk products in which the lactose content is partially hydrolyzed to glucose and galactose. Such products are better tolerated and will be able to widen the consumer circle for the enjoyment products made from the milk products. Introducing the hydrolyzed milk into animal nutrition provides significant benefits in weight gain and nutrition.

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Furthermore, there are very significant technological advantages to such lactose digestion. When the milk is concentrated to a dry matter content greater than 30%, it is difficult to store if, due to crystallization of a portion of the lactose, protein coagulation results. The same disadvantage is encountered in the ice-cream industry, 5 where it is not possible to use milk with high solids content due to a crystallization of lactose which is difficult to dissolve again.

Some methods have been proposed to remedy these disadvantages, e.g. hydrolysis of lactose at high temperatures, treatment with ion exchange resins and addition of riboflavin.

1 0 The first of these methods involves protein coagulation, the second alters the natural salt balance of the milk, and the third allows for the avoidance of Jactose precipitation, but it uses a very expensive addition and does not solve the dietary problems.

Therefore, the addition of. hydrolyzing enzymes. The use of 15 enzymes in solution has been widely used, but the addition of the commercially available enzymes gives the milk an unpleasant taste. Furthermore, after the action of the enzyme is completed, it is necessary to make this inactive and it remains in the milk as a denatured enzyme. In addition, the process requires very large amounts of enzymes (2-4% relative to the lactose weight, depending on the activity of the enzyme), which significantly affects the cost.

Another factor limiting the use of this method is the microbiological complications caused by such a hydrolysis process.

It is an object of the invention to provide an inexpensive and industrially applicable method for the digestion of lactose in milk and milk products for use in the manufacture of enjoyment or animal feed which is free of the aforesaid disadvantages.

The object is achieved by using an enzyme incorporated in fibers according to the invention, e.g. made in accordance with Italian Patent No. 836,462 filed June 30, 1968.

In such a method, it is economically and simply possible to obtain a filament structure which encloses the enzyme in a solid and durable manner.

When said fibers are placed in a column, the product can be treated continuously, which facilitates automatic operation. The uninterrupted workflow greatly simplifies the bacteriological problems as it enables the use of measures that cannot be used by other methods.

The fibers can sometimes be washed with a suitable detergent. The wash liquid can be added to a bactericide to disinfect the filaments, pipelines and applications.

DK 155489 B

3 containers.

Among bacterial ideas, good results have been achieved with quaternary ammonium salts, since many of these have no detrimental effect on the enzyme contained.

Furthermore, in addition to the bactericidal effect, some of the quaternary ammonium salts have a deterrent effect, which is very significant since the bactericidal action is greatly altered by residues of organics.

The other great advantage of the process of the invention is that the milk does not retain any additive, as is the case when the hydrolysis is carried out by soluble enzymes. Therefore, no heating is required to denature the enzyme and no unpleasant taste or odor is imparted to the treated milk.

A particularly significant advantage is the possibility of using such an enclosed enzyme for a long time and therefore to treat a very large amount of material without significantly impairing the hydrolytic activity. A sample of enzyme filament that was used to perform successive experiments to hydrolyze lactose in milk kept its activity unchanged for the 60 days over which it was tested.

The same amount of enzyme fiber, when placed in a glass column, was able to continuously hydrolyze lactose in milk for more than a month without loss of activity.

Furthermore, the enzyme envelope method enables fibers of different activity to be obtained, which makes it possible to shorten the contact time between the material to be treated and the enzyme carrier. The process according to the invention can be carried out on milk as such (whole milk), on partially skimmed milk, on concentrated milk and on 25 products which are more processed. The process can also be applied to whey.

The fiber may be constituted by cellulose derivatives such as cellulose acetate or by a synthetic polymer or copolymer such as polyamide, polystyrene nitrile, polystyrene, polymethyl etherylate, polyvinyl chloride, polyvinyl esters, polyvinylbutyral and the like.

Very good results are obtained using cellulose triacetate.

The procedure is illustrated in more detail by the following examples.

Preparation 35 Preparation of the insoluble enzyme: 24.6 g of cellulose triacetate ("Fluka") was dissolved with stirring in 260 g of methylene chloride (C.Erba), in a reactor.

