Patent Application
20120070558
The present invention relates to a novel process for preparing highly stable oil compositions and to the oil compositions obtained thereby. In particular, the present invention relates to highly stable, additive-free oil compositions and to highly stable, micronutrient enriched compositions.
Crude (or “unrefined”) oils and fats are protected from degradation by various naturally occurring antioxidants such as tocopherols. Unfortunately, during the refining process, these naturally occurring antioxidants and other beneficial micronutrients are largely removed. This problem can be exacerbated by modifications (such as fractionation, esterification or hydrogenation) that are used to adapt oils for a particular end use. As a result, fully refined and/or modified oils will have a tendency to become rancid relatively quickly thereby reducing their oxidative stability and shelf-life.
Oil refining typically consists of the following main steps: degumming and/or alkali refining, bleaching and physical refining and/or deodorising. Degumming is carried out, in its most simple form, by mixing the oil with citric or phosphoric acid (or any other food-grade acid) to remove phosphatides and soaps. The bleaching step targets impurities such as metals, trace phosphatides, pigments and peroxides to improve the colour and flavour of the refined oil by contacting the degummed oil with a bleaching earth or clay. Finally, during deodorising, free fatty acids (FFAs) and other volatile impurities are removed by treating (or “stripping”) the bleached oil with steam. The deodorised oil is then cooled and stored, ready for use. The deodoriser vapour is also recovered and condensed into a so-called FFA-rich distillate which can be used e.g. for animal feed and other applications.
Deodorisation has traditionally been carried out at temperatures of about 240-260° C. Unfortunately, this results not only in the stripping off of undesirable FFAs but also in the loss of various valuable volatile micronutrients, including antioxidants such as tocopherols.
A number of processes have been developed to address this problem. U.S. Pat. No. 5,932,261 (Global Palm Products), for instance, suggests using a gentler deodorising step (i.e. performed at a lower temperature) to reduce the loss of micronutrients. Unfortunately, this process is not only less efficient for the removal of FFAs, it is also inefficient at reducing carotenoid content, resulting in oils with an undesirable red colour.
Another solution that has been proposed is to actually introduce into the oil some distillate scum recovered from previous refining processes, thereby helping to restore micronutrient levels (see U.S. Pat. No. 2,363,672 from General Mills, for instance). This comes with the obvious disadvantage that one would simultaneously be reintroducing unwanted FFAs and other undesirable impurities. Recent developments (see US2004/0210070—from Cargill) have therefore focused on separating out, from the deodoriser distillate, two distinct streams: a micronutrient-rich condensate and an FFA-rich condensate. The micronutrient-rich condensate can then be stored and used, as a valuable additive, to increase the antioxidant content of other refined oils.
The drawback to this solution is that the use of such additives must be marked on food labels (as dictated by national laws and regulations) and may be perceived negatively by consumers.
There is therefore a drive by oil manufacturers and food producers to develop refined oils with desirable colour, taste and odour, which have a good oxidative stability but which do not rely on the use of additives.
The present invention addresses these needs.
According to one aspect of the present invention, there is provided a process for preparing a stable, non-hydrogenated oil composition, characterised in that it comprises the steps of:
According to another aspect of the present invention, there is provided an oil composition obtainable according to the above process.
According to a further aspect of the present invention, there is provided a refined, non-hydrogenated oil composition produced from a crude oil containing natural micronutrients, said refined oil composition having oxidative stability and comprising:
According to a further aspect of the present invention, there is provided a non-hydrogenated, stable oil composition comprising micronutrients in a proportion which is not in excess of their original concentration in the corresponding crude oil, said micronutrients having not been more than temporarily separated from the oil during processing.
According to another aspect of the present invention, there is provided a food, feed or beverage composition comprising an oil composition as defined herein.
The present invention provides a process for preparing a stable, non-hydrogenated oil composition, characterised in that it comprises the steps of:
The term “oil composition” as used herein refers to any edible (preferably refined) oil or fat derived, for example, from one or more vegetable and/or animal sources. The term includes both oils and/or fats from a single origin and blends of two or more oils and/or fats from different sources or with different characteristics. Preferably, it will refer to vegetable oils or vegetable oil blends. Examples of suitable vegetable oils include: soybean oil, corn oil, cottonseed oil, palm oil, palm kernel oil, peanut oil, rapeseed oil, safflower oil, sunflower oil, sesame seed oil, rice bran oil, coconut oil, canola oil and any fractions or derivatives thereof.
