NZ222937A - Proteinaceous water dispersible macrocolloid with smooth emulsion-like organoleptic character suitable for replacing fats in food - Google Patents

Description

22 2 9 3 Priority Date(s): ..* Complete Specification Filed: Class: J1QQ.I Vfc /. 3305 2> ^afe Q ^ 2 1 DEC 1990 Publication Date: P.O. Journal, No: . ....133?.; PATENTS FORM NO: 5 PATENTS ACT 1953 COMPLETE SPECIFICATION "PROTEIN PRODUCT" WE, JOHN LABATT LIMITED a company duly incorporated under the laws of Canada of ^51 Ridout Street North, -P-.0:—Dex 5870, London, Ontario, Canada, hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement 1 (followed by 1a) 222,937 - la - As used hereinafter, the term "denatured protein" is denatured protein other than denatured dairy whey protein.

The present invention relates to replacements for fat, both per se as well as in the preparation of food products, in prophylactic and therapeutic weight loss treatments, and high protein therapies, and to edible food products of the type wherein fats, which are normally present in concentrations sufficient to make an organoleptic contribution, are replaced by proteinaceous materials which possess the smooth organoleptic character of oil in water emulsions.

Fat-rich foods enjoy considerable popularity and make up a significant proportion of the diet of many people. The undesirable impact from a nutritional viewpoint of such consumption is widely recognized, and numerous attempts have been made to address the problem.

Perhaps the most direct approach has been to simply reduce the amount of fat present in any given food. U.S. Patent 3,892,873 exemplifies products in which multiple phase emulsions (e.g., oil/water/oil or water/oil/water) are employed to permit a reduction in the amount of fat present in certain fat-containing foods, without, it is claimed, unduly compromising the foods organoleptic character. In these products, the relationship of water and oil is modified in order ... maximize the kinesthetic contribution of the oil and so permit a proportionate reduction of the amount of oil required in the food in order to manifest any given level of the organoleptic contribution associated withli~"2 | viUNf990< 22 2 9 37 fats. While reducing the quantity of fat is highly desirable in as far as it goes, this approach is subject to very real limits on how far it can be carried. Even though the organoleptic contribution of the fat present 5 in the food is optimized, any resulting food product nevertheless retains a substantial proportion of the fat ^ necessarily commensurate with the desired mouth feel normally associated with the fats in such products. Therefore, although simple fat reduction has its advan-10 tages, this approach cannot be taken very far and does not hold the same potential benefits which are afforded by way of fat reduction through fat replacement.

The art is replete with proposals for the provision of fat-replacers in food products which are 15 then described as "calorie reduced". As one example, U.S. Letters Patent No. 3,600,186 relates generally to low calorie products, comprising liquid polyol polyesters. U.S. Letters Patent No. 4,461,782 provides baked products comprising polyol fatty acids polyesters 20 and microcrystalline cellulose as flour or starch replacements.

Sucrose polyesters are extolled as having the physical properties and appearance of normal fat, but at the same time are resistant to enzymatic hydrolysis in 25 the gut, which renders them undigestible. According to an article which appeared in the Economist, April 4, 1987, pages 87-88, however, sucrose polyesters have only been approved for use as protective coatings on fruit. Moreover, sucrose polyesters have an undesirable laxa-30 tive effect which necessitates the collateral use of hydrogenated palm oil or the like when sucrose polyesters are used in large quantities. Worse still is the fact that sucrose polyesters interfere substantially with the body's absorption of fat soluble vitamins, 35 especially vitamins A and E.

L ' » I 22 2 9 37 o o A more conventional approach to calorie reduced foods is exemplified by U.S. Letters Patent No. 4,143,163 which discloses smooth textured, high bulk food additive compositions made up of fibrous cellulose 5 coated with soluble gums and polyhydric alcohols and provided as particles ranging in size between 20 and 40 microns. Rather than replace fats in the absolute sense, the fibrous cellulose material increases the relative proportion of the indigestible material in the 10 food product. The use of other materials is intended to compensate in some degree for the poor mouth feel typically associated with high fibre foods.

