Use of an anti-staling enzyme mixture in the preparation of baked bread

Abstract

The invention provides a process of preparing baked bread by baking a farinaceous dough, said process comprising incorporating into the dough a combination of two or more enzymes including: maltogenic amylase in an amount of 750-75,000 maltogenic amylase units (MAU) per kg of flour, said maltogenic amylase having an optimum temperature above 50 C.; amyloglucosidase in an amount of 0.01-3.0 amyloglucosidase units (AGU) per unit of MAU activity
The combination of maltogenic amylase and amyloglucoside is a very effective anti-staling agent.

Claims

1. A process of preparing baked bread, comprising: (a) incorporating into farinaceous dough a combination of two or more enzymes comprising: (i) maltogenic amylase in an amount of 750-75,000 maltogenic amylase units (MAU) per kg of flour, said maltogenic amylase having an optimum temperature above 50 C.; and (ii) amyloglucosidase in an amount of 0.01-3.0 amyloglucosidase units (AGU) per unit of MAU activity; and, (b) baking the dough.

2. The process according to claim 1, wherein the amyloglucosidase is a polypeptide that is encoded by a DNA sequence that is found in a fungus strain of Aspergillus niger.

3. The process according to claim 1, wherein the amyloglucosidase has an optimum pH in the range of 1.5-5.5.

4. The process according to claim 3, wherein the amyloglucosidase has an optimum pH in the range of 2.0-4.5.

5. The process according to claim 1, wherein the amyloglucosidase is incorporated in the dough in an amount of 40-40,000 AGU per kg of flour.

6. The process according to claim 1, wherein the amyloglucosidase is incorporated in the dough in an amount of 0.05-0.50 AGU per unit of MAU activity.

7. The process according to claim 1, wherein the optimum temperature of the amyloglucosidase is at least 10 C. lower than the optimum temperature of the maltogenic amylase.

8. The process according to claim 1, wherein the maltogenic amylase has an optimum temperature in the range of 55-90 C.

9. The process according to claim 1, wherein the maltogenic amylase is a polypeptide that is encoded by a DNA sequence that is found in a strain of Geobacillus stearothermophilus.

10. The process according to claim 1, wherein the dough is a mixed rye/wheat flour dough.

11. The process according to claim 1, wherein the dough is prepared by combining flour, water, yeast, the maltogenic amylase, the amyloglucosidase and optionally other bakery ingredients.

12. The process according to claim 11, wherein the dough is fermented prior to baking.

13. The process according to claim 1, wherein the farinaceous dough is baked at a temperature in excess of 180 C.

14. The process according to claim 1, preparing the dough by incorporating a bread improver into the dough, said bread improver comprising a combination of two or more enzymes comprising: (a) maltogenic amylase in an amount of 7,500-75,000,000 maltogenic amylase units (MAU) per kg of dry matter, said maltogenic amylase having an optimum temperature above 50 C.; and (b) amyloglucosidase in an amount of 0.01-3.0 amyloglucosidase units (AGU) per unit of MAU activity.

15. The process according to claim 14, wherein the bread improver is a powder or a granulate having a mass weighted average particle size in the range of 10-1000 m.

Description

DETAILED DESCRIPTION OF THE INVENTION

(1) The invention provides a process of preparing baked bready by baking a farinaceous dough, said process comprising incorporating into the dough a combination of two or more enzymes including: maltogenic amylase in an amount of 750-75,000 maltogenic amylase units (MAU) per kg of flour, said maltogenic amylase having an optimum temperature above 50 C.; amyloglucosidase in an amount of 0.01-3.0 amyloglucosidase units (AGU) per unit of MAU activity.

(2) The term maltogenic amylase as used herein refers to a starch degrading enzyme having IUPAC Classification number EC 3.2.1.1. (glucan 1,4--maltohydrolase) that is capable of hydrolyzing maltotriose to maltose and glucose.

(3) The term amyloglucosidase as used herein refers to another starch degrading enzyme having IUPAC Classification number EC 3.2.1.3. Amyloglucosidase (or 1,4--D-glucan glucohydrolase) not only cleaves the last (1-4)glycosidic linkages at the non-reducing end of amylose and amylopectin, yielding glucose, but also cleaves (1-6) glycosidic linkages.

(4) Whenever reference is made herein to the optimum temperature of an enzyme what is meant is the temperature at which the enzyme activity is highest. For the maltogenic amylase the optimum temperature is suitably determined at pH 5.0. For the amyloglucosidase the optimum temperature is suitably determined at pH 4.2.

(5) The optimum pH of an enzyme is the pH at which the enzyme activity is highest. The optimum pH is suitably measured at 60 C.

(6) One unit of maltogenic amylase activity (MAU) is defined as the amount of enzyme required to release one nanomol of maltose per second at a concentration of 10 mg of maltotriose substrate per ml of 0.1 M citrate buffer, pH 5.0 at 37 C.

