Food or edible material: processes – compositions – and products – Fermentation processes – Of farinaceous cereal or cereal material
Reexamination Certificate
1999-04-05
2002-04-02
Wong, Leslie (Department: 1761)
Food or edible material: processes, compositions, and products
Fermentation processes
Of farinaceous cereal or cereal material
C426S018000, C426S019000, C426S020000, C426S549000
Reexamination Certificate
active
06365204
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to process for preparing a dough or a baked product prepared from the dough. More particularly, it relates to such a process where the bread has an improved softness, both when eaten on the same day and when eaten after several days of storage.
BACKGROUND OF THE INVENTION
It is well known that the softness of bread deteriorates during storage from the time of baking to the time of consumption. The term staling is used to describe such undesirable changes in the properties of the bread. Staling results in an increase of the firmness of the crumb, a decrease of the elasticity of the crumb, and changes in the crust, which becomes tough and leathery.
Enzymatic retardation of staling by means of various amylases has been described. Thus, U.S. Pat. No. 2,615,810, U.S. Pat. No. 3,026,205 and O. Silberstein, “Heat-Stable Bacterial Alpha-Amylase in Baking”, Baker's Digest 38(4), August 1964, pp. 66-70 and 72, describe the use of alpha-amylase. WO 91/04669 (Novo Nordisk) describes the use of a maltogenic alpha-amylase from
Bacillus stearothermophilus
. It is also known to use &bgr;-amylase to retard staling.
It is also known to add a phospholipase to dough. Thus, U.S. Pat. No. 4,567,046 and EP 171,995 (both to Kyowa Hakko) disclose that the addition of phospholipase A enhances the properties of dough and bread, including retardation of the staling.
M. R. Kweon et al., Journal of Food Science, 59 (5), 1072-1076 (1994) disclose the effect of 2-4% by weight of phospholipid hydrolysate together with an antistaling amylase on the retrogradation of starch in bread.
SUMMARY OF THE INVENTION
The inventors confirmed that the addition of an anti-staling amylase reduces the rate of crumb firming during storage for 1-7 days after baking, but they found that there is a need to improve the softness in the initial period after baking, particularly the first 24 hours after baking. They further found that this can be achieved by using a phospholipase, so that bread made by the combined use of an anti-staling amylase and a phospholipase has improved softness, both when eaten on the same day and when stored for several days after baking. There is no significant change in the taste or smell of the baked product.
Accordingly, the invention provides a process for preparing a dough or a baked product prepared from the dough which comprises adding to the dough an anti-staling amylase and a phospholipase. The invention also provides a dough and a pre-mix comprising these ingredients.
DETAILED DESCRIPTION OF THE INVENTION
Anti-staling Amylase
The anti-staling amylase used in the invention may be any amylase that is effective in retarding the staling (crumb firming) of baked products.
The amylase preferably has a temperature optimum in the presence of starch in the range of 30-90° C., preferably 50-80° C., particularly 55-75° C., e.g. 60-70° C. The temperature optimum may be measured in a 1% solution of soluble starch at pH 5.5.
The anti-staling amylase may be an endo-amylase, preferably a bacterial endo-amylase, e.g. from Bacillus. A preferred example is a maltogenic alpha-amylase (EC 3.2.1.133), e.g. from Bacillus. A maltogenic alpha-amylase from
B. stearothermophilus
strain NCIB 11837 its commercially available from Novo Nordisk A/S under the tradename Novamyl®. It is further described in U.S. Pat. No. 4,598,048 and U.S. Pat. No. 4,604,355 and in C. Christophersen et al., Starch, vol. 50, No. 1, 39-45 (1997).
Other examples of anti-staling endo-amylases are bacterial alpha-amylases, derived e.g. from Bacillus, particularly
B. licheniformis
or
B. amyloliquefaciens.
The anti-staling amylase may be an exo-amylase such as &bgr;-amylase, e.g. from plant (e.g. soy bean) or from microbial sources (e.g. Bacillus).
The anti-staling amylase is added in an effective amount for retarding the staling (crumb firming) of the baked product. The amount of anti-staling amylase will typically be in the range of 0.01-10 mg of enzyme protein per kg of flour, e.g. 1-10 mg/kg. A maltogenic alpha-amylase is preferably added in an amount of 50-5000 MANU/kg of flour, e.g. 100-1000 MANU/kg. One MANU (
M
altogenic
A
mylase
N
ovo
U
nit) may be defined as the amount of enzyme required to release one Smog of maltose per minute at a concentration of 10 mg of maltotriose (Sigma M 8378) substrate per ml of 0.1 M citrate buffer, pH 5.0 at 37° C. for 30 minutes.
