GB2031937A - Powdered lipid composition and its production and use - Google Patents

Abstract

An edible dry, friable powdered lipid composition for human or animal consumption consists of spray-dried particles each comprising fat and/or oil, protein, and emulsifier, in the absence of any additional particulate coating material on the particles, the total lipid content of the composition being more than 90% by weight and preferably not more than 96% by weight. This product may be used as a feed ingredient for ruminants, and satisfactory pelletted feedstuffs can be achieved having lipid contents of, for example, 5-12% by weight.

Description

SPECIFICATION Powdered lipid composition and its production and use This invention relates to a powdered lipid composition, a process for manufacturing such a composition, and the use of such a composition as a food ingredient for human consumption and for ruminants.

It is desirable to add fats or liquids to the diet of certain animals, such as cows and other ruminants, since diets of natural nutrient density tend to be so bulky that an animal's appetite is satisfied before it has received the full amount of nutrient which it is potentially capable of using to produce dairy products or meat. Bulk fat in the diet interferes with the rumination process and it is therefore desirable to provide the fat in a form which does not do so, for instance by mixing it with a non-fatty carrier material.

Known attempts to provide the fat in a suitable form have included coating the surfaces of known food pellets with fat by spraying or other means, but this technique has been found to be messy and wasteful, gives imprecise control over the level of fat in the finished product, and allows only relatively low quantities of fat to be added if a commercially handleable product is to be produced. Another approach has been to soak carriers such as straw or vermiculite in fat in several stages, but although relatively high levels of fat can thus be incorporated in the carriers, the carriers themselves have undesirably high bulk and substantially no nutritional value, and it has been found in practice that if more than 2 or 3 percent of fat in this form is incorporated into normal feed pellets, there is an undesirable tendency for the fat to be expressed during the pelleting process.

The requirement of young animals, before and after weaning, for diets containing total lipid levels of more than 5% by weight can be satisfied by pelleted feedstuffs containing as an ingredient the composition according to the present invention.

Powdered lipid compositions for human consumption are known, for example, as ingredients in bakery and in "instant" dessert toppings.

The present invention provides an edible, dry, friable, powdered lipid composition consisting of spray-dried particles each comprising fat and/or oil, protein, and emulsifier, in the absence of any additional particulate coating material on the particles, the total lipid content of the composition being more than 900/a by weight and preferably not more than 96% by weight.

The term "total lipid content" is used herein to include the preferred emulsifiers which are themselves lipids, e.g. glycerol monostearate, in addition to fats and oils as such, and any other lipids which may be present.

The powdered lipid composition according to the present invention can be.prepared by a process comprising (1) incorporating air into a solution of the protein and the emulsifier in which the fat and/or oil is emulsified, the amount of air thus incorporated being sufficient for a substantial puff drying effect during subsequent spray drying of the resulting emulsion, and (2) spray drying the emulsion under conditions which bring about said puff drying while limiting the thermal shock experienced by the sprayed emulsion particles during drying to a level below that at which the dried protein ceases to protect the dried particles from adhesion to one another and to the spray-drying equipment. "Thermal shock" means an undesirably high rate of rise in temperature or an undesirably long period of exposure to high temperature. "Puff drying" is spray drying in which the particles of the spray to be dried contain air (or other gas) so that when they meet the hot drying gas rapid expansion and fracturing of the particles occur and speed up the drying of the particles.

We have discovered that the combination of puff drying with relatively gentle thermal drying can be regulated to produce dry, friable, powdered compositions having total lipid contents of more than 90%, usually at least 92%, and preferably about 95%, by weight, in the absence of any additional particulate coating without any significant agglomeration of the dried particles.

This new product can be produced so economicallythat it is commercially attractive as a very highlipid-content feed ingredient for ruminants, although it can of course be used for other purposes, where different cost factors may apply.

Once suitable relatively gentle spray drying conditions have been established by trial and error adjustments of the various spray drying parameters, drying can be carried on for extended periods of some days without unacceptable accumulation of adherent particles in the drier.

While known high-pressure injection equipment can be used to incorporate the necessary air in the emulsion, it is preferred to use a different method which not only eliminates the need for special equipment, but produces a superior result in that the dried product has a higher bulk density. In this preferred method, the air is directly incorporated from the ambient atmosphere by mechanical agitation of the emulsion at an appropriate viscosity, which enables the solution to retain a suitable amount of the air.

While any equipment which can be adjusted to produce the requisite spray drying conditions could be used, it is preferred to use a vertical countercurrent spray drier, since the counter-flow of the sprayed particles of the emulsion against the incoming hot air tends to cool the air approaching the position where the spray particles first encounter it. This helps to achieve the necessary gentle drying with limitation of the thermal shock experienced by the particles. It has been observed that satisfactory drying is accompanied by a rapid and complete change from sticky spherical spray particles te friable irregular angularly shaped particles.A drier of the kind mentioned arranged to introduce the hot air (e.g. at about 140"C.) substantially tangentially to the direction of flow of the sprayed particles has been found to give particularly good results.

