IE65633B1

IE65633B1 - Process for the removal of cyclodextrin residues from fats and oils

Info

Publication number: IE65633B1
Application number: IE421491A
Authority: IE
Inventors: Jan Dr Cully; Utz Dr Kohlrausch; Heinz-Ruediger Dr Vollbrecht
Original assignee: Sueddeutsche Kalkstickstoff
Priority date: 1990-12-21
Filing date: 1991-12-04
Publication date: 1995-11-01
Also published as: HUT61163A; EP0492475A1; JPH04296396A; DK0492475T3; NO915069D0; NZ240920A; CA2058038A1; PL165829B1; PL292867A1; RU2086618C1; DE59104331D1; EP0492475B1; CZ404691A3; IE914214A1; ZA919676B; HU914055D0; NO915069L; ES2067840T3; HU208474B; AU8963091A

Abstract

To remove cyclodextrin residues from fats and oils, the latter are emulsified in water and the cyclodextrin is enzymatically degraded with the aid of at least one alpha -amylase selected from the alpha -amylases produced by microorganisms of the group Aspergillus niger, Aspergillus oryzae, Bacillus polymyxa, porcine pancreatic amylase, Bacillus coagulans and Flavobacterium, and/or of preferably a CTGase selected from the CTGases produced by bacteria of the group Bacillus, Klebsiella, Micrococcus and alkalophilic bacteria.

Description

The present invention is concerned with a process for the removal of cyclodextrin residues from fats and oils from which complexable, undesired substances,. for example sterols, especially cholesterol, free fatty acids, vitamins, colouring materials and other impurities have been removed with the help of cyclodextrin and which still have a certain residual content of cyclodextrin.

It is known that increased cholesterol levels in the blood serum of humans represent an increased risk factor for arteriosclerosis and for coronary heart disease. For this reason, the endeavours of the foodstuff industry are markedly to reduce the content of cholesterol and cholesterol esters in fat-rich foodstuffs of animal origin, an important problem thereby being substantially to maintain the sensory and nutritional-physiological properties of the foodstuffs.

A relatively gentle process for the removal of cholesterol derivatives is the complexing of these substances with β-cyclodextrin and separation of the complex formed.

According to EP-A 0 256 911, a liquefied fat mass is treated with a solid cyclodextrin, the cholesterol value being said to be reduced by up to 80%. However, for this purpose, a repeated cyclodextrin treatment is necessary. -3From W. Schlenk and V.M. Sand (J.S.C.S., 84, 2312/1961), it is known to complex free fatty acids with cyclodextrin.

In the case of these processes, it is an important 5 problem that a certain amount of the dissolved cyclodextrin remains behind in the fats and oils when the previously known methods are employed for the separation thereof. Normally, cyclodextrins (α, β- and Γ), which are annular oligosaccharides consisting of 6 to 8 glucose units, are not toxicological. Thus, tests for the acute toxicity in mice and rats have also given no indication of a toxic effect in the case of oral administration. Nevertheless, in many countries, cyclodextrins have hitherto not been permitted as food additive.

Therefore, it is an object of the present invention to provide a process for the removal of cyclodextrin residues from fats and oils which, without great technical expense, makes possible a substantial and selective removal of cyclodextrin from the treated starting materials.

Thus, according to the present invention, there is provided a process for the removal of cyclodextrin residues from fats and oils, wherein fats and oils are emulsified with water and the cyclodextrin is broken down enzymatically with the help of at least one ttamylase selected from hog pancreatic amylase and the i -4α-amylases formed by micro-organisms of the group Aspergillus niger, Aspergillus oryzae, Bacillus polymyxa ; and Bacillus coagulans, as well as Flavobacterium and/or preferably of a CTGase selected from the CTGases formed by bacteria of the group Bacillus, Klebsiella, Micrococcus and alkalophilic bacteria.

Surprisingly, we have shown that, in this way, a practically complete breakdown of the cyclodextrin in fats and oils can be achieved in an economically acceptable way. This is surprising because cyclodextrins have been described as being potent inhibitors of the a- and β-amylases (see R.J. Weselake and R.D. Hill, Cereal Chem., 60, 98/1983) and are substantially resistant to most a- and β-amylases. We have now found that a few types of α-amylase, for example those from Bacillus polymyxa and Aspergillus oryzae, as well as hog pancreatic amylase, are admittedly able to hydrolyse cyclodextrins but with low velocities. Therefore, it was especially surprising and not foreseeable that this activity would suffice to break down the cyclodextrin in fat and oil emulsions relatively quickly and completely.

In the process according to the present invention, ϋ the starting material, consisting of fats and oils of animal or vegetable origin, for example- butter fat, hog and beef fat, goose fat, fish oils, sunflower oils and the like, which, because of a treatment with cyclo-5dextrin, still have a residual content of cyclodextrins of, for example, 0.001 to 1.0X by weight, are subjected to an enzymatic treatment.

