CA1097979A

CA1097979A - Food manufacture

Info

Publication number: CA1097979A
Application number: CA291,277A
Authority: CA
Inventors: John W. Chidlow; Philip Porter
Original assignee: Unilever PLC
Current assignee: Unilever PLC
Priority date: 1976-11-23
Filing date: 1977-11-21
Publication date: 1981-03-24
Also published as: CS235066B2; BE861026A; ATA830777A; ZA776963B; DK147152B; IE46093L; IT1091299B; DE2751614A1; GB1596505A; NO147818B; FR2392675B1; FR2392675A1; SE433033B; AU514767B2; AU3075777A; IN147365B; LU78570A1; NL7712830A; DK147152C; JPS5379046A

Abstract

Abstract The invention provides a process for the preparation of a pre-mix in the form of a free-flowing particulate composition in which a minor but essential foodstuff ingredient such as an oral vaccine, a vitamin or a trace element is dispersed uniformly throughout a carrier material which forms the bulk of the pre-mix, in which the carrier material comprises a dry particulate mixture of an edible inert powder and a lactose source, the lactose content of the mixture having from about 20 to about 50% by weight, and the pre-mix is formed by intensely agitating the carrier material and simultane-ously spraying the carrier material with an aqueous solution or slurry of the foodstuff ingredient, the solution or slurry being applied in an amount from about 1 to about 12% by weight of the carrier material. Preferably the solution or slurry applied to the carrier material additionally contains a food-grade colouring agent.

Description

c0.113 ~ ~ 7 ~

The present invention relates to the preparation of pre-mixes use~,l in the manufacture of foodstuffs for humans and for animals, wnich pre-mixes incorporate minor but essential ingredients such as oral vacc mes, vitamins, trace elements and the like.
Pre-mixes are used to assist the blending of such minor but essential ingredients into ~oodstuffs in a homoger.eous manner, ~nd the invention is concerned with the preparation of pre-mixes in the form of free-flowing particulate compositions in which the minor but essential ingredient, or each such ingredient where more than one is to be incorporated in a common pre-mix, i9 dispersed unifo~mly throughout a carrier material which forms the bulk of the pre-mlx~
For the purposes of this specification, an oral vaccine or other minor but essential ingredient will be referred to aq an "active ingredient".
Conventional pre-mixes wnich typically comprise the active ingredient dispersed by mechanical means in a dry carrier such as flour or other milled grain, tend to be unsatisfactory because it is difficult to obtain a uniform dispension of the active ingredient throughout the bulk of carrier by simple mixin~, espeaially where the active ingredient is best handled as a liquid. The ir,vention provides a method of making a pre-mix involving simple steps and which can lead to greater uniformity of distribution of the active ingredient.

. .
The invention provides a process for the preparation of a pre-mix, in which process a dry particulate mixture of an ~ `

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edible inert p~wder and a lactose source, the lactose content of the dry par~iculate mixkure being from about 20 to about 50%
by weight, is intensely agitated and while so lntensely agitated-is sprayed with an aqueous solution or slurry of an active ingredient, the solution or slurry being applied in an amount of from about 1 to about 12~ by weight of the dry particulate mixture.
Preferably the lactose content of the dry particulate mixture is at least about Z % by weight, and ideally the lactose content is at least about 25% by weight. Preferably the lactose content of the dry particulate mixture is not greater than about 45~ by weight, and ideally not greater than about 35% by weight.
Preferably the amount of the solution or slurry applied to the dry particulate mixture is at least 2% by weight.
Preferably the amount of the solution or slurry is not greater than about 10~, and ideally not greater than ahout 6%9 by weight.
The edible inert powder should comprise, together with the lactose source, the bulk of the dry particulate mixture, although other materials can be present in a total amount not exceeding, say, 15% by weight of the dry particulate mixture provided that any such additional material does not interfere unduly with the flow propertieq of the dry particulate mixture or with the desired properties o~ the pre-mix when formed.
Ihe edible inert powder can be any such powder which is essentially lactose-free, and which is not more than sparingly c0.113 3L~ 7~