Oil compositions obtainable according to the above process are also part of the present invention as described in more detail below.
The term “oil composition” will be used to distinguish an edible or refined oil and/or fat from a crude oil which is an oil and/or fat in its pre-refined, raw state, i.e. as extracted from its original source. Crude oils contain high levels of free fatty acids (FFAs), impurities and/or other contaminants such as pesticides or polyaromatic hydrocarbons (which may cause some food-safety concerns or impart some undesirable colour, taste or odour to the oil). Both the impurities/contaminants and FFAs must be removed before the composition is deemed food-safe.
Advantageously, the process of the present invention is able to achieve this whilst maintaining or even enhancing the oil's micronutrient levels. The term “micronutrient” as used herein refers to any compound (a) which may have some nutritive or beneficial effect for the consumer or for the stability of the oil composition itself, even when used only in very small quantities, and (b) which is naturally present, even if only in trace amounts, in crude oils. Micronutrient levels will typically be expressed in “parts per million” (ppm or mg/kg), with certain micronutrients having established concentrations (see, for example, the Codex standards on oils—www.codexalimentarius.net—which provides established levels of various micronutrients in crude oils and certain maximum permitted levels in refined oils). For the sake of the present invention, we will refer to the micronutrient level in a crude oil as being the industry-established average level of that particular micronutrient in a specific oil type.
Examples of micronutrients of particular interest for the present invention include, but are not limited to, tocopherols and tocotrienols, sterols, sterol-esters, (poly)phenols, squalenes, certain phospholipids, specific triglycerides and diglycerides and any mixtures of two or more thereof. Micronutrients of particular interest for the present invention include tocopherols and tocotrienols.
Tocopherols and tocotrienols are fat-soluble antioxidants associated with a number of health benefits (neurological development, fertility, etc.) thanks to their Vitamin E activity. They both feature a chromanol ring (with a hydroxyl group that can donate a hydrogen atom to reduce free radicals and a hydrophobic side chain which allows for penetration into biological membranes) and both occur in alpha, beta, gamma and delta forms (determined by the number of methyl groups on their chromanol ring). Tocotrienols differ from their analogous tocopherols by the presence of three double bonds in their hydrophobic side chain. Although the various tocopherols and tocotrienols each have a slightly different biological activity, for ease of reference herein, they will all be referred to under the heading of TOCOLS (unless expressly mentioned otherwise).
Thus, according to one particular embodiment, the present invention provides a process for producing oil compositions which can preserve TOCOL levels or even enhance them. The process of the present invention will now be described in more detail.
In a first step of the process of the present invention, a crude oil is provided. The crude oil may be a single-origin oil or a blend of oils, as defined above. As part of the process of the invention, the crude oil will necessarily be deodorised. Preferably, however, prior to deodorising, it may also be degummed, physically refined, alkali refined and/or bleached. Each of these steps may be carried out on a continuous basis or as batch processes. Preferably, the steps will be continuous.
Degumming
Any of a variety of degumming processes known in the art may be used. One such process (known as “water degumming”) includes mixing water with the crude oil and separating the resulting mixture into an oil component and an oil-insoluble hydrated phosphatides component, sometimes referred to as “wet gum” or “wet lecithin”. Alternatively, phosphatide content can be reduced (or further reduced) by other degumming processes, such as acid degumming, enzymatic degumming (e.g., ENZYMAX from Lurgi) or chemical degumming (e.g., SUPERIUNI degumming from Unilever or TOP degumming from VandeMoortele/Dijkstra CS).
Alkali Refining
If so desired, crude or degummed oil may be refined via alkali refining. In alkali refining, the oil is commonly mixed with a hot, aqueous alkali solution, producing a mixture of partially refined or “neutral” oil and soapstock. The soapstock is then separated off and the partially refined oil is delivered to the next refining step.
