BG64008B1 - Glucose syrup with specific properties and method for its preparation - Google Patents

Abstract

The invention relates to new compositions based on starch of enzymic hydrolyzed glucose syrup with dextrose equivalent between 30 and 50 and saccharic spectrum where fraction DP1-DP3 is from 30 to 60%, fraction DP4-DP6 is from 25 to 16%, fraction DP7-DP9 is from 14 to 19% and fraction over DP9 is from 38 to 18% of the dry substance. The invention also relates to method for the production of glucose syrup by treating starch with enzymes. The method is of particular importance for the production of new glucose syrup compositions. It consists in the treatment of liquefied starch substrate by enzymic mixture in a single stage of enzyme hydrolysation where the enzymic mixture includes bacterial -amylase, maltogenous amylase and glucoamylase. 14 claims

Description

Technical field

The present invention relates to a novel method for the preparation of enzymatically hydrolyzed glucose syrup, which can be used as a counterpart for standard acid hydrolyzed glucose syrups, i. glucose syrups with DE ranging from 30 to 50, and to new syrups which can be prepared in this way.

BACKGROUND OF THE INVENTION

Standard acid-hydrolyzed glucose syrups are prepared by acidifying a suspension of starch to pH 2.0. The suspension is then pumped into a continuously operating reactor operating at elevated temperature and pressure. After a suitable period of time, the liquid returns to atmospheric conditions and is neutralized. This liquid clarifies, decolourises with activated charcoal and concentrates to the final syrup. The acidic method is generally used for syrups in the range of 30-50 DE (dextrose equivalent). Acid hydrolysis always gives a product of a specific composition because of the arbitrary hydrolysis of starch. The main disadvantages of the process are the high content of salts in the syrup and the need for special apparatus to carry out the reaction of acid hydrolysis.

Acid hydrolysis of glucose syrups is commonly used for candy when boiled. This reduces the tendency of sucrose to crystallize, slows down the tendency to form a flaky-grained surface and promotes the body and "mouth feel" when consuming the sugar product. Glucose syrups are also used for hard caramel, homemade fondant and fondant, where they prevent, delay or control the sucrose granulation. These acid hydrolyzed glucose syrups represent a market of more than 400,000 tonnes of dry matter throughout Europe.

The acid-hydrolyzed glucose syrups used today are further purified by extensive demineralization, resulting in better color stability and improved organoleptic properties. These additional purification steps, which are required for the production of refined products, require additional equipment and cause additional production costs. On this basis, alternatives to acid-hydrolyzed glucose syrups have been developed that are based on acid-enzyme or enzyme-hydrolyzed syrups. These products are already used for many nutritional applications. These syrups are characterized by DE, which is the same as the DE of acid-hydrolyzed syrups, but they differ significantly in sugar spectrum and rheological properties. A comparison of acid-hydrolyzed, acid-enzyme and enzymatic hydrolyzed syrups with the same DE is illustrated in Table 1.

Table 1.

Comparison of glucose syrup types obtained by:

Acid hydrolysis Acid-enzyme hydrolysis Enzyme-enzymatic hydrolysis DE value 42 42 4 Sugar spectrum (wt.%) Dextrose 19 6 2.5 Maltose 14 45 56 Maltotriose 12 12 16 Maltotherapy 10 3 0.7 Malpentaentosis 8 2 0.4 Maltohexosis 7 2 0.7 Higher sugars 30 30 23,7

Other types of syrups having a sugar spectrum close to that of acid hydrolyzed syrup are also for sale. These syrups are prepared by mixing acidic or enzymatically hydrolyzed syrups with high maltose and / or 95 DE glucose syrup.

It is generally accepted that direct enzymatic hydrolysis of starch in acid-hydrolyzed syrup would have many advantages, namely:

- hydrolysis of starch by a soft biochemical method;

- reducing the formation of the color precursor hydroxymethylfurfural;

- non-formation of anhydroglucose as a by-product;

- reduction of ash content due to reduction of acid requirement;

- more economical further processing and purification.

Without prejudice to the fact that these advantages are well known, there are no known syrups produced to be obtained by single-step enzymatic hydrolysis of a liquefied starch substrate and having a sugar spectrum comparable to that of acid hydrolyzed syrups.

In the publication “Labo-Pharma-Probl. Tech., Vol. 29, No. 310, 1981, pp. 443-447 "provides a review of various methods for the hydrolysis of starch to sugar syrup and the distribution of sugar (by the degree of DP polymerization) in this method, corresponding to the level discussed above.

DE 4125969 describes a method using a mixture of certain enzymes for the hydrolysis of natural starch directly into syrup with a high glucose content (DE> 80). This type of syrup is very different from the so-called acid-hydrolyzed glucose syrups, which the present invention aims to create a counter product.

