Food or edible material: processes – compositions – and products – Fermentation processes – Of whole egg or yolk
Reexamination Certificate
2002-10-18
2004-08-10
Hendricks, Keith (Department: 1761)
Food or edible material: processes, compositions, and products
Fermentation processes
Of whole egg or yolk
C426S614000
Reexamination Certificate
active
06773731
ABSTRACT:
FIELD OF THE INVENTION
This invention pertains to a novel liquid egg yolk product which contains lysophospholipoprotein. More particularly, this invention pertains to a novel liquid egg yolk product containing lysophospholipoprotein from a phospholipoprotein modified using a non-animal derived phospholipase A, and a process therefor, which is kosher, does not have a porcine or bovine source, and does not contain appreciable levels of amylase. The product is useful as an emulsifier in foodstuffs such as sauces, spreads, mayonnaise, dressings, salad dressings, and the like.
BACKGROUND OF THE INVENTION
Phospholipases are enzymes which act on phospholipids which are found in animal and vegetable cells. Phospholipases are selective enzymes which are classified according to their site of action in the phospholipid molecule. Thus, a phospholipase A1 hydrolyzes the bond between the fatty acid and the glycerine residue at the 1-position of the phospholipid.
The hydrolysis of a phospholipid by a phospholipase results in the production of a “lysophospholipid”. Although phospholipids have many industrial uses, lysophospholipids have been shown to be particularly suitable for certain industrial applications. Lysophospholipids have a high solubility in water and this property gives them enhanced emulsification properties in oil/water emulsions. Lysophospholipids have an ability to form emulsions which are reasonably stable to changing pH conditions, including acid conditions, and they are resistant to changing temperatures. The ability of the lysophospholipid to form an oil-water or water-oil emulsion is not reduced by the presence of ions, such as magnesium or calcium ions.
The foregoing properties of the lysophospholipids make them particularly desirable for use in the food, cosmetics and pharmaceutical industries. It has been demonstrated that the conversion of a phospholipid to a lysophospholipid in a phospholipid containing substance, such as a food product, generally leads to an improvement in the stability of that substance.
The most commonly used phospholipase in the industrial hydrolysis of phospholipids is pancreatin, which is an enzyme prepared from the pancreas of pigs. Enzymatic hydrolysis of a phospholipid, using a phospholipase isolated from a micro-organism is, however, known. Such hydrolysis using a phospholipase A is described, for example, in Japanese Unexamined Patent Publication No. Sho-58-212783, and the hydrolysis using a lipase is described in Japanese Unexamined Patent Publication No. Sho63-42691. Furthermore, the enzyme Taka-Diastaseh™, which was isolated from a species of Aspergillus,
A. oryzae,
[Biochem. Z., 261 (1933) 275], has demonstrated a lipase activity which is capable of hydrolyzing a phospholipid. The enzymes isolated from microorganisms have been shown to have less activity than porcine pancreatic enzyme. Moreover, the microorganisms produce amylase and protease as by-products, which are undesirable because they break down starch and proteins and lead to emulsion instability.
Although pancreatin has better properties than enzymes isolated from microorganisms, hydrolysis of a phospholipid using pancreatin has many disadvantages. Firstly, it may be necessary to make continual adjustments to the pH of the reaction mixture during hydrolysis of a phospholipid substrate with porcine pancreatin. The optimum pH for activity of pancreatin is in the range from neutral to weakly alkaline. During the hydrolysis reaction, however, the release of free fatty acids causes the pH to drop, that is, it increases the acidity of the reaction mixture, so that unless counter action is taken, the mixture will become acidic, and therefore outside the pH range for optimum activity of the enzyme.
Traditionally, heat treatment has been used to deactivate the residual enzyme in processes involving the use of enzymes. However, porcine pancreatin has another disadvantage because it is not fully deactivated by heat treatment, and even treatment of the enzyme at a temperature of 95° C. for 30 minutes may not sufficiently deactivate the residual enzyme. The use of a higher temperature is impossible in view of the sensitivity of the phospholipid and free fatty acids to heat.