Bleaching
The crude or partially refined oil may then be delivered to a bleaching system. The nature and operation of the bleaching system will depend, at least in part, on the nature and quality of the oil being bleached. Generally, the raw or partially refined oil will be mixed with a bleaching agent which combines with oxidation products, trace phosphatides, trace soaps, and other compounds adversely affecting the colour and flavour of the oil. As is known in the art, the nature of the bleaching agent can be selected to match the nature of the crude or partially refined oil to yield a desirable bleached oil. Bleaching agents generally include natural or “activated” bleaching clays, also referred to as “bleaching earths”, activated carbon and various silicates. A skilled person will be able to select a suitable bleaching agent from those that are commercially available.
Deodorising
According to an essential element of the invention, the crude, partially refined or bleached oil must undergo a physical refining step referred to as “deodorising”. The deodorising process and its many variations and manipulations are well known in the art. Preferably, it will include introducing the oil into a deodoriser and contacting it with steam to vaporize and drive off free fatty acids and other volatile impurities, resulting in a deodorised oil and a vapour stream.
The deodoriser may be any of a wide variety of commercially available deodorizing systems, including both multi-chamber deodorisers (such as those sold by Krupp of Hamburg, Germany; De Smet Group, S.A. of Brussels, Belgium; Gianazza Technology s.r.l. of Legnano, Italy; Alfa Laval AB of Lund, Sweden, or others) and multi-tray deodorisers (such as those sold by Krupp, DeSmet Group, S.A., and Crown Ironworks of the United States).
The deodoriser is desirably maintained at an elevated temperature and a reduced pressure to better volatilise the FFAs and other volatile impurities. The precise temperature and pressure may vary depending on the nature and quality of the oil being processed. According to one possible embodiment of the invention, the deodoriser will be maintained at a pressure of no greater than 10 mm Hg. Preferably, it will be maintained at a pressure of no greater than 5 mm Hg, e.g., 1-4 mm Hg.
The temperature in the deodoriser may be varied as desired to optimize the yield and quality of the deodorised oil. At higher temperatures, reactions which may degrade the quality of the oil will proceed more quickly. For example, at higher temperatures, cis-fatty acids may be converted into their less desirable trans form. Operating the deodorizer at lower temperatures may minimize the cis-to-trans conversion, but will generally take longer to remove the requisite percentage of volatile impurities. For most vegetable oils, maintaining the oil at a temperature of 200° C. or higher should suffice. In many circumstances, an oil temperature of about 230-285° C. is suitable, with temperatures of about 240-270° C. being useful for many oils.
In one exemplary embodiment useful in physically refining palm oil, the deodoriser will be maintained at a pressure of 2-3 mm Hg and the oil will be heated to a temperature of about 260-270° C. Temperatures of about 240-250° C. and pressures of about 1-4 mm Hg are appropriate for deodorizing hydrogenated oils and alkali-refined soybean oil, rape oil and sunflower oil. For physical refining of coconut oil or palm kernel oil, temperatures of about 240-245° C. and pressures of about 1-4 mm Hg are preferred. Coconut oil which has been alkali refined may be deodorised at a lower temperature of about 200-220° C. and at a pressure of about 2-3 mm Hg. The exact temperature and pressure to be used in any given situation will readily be determined by the skilled person.
A quantity of steam is delivered to the deodoriser, e.g. through low-pressure steam lines (at 1-5 Bar for example), and is then sprayed into the oil. As the steam, which may be superheated, bubbles through the oil, it will help strip it of its FFAs and other volatile impurities. The flow rate of steam through the oil will vary depending on the nature and quality of the oil being deodorised and the pressure and temperatures in the deodoriser. Generally, though, steam flow rates in the order of 0.7-2.5 weight percent (wt. %) of the oil flow rates should suffice for most common processing conditions. This produces a steam-containing vapour stream which is delivered from the deodoriser to one or more condensers.
Condensing
Traditionally, the vapour stream would have been condensed into a single deodoriser distillate. According to the process of the present invention, however, the vapour stream will be condensed into at least a micronutrient-rich condensate and one or more other micronutrient-poor condensates or waste streams.