DE 3012143 describes a continuous process for the hydrolysis of starch to glucose syrup by a mixture of α-amylase and amyloglycosidase, also producing a sugar syrup of more than 80 CE.

SUMMARY OF THE INVENTION

According to the invention it has been surprisingly found that glucose syrups having a sugar spectrum and rheological behavior comparable to those of acid hydrolyzed syrup can be obtained.

Therefore, it is an object of the present invention to provide a novel starch-based product, enzymatically hydrolyzed glucose syrup with specific properties.

The glucose syrup of the invention is based on a starch enzyme hydrolyzed glucose syrup having a DE value (dextrose equivalent) between 30 and 50 and a sugar spectrum in which:

the DP fraction _t -DP ₃ is from 30 to 60%, the DP fraction ₄ -DP ₆ is from 25 to 16%, the DP ₇ -DP ₉ fraction is from 14 to 4% and the fraction over DP _g is from 38 to 18% the dry substance (ds).

Preferred glucose syrups according to the invention have DE values between 36 and 45 and a sugar spectrum in which:

the DPj-DPj fraction is from 38 to 55%, the DP fraction ₄ -DP ₆ is from 24 to 17%, the DP ₇ -DP ₉ fraction is from 13 to 4.5% and the fraction over DP ₉ is from 32 to 21% of a dry substance wherein the most preferred glucose syrups according to the invention have a DE value between 38 and 42 and a sugar spectrum in which:

the DPj-DP ₃ fraction is from 40 to 52%, the DP fraction ₄ -DP ₆ is from 24 to 18%, the DP ₇ -DP ₉ fraction is from 13 to 5% and the fraction over DP is from 30 to 32% of the dry substance.

According to the invention, well-defined conditions of a dual enzyme process are also developed to allow the preparation of such a novel glucose syrup.

It is therefore an object of the invention also to provide a novel method for the preparation of glucose syrup by treatment of starch with enzymes.

The method according to the invention consists in treating the liquefied starch substrate by means of an enzyme mixture in a single step of enzymatic hydrolysis, wherein the enzyme mixture consists of bacterial α-amylase, maltogenic amylase and glucoamylase.

The starting material for the process according to the invention is liquefied starch, as can be obtained, for example, by liquefaction of native starch with thermostable α-amylase to DE 10-12, deactivation of thermostable α-amylase and cooling of the liquefied starch to a temperature of about 60 ° C. .

Although other starting liquefied starch substrates may be considered for the process according to the invention, the specific liquefied starch mentioned in the example is most preferred.

The enzymes used in the enzyme mixture according to the invention are widely available on the market.

The preferred glucoamylase, exo-1,4-a-O-glucosidase, may in particular be obtained from a selected strain of Aspergillus niger by anaerobic fermentation.

The recommended reaction conditions for this enzyme are pH 4.5 and T 60 ° C. The enzymatic activity of glucoamylase (AGU) is defined as the amount of enzyme that hydrolyzes 1 μιηοΐ / min maltose under standard conditions (T 25 ° C; pH 4.3; reaction time 30 min).

Bacterial α-amylase is preferably an endoamylase that hydrolyzes 1,4-glucosidic bonds in gelled starch, α-amylase can be obtained by fermentation of a selected strain of Bacillus subtillis.

Recommended operating conditions for this enzyme are pH 6-6.5 and T from 70 to 90 ° C. The enzyme activity of α-amylase (KNU) is defined as the amount of enzyme that breaks down 5.26 g of starch per hour under the standard Novo method for determining α-amylase under standard conditions (substrate - soluble starch; Ca-content in solvent 0 , 0043 M; T37 ° C; pH 5.6).

The preferred maltogenic amylase (EC 3.2.1.133) hydrolyzes 1,4-α-glucosidic bonds in starch, partially hydrolyzed starch and low molecular weight oligosaccharides, including maltotriose. The maltose units are removed in stages from the unreduced ends of the chain. The enzyme that can be derived from Bacillus stearothermophillus can be expressed in and produced by a genetically modified strain of Bacillus subtillis. For industrial applications, the recommended operating conditions are 60 ° C and pH 5.0-5.5. The enzyme activity of this maltogenase is defined as the amount of enzyme that hydrolyzes 1 μιηοΐ maltotriose under standard conditions (substrate concentration 10 mg / ml; T 37 ° C; pH 5.0; incubation time 30 min).

The only step of enzymatic hydrolysis, i. the sugaring step applied to the starting substrate according to the invention is preferably carried out at a temperature in the range of 55 to 65 ° C for a period of 10 to 48 hours, at a pH between 4.9 and 5.1; especially preferably at a temperature in the range of 60 to 62 ° C for a period of 18 to 24 hours and a pH between 4.9 and 5.1.

Of course, shorter or longer reaction times are not excluded, but this would result in too high an enzyme cost or too large investment in storage or capacity of the reaction vessels.