FEMS Microbiol. Lett. 3(2), 85-7, Vol. 3, No. 2, 1978 discloses the detection of phospholipase A1 activity in various filamentous fungi, including Aspergillus strains, but there is no disclosure of the isolation and purification of the enzyme. Biological Abstracts, vol. 72, Philadelphia, Pa., Abstract No. 012592, discloses the purification and characterization of phospholipids by various phospholipases.
It is known from British patent specification GB-B-1,525,929 (Unilever) to treat phospholipoproteins or phospholipoprotein containing materials, such as egg yolk, whole egg, blood serum, wheat protein, soybean, and the like, with phospholipase A. The phospholipase A is also active when the phospholipid is complexed with protein. After the treatment with the phospholipase, the lysophospholipoprotein is formed. The lysophospholipid is complexed with a protein. The lysophospholipoprotein containing material disclosed in GB-B-1,525,929 has achieved considerable commercial success as an emulsion stabilizer, particularly in oil-in-water emulsions. They enabled the manufacture of sterilizable emulsions, which in practice turned out to be commercially very successful, because they had a long shelf life and an excellent creamy taste.
The following patents disclose subject matter which is related to or relevant to the subject invention.
Japanese Abstract No. 58212783 A2, Kyowa Hakko Kogyo Co. Ltd., discloses a process whereby a microorganism, e.g.
Streptomyces scabies
ATCC15485 or
Streptomyces achromogenes
variety
streptozoticus
NRRL2697, belonging to the genus Streptomyces, and having the ability to produce phospholipase A, is cultivated in a culture medium at 22° C. to 40° C. and a neutral or slightly alkaline pH for about 2 to 6 days. The phospholipase A is collected mainly from the culture fluid.
Japanese Abstract No. 06153939 A2, Snow Brand Milk Prod. Co. Ltd., discloses a process whereby an alga of the genus Euglena (preferably Euglena gracilis) having the ability to produce phospholipase A is cultured in a culture medium containing a carbon source (preferably glucose), a nitrogen source (preferably glutamic acid or diammonium hydrogenphosphate) at 4-35 ratio (C/N) under conditions of preferably pH 3.0-4.5, 20-32° C. culture temperature and irradiation with light or in the dark for 3-7 days, to produce and accumulate phospholipase A in the organism. The resultant phospholipase A is then separated and collected to provide the objective phospholipase A.
U.S. Pat. No. 5,521,080, Hattori et al., discloses a method for preparing a phospholipase A1 which comprises (a) culturing a phospholipase A1 producing strain of Aspergillus under conditions which allow for the production of the phospholipase A1; (b) after culturing, diluting the culture with water or an appropriate buffer solution; (c) filtering the resulting solution under pressure to remove any insoluble matter; and optionally (d) purifying the enzyme.
U.S. Pat Nos. 5,378,623 and 5,538,874, Hattori et al., are related and disclose a phospholipase A1 which is capable of hydrolyzing a phospholipid to produce a 2-acyl lysophospholipid and is obtainable from species of the fungus Aspergillus.
EP 0 575 133 B1, Sankyo Company Limited, discloses a phospholipase A1 obtainable from fungus selected from
Aspergillus niger
and
Aspergillus oryzae
characterized in that said phospholipase A1: (a) hydrolyzes phospholipid between about pH 2.5 and about pH 6.0; (b) has a molecular weight of between about 30,000 and about 40,000 daltons, as determined by sodium dodecyl sulphate polyacrylamide gel electrophoresis; (c) has a stability to temperature with an upper limit of between about 45 and about 90° C.; (d) has a pI under isoelectric point electrophoresis at about pH 2.8 to about pH 4.5; and (e) has an optimum temperature for activity of from about 30 to about 65° C.
Campbell James S.
te Bokkel Derk W.
Thatcher Kristen D.
Hendricks Keith
Oyen Wiggs Green & Mutala
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