(7) One unit of amyloglucosidase activity (AGU) is defined as the amount of enzyme required to release one nanomol of glucose per second at a concentration of 10 mg of maltose substrate per ml of 0.1 M citrate buffer, pH 5.0 at 37 C.

(8) The present method can suitably employ different types of amyloglucosidases. Preferably, the amyloglucosidase employed is a polypeptide that is encoded by a DNA sequence that is found in a fungal strain of Aspergillus, Rhizopus or Talaromyces. Examples of suitable fungi include Aspergillus niger, Rhizopus delemar, Rhizopus niveus, Rhizopus oryzae and Talaromyces emersonii. Most preferably, the amyloglucosidase employed in accordance with the present invention is a polypeptide that is encoded by a DNA sequence that is found in a strain of Aspergillus niger.

(9) The amyloglucosidase employed in the present process typically has an optimum pH in the range of L5-5.5, especially in the range of 2.0-4.5.

(10) The amyloglucosidase is advantageously incorporated in the dough in an amount of 40-40,000 AGU per kg of flour, more preferably of 80-23,000 AGU per kg of flour. Expressed differently, the amyloglucosidase is preferably incorporated in the dough in an amount of 0.05-0.50 AGU per unit of MAU activity, most preferably in an amount of 0.10-0.30 AGU per unit of MAU activity.

(11) The maltogenic amylase employed in the present process preferably has an optimum temperature in the range of 52-90 C., most preferably in the range of 55-85 C.

(12) The optimum pH of the maltogenic amylase preferably lies in the range of 4.0-7.5, most preferably in the range of 4.5-7.0.

(13) The inventors have found that staling can be minimized very effectively even if the amyloglucosidase has an optimum temperature that is substantially lower than the optimum temperature of the maltogenic amylase. Preferably, the optimum temperature of the amyloglucosidase is at least 10 C., more preferably at least 12 C. and most preferably at least 14 C. lower than the optimum temperature of the maltogenic amylase. Typically, the optimum temperature of the amyloglucosidase is less than 55 C.

(14) The maltogenic amylase employed in accordance with the present invention preferably is a polypeptide that is encoded by a DNA sequence that is found in a Bacillus strain, most preferably in a strain of Geobacillus. stearothermophilus.

(15) The maltogenic amylase is typically incorporated in the dough in an amount of 1,000-40,000 MAU per kg of flour, most preferably of 1,500-7,500 MAU per kg of flour.

(16) In accordance with one preferred embodiment, the bread dough employed in the present process is a mixed rye/wheat flour dough. In accordance with another preferred embodiment, the bread dough is wheat flour dough.

(17) In the present process the farinaceous dough is typically prepared by combining flour, water, yeast, the maltogenic amylase, the amyloglucosidase and optionally other bakery ingredients.

(18) Besides the maltogenic amylase and the amyloglucosidase, the present process may employ other food-grade enzymes, such as -amylase, xylanase and protease.

(19) The farinaceous dough is preferably baked at a temperature in excess of 180 C., more preferably at a temperature in excess of 200 C. In case the dough is a yeast containing dough, the dough is preferably fermented prior to baking.

(20) In accordance with a particularly preferred embodiment of the present process the dough is prepared by incorporating a bread improver into the dough, said bread improver comprising a combination of two or more enzymes including: maltogenic amylase in an amount of 7,500-75,000,000 maltogenic amylase units (MAU) per kg of dry matter, said maltogenic amylase having an optimum temperature above 50 C.; amyloglucosidase in an amount of 0.01-3.0 amyloglucosidase units (AGU) per unit of MAU activity.

(21) The aforementioned bread improver is typically employed in the bread dough in a concentration of 0.1-10%, especially of 0.3-5% by weight of flour.

(22) Typically, the amyloglucosidase is present in the bread improver in an amount of 100-120,000,000 AGU per kg of dry matter, even more preferably in an amount of 500-30,000,000 AGU per kg of dry matter and most preferably of 750-4,000,000 AGU per kg of dry matter.

(23) Besides the maltogenic amylase and the amyloglucosidase the bread improver employed in the present process preferably comprises one or more, more preferably two or more and most preferably three or more of the following bakery ingredients: emulsifier; triglyceride oil or fat; other enzymes, notably enzymes selected from -amylases, hemicellulases, lipases, proteases and combinations thereof; gluten; ascorbic acid; preservation aids, for example, calcium propionate; chemical leavening agent; cereal flour.

(24) Typically, the aforementioned bakery ingredients together represent at least 50 wt. %, more preferably at least 70 wt. % of the bread improver.

(25) The bread improver used in the present process preferably is a liquid or a particulate product. More preferably, the bread improver is a powder or a granulate having a mass weighted average particle size in the range of 10-1000 m, more preferably of 50-800 m, most preferably of 100-500 m.