During the enzymatic hydrolysis step, it is preferable that the dry matter content of the reaction mixture is between 30 and 40%, more preferably between 32 and 37% and especially preferably between 33 and 35%.

The method according to the invention is particularly suitable for the preparation of new glucose syrups according to the invention as defined above.

The enzyme concentrations and enzyme ratios during the enzymatic hydrolysis step according to the invention depend entirely on the process conditions employed and the specific glucose properties that it is desirable to obtain.

These concentrations can easily be determined by those skilled in the art based on the data provided by the commercial enzyme provider used in the method and / or by using mathematical calculations based on empirical models as already known in the art ("Development and field confirmation of a mathematical model foramyloglucosidase / pullulanase sacharification ”by TR Swanson et al. Starch / Staerke (1986), 38 (II), 382-387). An empirical model can be constructed on the basis of the information obtained from planned experimental experiments on sugaring. By selecting the appropriate model, equations are obtained from which the amount (% by weight) of different DP fractions can be calculated as a function of the concentration of different enzymes and time. Empirical equations are then used to calculate those combinations of enzyme concentrations and reaction times that best fit the sugar spectrum of the acid hydrolyzed glucose syrup to be compared.

Examples of carrying out the invention

The invention is further illustrated and explained by the following examples describing a number of specific embodiments of the invention. The specific features of these examples are described only as preferred embodiments of what is contemplated within the above general description of the invention and should in no way be construed as limiting the scope of the invention as such and as set forth in the claims.

Example 1. The native starch was suspended in water at a concentration of 33-35% dry matter (d.s.) and at slightly acidic pH (3.5-4.0). This suspension was then gelled at 160 ° C. After cooling to 95 ° C, the pH was adjusted to 5.7-5.9 and thermostable α-amylase (0.5-0.6 ml comm./kg d.s.) was added. This suspension is then further liquefied for 2-3 hours at 90-95 ° C until it is reached

DE 10-12. The α-amylase was then inactivated by bringing the pH to 4, with the liquid starch heated for a further 5 min at 95 ° C.

This substrate was then cooled to 5 60 ° C and the pH adjusted to 5.0. To this liquefied starch is added a mixture of enzymes composed of glucoamylase, maltogenic amylase and bacterial α-amylase. The following enzyme amounts are used:

AMG 300L maltogenase 4000L

BAN 480L

AGU / kg d.s.

96MANU / kgd.s.

14KNU / kgd.s.

After a reaction time of 20 h, the reaction was stopped by adjusting the pH to 3.5 and the solution heated to 85 ° C by for example steam injection to destroy as soon as possible all remaining enzyme activity. Under these reaction conditions, enzymatically hydrolyzed 38DE syrup is obtained which has a composition and properties comparable to those of acid hydrolyzed 38DE syrup (compare Table 2).

Table 2.

Comparison of glucose syrup obtained in example 1 with conventional syrup with DE 38 obtained by acid hydrolysis

Acid DE38 DE38 enzyme Sugar spectrum (wt.%) DPI 15.9 13,0 DP2 12.9 15.0 DP3 9.9 14.9 DP4 9.5 7.8 DP5 7.9 7.2 DP6 6.6 7,6 DP7 5.4 3.7 DP8 4.3 1.4 DP9 4.0 2.2 > DP9 23.6 27.0 ERH (2) 32,25 32.47 Tg (97% d.s.) 103.7 ° C 104.1 ° C Viscosity (mPas) (2) 8217 8177

(1) ERH candy when boiling: 50 48.5% solids in syrup, 48.5% sucrose, 3% water (2) viscosity at 80% d.s. and 50 ° C

Example 2. Native starch was suspended in water at a concentration of 33-35% d.s. and at slightly acidic pH (3.5-4.0). The suspension was then gelled at 160 ° C. After cooling to 95 ° C, the pH was adjusted to 5.7-5.9 and thermostable α-amylase (0.5-0.6 ml comm / kg d.s.) was added. The suspension was then further liquified for 5 to 3 hours at 90-95 ° C until DE 10-12 was reached. The α-amylase is then inactivated by bringing the pH to 4, with the liquid starch heated for an additional 5 minutes at 95 ° C. This substrate was then cooled to 60 ° C and the pH was adjusted to 5.0. To this liquefied starch is added a mixture of enzymes composed of glucoamylase, maltogenic amylase and bacterial α-amylase. The following enzyme amounts are added:

- AMG 300 L 16,6 AGU / kg d.s.

- maltogenase 4000 L 48 MANU / kg d.s.

- BAN 480 L 12 KNU / kg d.s.

After a reaction time of 20 h, the reaction was stopped by adjusting the pH to 3.5 and heating the solution to 85 ° C by, for example, steam injection to destroy as quickly as possible all remaining enzyme 10 activity. Under the reaction conditions used, enzyme hydrolyzed 42DE syrup is obtained which has a composition and properties comparable to those of acid hydrolyzed 42DE syrup (compare Table 3).