The particle size and velocity must be adjusted to suit the conditions so that the particles undergo rapid drying in the hot air zone or "curtain" before falling into the relatively cool zone towards the bottom of the drier.

Rotating disc-type atomisers, and less preferably, other types of atomisers, e.g. nozzle types, can be used to spray the emulsion in the drier.

The drier may be constructed of any convenient materials capable of withstanding the temperatures and other conditions encountered in use, mainly metal construction being usual.

It is important that the dried powder be handled appropriately. In particular it must not be subjected to pneumatic handling, since the high velocities usually achieved tend to cause impacts which break up the particles, allowing the lipid to exude with obviously undesirable effects on the storage life of the product. It has been found, somewhat suprisingly, that slow moving sweeper gear can be used to extractthe powder from a flat-bottomed drier without causing any significant degree of exudation, the recovered powder then being conveyed by a vibrator to bucket elevators and thence into a cooler of known type.

The powdered lipid composition of the present invention, by virtue of its very high total lipid content, is particularly useful as a feed ingredient for ruminants.

We have found that total lipid contents of more than 90% by weight can be achieved, 92% or even 95% lipid content being quite practicable. The preferred protein is a soluble protein, preferably derived from milk, e.g. casein or a water-soluble caseinate or co-precipitate, although use of other soluble proteins such as soya protein or other vegetable proteins is technically feasible, and materials containing casein in admixture with other non-fat milk solids may also be used, provided that the chosen material is capable of forming a solution which can satisfactorily incorporate the air before being spray dried.It is preferred to use water-soluble caseinates, such as sodium or potassium caseinate, but it is also possible to produce spray dried particles containing casein itself by using an ammoniacal solution in which the casein is in the form of ammonium caseinate, ammonia being driven off during the spray drying to regenerate the casein. The waterinsolubility of the resulting casein may be advantageous in the finished spray dried product, but in practice the caseinates which are soluble in water of substantially neutral pH are usually preferred, in order to avoid having to cope with ammonia fumes in the production plant.

Emulsifiers giving the particles the necessary thermoplastic properties for successful spray drying can be selected by trial and error, and suitable quantities of the emulsifier can readily be determined, at least 1% emulsifier usually being used, and 5% emulsifier being preferred, based on the weight of the finished product. Emulsifiers which are them selves lipids having a melting point of at least40 C.

are preferred, and a preferred formula comprises 90 /0 fat or oil, 5% protein, and 5% emulsifier lipid. For ruminant feed ingredients, it is advantageous to use an edible emulsifier which has a physiological effect similar to that of fat when eaten by a ruminant, the preferred emulsifier being glycerol monostearate (GMS). Other suitable emulsifiers are, for example, distilled monoglycerides, polyglycerol esters, propylene glycol esters, sorbitan esters, lactylates, lactopalmitates, diacetyl tartaric acid esters, sucroglycerides, and mixtures thereof.

A preferred specification for the product is (percentages by weight): moisture less than 1% total lipid (+ emulsifier) not less than 9.3% protein not less than 3.8% Suitable fats and oils for use in the composition according to the invention include, for example, solid fats such as beef tallow, hog fat, coconut oil, palm oil and palm kernel oil, and suprisingly, liquid (at ambient temperatures or even down to below zero Celsius) fats and oils such as soya oil, cotton seed oil, linseed oil or corn oil or combinations of these oils. Preferably, a fat is used which has a melting point substantially higher than the normal storage temperature to be encountered by the feed ingredient product.

The solution of the soluble protein, e.g. the aforementioned sodium caseinate, may be dissolved at 60 C and vigorously agitated in orderto incorporate air. The selected fat and/or oil and emulsifier, preferably pre-blended together, are added with agitation at high speed until a good emulsion is formed.

This emulsion is then homogenised at 80-850C, preferably until the lipid particle size of the emulsion is less than 4 microns.

The following is a specific Example of the invention.

EXAMPLE An emulsion of 90 kilos of tallow/lard blend, 5 kilos of glycerol monostearate, and 5.5 kilos of sodium caseinate in 300 litres of water is prepared as follows. The water is metered into a steam jacketed mixing vessel and heated to 60"C. Sodium caseinate is added and dissolved with vigorous agitation. This agitation is continued until sufficient air has been incorporated into the caseinate solution, preferably not less than 80% by volume. When the required volume has been acbieved, a pre-blended combination of the fat blend and the glycerol mono-stearate is added and the whole mixture is agitated at high speed until well emulsified. The emulsion is then heated to 85"C, and pumped through a homogeniser which homogenises the emulsion at a pressure of 70 Kg/cm2. The homogenised solution is then pumped to a spray drier, and a dry friable product having a moisture content of less than 1% is recovered and cooled.

The animal fat blend used in this Example has the following characteristics: free fatty acid - less than 1.5%; peroxide value - less than 3 milliequiv/kilo; melting point - 37 to 45"C; colour - cream; smell bland; moisture - less than 1%.

The sodium caseinate used has the characteris tics: protein content - 85 to 92%; moisture - less than 12%; pH - 6.6 to 6.9; flavour- bland; colour-white to cream; solubility - completely soluble in water at pH 6.5 to 7.0; sediment - disc B maximum.