One alternative to the problems associated with the often poor palatability of high fibre supple-15 mentation, involves the use of various aqueous gels as fat replacers. U.S. 4,305,964 relates to a fat replacer wherein gelled water beads based on aqueous dispersions o£ hydrated hydrocolloids are in turn dispersed in an oil-in-water emulsion. Notwithstanding whatever nutri-20 tional benefit that may be associated with the proportionately small amounts of hydrocolloid that is present in these gels, these compositions make no substantial direct nutritive contribution to a consumer's diet. U.S. 4,510,166, relates to a starch/water gels, that are 25 taught as being useful as oil or fat replacers. The only nutritional benefit, apart from replacing oil or fat, that is afforded through this approach is the calorie value of the 10-50% of starch that these gels contain. In diets already rich in carbohydrates, this 30 contribution, by itself, is of dubious value.

As stated, it is well known that, from a nutritional point of view, high fat levels in foods are not desirable, regardless of however optimized their organoleptic contribution may be. The dilution of fat 35 through the use of fibre additives has some advantages, but gives no direct nutritional benefits to the con- 22 2 9 37 .A —, ■* i sumer, although the consumption of a high fibre diet has been favorably associated with avoiding certain forms of intestinal disease. Water-gel-based fat replacers do not evidence any such additional benefits. The 5 replacement of fats with sucrose polyesters also affords no direct nutritional benefit to the consumer, even though it apparently does have the advantage of sequestering cholesterol in the gut before the cholesterol can be absorbed into the body. 10 It would be most advantageous if a fat replacer additionally, could make a direct and desirable contribution to the consumer's nutritional requirements.

U.S. patent 4,;308,294, makes some in-roads in this respect, by utilizing between 0.5 to 30% protein in 15 a fat replacer comprising a whipped, hydrated protein/-gum complex which is dispersed in a partially gelatinized, acidified starch-in-water phase. However, Column 2, lines 62 to 68 teaches that the desired oil-replacement properties are dependent on the organoleptic con-20 tribution of the swollen starch granules.

Under normal conditions, the healthy adult human's nitrogen equilibrium can be maintained with daily protein intake of 0.9 grams per kilogram of body weight per day. A fat replacer which is also a nutri-25 tional protein source could readily meet these requirements and provide both prophylactic and therapeutic benefits in respect of generalized protein deficiency conditions as well as of potential benefit in the treatment of obesity, arteriosclerosis and possibly a number 30 of eating disorders as well.

There exists a need in the art for natural, nutritive materials which have a substantially smooth, emulsion-like, organoleptic character and for food products containing the same as at least a partial 35 replacement for fats. 222937 SUMMARY OF THE INVENTION The present invention relates to protein-aceous, water-dispersible macrocolloid particles which in a hydrated state have a substantially smooth, oil-in-5 water emulsion-like, organoleptic character. Macro-colloid products according to the invention comprise a homogeneously sized and shaped population of substantially non-aggregated particles of denatured protein (as hereinbefore defined).

The particles are characterized by being substantially 10 spheroidal when viewed at about 800 power magnification under a standard light microscope. Such particles are characterized by having, in a dry state, a mean diameter particle size distributipn ranging from about 0.1 microns to about 2.0 microns. In their preferred form, 15 less than about 2 percent of the total number of the macrocolloid particles exceed 3.0 microns in diameter. Novel particulate denatured protein products of the invention, when dispersed in an aqueous medium, exhibit a mouth feel most aptly described as emulsion-like — 20 approximating that associated with oil-in-water emulsions.

Suitable protein sources are animal, vegetable and microbial proteins including, but not limited to, ' egg and milk proteins, plant proteins (especially 25 including oilseed proteins obtained from cotton, palm, tape, safflower, cocoa, sunflower, sesame, soy, peanut, and the like), and microbial proteins such as yeast proteins and the so-called "single cell" proteins. Preferred proteins include undenatured dairy whey protein. 30 (especially sweet dairy whey protein), and non-dairy-whey proteins such as bovine serum albumin, egg white albumin, and vegetable whey proteins (i.e., non-dairy whey protein) such as soy protein. Raw material sources providing soluble globular, non-fibrous proteins which 35 have not previously been subjected to protein denaturing processing (e.g., during isolation) are preset preferred. © 222937 Products of the present invention also include a proteinaceous, water-dispersible macrocolloid comprising substantially non-aggregated particles of denatured protein (as hereinbefore defined) where substantially all of the total combined 5 mass of said particles in a dry state is made up of particles having volumes of about 5 x 10~4 cubic microns to about 5.5 cubic microns, and wherein the majority of the said particles are substantially spheroidal as viewed at 800 power magnification under a standard light 10 microscope.