According to one embodiment of the invention, the vapour stream from the deodoriser will be introduced into in a recovery condenser, where it will be partially cooled to an intermediate temperature to preferentially condense the less volatile desired components (and thereby yielding a micronutrient-rich condensate). Most of the more volatile impurities will remain largely in vapour form. The temperature and quench rate of the vapour in the recovery condenser can be controlled to increase recovery of the desired components while minimizing the percentage of impurities passing into the micronutrient-rich condensate.
An intermediate temperature in the order of 50-90% of the initial temperature of the deodorised oil may, for example, be appropriate. Preferably, an intermediate temperature of about 60-80% will be used and, in certain embodiments, 70-80%. Alternatively, the intermediate temperature will be about 0-90° C. lower than the initial temperature, with a temperature differential of about 0-40° C., preferably of about 10-40° C., being useful in many deodorisers. In one specific embodiment suitable for processing palm oil, the vapor stream is cooled in the recovery condenser to an intermediate temperature of no less than 170° C., e.g. to 170-240° C.
The micronutrient-rich condensate will preferably include a substantial fraction, preferably greater than 50%, more preferably greater than 70%, more preferably greater than 80%, more preferably greater than 90% and optimally greater than 95% by weight, of the desirable components (micronutrients) from the vapour stream. At the same time, it should have a relatively minor fraction of any undesirable impurities. Thus, the recovery condenser will yield a relatively impurity-poor micronutrient-rich condensate and a relatively impurity-rich, micronutrient-poor by-product vapour (which may then be delivered to a by-product condenser for further processing).
Blending
The micronutrient-rich condensate, once isolated or separated from the vapour stream, will be blended with the deodorised oil. Preferably, the condensate and the oil will be blended on a continuous basis. In practice, the micronutrient-rich condensate will be recovered and brought into contact with the deodorised oil once the later has exited the deodoriser.
The condensate and oil may be blended using standard oil blending techniques. For example, the condensate may be brought into contact with the deodorised oil via one or more spray heads in fluid communication with a deodorised oil collection vessel. The flow rate of the condensate into the deodorised oil (or the quantity of condensate being blended with the oil) will depend, of course, on the desired end product (namely whether it is desired to produce e.g. a stable but additive-free composition or a micronutrient-enriched composition—as defined in more detail below).
Thus, according to one particular embodiment, only enough condensate will be returned to the oil to compensate for micronutrient losses caused by the refining process. For example, if the crude oil contains 1000 ppm TOCOLS (the Codex standard states that palm oil, for instance, contains up to 1500 ppm total TOCOLS), then the condensate will be dosed such as to return the level of TOCOLS in the refined oil to approximately 1000 ppm.
Preferably, the condensate will be blended with the deodorised oil such that the resulting composition contains 75-100%, preferably 90-100% by weight of the crude oil micronutrient content. In this embodiment, the micronutrients will only have been temporarily separated from the oil before being blended back. The oil will therefore, and advantageously, not need to be labelled as containing any additives.
As will be seen below, in a preferred embodiment, the process of the present invention may include some additional, final refining steps. Since these may result in a further loss of micronutrient content, it may be desirable to add back more than 100% by weight of the condensate in order, in effect, to “pre-compensate” for these further losses. Alternatively, it may be desirable to blend back more than 100% by weight of the condensate to produce a micronutrient-enriched composition. Such an enriched composition may contain, for example, up to 2500% by weight of the micronutrient content of the crude oil.
Further Refining
The oil composition obtained by blending the deodorised oil and the micronutrient-rich condensate, as described above, may be used as such. Preferably, however, the process of the present invention will include one or more further refining steps.
According to one possible embodiment, before returning the temporarily removed condensate to the deodorised oil, it may itself be subjected to further refining steps (e.g. alkali refining, bleaching and/or deodorising, as previously defined). Alternatively, additional refining steps may be performed after blending the oil and the condensate. These additional refining steps will preferably include an FFA-removal step such as a mild deodorising step. The term “mild deodorising” as used herein refers to a deodorising process which is carried out under less severe conditions than the standard deodorising process described above (e.g. for less time and/or at a lower temperature). This will reduce micronutrient losses while ensuring that a minimum level of FFAs and other volatile impurities remain in the final oil composition
Thus, according to one particular embodiment of the present invention, there is provided a process for preparing an oil composition, characterised in that it comprises the steps of:
Modifications
In addition to the above refining steps, the process of the present invention may also include one or more modification steps. These may be selected from one or more chemical, physical or enzymatic modifications or any combination thereof. Preferably, the process will include one or more esterification or interesterification and/or fractionation steps.