soluble in water. A wide range of materials can be employed, such a~: feed meals commonly used as ingredients in compound I-oodstuffs, for example milled grain, bean meal and soya meal provided that not too many oily or water-soluble components are present; organic wastes and fillers used in am mal foodstuffs~
such as beat pulp, poSato pulp and feather meal; and inorganic fillers such as kaolin, kaolinite, silica and chalk. Care should be taken to ensure that the inert powder chosen is not one whose maxLmum permitted level in the final foodstuff to which the pre-mix is to be added unduly restricts the formulation of the pre-mlx. Preferably the inert powder chosen is one that can be included at a level of up to at least about 0.5% by weight in the final ~oodstuff, and ideally at an inclusion level of at least about 1.5% by weight. Ideal inert powders are commercially-available flours such as wheat flour, corn flour, rice flour and potato flour. Most commerc_ally-available ~lours contain about 12% by weight of moisture, and these flours can be used to produce acceptable pre-mixes according to the invention. However, we prefer to use dried flours, ie flours having a moisture content of less than about 10% by weight. The use of dried Plour can impart a longer storage life to the pre-mix.
The lactose source can be any commercially-available lactose-containing compo3ition hav mg a sufficently high lactose content and not containing a significant amount of any other ingredient which can interfere with the formation or properties of the pre-mix. A level of about 50% lactose by _ 4 -c~

weight can be regarded as a practical minimum in most circum~tances, and a higher level will generally be preferred.
Fat is an example of an ingredient which can be undesirable in the lactose source, or for that matter in the pre-mix generally, and hence lactose sources of high fat content should be avoided. For this reason, skimmed milk is not recommended for use as a major lactose source, although in some instances minor amounts of skimmed milk powder may be incorporated provided that the bulk of the lactose in the pre-mix comes from some other source. ~ure lactose powder can be used as a lactose source, but lactose powder is a relatively expen ve commodity and is only preferred where, for taste reasons, other lactose sources would be unsuitable.
In a preferred embodiment of the lnvention particularly suitable for the preparation of pre-mixes useful in animal feedstuffs, the lactose source mcorporated in the dry particulate mixture is whey powder~ Whey powder typically contains about 75~ by weight of lactose. In this embodiment, the dry particulate mixture should comprise from about 40 to about 70~ by weight of the edible inert powder and frcm about 60 to about 30% of weight of the whey powder. Preferably the edible inert powder comprise at least about 50%, and ideally at least about 55%, by weight of the dry particulate mixture.
Preferably the edible inert powder comprises not more than about 65~ by weight of the dry particulate mixture. Preferably the whey powder comprises at least about 35% by weight of the dry particulate mixture, and preferably the whey powder c0.113 7 ~
`:
comprises not more than about 50%, ideally not more than about 45%, by weight of the dry particl~1ate mixture.
A further preferred feature of the invention is the incorporation of a small quantity of a weak edible acid in the pre-mix. Preferably this acid should comprise from about 1 to about 10% by weight of the pre-mix. Ideally the acid comprises at least about 2% by weight of the pre-mix. Ideally the acid does not comprise more than about 6% by weight of the pre-mix.
Although usually the acid be incorporated in the dry particulate mixture to which the solution or slurry is applied, it can in some instances be practical and useful to incorporate some or all of the acid in the solution or slurry. Citric acid is preferred, but other edible acids such as tartaric acid and ascorbic acid can be used~ Edible acid salts such as sodium di-hydrogen phosphate can be used where the presence of the sodium will not lead to undue salt balance problem m the human or animal consuming the foodstuff. We infer from in vit~Q
tests that the presence of the weak edible acid enhances the release of the active ingredient when the foodstuff incorporating the pre-mix enters the gut~
A further preferred embodiment of the invention is the incluslon of a ~ood grade colouring agent in the aqueous solution or slurry applied to the dry particulate mixture.
Preferably the colourirg agent is water-soluble. The objective is to ensure that the distribution o~ the aqueous solution or slurry throughout the dry particulate mixture can be seen clearly. Thus the colour chosen should be one that .