The enzyme solution was prepared by dissolving 1.43 g of β-galactosidase (BD1 in a glycerol-water mixture (20:80 v / v)) to give a total volume of 50 ml. The enzyme solution was purified. fiio'Pi-Af · i an afVnilet- Γϋπ (· τϊfnop \ toA F-ra da.n

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clear solution was taken out 32 ml which was added to the polymer solution.

The phases were emitted by vigorous stirring at 0 ° C for 30 minutes.

The emulsion was poured into a spinning apparatus at 6 ° C and spun under the nitrogen atmosphere.

The filament was coagulated in toluene at room temperature and recorded on a winding machine. It was dried under vacuum overnight to remove toluene.

Example 1

A column with> an inner diameter of 25 mm and a length of 1 400 mm was used.

This was filled with 50 g of the enzyme fibers prepared according to Example 1, the fibers being placed at random and pressed so that the entire column volume was filled. The column was provided with a thermostatic jacket in which water was circulated at 25 ° G.

With a dosing pump, milk was withdrawn from a container kept at + 4 ° C (lactose = 4.9%, lipids = 1.1%). The milk passed through a heat exchanger in which its temperature was brought to 25 ° C, introduced at the bottom of the column, passed through the enzyme fiber and taken from the top of the column, then passed a heat exchanger which cooled it to + 4 ° C.

The dosing pumps were kept constant at 150 ml / h. During the operation of the column, the hydrolysis of the lactose in the outgoing milk reached 53% ·

Example 2

Proceed as in Example 1, except that the column was fed with milk 25 at varying speed (Q).

The degree of hydrolyzing of the lactose in the outgoing milk was determined.

The following test results were obtained:

Flow rate (Q) ml / h Hydrolyzed lactose 7® 150 53.00 30 300 28.00 600 18.20 1200 9-, 20 3200 2.50 33 Example 3

These experiments were performed using the same 50 g of enzyme filament placed in the same column as in Example 1. 380 ml of milk (lactose = 4.95 7., lipids = 1.1%) were passed over and over again through the enzyme fibers. The degree of hydrolyzing of lactose was determined over time as a function of flow (Q). The working temperature was 25 ° 0.

DK 155489 B

The results obtained were:

Hydrolyzed lactose%

Time Q = 800 ml / h Q = 3200 ml / h 30 '11.80 10.80 5 45 · 21.50 19.10 60 · 25.70 23.60 90 »33.70 35.00 120» 41, 00 44.50 150 '47.00 50.20 10 180' 52.50 55.00 210 »59.00 63.00 240» 63.50 67.00

Example 1 4 1 5 Using the same * 50 g of enzyme filament placed in the same column, the influence of the working temperature was determined. 380 ml of milk was passed again and again past the enzyme fibers and the degree of hydrolysis was determined after one hour.

The dosing pump was kept constant at 320 ml / h while the operating temperature was changed.

Temperature Hydrolyzed lactose%, after 1 hour 15 ° C 17.45 25 ° C 22.80 35 ° C 29.54 Example 5

The same 50 g of filament placed in the same glass column was used. Through this, 380 ml of partially skimmed milk (lipids = 1.1%) was passed, with the passing milk recycled. The degree of hydrolysis was determined as a function of time. Pump performance and operating temperature were kept constant. Experimental data 30 shows the time dependence of the degree of hydrolysis of the lactose.

Time Hydrolyzed lactose% 1 h 20.60 2 h 36.30 3 h 47.20 35 4 h 56.20 5 h 62.40 6 h 73.40 7 h 79.40 8 h 88.00

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Example 6

Using the method described in the above Preparation, 50 g of enzyme fiber containing 75 mg of β-galactosidase (BDH) was prepared per ml. gram. The fiber was placed at random orientation in a glass column having a diameter of 5 mm and a height of 400 mm.

Partially skimmed milk (lipids = 1.17, lactose 4.8%) was added in an amount of 150. M / h. The temperature was 25 ° C.

During the operation of the column, the lactose in the outgoing milk was hydrolyzed for 81.4% rs.

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Example 7

Proceed as in Example 6, however, to the column, whole milk was added (3.5% lipids and 4.85% lactose). 76% of the lactose was hydrolyzed.