Preferably, there are thereby used ¢-amylases 5 selected from hog pancreatic amylase and the a-amylases formed by micro-organisms of the group Aspergillus niger, Aspergillus oryzae, Bacillus polymyxa and Bacillus coagulans, as well as Flavobacterium. From the group of the CTGases (cyclodextrin trans-^lycosylases = EC 2.4.1.19), those CTGases formed by bacteria of the group Bacillus (for example Bacillus macerans, Bacillus megaterium, Bacillus stearothermophilus, Bacillus circulans and Bacillus ohbensis), Klebsiella (for example pneumoniae), Micrococcus (for example varians) and alkalophilic bacteria, for example Nos. 38-2 and 17-1, are especially preferred. The mentioned enzymes can also be expressed from host cells of other origin by methods of genetic manipulation. These a-amylases and CTGases make possible a practically complete break20 down of the cyclodextrin. The necessary amount of enzyme thereby depends essentially upon the initial content of cyclodextrin in the fat or oil and, in the case of α-amylase, is usually from 10 to 500 FAU per g of cyclodextrin to be removed (1 FAU = one fungal a25 amylase unit breaks down 5.2 g of starch in one hour under standard conditions (substrate: soluble starch, incubation time 7 to 20 minutes, temperature 37°C, -6pH = 4.7)). In the case of the CTGases, these are preferably used in an amount of 0.5 to 20 U per g of cyclodextrin to be removed (1 unit = conversion of 1 pmol of substrate per minute). It is also possible to use larger amounts of enzyme. However, in general this is uneconomical because an improved effect is not obtained. According to a preferred embodiment of the process according to the present invention, mixtures of a-amylase and CTGase are used.

It is important for the present invention to use the fat or oil in the form of an oil-water emulsion.

For this purpose, the starting material, possibly after liquefaction, is emulsified in water, preferably 0.1 to 5 kg of water thereby being added per kg of fat or oil.

The water can already contain the α-amylase and/or CTGase. However, the enzyme can also be added to the emulsion after the formation thereof. Before the . addition of the enzyme, the pH value of the water or of the emulsion is preferably adjusted to one which is favourable for the enzyme used and especially to one which is optimal for the enzyme used. The adjustment of the pH value is preferably carried out with buffer substances and especially edible substances, for example citric acid, lactic acid and salts thereof.

Co-factors, for example divalent ions, such as calcium or magnesium ions, can possibly be added in trace amounts to the emulsion. Furthermore, acceptors, for -7example glucose, can also be admixed with the CTGases.

The treatment conditions, for example temperature and period of time, can be varied within certain Unit» but the fats and oils should be present in the liquid phase, i.e. the enzymatic decomposition should be carried out at a temperature between the melting point of the fat or oil in question and 70°C. The temperature for the enzymatic decomposition is preferably from 25 to 55°C, in which case treatment times of from 1 to 5 hours are usual.

With the help of the process according to the present invention, it is possible to carry out a substantial and selective removal of the cyclodextrin from the treated fat or oil in a technically especially simple manner, the content of residual cyclodextrin thereby being below a limit of detection of < 10 ppm.

The following Examples are given for the purpose of illustrating the present invention: Example 1. kg of fish oil which has been pretreated with β-cyclodextrin, with a residual content of β-cyclodextrin of 150 ppm, was mixed with 1 kg of water and emulsified at 40°C. The pH value of the emulsion was adjusted with citric acid to 5.5. Subsequently, 50 FAU of an a-amylase mixture from Aspergillus oryzae were added thereto in the form of the commercially available product Fungamyl 800 (Novo). After incubation for -82 hours at 40°C, β-cyclodextrin could no longer be detected (detection limit 10 ppm).

Example 2. kg of a butter oil pretreated with β-cyclodextrin 5 with a residual content of β-cyclodextrin of 2500 ppm was emulsified in 1 kg of water at 50°C. The pH value of the emulsion was adjusted to 6.2 with citric acid and incubated for 2 hours at 50°C with 250 FAU of an α-amylase from Bacillus coagulans (non-purified prepar10 ation). After this treatment, β-cyclodextrin could no longer be detected (detection limit 10 ppm).

Example 3. kg of beef tallow'with a residual content of a-cyclodextrin of 200 ppm was emulsified in a 5 mmol/1 solution of calcium sulphate at 40°C and the pH value was adjusted to 6.5 with citric acid. Subsequently, g of glucose and 20 U of a CTGase from Bacillus macerans were added to the emulsion. After incubation at 40°C for 2.5 hours, α-cyclodextrin could no longer be detected (detection limit 10 ppm).

Claims

Patent Claims

1. Process for the removal of cyclodextrin residues from fats and oils, wherein the fats and oils are emulsified with water and the cyclodextrin is broken 5 down enzymatically with the help of at least one aamylase selected from hog pancreatic amylase and the I ! a-amylases formed by micro-organisms of the group ϋ ; Aspergillus niger, Aspergillus oryzae, Bacillus i a | polymyxa and Bacillus coagulans, as well as Flavoj 10 bacterium and/or preferably of a CTGase selected from I the CTGases formed by bacteria of the group Bacillus, Klebsiella, Micrococcus and alkalophilic bacteria.

2. Process according to claim 1, wherein the a| amylase is used in an amount of from 10 to 500 FAU per g 15 of cyclodextrin to be removed.

3. Process according to claim 1, wherein the CTGase is used in an amount of from 0.5 to 20 U per g of cyclodextrin to be removed.

4. Process according to any of the preceding claims, 20 wherein the enzymatic decomposition is carried out at a temperature between the melting point of the fat or oil and 70°C. 5. Process according to claim 4, wherein the enzymatic decomposition is carried out at a temperature 25 of from 25 to 55°C. 6. Process according to any of the preceding claims, wherein 0.1 to 5 parts by weight of water are -10emulsified with 1 part by weight of fat or oil. 7. Process according to claim 1 for the removal of cyclodextrin residues from fats and oils, substantially as hereinbefore described and exemplified.

5. 8. Fats and oils, whenever freed from residues of cyclodextrin by the process according to any of claims 1 to 7.