c~.113 is clearly distinct from the base colour of the dry particulate mixture. In most embodiments of the invention, the base colour of the dry particulate mixture will be essentially white. Apart from this constraint, and the desirabili~y of using a colouring agent that is cost effective, the selection of the colour is entirely a matter of aesthetics.
The invention utilises the ability of lactose to absorb small quantities of water to form a glass-like solid. In a pre-mix prepared according to the invention, it is observed that the pre-mix comprises a multitude of small hard particles, each consisting of the edible inert powder bound by the lactose glass, distributed throughout the bulk of the dry particulate mixture. It is further observed that the active ingredient is almost wholly located in the lactose-bound particles. This is well demonstrated when a colouring agent is also included, because it is apparent to the eye that the colour is concentrated in the lactose-bound particles.
Arising from the critical selection of the proportl.ons of the lactose to the edibie inert powder, the pre-mix of the invention represènts a composition which has a uniform distribution of particles containing the active ingredient throughout its bulk and yet is a free-flowing particulate composition having little tendency to lump or ~egregate.
Moreover, with the aid of the colouring ~gent when incorporated, it i3 po~sible to perceive the unifot~
distribution of the particles co~taining the active ingredientO
The pre-mix has the additional advantage that the individual co. 11~

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particules containing the active ingredients can be physically separated from the bulk of the edible inert powder, for example by hand or by screening, and assay of the active ingredient can be performed readily on the separated particles.
The pre-mixes of the invention are useful for a wide variety of active ingredients, However, a preferred use of these pre-mixes is in the incorporation of oral vaccines in foodst~ffs. The invention is ideally suited to the preparation of pre-mixes containing endotoxins derived from bacterial strains implicated in gastro-intestinal disorders~ Such endotoxins, when substantially free from association with any of the living bacteria, promote when administered orally a highly effective immune response to the bacteria. In particular this has been well demonstrated for Escherich a coli~ and other gut~infective bacteria have proved susceptible also. An oral vaccine for pigs has been developed in which the endotoxins are derived from one or more of the E, coll strains 08, 045, 0138, 0139, 014t, 0149 and 0157O An animal feedstuff incorporating such an oral vaccine is described and claimed in our British patent No. 1,336,015. An analogous oral vaccine for calves contains endotoxins derived from one or more of the ~_QQli strains 08, 09, 015, 026, 078, 086, 0114, 0115, 0137 and 0139. The calf vaccine can in addition usefully contain endotoxins derived from SalmQnella dubL~ and/or SalmQnella himurium. An animal feedstuff incorporating such an oral vaccine is described and claimed in our British patent No. 1~401~280J A similar oral vaccine for lambs, incorporating c0.113 endotoxins derived from the E. coli strains 08, 09, 015, 020 078, 0114, 0137 and 013g, is described in our British patent No. 1,462,384 and an animal feedstuff containing the oral vaccine is claimed therein.
Alternative active ingredients include antibiotics such as anticoccidial drugs; hormones; vitamins such as A and D, and provitamins such as beta-carotene; trace elements and minerals, such as sources of calcium, phosphorous, iron, manganese, copper and iodine; growth promoters; and ~lavours and perfumes.
The need for such active ingredients to be present in foodstuffs for human and animal consumptton is well known and well-documented in the technical literature, as also is the nature of such active ingredients and the extent to which they are available commercially. The nature o~ such active ingredients ~er se does not form part of the invention.
The concentration of the active ingredients in the aqueous solution or slurry is not critical, subject to the proviso that the viscosity of the solution or slurry must be such that the solution or slurry can be sprayed as very ~ine droplets onto the dry particulate mixture.
Pre-mixeq comprising more than one ac~ive ingredien~ can be prepared. All of the active ingredients involved can be included in a single aqueous solution or slurry i~ desired.
In some instances, the non-simultaneous application of a separate solution or slurry for individual active ingredients can be practical and advantageou3. Where separate solutions or slurries are used1 the incorporation of a distinctly different _ g _ c0.113 colouring agent in each solution or slurry can enable particle~
containing the different active m gredients to be identified in the resulting pre-mix.
Physical preparation of the pre-mix of the invention can be accomplished us.ing any conventional equipment capable of intensely agitating a particulate material and simultaneously finely spraying a liquid onto the particulate materiall Horizontal ribbon mixers can be used, and vertical spray mixers such as the "Schugi"*mixer represent alternatives. If desired, the pre-mix can be prepared in a ~luidised bed equipped with a spray head for the solution or slurry.
It will be appreciated that the particle size of the materials making up the dry particulate mixture, and also the droplet size of the solution or slurry when sprayed thereon, will influence the particle sizes found in the resulting pre-mix. By varying these parameters, it is possible to produce pre-mlxes having different particles size distribution and in which the active ingredient is present m a large number of very minute particles, or in a lesser number of relatively large particles. Thus the invention makes it possible for a pre-mix to be tailored to meet different product requirements.
The general principles governing the effects of substrate particle size, solutionJslurry viscosity, spraying nozzle design and spraying pressure are well known to those skilled in food techrology and related arts, and the techniques required for the physical production of a pre-mix in accordance with the invention are in themselves quite standard technology.