The glycerol monostearate used in this Example has a free fatty acid content of less than 2 and a monoester content of not less than 40%.

The product according to this invention has the advantage of being readiiy re-emusifiable at temperatures above the lipid melting point.

The product can be fed to humans as a foodstuff ingredient, and to ruminants, for example by incorporation in or mixing with their feedstuff, with highly satisfactory results in terms of handling, storage, and cost-effectiveness.

Pelletted feedstuffs have been satisfactorily prepared (without exudation of the lipid) using known pelletting equipment. Highly desirable total lipid contents of 5-12%, typically 8-10%, by weight, based on the total feedstuff weight, have been achieved using the new product. For example, the new product can be used to add up to 8% lipid to feedstuffs having a residual natural lipid content of about 4%, while with zero natural lipid content, the new product can be used to provide a satisfactory pelletted feedstuff having up to at least 100/o lipid content, on the aforesaid basis.

Feedstuffs having metabolizable energy levels exceeding 13.6 MJ/kg, typically 14-15 MJ/kg, can thus be produced, and it has been found that cows of about 500 kg. liveweight can consume daily up to 1.3 kg of lipid by way of such feedstuffs without depression of appetite, milk yield, or butterfat yield, whereas such depression is usually observed when cows eat more than 0.5 kg per day of lipid by way of conventional feedstuffs. Consumption of the feedstuffs according to the present invention can, in some conditions, increase the milk and/or butterfat yield.

Claims (26)

1. An edible, dry, friable, powdered lipid composition consisting of spray-dried particles each comprising fat and/or oil, protein, and emulsifier, in the absence of any additional particulate coating material on the particles, the total lipid content of the composition being more than 90 /O by weight.

2. A composition according to claim 1, wherein the total lipid content is not more than 96% by weight.

3. A composition according to claim 1 or 2, wherein the protein is a water-soluble casein derivative.

4. A composition according to claim 3, wherein the protein is sodium or potassium caseinate.

5. A composition according to claim 3, wherein the protein is a water-soluble protein of plant origin.

6. A composition according to any one of the preceding claims, wherein said fat and/or oil is one which is normally liquid at ambient temperatures.

7. A composition according to any one of claims 1 to 5, wherein said fat and/or oil has a melting point higher than the normal storage temperature to be encountered by the composition.

8. A composition according to any one of the preceding claims having at least 92% by weight total lipid content.

9. A composition according to claim 8, having substantially 95% by weight total lipid content.

10. A composition according to claim 9, comprising, by weight, substantially 90% fat or oil, 5% protein, and 5% emulsifier lipid.

11. A composition according to any one of the preceding claims, wherein the average size of the individual lipid material particles is less than 4 microns.

12. A composition according to any one of the preceding claims, wherein the emulsifier has a melting point of at least400C.

13. A composition according to any one of the preceding claims, wherein the emulsifier is a material having a physiological effect similar to that of fat when eaten bya ruminant.

14. Acomposition according to claim 12, wherein the emulsifier is glycerol monostearate.

15. A composition according to claim 12, wherein the emulsifier comprises one or more of distilled monoglycerides, polyglycerol esters, propylene glycol esters, sorbitan esters, lactylates, lactopalmitates, diacetyl tartaric acid esters, sucroglycerides, and their mixtures.

16. A composition according to claim 1, substantially as described in the foregoing Example.

17. A process for preparing a powdered lipid composition according to claim 1, comprising (1) incorporating air into a solution of the protein and the emulsifier in which the fat and/or oil is emulsified, the amount of air thus incorporated being sufficient for a substantial puff drying effect during subsequent spray drying of the resulting emulsion, and (2) spray drying the emulsion under conditions which bring about said puff drying while limiting the thermal shock experienced by the sprayed emulsion particles during drying to a level below that at which the dried protein ceases to protect the dried particles from adhesion to one another and to the spraydrying equipment.

18. A process according to claim 17, wherein the air is directly incorporated from the ambient atmosphere by mechanical agitation of the protein/fat and/or oil mixture.

19. A process according to claim 17 or 18, wherein the emulsion is formed by blending together fat and/or oil and the emulsifier and then incorporating this mixture in the solution of the protein.

20. A process according to claim 17 substantially as hereinbefore described.

21. A lipid composition when prepared by the process of any of claims 17 to 20.

22. Afoodstufffor human consumption comprising a lipid composition as claimed in any of claims 1 to 16 or21.

23. Afeedstufffor ruminants comprising a lipid composition as claimed in any one of claims 1 to 16 or21.

24. A feedstuff according to claim 23 in pelletted form having a total lipid content of 5-12% by weight based on the total weight of the feedstuff.

25. A feedstuff according to claim 24 having a total lipid content of 8-10% by weight.

26. A method of feeding a ruminant, which comprises feeding to said ruminant a feedstuff according to claim 23, 24 or 25 in an amount insufficient to depress the ruminant's appetite, milk yield, or butterfat yield.