In order to effect the desired kinesthetic attributes associated with the present invention, (i.e., in order to give rise to. a smooth, lubricious tactile impression) the majority of the particles of the present 15 compositions preferably have a non-scabrous or substantially spheroidal topology. The term "substantially spheroidal" herein embraces shapes spanning the spectrum of spheres, and oblate or prolate spheroids. Compositions wherein spheres are the exclusive or predominant 20 species are most preferred. The presence of other spheroidal shapes in compositions of the invention is acceptable, but compositions wherein such other spheroidal shapes predominate or are the exclusive species are less preferred. The presence of rodiform 25 and filamentous particles, while tolerable, is less preferred. Spiculate particles are highly undesirable. Particles preferably have diameters (long axes in the case of non-spheres) which as measured in a dried state, fall in the low micron to near sub-micron range. 30" Protein denaturation herein follows from processes which are in general irreversible, and which result in alternations of the native, (i.e., undenatured) protein state in a manner which predisposes the protein's molecular accretion in the form of the above-mentioned particles. By way of example of such processes, there are disclosed herein processes (n °\ tZ21 JUN19902j \ 222r»r>7 thermal denaturation of proteins amenable to such treatment is employed to effect the above-mentioned accretion.

In one aspect, processes of the invention comprise heating undenatured substantially soluble and heat coagulable proteins other than denatured diary whey proteins at heat denaturing temperatures in an aqueous solution at a pH less than the isoelectric point of said proteins, under shear conditions selected and carried out for a time sufficient to avoid the formation of any substantial amounts of fused particulate proteinaceous aggregates having diameters in excess of about 2 microns while also forming denatured proteinaceous macrocolloidal particles which are greater than about 0.1 micron in diameter.

In accordance with yet another aspect of the present invention, there is provided a process substantially as hereinabove described wherein the formation of any substantial amounts of fused particulate proteinaceous aggregates having volumes in excess of 5.5 cubic microns is avoided, while also forming denatured proteinaceous macrocolloidal particles which are greater than about 5 x 10"^ cubic microns in volume.

Such processes according to the present invention are advantageously applied to aqueous solutions of heat coagulable protein other than denatured dairy whey proteins, which are characterised by having a protein concentration between 10J£ and about 20? (by weight). In general, protein raw material sources for practice of the invention should include in excess of about 80 percent soluble proteins and preferably in excess of about 90 percent soluble protein.

Protein sources providing less than about 80 percent soluble protein are likely to include ab initio oversized particles and/or particle aggregates which can significantly detract from the desired organoleptic characteristics of products of the invention. The pH of the protein solutions is establisKerh-belowjthe midpoint \ ^ " ■ 222937 sized particle populations while pH conditions substantially below the isoelectric curve midpoint will promote 10 formation of particles with extremely small average diameters. Preferably, the pH of solutions is established at about 1 pH unit below the midpoint of the isoelectric curve of the_protein source material. Where needed, adjustments in pH may readily be effected 15 through use of organic or inorganic acids or bases.

If desired, protein solutions employed in the practice of the invention may be chemically or physically pre-treated to remove undesired non-protein or even proteinaceous constituents including peptides and 20 amino acids. By way of example, dried sweet dairy whey ^protein concentrates (already treated by ultrafiltration vL to remove, e.g., substantial amounts of non-protein nitrogenous compounds and lactose) may be subjected to extraction processing for removal of fats and choles-25 terol as well as other components which might contribute to "off" flavors when the products of the invention are employed as fat replacements or substitutes in food products. As an alternative to ultrafiltration, undenatured dairy whey may be subjected to chromatographic purification to 30 remove lactose, salts and most other non-protein components, leaving lactalbumins and lactoglobulins as the principal protein constituents.