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As far as the particle size of the ingredients in the dry particulate mixture is concerned, we have found that standard co~mercially-available ingredients are quite adequate.
~tandard flours, in which, for example, all but a trace of the particles are less than 200~ in diameter, are perfectly suitable. So too are commercially-available whey powder and lactose powder. In general, it can be stated that each ingredient of the dry particulate mixture should preferably have a particle si~e such that at least 80% by weight of the ingredient will pass through a 500~ screen, and ideally at least 90~ by weight of each ingredient will pass through such a screen.
Preferably the quantity of solution or slurry applied to the dry particulate mixture, and the spraying conditions used, should be selected such that the resulting pre-mix contains at least about 1000 lactose-bound particles containing the active ingredients per gram of pre-mix. Ideally a pre-mix of the invention will contain an even higher number of lactose bound particles containing the active ingredients9 and a level of at least about 2000 lactose bound particles containing the active ingredient per gram of pre~mix should be aimed for. In an ideal pre~mix according to the invention, at least about 95~ by weight of the active ingredient will be contained in distinct lactose-bound particles separable from the bulk of the pre-mix.
A pre-mix of the mvention can be incorporated in a human or animal foodstuff by simple admixture, the proportion of c0.113 79~

pre-mix per unit weight of the foodstuff being chosen with regard to the concentration of the active ingredient present in the pre-mix and the concentration of the active ingredient desired in the foodstuff. In the preparation of compounded animal feedstuffs, the pre-mix can be added to nutrient materials at the milling stage. The nature of the nutrient materials that comprise the human or animal foodstuff in which the pre-mix is incorporated i5 not critical to the invention.
Any of the usual protein, carbohydrate and fat materials can be used.
The pre-mix of the invention is a vendable product in its own right, as it can be sold for incorporation in foodstuffs made by different manu~acturers.
Specific embodiments of the invention will now be described, by way of example only.
Exa~
250 kg of a dry particulate mixture was prepared by mixing together the following ingredients:
Ingredien~ ~5~U ~ b~
Dried wheat flour 58 Cheese whey powder 38 Citric acid 4 The dried wheat flour was a commercial product containing 4,8% moi~ture by weight. Over g9% by weight of the flour passed through a 195~ screen. The cheese whey powder was also a commercial product, containing 6.1% by weight of moi~ture.
Qver 99% by weight of the whey poT~der passed through 53~
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screen, and over 68~ by weight passed through a 195u screen.
The dry particulate mixer was fed to a Gardner horizontal ribbon mixer fi~ted with 6 hollow-cone M2 ~praying nozzles.
While the dry particulate m~xture was intensely agi~ated in the mixer, it was sprayed with 12.5 litres (5% by weight) of an aqueous slurry of E. coli endotoxin material prepared according to procedure A of Example 3 of British patent speciPication No.
1,366,015 and in which slurry had been incorporated 125 gm of a commercially-available food-grade red azo dyestuffO The activity of the slurry was 3000 haemagglutination un~ts of endotoxins for each ~_Qli serotype per ml. Spraying time was 30 minutes. Mixing was continued for several minutes after completion of spraying, to ensure even distribution of the pre-mix ingredients.
The pre-mix so ~ormed was seen to comprise a free flowm g powder of very pale pin~ colour uniformly throughout which was di~persed a large number of tiny, hard, intensely-coloured red particles.
The intensely-coloured particles could be readily serparated from the bulk of the pre-m1x, and analysis revealed that over 98% of both the dyestuff and the vaccine activity reqided in the intensely-coloured particles.
A particle size analysis of the pre-mix yielded the following result:

