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Deaeration processRelated Patent Categories: Food Or Edible Material: Processes, Compositions, And Products, Products Per Se, Or Processes Of Preparing Or Treating Compositions Involving Chemical Reaction By Addition, Combining Diverse Food Material, Or Permanent Additive, Fat Or Oil Is Basic Ingredient Other Than Butter In Emulsion Form, Having Ester Other Than Triglyceridic CarboxylicDeaeration process description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070148315, Deaeration process. Brief Patent Description - Full Patent Description - Patent Application Claims
FIELD OF THE INVENTION [0001] The present invention relates to a process for producing an oil, or an polyunsaturated fatty acid (PUFA). The process involves deaerating an aqueous liquid comprising cells from which the oil or PUFA is (later) obtained. After deaeration, the cells may be pasteurised. The oil or PUFA may then be extracted, purified or isolated from the cells. BACKGROUND OF THE INVENTION [0002] Polyunsaturated fatty acids, or PUFAs, are found naturally and a wide variety of different PUFAs are produced by different single cell organisms (algae, fungi, etc). One particularly important PUFA is arachidonic acid (ARA) which is one of a number of Long Chain Poly-Unsaturated Fatty Acids (LC-PUFAs). Chemically, arachidonic acid is cis-5,8,11,14 eicosatetraenoic acid (20:4) and belongs to the (n-6) family of LC-PUFAs. [0003] Arachidonic acid is a major precursor of a wide variety of biologically active compounds, known collectively as eicosanoids, a group comprising prostaglandins, thromboxanes and leukotrienes. Arachidonic acid is also one of the components of the lipid fraction of human breast milk and is thought to be essential for optimal neurological development in infants. Arachidonic acid has a wide variety of different applications including use in infant formula, foodstuffs and animal feeds. [0004] WO-A-97/37032 refers to the preparation of a microbial PUFA-containing oil from pasteurised biomass. However, there is no disclosure of deaeration prior to pasteurisation. [0005] WO-A-04/001021 published on 31 Dec. 2003 describes more detailed pasteurisation conditions. [0006] Processes involving heating biomass, or microbial cells, are known. WO-A-97/37032 describes that microbial cells can be pasteurised prior to extraction to a PUFA therefrom in the form of an oil. However, the present applicants have found that inclusion of a deaeration process can improve the quality of the oil that can be extracted from the cells. In particular, the resulting oil may oxidise less, or be less oxidised, and may have a lower peroxide value (POV) and/or anisidine value (AnV). DESCRIPTION OF THE INVENTION [0007] The present invention therefore provides an improved process for producing an oil, or a polyunsaturated fatty acid (PUFA). The improvement is the use of deaeration preferably prior to pasteurisation. [0008] A first aspect of the present invention therefore relates to a process for producing an oil, or a polyunsaturated fatty acid (PUFA), the process comprising: [0009] a) deaerating an aqueous liquid comprising cells; and [0010] b) obtaining the oil or PUFA from the cells. [0011] The aqueous liquid is preferably a broth or culture medium, such as a fermentation broth or a broth resulting from fermentation. It may be a liquid taken or removed during fermentation, although preferably it is a broth at the end of fermentation. The cells are preferably microbial cells. The microbial cells may be alive prior to, during and/or after deaeration. [0012] The deaeration of the aqueous liquid preferably results in the removal of air, such as entrained, entrapped, undissolved and/or dissolved air. The process may therefore effectively be, or comprise, a degassing. It may remove gas (e.g. air bubbles). Preferably, the process will remove oxygen, such as dissolved oxygen (e.g. in an entrapped form, or as bubbles). In this context "dissolved" refers to the gas, such as air or oxygen, being present or dissolved in the aqueous liquid (rather than any gas inside the cells). [0013] The deaeration process may also result in other gases being removed from the aqueous liquid, for example carbon dioxide. [0014] The deaeration, because it can preferably remove at least part of the dissolved and/or some undissolved oxygen, can result in reduced oxidation. This may mean that the PUFA and/or the oil may be less oxidised, and therefore of better quality. [0015] It is not immediately apparent that removal of oxygen would be advantageous, because of course the microbial cells require oxygen in order to be able to survive and grow. Indeed, in many fermentation processes, including the preferred processes of the invention, air is supplied to the microbial cells, for example supplied to (such as bubbled into) the aqueous liquid, or culture medium. The cells will divide and grow, and preferably in so doing will also biosynthesise one or more PUFAs. The idea then of stopping oxygen or air supply during the fermentation process in order to effect deaeration, would not be necessarily thought to be an advantageous strategy because this might result in the cells dying, or at the very least their ability to produce PUFAs and other valuable compounds might be compromised. [0016] Deaeration is known for foodstuffs, such as milk, and orange juice, and also in some industrial processes, such as in the manufacture of paper. However, it will be realised that these processes are in a different field from the fermentation of microbial organisms, in particular in order to produce a compound to be extracted, and in those (prior art) systems there are no (living) cells. In some prior art processes, deaeration is performed to reduce bacterial growth, whereas in the present invention, microbial cell growth and survival (including bacterial cells), in order to produce PUFAs, is an important element of the fermentation process that requires oxygen. [0017] There are a number of ways of performing deaeration, including the following: [0018] a) application of vacuum (or reduced pressure); [0019] b) mechanical deaeration/de-gassing (stirring, vibration, use of accelerative forces, e.g. g-force, such as in a centrifuge or a cyclone); [0020] c) viscosity changes (either by dilution with water or other liquids, or by temperature change); [0021] d) change in fermentation conditions, for example a reduction in airlift, air sparging, or the supply of oxygen or air during fermentation, or a reduction in stirring rate; [0022] e) pH change, for example by lowering pH or acidification (e.g. by using carbon dioxide, which when it dissolves in the liquid it forms carbonic acid); [0023] f) filtration, for example by using a filter, capillary or membrane, such as a (preferably inert) polymer, for example PTFE; [0024] g) gas displacement, with an inert gas such as nitrogen or a noble gas such as helium; [0025] h) chemical deaeration, for example using an oxygen scavenger, for example sodium sulphite or hydrazine; [0026] i) time, such as allowing the aqueous liquid to rest, or under conditions that allow a gas such as oxygen or air to diffuse out of the liquid; and/or [0027] j) a combination of one or more of the above methods. [0028] Each of the above nine deaeration methods will now be discussed in more detail. 1. Vacuum (or Reduced Pressure) [0029] A vacuum can be applied above the surface of the aqueous liquid. However, a true vacuum need not always be necessary, instead a preferred method involves a reduction of pressure above the surface of the aqueous liquid, for example while it is in a vessel, such as a fermenting vessel. Preferably the pressure above the aqueous liquid is less than atmospheric or room pressure, or at least represents a reduction in pressure when compared with the pressure inside the fermentor vessel (or pressure during fermentation). There may thus be a pressure reduction when deaeration is to begin, for example once fermentation has finished. [0030] The vacuum or reduced pressure may be applied in a separate vessel from the one in which fermentation took place (such as the fermentor). Liquid may therefore be transferred to a vacuum workstation, or a separate container where a vacuum is applied or can be present. I n this context, when discussing the application of a "vacuum" as one of the methods of deaeration, this should be understood as the application of reduced pressure to the aqueous liquid. This is because it is not absolutely essential that a total vacuum be applied. [0031] Preferably, the pressure applied (during the vacuum deaeration stage) is no more than 800, preferably no more than 600, and optimally no more than 400 mbara (millibar pressure absolute). Under certain circumstances, using the correct equipment, the pressure is preferably no more than 200 or 100 mbara. Preferably the reduced pressure is from 50 to 600 mbara, such as 100 to 500 mbara, and optimally from 200 to 450 mbara. [0032] In a preferred embodiment the aqueous liquid, such as after fermentation, is transferred to a vessel having a reduced pressure, in other words a pressure less than the fermentor (or other vessel from which the aqueous liquid is being transferred). The transfer of the aqueous liquid from these two vessels (such as from a fermentor to reduced pressure vessel) may be assisted, or caused by, that difference in pressure. There may therefore be a transfer pressure, representing the pressure that the aqueous liquid is subjected to during movement from one vessel to the other. This transfer pressure is preferably no more than 0.7, such as 0.6, and preferably no more than 0.5 bar. The transfer pressure may be between 0.7 and 0.3 bar, such as from 0.6 to 0.4 bar. [0033] The reduced pressure vessel may have means for increasing the surface area of the aqueous liquid, to assist deaeration. Thus the aqueous liquid may take on the form of a film, such as a thin film. The aqueous liquid may be forced into a film (such as a thin film) by a mechanical device, for example a nozzle, such as an umbrella nozzle, or a parasol deaerator. The aqueous liquid may therefore be forced onto a curved surface while reduced pressure is applied. By increasing the surface area of the aqueous liquid, such as by forming a film or a spray, this can assist deaeration process, and can result in more efficient degassing. The level of the aqueous liquid inside the reduced vacuum vessel (which will contain the nozzle or curved surface onto which the aqueous liquid is forced) may be from 1 to 2 tenths full. The then deaerated aqueous liquid may then be transferred to a pasteurisation or heating vessel or workstation. Continue reading about Deaeration process... Full patent description for Deaeration process Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Deaeration process patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Deaeration process or other areas of interest. ### Previous Patent Application: Peanut butter having a non-hydrogenated vegetable oil based high diglyceride emulsifier Next Patent Application: Egg that is agitated with edible composition, method and device for manufacturing it Industry Class: Food or edible material: processes, compositions, and products ### FreshPatents.com Support Thank you for viewing the Deaeration process patent info. 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