Hydrated macrocolloid products of the invention are readily prepared from protein solutions through controlled application of heat and high shear con^irt^E^^^ •'! facilitative of controlled protein denaturation in a o'\ I 2 1 J'!'^9od m of the isoelectric curve of the proteins in solution (i.e., the midpoint of the composite curve of the various isoelectric points of individual protein components), but not so low as to allow for substantial 5 acidic hydrolysis of the protein. In general, establishing the pH at or near the midpoint of the isoelectric curve will tend to promote formation of larger -' V.r"• V'V 22 2 9 37 o J physical and chemical context allowing for the formation of non-aggregated proteinaceous particles of the desired size and shape. The particles formed during denatura-tion are generally spherical in shape and have average 5 diameters in excess of about 0.1 microns. The formation of particles in excess of about 2 microns in diameter and/or formation of aggregates of small particles with aggregate diameters in excess of 2 microns is substantially avoided. Alternatively, the formation of par-10 tides or aggregates of particles having volumes in excess of 5.5 cubin microns is avoided while forming substantial numbers of particles having volumes of 5 x 10~4 cubic microns ox more. The protein denaturing temperatures employed and the duration of heat treatment 15 will vary depending upon the particular proteinaceous starting material. In a like manner, the specific high shear conditions including the duration of shear applied to protein solutions will also vary. Illustratively, sweet diary whey protein solutions having a pH of 3.5 to 20 5.0 may be treated according to the invention at temperatures ranging between 80°-130°C for as little as 3 CD- seconds to 15 minutes at 7,500 to 10,000 reciprocal seconds of shear.

The above are specific processing conditions 25 which have been found in the production of many products according to the present invention. However, the £2) specific shear rates suitable for any selected protein substrate can be readily determined by way of routine empirical trials, utilizing whatever processing appar-30 atus is selected.

During denaturation processing according to the invention, undenatured proteins in solution interact to form insoluble coagulates and the controlled application of heat and high shear forces operate to insure 35 formation of non-aggregated particles within the desired size range. Depending upon the specific properties of i itsaacas« x' . ' 22 2 9 37 n o i O dissolved commercial protein materials and the properties of non-protein constituents in the solutions of these materials, the application of heat and high shear alone may not optimally allow for the avoidance of over-5 sized particle aggregates. In such situation, it is within the scope of the invention that one or more materials such as lecithin, xanthan gum, malto-dextrins, carageenan, datem esters, alginates, and the like, ! ("aggregate blocking agents") be added to the protein solutions, most preferably prior to heat denaturation processing. Depending upon the aggregate blocking agent(s) selected, these materials may be added in concentrations ranging from as little as 0.1 to upwards of 10% by weight. Pre-hydration of the aggregate blocking 15 agents has been found to facilitate their addition to protein solutions. If properly selected and treated, these aggregate blocking agents together with the w uncoagulated proteins may further contribute to the lubricity of the system thereby enhancing the creamy 20 impression.

| In preferred protein solutions processed -j . according to the invention there may also be present one or more polyhydroxy compounds, preferably mono-, di-, or | tri-saccharides such as glucose, fructose, lactose and the like. These may be present as a component in the j source materials employed to provide the soluble pro teins (e.g., lactose (or the products of its enzymatic hydrolysis, glucose and galactose if an optional lactase treatment is employed) present in dried whey protein 30 concentrates) or may constitute additives to the protein solutions. The relative concentration of polyhydroxy compound in various protein solutions is subject to wide variance. Certain proteinaceous starting materials (e.g., diary whey protein purified by column chroma-35 tography) which include essentially no sugars or other polyhydroxy compounds can rather readily be processed to \ ;>■« 22 2 9 3 7 (Ti - ii - yield macrocolloids of the invention, but somewhat improved products result attending the incorporation of lactose, particularly when an aggregate blocking agent is to be added to the protein solution. Other solutions 5 of proteinaceous starting materials (e.g., egg white and bovine serum albumin) greatly benefit from addition of, e.g., lactose, to secure optimal efficiencies in production of products of the invention. Thus, from 0 to about 100%, by weight of the protein, or more poly-10 hydroxy compound (preferably sugars and most preferably reducing sugars such as lactose) may be added to protein solutions processed according to the invention.