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' Dre-mix 1999 0.4 800 - 1999 3.4 600 - 799 2.6 ~: 350 - 599 L~oO
250 - 349 6.4 149 - 249 17.0 125 - 148 11.4 74 -. 124 38.6 < 74 16.2 A particle count made on a ~ample of the pre-mix revealed that there were approximately 5000 intensely-coloured lactose-bound particles per gram of the pre-mix.
This pre-mix was incorporated at levels of 0.5, 1.0 and 1.5% by weight in a standard feed composition ~or young pigs.
The feed composition was milled and pelletted to give a creep feed consisting of small pellets, one gram of feed cGnsisting of approximately 10 pellets. On average, each pellet would have contained 2.5 lactose-bound particles at the 0.5%
inclusion level. Pi~s fed on these feeds accepted them readily, and enjoyed the prophylactic benefits described in our British patent ~pecification No. 1,366,015.
~xam~les 2 an~ ~
The procedure of Example l was repeated on two further 250kg batches of a dry particulate mixture of composition identical to that used in Example 1. In this instance, .
: 14 c0.113 however, both batches were ~prayed with 7 litres (2.8~ by weight) of the aqueous slurry, and m Example 3 the M2 spraying no~zles were replaced by M6 nozzles. The spraying time in Example 2 was 12 minutes, and in Example 3 it was 5.5 mm utes.
As in Example 1, a pre-mix consisting of a large number of minute intensely-coloured particles dis~ributed uniformly through a pale-coloured powder resulted. The M6 nozzle induced the formation of some larger particles, consistent with the larger droplet size associated with this nozzle. However, the pre-mix of Example 3 was in no way inferior to that of Example 2. A particle size analysis of each pre-mix gave the following results:

partiLQdiameter (~1 ~ bv wei~ht of vre-mix > 1g99 0.2 0.4 800 - 1999 0.4 3.6 600 - 799 0.6 3.0 350 - 5g9 2.2 2.2 250 ~ 349 6. 4 2. 6 149 - 249 50.6 29.6 125 - t48 11O4 13.4 74 - 124 15.0 29.6 '~ 74 13.2 15.4 The pre mixes of Example 2 and Example 3 wer~ each incorporated in standard pig feed compositions, and gave excellent results in feeding trials,

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A process for the preparation of a pre-mix in the form of a free-flowing particulate composition in which a minor but essential foodstuff ingredient such as an oral vaccine, a vitamin or a trace element is dispersed uniformly throughout a carrier material which forms the bulk of the pre-mix, in which process the carrier material comprises a dry particulate mixture of an edible inert powder and a lactose source, containing at least 50%
lactose, the lactose content of the mixture being from about 20 to about 50% by weight, and the pre-mix is formed by intensely agitating the carrier material and simultaneously spraying the carrier material with an aqueous solution or slurry of the food-stuff ingredient, the solution or slurry being applied in an amount of from about 1 to about 12% by weight of the carrier material.

2. A process according to Claim 1 in which the lactose content of the carrier material is at least about 25% by weight.

3. A process according to Claim 1 in which the lactose content of the carrier material is not greater than about 35%
by weight.

4. A process according to any one of Claims 1, 2 or 3, characterised in that the amount, by weight, of solution or slurry applied to the carrier material is at least about 2% but not greater than about 6% by weight.

5. A process according to Claim 1 in which the edible inert powder is a flour.

6. A process according to Claim 5 in which the flour has a moisture content of less than about 10% by weight.

7. A process according to Claim 1 in which the lactose source is whey powder.

8. A process according to Claim 7 in which the carrier material comprises, by weight, from about 40 to about 70% of the edible inert powder and from about 60 to about 30% of whey powder.

9. A process according to Claim 8 in which the carrier material comprises, by weight, from about 50 to about 65% of flour and from about 35 to about 50% of whey powder.

10. A process according to Claim 1 in which the carrier material additionally comprises from about 1 to about 10% by weight of a weak edible acid.

11. A process according to Claim 10 in which the weak edible acid is citric acid.

12. A process according to any one of Claims 1, 9 or 10 in which the solution or slurry incorporates a food-grade colouring agent.

13. A process according to any one of Claims 1, 9 or 10 in which the essential foodstuff ingredient is an oral vaccine comprising endotoxins derived from one or more bacterial strains implicated in gastro-intestinal disorders, the endo-toxins being substantially free from association with any living bacteria.