Phospholipase
The phospholipase may have A
1
or A
2
activity to remove fatty acid from the phospholipid and form a lyso-phospholipid. It may or may not have lipase activity, i.e. activity on triglycerides. The phospholipase preferably has a temperature optimum in the range of 30-90° C., e.g. 30-70° C.
The phospholipase may be of animal origin, e.g. from pancreas (e.g. bovine or porcine pancreas), snake venom or bee venom. Alternatively, the phospholipase may be of microbial origin, e.g. from filamentous fungi, yeast or bacteria, such as the genus or species Aspergillus,
A. niger
, Dictyostelium,
D. discoideum
, Mucor,
M. javanicus, M. mucedo, M. subtilissimus
, Neurospora,
N. crassa
, Rhizomucor,
R. pusillus
, Rhizopus,
R. arrhizus, R. japonicus, R. stolonifer
, Sclerotinia,
S. libertiana
, Trichophyton,
T. rubrum
, Whetzelinia,
W. sclerotiorum
, Bacillus,
B. megaterium, B. subtilis
, Citrobacter,
C. freundii
, Enterobacter,
E. aerogenes, E. cloacae
Edwardsiella,
E. tarda
, Etwinia,
E. herbicola
, Escherichia,
E. coli
, Klebsiella,
K. pneumoniae
, Proteus,
P. vulgaris
, Providencia,
P. stuartii
, Salmonella,
S. typhimurium
, Serratia,
S. liquefasciens, S. marcescens
, Shigella,
S. flexneri
, Streptomyces,
S. violeceoruber
, Yersinia, or
Y. enterocolitica
. A preferred phospholipase is derived from a strain of Fusarium, particularly
F. oxysporum
, e.g. from strain DSM 2672, as described in copending PCT/DK 97/00557.
The phospholipase is added in an amount which improves the softness of the bread during the initial period after baking, particularly the first 24 hours. The amount of phospholipase will typically be in the range of 0.01-10 mg of enzyme protein per kg of flour (e.g. 0.1-5 mg/kg) or 200-5000 LEU/kg of flour (e.g. 500-2000 LEU/kg).
A phospholipase with lipase activity is preferably added in an amount corresponding to a lipase activity of 20-1000 LU/kg of flour, particularly 50-500 LU/kg. One LU (Lipase Unit) is defined as the amount of enzyme required to release 1 &mgr;mol butyric acid per minute at 30.0° C.; pH 7.0; with Gum Arabic as emulsifier and tributyrin as substrate.
Phospholipase Activity (LEU)
In the LEU assay, the phospholipase activity is determined from the ability to hydrolyze lecithin at pH 8.0, 40° C. The hydrolysis reaction can be followed by titration with NaOH for a reaction time of 2 minutes. The phospholipase from porcine pancreas has an activity of 510 LEU/mg (taken as standard), and the phospholipase from
Fusarium oxysporum
has an activity of 1540 LEU/mg.
Phospholipid
The phospholipase may act on phospholipid provided by flour in the dough, so the separate addition of a phospholipid is not required. However, the softening effect may be increased by adding a phospholipid, preferably in an amount of 0.05-20 g/kg of flour, e.g. 0.1-10 g/kg. The phospholipid may be a diacyl-glycero-phospholipid, such as lecithin or cephalin.
Dough
The dough of the invention generally comprises wheat meal or wheat flour and/or other types of meal, flour or starch such as corn flour, corn starch, rye meal, rye flour, oat flour, oat meal, soy flour, sorghum meal, sorghum flour, potato meal, potato flour or potato starch.
The dough of the invention may be fresh, frozen or par-baked.
The dough of the invention is normally a leavened dough or a dough to be subjected to leavening. The dough may be leavened in various ways, such as by adding chemical leavening agents, e.g., sodium bicarbonate or by adding a leaven (fermenting dough), but it is preferred to leaven the dough by adding a suitable yeast culture, such as a culture of
Saccharomyces cerevisiae
(baker's yeast), e.g. a commercially
Fuglsang Claus Crone
Nilsson Lone
Spendler Tina
Garbell Esq. Jason I.
Lambiris Esq. Elias J.
Novozymes
Wong Leslie
LandOfFree
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