Oil modification is generally applied to change the melting and crystallization properties of an oil. Fractionation is used to separate liquid and solid fractions of an oil through crystallization, resulting in two oil products, one with a decreased melting point and one with an increased melting point. Esterification is a process in which fatty acids are either randomly or in a targeted manner exchanged along the glycerol backbone. The exchange can take place between two or more different types of oils or within a single oil in order to randomize the distribution of fatty acids along the glycerol backbone.
The timing of these modifications will of course depend on the desired end composition and the skilled person will be able to determine their preferred order. For example, the oils may be modified before the refining steps, after refining but before blending with the micronutrient-rich condensate, after blending or any combination thereof.
Thus, according to one particular aspect of the present invention, there is provided a process for preparing an oil composition, characterised in that it comprises the steps of:
The process of the present invention provides oil compositions which will have good stability, in particular, good oxidative stability (i.e. they will be more resistant to developing rancidity than corresponding oils with lower levels of micronutrients and, in particular, lower levels of TOCOLs). Thus, unlike methods of the prior art (see U.S. Pat. No. 2,363,672 for example), it will not be necessary to use hydrogenation to impart stability. Hydrogenation changes unsaturated fatty acids into saturated fatty acids and is typically used to increase the melting point of an oil. Accordingly, although the process of the present invention does not need to (and will preferably not) include a hydrogenation step, such a step may be incorporated by the skilled person, for instance to alter the texture or melting point of the composition.
The process of the present invention may further include the optional step of mixing in one or more additional oils. This step may be performed at any stage. For example, one or more oils may be mixed to the blend of deodorised oil and condensate. Alternatively, it may be mixed with the deodorised oil before blending with the condensate (either before or after modification if a modification step is included). The one or more additional oils may be crude, partially or fully refined oils or mixtures thereof. The most appropriate oil type and timing of addition will be apparent to the person skilled in the art based on the desired final product.
Products obtainable according to the above-defined process, with its various possible embodiments, are also part of the present invention. They will now be described in more detail.
The present invention provides a process for producing two main categories of oil compositions: those which are micronutrient-enriched and those which are additive-free but which still have good oxidative stability, as defined above. These compositions as such are also part of the present invention.
In particular, the present invention provides a refined oil composition produced from a crude oil containing natural micronutrients, said oil composition comprising:
As noted above, the term “oil composition” as used herein refers to an edible oil or oil blend. The term “refined oil” takes its normal meaning in the art, that is to say an oil or oil blend that has undergone a refining process as exemplified above. By definition therefore, a refined oil will be free, or substantially free, of undesirable impurities. FFAs, for example, should be present in the composition in an amount of less than 0.1%, preferably less than 0.05% even more preferably less than 0.01% by weight. Similarly, to ensure the composition has an appealing neutral colour, carotenoids should be present in an amount of no more than 1%, preferably no more than 0.1%, more preferably no more than 0.01% by weight.
The compositions will have good oxidative stability without being hydrogenated. According to one broad perspective, the composition may have a micronutrient content equal to between 75 and 2500% by weight of the micronutrient content of the crude oil. Typically however, the skilled person will either select to maintain a micronutrient content as close as possible to its crude levels or to enhance the micronutrient content to levels which are higher than the corresponding crude levels. These two possibilities will be described in more detail below.
Additive-Free Compositions
The term “additive-free” as used herein refers to a composition which does not have to be labelled as containing any additives according to Article 6.4(c) of the EU Food Labelling Directive 2000/13:EC. This states that “constituents of an ingredient which have been temporarily separated during the manufacturing process and later reintroduced but not in excess of their original proportions” do not have to be listed as separate ingredients. Thus, the present invention provides oil compositions containing micronutrients in a proportion which is not in excess of their original concentration in the corresponding crude oil, said micronutrients having not been more than temporarily separated from the oil during processing. For example, the present invention provides a refined oil containing TOCOLS in an amount which is sufficient to ensure oxidative stability but which is not in excess of the corresponding crude oil TOCOL content, said TOCOLS having not been more than temporarily separated from the oil during processing.