Protein raw materials useful in the present process including animal, vegetable and microbial pro-15 teins selected from the group consisting of albumins; globulins; glutelins, heat coagulable, soluble conjugated proteins; heat coagulable, soluble derived proteins; and, mixtures thereof.

Controlled denaturation processes of the 20 invention essentially involves "removal" of protein molecules from solution by the association of numerous of these protein molecules with each other to form a protein coagulum which is rendered insoluble through application of heat. Further composition and process 25 controls are instituted to prevent the growth of the size of such coagula beyond the desired range. Because salts can substantially affect the solubility and tendency toward coagulation of proteins in aqueous solution, it is within the contemplation of the present 30 invention that routine adjustments be made in the concentration of salts in solutions which are to be subjected to heat and high shear conditions.

Optional ingredients of protein solutions employed in practice of the invention include colorants, 35 flavors, stabilizers, preservatives, and the like in quantities sufficient to provide desired characteristics for the products.

A r> r^ ..\« V J -. » 22 2 9 37 The present invention also provides edible compositions or food products in which fats normally present in the product have been replaced by a hydrated proteinaceous materials according to the invention. 5 Such foods include reduced calorie products such as salad dressings, mayonnaise-type dressings and spreads and ice cream-like frozen desserts. Further reductions in calorie content may also be produced with the mate-j rials of the present invention in conjunction with high- ! 10 potency sweeteners such as aspartame, alitame, acesul- fame K and sucralose. Compositions of the present invention may also be supplemented with vitamins and/or minerals.

• Brief Description of the Drawing The invention will be better understood from the following detailed description taken in conjunction with the accompanying figures of the drawings, wherein: Fig. la is a sectional view showing an embodi-20 ment of processor apparatus designed for batch operation in practice of the invention; 0 ■ Fig. lb is a plan view of a blade of the processor of Fig. la; Fig. 2 is a view similar to Fig. 1 but showing 25 apparatus designed for continuous flow operation; Fig. 3 is a sectional view taken on the line Q 3-3 of Fig. 2; Fig. 4 is a sectional view taken on the line 4-4 of Fig. lb; and 30 Fig. 5 is a view illustrating the operation of the processor; Fig. 6 is a photomicrographic view at 1000X magnification of a sample of whey protein macrocolloid according to the invention; Fig. 7 is a photomicrographic view at 1000X magnification of a sample of bovine serum albumin macrocolloid according to the invention; | 22 2 9 37 n O Fig. 8 is a photomicrographic view at 1000X magnification of a sample of egg white albumin macrocolloid according to the invention; and Fig. 9 is a photomicrographic view at 1000X magnification of soy protein macrocolloid according to the invention.

Detailed Description of the Invention It has been determined according to the 10 present invention that proteinaceous water-dispersible roacrocolloids which in a hydrated state have a substantially smooth, emulsion-like, organoleptic character may be produced from a varie.ty of protein materials. The proteinaceous, water-dispersible macrocolloids are com-15 prised of substantially non-aggregated particles of denatured protein which are characterized by having in a dry state a mean diameter particle size distribution ranging from about 0.1 microns to about 2.0 microns, with less than about 2 percent of the total number of 20 particles exceeding 3.0 microns in diameter. The particles are further characterized by being generally •"T\ ■ spheroidal as viewed at about 800 power magnification under a standard light microscope.

The macrocolloid materials may be produced by 25 controlled denaturation from a wide variety of proteinaceous starting materials which, before processing, are substantially soluble in water and are substantially undenatured.

Aqueous dispersions of the macrocolloids of 30 the present invention are characterized by a substantially smooth, emulsion-like, organoleptic character and may be used according to the present invention as high protein-low calorie fat replacers. Also provided by the invention are foods which include as ingredients or are 35 based on the macrocolloids.

In respect to the use of the terms "mouth feel" and "organoleptic character" herein, it will be i i « * * 22 2 9 37 appreciated that such relates generally to a group of tactile, feeling sensations which, while common to the body as a whole, are particularly acutely perceived in the lingual, bucal and esophageal mucosal membranes.