Table 3.

Comparison of glucose syrup obtained in Example 2 with ordinary syrup with DE42 obtained by acid hydrolysis

Acid DE38 DE38 enzyme Sugar spectrum (wt.%) DPI 19.7 19,1 DP2 16.4 14.5 DP3 9.5 17,0 DP4 7.9 6,9 DP5 6,7 6,8 DP6 5.5 5.5 DP7 4.7 2.6 DP8 3.9 1.3 DP9 3.4 1.5 > DP9 22.3 24.6 ERH (2) 31,47 31,12 Tg (97% d.s.) 98 ° C 94 ° C Viscosity (mPas) (2) 6300 5900

(1) ERH-candies at boiling point: 48.5% solids in syrup, 48.5% sucrose, 3% water (2) viscosity at 80% d.s. and 50 ° C

Claims (14)

Claims An enzyme hydrolyzed glucose starch based syrup having a DE value (dextrose equivalent) between 30 and 50 and a sugar (DP degree of polymerization) spectrum in which: the fraction ϋΡ, -DPj is from 30 to 60%; the DP ₄ -DP ₆ fraction is from 25 to 16%; the DP ₇ -DP ₉ fraction is from 14 to 4%; the fraction above DP is from 38 to 18% of the dry matter. Glucose syrup according to claim 1, characterized in that it has a DE value between 36 and 45 and a sugar spectrum in which: the DPj-DPj fraction is from 38 to 55%; the DP ₄ -DP ₆ fraction is from 24 to 17%; the DP ₇ -DP fraction is from 13 to 4.5%; the fraction above DP is from 30 to 21% of the dry matter. Glucose syrup according to claim 1, characterized in that it has a DE value between 38 and 42 and a sugar spectrum in which: the DP, -DP ₃ fraction is from 40 to 52%; the DP ₄ -DP ₆ fraction is from 24 to 18%; the DP ₇ -DP ₉ fraction is from 13 to 5%; the fraction above DP is from 30 to 22% of the dry matter. 4. A method of producing glucose syrup by treatment of starch with enzymes, characterized in that the liquefied starch substrate is treated by an enzyme mixture in a single step of enzymatic hydrolysis, wherein the enzyme mixture contains bacterial α-amylase, maltogenic amylase and glucoamylase. 5. The method of claim 4, wherein the enzymatic hydrolysis step is carried out at a temperature in the range of 55 to 65 ° C for a period of 10 to 48 hours, at a pH of between 4.9 and 5.1. The method according to claim 4, characterized in that the enzymatic hydrolysis step is carried out at a temperature in the range of 60 to 62 ° C, for a period of 18 to 24 hours, at a pH between 4.9 and 5.1. Method according to any one of the preceding claims, characterized in that during the enzymatic hydrolysis step the dry matter content of the reaction mixture is between 30 and 40%. A method according to claim 7, characterized in that during the enzymatic hydrolysis step the dry matter content of the reaction mixture is between 32 and 37%. A method according to claim 7, characterized in that during the enzymatic hydrolysis step the dry matter content of the reaction mixture is between 33 and 35%. A method according to any one of the preceding claims, characterized in that the liquefied starch substrate has a DE of 10 5 to 12. A method according to any one of the preceding claims, characterized in that the liquefied starch substrate is obtained by pre-treatment of native starch 10 with thermostable α-amylase followed by deactivation of thermostable α-amylase. A method according to any one of the preceding claims for the preparation of glucose syrup, characterized in that the glucose syrup 15 syrup has a DE value between 30 and 50 and a sugar spectrum in which: the DP, -DP ₃ fraction is from 30 to 60%; the DP ₄ -DP ₆ fraction is from 25 to 16%; the DP ₇ -DP fraction is from 14 to 4%; the fraction above DP is from 38 to 18% of the dry matter. A method according to any one of the preceding claims for the preparation of glucose syrup, characterized in that the glucose syrup has a DE value between 36 and 45 and a sugar spectrum in which: the fraction of OP ^ BR3 is from 38 to 55%; the DP ₄ -DP ₆ fraction is from 24 to 17%; the DP ₇ -DP fraction is from 13 to 4.5%; the fraction above DP ₉ is from 32 to 21% of the dry matter. A method according to any one of the preceding claims for the preparation of glucose syrup, characterized in that the glucose syrup has a DE value between 38 and 42 and a sugar spectrum in which: the DP, -DP ₃ fraction is from 40 to 52%; the DP ₄ -DP ₆ fraction is from 24 to 18%; the DP ₇ -DP ₉ fraction is from 13 to 5%; the fraction above DP is from 30 to 22% of the dry matter.