The exact micronutrient content will of course depend on the oil composition under consideration. For example, an oil composition derived from coconut oil will have a lower TOCOL content than one derived from palm oil. Indeed, crude coconut oil typically contains only up to 50 ppm total TOCOLS whereas palm oil may contain up to 1500 ppm (see Codex Standard for Named Vegetable Oils—Codex-Stan 210-1999). According to one illustrative embodiment, the oil composition of the present invention will contain between 600 and 1200 ppm TOCOLS.
In any event, a skilled person will readily be able to determine crude micronutrient content and will thereby be able to define the appropriate micronutrient content of the final oil composition. Preferably, the oil composition of the present invention will have a micronutrient content of between 75 and 100%, more preferably of between 80 and 100%, more preferably of about 90% by weight of the corresponding crude oil content.
According to a particular aspect of the present invention, there is provided an additive-free refined oil composition comprising:
It is indeed an advantage of the present invention that we are able to provide stable, micronutrient-preserved compositions which are relatively free of or low in undesirable compounds (and which do not need to be hydrogenated).
Enriched Compositions
According to an alternative embodiment, the present invention also provides oil compositions, preferably refined oil compositions, which are micronutrient-enriched. The term “enriched” as used herein refers to oil compositions having a micronutrient content which exceeds that of the corresponding crude oil.
Thus, according to a particular embodiment of the present invention, there is provided a refined oil composition comprising micronutrients in an amount of between 100 and 2500%, preferably of between 125 and 1000%, more preferably of between 150 and 500%, more preferably of between 150 and 250% by weight of the corresponding crude micronutrient content.
For example, micronutrient-enriched compositions of the invention may have a TOCOL content of more than 800 ppm, preferably more than 1000 ppm. Again, the exact micronutrient content of each composition will be determined based on the desired end product and on the micronutrient content of the corresponding crude oil. In particular, the skilled person will be able to determine the optimal level of micronutrients based on oil type and intended use. For instance, for some applications, it could be important not to “overload” an oil with anti-oxidants as they could then start acting as pro-oxidants. The enriched compositions of the invention have the advantage of oxidative stability without the need for hydrogenation.
The oil compositions of the present invention, whether micronutrient-enriched or -preserved, will be, in all other respects, like any other oil or oil blend and can be used in the same way, e.g. for the preparation of food and/or beverage compositions, for feed applications or for industrial or technical uses. Such compositions are therefore also part of the present invention.
Food and Beverage Compositions
The products of the present invention may be packaged and sold as such (i.e. as stable, bottled oils) or they may be further blended with one or more other oils or oil compositions and/or with one or more other ingredients, including, if desired, with one or more additives. Where the oil composition of the invention is blended with one or more other oils, these will preferably be deodorised oils and, even more preferably, oil compositions obtainable according to the process of the present invention.
Such compositions and blends may be used for any desired purpose, e.g. in the food and beverage industry. Thus, according to one particular embodiment, the present invention provides a food and/or beverage composition comprising an oil composition or blend as described above.
The products of the invention may, in particular, be used in bakery products (e.g. cakes, breads, doughs, pastries, batters, etc.), culinary products (e.g. bouillons), frozen products (e.g. pizzas, fries, etc.) or dairy products (e.g. cheese products, yogurts, ice-creams, etc.), in fat-based products per se (such as margarines or frying oils), in infant formulas, nutritional supplements and so on, just like any other oil or oil composition.
The products of the invention may be used to provide or to increase oxidative stability (without the need for hydrogenation) and/or they may be used to improve or supplement the nutritional value of a food, feed and/or beverage composition (e.g. by increasing vitamin content).
| Number | Date | Country | Kind |
|---|---|---|---|
| 09006991.5 | May 2009 | EP | regional |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP2010/003181 | 5/26/2010 | WO | 00 | 11/23/2011 |