More precisely, the terms "mouth feel" and "organoleptic character" as used herein are in reference to one of the above-mentioned group of sensations and in particular, to those sensations associated with the tactile perception of fineness, coarseness and greasiness. This 10 tactile impression is generally appreciated in the mouth proper wherein subtle differences between various foods are most readily perceived.

Thus, the novel protein products of the present invention, when dispersed in an aqueous medium, 15 exhibit a mouth feel and organoleptic character most aptly described as emulsion-like. Obviously, the degree of hydration of the protein affects its Theological properties, and hence the manner in which the materials are perceived. The mouth feel of these products desir-20 ably and closely approximates that associated with fat-in-water emulsions. © * The pseudo-emulsion character of the novel protein products of the present invention is manifest in gravitationally stable macrocolloidal dispersions of the 25 heat denatured coagulated protein particles, which range in size from about 0.1 to about 2.0 microns in (2) diameter. Such dispersions approximate the visual and organoleptic impressions normally associated with oil-in-water emulsions such as (by ascending order of the 30 concentration of the novel materials in some corresponding products obtainable through the practice of the present invention) coffee-whiteners, pourable salad dressings, spoonable salad dressings, spreads and icings.

It will be appreciated that the term "solution" is often used in the protein art as a synonym for what is in fact a true colloidal dispersion of un- '--V V 22 2 9 3 7 denatured proteins. Such undenatured protein particles have sizes of about 0.001 to about 0.01 microns such that the stability of colloidal dispersions of these are dependent upon the net electrical charges on the protein 5 molecules and, particularly at pHs near the isoelectric point thereof, on the affinity of these proteins for water molecules. Thus, such undenatured proteins properly fall within the ambit of the smaller ranges of particles studied in colloid chemistry, as defined in 10 the Condensed Chemical Dictionary, 9th Edition, page 222. In contradistinction thereto, the denatured protein particles of the present invention range in size from about 0.1 to about 2.0 microns, and hence include particles nearer and above the upper limit of the size 15 range set out in the above-mentioned definition. Mot-withstanding the heat denaturation processing of the proteins of the present invention, the general colloidal character thereof (i.e., the stability of dispersions of such particles in an aqueous medium) is not lost. 20 Accordingly, novel protein dispersions within the context of the present invention resist protein sedimenta-' tion from neutralized aqueous suspensions at forces as high as 10,000 gravities (at a pH about 6.5 to 7.0). Hence, the term "macrocolloidal dispersions" is used 25 herein for the purpose of distinguishing between "solutions" of undenatured proteins (i.e., "true colloid dispersions") and those based on the novel proteins of the present invention (hereinafter "macrocolloidal dispersions"). Similarly, the denatured coagulated pro-30 teins of the present invention is hereinafter referred to as a macrocolloid to be distinguished from a true colloid which pursuant to the above-cited dictionary definition means a substance wherein the particle sizes are not greater than 1 micron. This distinction 35 reflects the relatively larger size which is typical of the particles of the denatured coagulated protein products of the present invention. 22 2 9 37 1 The particularly desired organoleptic quali-—^ ties of the macrocolloid materials according to the present invention are particularly dependent upon the sizes and shapes of the macrocolloid particles.

■ Specifically, it has also been found that dispersions of larger, denatured protein coagulates ^ (i.e., with diameters greater than about 3 microns when dried) impart an undesirable chalky mouth feel to foods so supplemented. This chalkiness can be identified as 10 being a less coarse variant of the gritty mouth feel of known heat denatured proteins (about 15-175 microns). It appears that a sharply defined perceptual threshold is crossed as the number> of particles of protein coagulate with diameters larger than about 2 to 3 15 microns in their largest dimension increases.

Fibrous particles having lengths generally greater than about 5 microns and diameters generally less than about 1 micron produce pastes which are smooth but dilatant (as more force is applied between the 20 tongue and palate, an increasing sense of solid substance is perceived). As fibers become shorter approaching spherical shapes, this character decreases.