Example 8

Proceed as in Example 6, however, to add to the column total skimmed milk (lipids = 0.3%, lactose = 5.10%). 78% of the milk's lactose was hydrolyzed.

Example 9

As in Example 6, with the exception that whey (4.9% lactose) was added to the column at pH 6.7. 72% of the lactose of the whey was hydrolyzed.

Example 10

50 g of enzyme fiber were prepared in a similar manner as described in the above Preparation containing 75 mg of β-galactosidase (BDH).

In preparing the emulsion, a ratio of 1.6 between the volume of aqueous phase (ml) and the weight (g) of polymer solids was used. The filament, which was 30 more porous, was placed in a column of 25 mm diameter and height 250 mm. The column was fed to milk (lipids = 1.1%) at a rate Q = 300 ml / h and the column was maintained at 25 ° C with a thermostat.

In the milk from the column, 66% of the lactose was hydrolyzed.

Example XI

2 g of enzyme fiber was contacted with 50 ml of partially skimmed milk in a 150 ml flask. The flask was placed in a shaking thermostatically controlled bath of 25 ° C. After 4 hours, the milk was separated from the filament. The bacterial content and the percentage of lactose hydrolysis were determined.

The well-pressed enzyme filament was washed with a suitable solution of

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detergent and bactericide.

After being pressed and dried between two pieces of filter paper, the filament was again used under the same conditions. Subsequent experiments were then undertaken, with the degree of lactose hydrolyzing and bacterial counts of the treated milk ^ determined after each experiment. Several quaternary ammonium salts were tested by this method to determine their effect on the enzyme and on the microorganisms. Among the bactericides tested are the following: "Fardi 7" (Farmitalia), "Straminol" (Brocco), benzalkonium chloride and "Anfocid" (Gianni), "Tego 51" (Italian Tego), "Steramine H" (Formenti) as well as other antibacterial agents such as phenol, hydrogen dioxide, hypochlorite, iodoform and antibiotics.

The best results were obtained using the quaternary ammonium salts, especially "Steramine H" and "Fardi 7".

The enzymatic activity was determined during the performance of these successive experiments. The same sample of enzyme fiber could be used in 80 hydrolysis experiments while maintaining constant activity.

Example 12

A column with a diameter of 25 mm and a height of 400 mm and 50 g of enzyme filament prepared according to the above Preparation were used and 20 were used for several days. After each experiment, the fiber was washed with an aqueous solution containing 0.25% "Steramine H" at room temperature. After the washing liquid was drained, 500 ml of milk was passed in a closed circuit. The pump speed was 500 mh / h and the working temperature 25 ° C. At time intervals, the degree of hydrolyzing and bacterial counts were determined in the treated milk.

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The test results were as follows:

Time Hydrolyzed lactose% Microorganisms per ml 60 '18.8 120,000 95' 28.4 170,000 3Q 120 '33.6 300,000 35

Claims (10)

A process for enzymatic cleavage of lactose in milk-containing products for use in the manufacture of enjoyment agents, especially eating ice cream, or animal feed, characterized by treating the lactose-containing material with β-galactosidase incorporated into a fiber. Process according to claim 1, characterized in that the process is performed continuously. 3. A process according to claim 2, characterized in that the enzymatic reaction is interrupted by washing operations with detergents. Method according to claim 3, characterized in that a bactericide is added to the detergents. Process according to claim 4, characterized in that the bacterium is quaternary ammonium salt. Process according to any of the preceding claims, characterized in that the enzyme is incorporated in a cellulose derivative or a synthetic polymer or copolymer such as a polyamide compound, polyacrylonitrile, polyacrylates, polymethacrylates, polyvinyl chloride, polyvinyl esters and polyvinylbutyral. Process according to claim 6, characterized in that the fiber 20 containing the enzyme consists of cellulose triacetate. Process according to claims 1-7, characterized in that the lactose-containing material consists of or contains milk which is partially foamed. Process according to claims 1-7, characterized in that the lactose-containing material contains concentrated milk. Process according to claims 1-7, characterized in that the lactose-containing material contains whey. 30 35