(26) Another aspect of the invention relates to a baked bread that is obtained by a process as defined herein before.

(27) The invention is further illustrated by, but not limited to the following examples.

EXAMPLES

Example 1

(28) Rye/wheat bread dough was prepared on the basis of the recipe shown in Table 1 and by mixing the ingredients in a Diosna mixer for 6 min slow, and 2 min fast.

(29) TABLE-US-00001 TABLE 1 % by weight of flour Rye flour Type 1150 70 Wheat flour Type 550 30 Water 80 Bread improver .sup.1 2.5 Acid improver .sup.2 2.5 Salt 2.1 Compressed yeast 1.5 Anti-staling enzyme 0.008 (80 ppm) .sup.1 WB 24 from CSM Deutschland GmbH .sup.2 Backsauer R22 from CSM Deutschland GmbH

(30) Two different doughs were prepared using the following the anti-staling enzymes:

(31) Product I: 80 ppm Novamyl 10,000 BG: 6,080 MAU per kg flour

(32) Product II: 60 ppm Novamyl 10,000 BG: 4,560 MAU per kg flour+20 ppm Bakezyme AG 800 BG: 840 AGU per kg flour (ex DSM, Netherlands)

(33) The activities of the aforementioned commercial enzyme preparations are specified in Table 2

(34) TABLE-US-00002 TABLE 2 Enzyme activity Novamyl 10,000 BG 76,000 MAU/g Bakezyme AG 800 BG 42,000 AGU/g.sup.

(35) After mixing the dough was rested for 30 min at ambient. After that 1100 g pieces of dough were moulded, put into a tin, and fermented for 50 min at 32 C. After fermentation the dough pieces were baked for 50 min in a deck oven. The oven temperature was programmed to remain at 260 C. for 10 minutes and then to decrease linearly from 260 to 230 C. during the following 40 min.

(36) Breads were stored in a standard polyethylene bag at ambient up to 9 days.

(37) Crumb firmness was measured by a TA.XT Plus texture analyzer from Stable Micro Systems. The method used was as follows: A cylinder of bread crumb was cut from the centre of the baked bread. The diameter of the cylinder was 45 mm and the length was 30 mm. The diameter of the measuring probe was 50 mm, test speed was 2 mm/sec, and the probe entered the breadcrumb for 10 mm. The force required to do this was measured in g and equals hardness.

(38) The results obtained for the two different products, based on 4 replicates, are shown in Table 3.

(39) TABLE-US-00003 TABLE 3 Crumb hardness (in g) Storage time Product I Product II 3 days 1574 1578 4 days 1817 1590 7 days 1905 1692 8 days 1985 1780 9 days 2075 1914

Example 2

(40) Wheat dough was prepared on the basis of the recipe shown in Table 4 and by mixing the ingredients in a Diosna spiral mixer for 2 min slow, and 6 min fast.

(41) TABLE-US-00004 TABLE 4 % by weight of flour Wheat flour Type 550 100 Water 58 Compressed yeast 3.0 Bakery margarine 3.0 Salt 2.0 Acid improver .sup.1 1.0 Calcium propionate 0.15 Anti-staling enzyme 0.005 (50 ppm) .sup.1 Backsauer R22 from CSM Deutschland GmbH

(42) Two different doughs were prepared using the following the anti-staling enzymes:

(43) Product I: 50 ppm Novamyl 10,000 BG

(44) Product II: 36 ppm Novamyl 10,000 BG+7 ppm Bakezyme AG 800 BG (ex DSM, Netherlands)

(45) After mixing, the dough was rested for 10 minutes. After that 550 g pieces of dough were moulded, put into a tin, and fermented for 50 min at 32 C. Next, the dough pieces were baked for 33 min in a Wachtel deck oven at 240 C.

(46) Breads were stored in a standard polyethylene bag at ambient up to 9 days.

(47) Crumb firmness was measured with the same method as described in Example 1.

(48) The results obtained for the two different products, based on 4 replicates, are shown in Table 5.

(49) TABLE-US-00005 TABLE 5 Crumb hardness (in g) Storage time Product I Product II 3 days 625 495 4 days 682 574 7 days 756 705 8 days 823 773 9 days 957 856

Example 3

(50) The activity of Spezyme GA 300 N (Genencor) was determined around 1994. The measured activity was 460 AGU/l.

(51) Gerrard et al. (The Role of Maltodextrins in the Staling of Bread, Journal of Cereal Science 26 (1997) 201-209) describe an experiment in which maltogenic amylase (Novamyl) and glucoamylase (GA300N, Genencor) were added to a bread dough in a concentration of 0.8 mg per g flour and 20 l per g flour, respectively. Since the maltogenic amylase has an activity of 11.4 MAU per mg, it can be calculated that in this particular experiment amyloglucosidase was applied in an amount that is much higher than 3 AGU per unit of MAU activity.