The shapes of particles are also important as particles which are generally spheroidal tend to produce 25 a smoother, more emulsion-like organoleptic sensation. Where increased proportions of macrocolloid particles are generally spheroidal or where the macrocolloid particles are more perfectly spheroidal, it may occur that somewhat greater proportions of particles may have 30 diameters greater than about 2 microns without detriment to the organoleptic character of the macrocolloid mixture. As alluded to hereinbefore, however, rod-like particles with diameters greater than about one micron tend to produce a chalky to powdery mouth feel. 35 Particle sizes approaching 0.1 microns con tribute a greasy mouth feel which may be objectionable if it is perceived as the dominant tactile character- I 22 2 9 37 istic in a product which is intended to simulates an oil in water emulsion product. Where it is desired to pro-duce a product wherein a greasy mouth feel is attractive, such as a butter-like spread, such particle size 5 would be useful. Because the perceived transition between an emulsion-like mouth feel and a greasy mouth feel appears to be much more gradual than is the transition between the former and the chalky mouth feel, greater proportions of particles on the order of 0.1 10 microns in diameter are acceptable in macrocolloids of the present invention. Thus, provided that the mean particle size is not less than 0.1 microns, the emulsion-like character is dominant, notwithstanding that the distribution itself may include a substantial 15 proportion of individual particles having diameters smaller than 0.1 microns.

Proteins useful in the present process include those from such varied and diverse sources as vegetable whey from oil seeds, mammalian lactations, blood serum 20 and avian ova.

Preferably, the present process relates to O proteins which are globular proteins when in their native state.

From the perspective of traditional protein 25 classification, the present process applies to proteins that are soluble in aqueous solvent systems and are ! ^ selected from amongst the simple, conjugated and derived proteins. Suitable simple proteins include: albumins, globulins and glutelins. Suitable conjugated proteins 30 include: nucleoproteins; glycoproteins and mucco-proteins, (also known collectively as glucoproteins); phosphoproteins (sometimes themselves classed as simple proteins); chromoproteins; lecithoproteins; and, lipoproteins. Heat-coagulable derived proteins are also 35 suitable.

Simple proteins not useful in the present process are the albuminoids (a.k.a. scleroproteins) such o r\ O 22 2 9 37 as elastins, keratins, collagens and fibroins, all of which are insoluble in their native states. Protamines (a.k.a. protamins) and histones are not heat coagulable and are therefore unsuitable as raw materials for the 5 present heat denaturing process.

Conjugated proteins which are both soluble and heat coagulable are useful in the present process.

Similarly, derived proteins (i.e., the products of various proteoclastic or denaturing pro-10 cesses) which, notwithstanding their derivation, remain both soluble and heat coagulable, are also useful as raw materials in the present process, provided, of course, that they are not, by virtue of their derivation, rendered, ab initio, incompatible with the manifestation 15 of the desired, organoleptic properties in the final product of the present process. In general, however, many proteins, metaproteins (a.k.a. infraproteins), coagulated proteins, proteoses, peptones and peptides (a.k.a. polypeptides) lack one or both of these pre-20 requisite characteristics.

Beat coagulability, in accordance with the practice of the present process, takes into account any particular protein's innate capacity to form insoluble masses under heat/shear conditions. The purity of the 25 protein sample, and the degree of denaturation or incipient latent denaturation of the sample, all bear directly or indirectly on the suitability of the protein for use as a raw material in the present process.

For the purposes of the present process, a 30 protein is "soluble" if it is about 80% or more soluble in accordance with the criteria set forth herein below. A solubility of greater than 90% is preferred.

Solubility is measured, under non-denaturing conditions, using the solvent system that will be used 35 in processing. In light of the present disclosure, a man skilled in the art will have no difficulty in selecting a suitable solvent system, having regard for :-v. - ' 4ft 22 2 9 3 n r*>. the solubility characteristics of the particular protein ^ to be processed, and including the corresponding pH and temperature parameters called for in the process. In general, solubility is influenced by a number of 5 intrinsic and extrinsic factors. Of primary importance in solvent selection are pH, salt concentration, temperature and the dielectric constant of the solvent. By way of example, while albumins are soluble in water, globulins are insoluble in water but soluble in salt 10 solutions. To a lesser extent, protein purity, in terms of both other proteins and non-protein constituents, also influences solubility. Accordingly, while an impure sample may not exhibit the prerequisite solubility, a purer sample may. Note, however, that the 15 purer any given sample of a single species of protein is, the more critical close adherence to the selected processing parameters becomes.

J t The solubility of the protein is measured by j dispersing 10 grams of protein in 190 grams of the | 20 selected solvent system in a Waring blender for one or i two minutes. The resulting dispersion is divided into J. two portions. One such portion is centrifuged for 25 minutes in a Beckman L8-70 centrifuge using an SW-55 rotor (Beckman, Palo Alto, CA) at 11,000 r.p.m. 25 (17,000 g) and 22°C. The supernatant of the centrifuged portion is then collected. Protein contents of both the (2) uncentrifuged portion (Soltuion No. 1) and the supernatant of the centrifuged portion (Solution No. 2) are determined based on nitrogen analysis using a Carlo 30 Erba Nitrogen analyzer (Model 1500, Milan, Italy) and the percent solubility is thus calculated according to the formula: . - _ % Protein in Solution No. 2 ..

% Soluble Protein - % Protein in solution No. 1 x 100 While solutions may be centrifuged at higher rates (up to 50,000 rpm and 330,000 g) with the result that higher percentages of materials are collected, it has been found that protein materials which are greater srr> ' "J 22 2 9 3 than about 85% soluble according to the recited test methodology at 17,000 g, are generally sufficiently fl stable in dispersion, or "soluble," for purposes of the present invention.

The preferred protein for a particular use may vary according to considerations of availability, expense, and flavor associated with the protein as well as the nature of impurities in and other components of the protein source. Preferred proteins of the present 10 invention include globular proteins such as bovine serum albumin, egg white albumin and soy protein, with dairy whey protein being particularly preferred. Sources of proteins which may be subject to treatment according to the present invention often comprise various impuri-15 ties. It is desirable therefore that where proteins useful with the invention are naturally associated with insoluble components, such components be smaller than the 3.0 micron limit or be removable prior to processing or rendered smaller than that limit in the course of 20 processing.

Once a specific protein source is selected, © the protein solution is treated for relatively short times to relatively specific temperature, shear and pH conditions. Depending on the protein, the presence of 25 specified amounts of polyhydroxy compounds (e.g., sugars}, aggregate blocking agents and other optional 0 ingredients will assist in optimizing the yield of desired products. The macrocolloids are produced according to a controlled heat denaturation process 30 during which high shear is utilized to prevent the formation of any significant amounts of large particle size protein aggregates. The denaturation process is carried out at a pH less than the midpoint of the isoelectric curve of the selected protein and preferably at a pH 35 about 1 pH unit below the midpoint of the isoelectric curve. The process may be carried out at lower pHs with the requirement that the processing pH should not be so V ■***"" 22 2 9 37 0 ! low a$ to result in acid degradation of the protein and the limitation that the pH should generally not be less than about 3.

The precise temperatures and shear conditions 5 applied in macrocolloid preparation are routinely selected and extend out for times sufficient to form denatured proteinaceous macrocolloidal particles which are greater than about 0.1 microns in diameter while avoiding the formation of any substantial amounts of 10 fused particulate proteinaceous aggregates in excess of about 2 microns. Preferred shear conditions for processing a given protein solution are best determined by using "oversize" particle testing.

Particle size testing provides a measure of 15 organoleptic quality of the products 6f the present invention.

One of the simplest and most rapid of the techniques available to a man skilled in the art involves the preparation of an optical slide in a manner 20 which is analogous to the preparation of clinical blood smears. Pursuant to this method, an appropriate dilution of the dispersed macrocolloid is first prepared and adjusted to a pH preferably in the range of 6.5 to 7. High speed magnetic stirring, ultrasonication or 25 homogenization is then applied to fully disperse any weak associations there might be between the individual O macrocolloid particles. A small amount (e.g., 8 micro liters) of the diluted, neutralized dispersion is then applied to a glass microscope slide of the variety often 30 used in biological studies, and allowed to dry. The sample is viewed under known magnification using "ruled" occular eyepieces with well-known methods. The dispersed macrocolloidal particles of the sample was then visually compared with the reticules on the occular to 35 provide a good estimation of the statistical incidence of oversize or aggregated particles within the population as a whole. - dsvw.; •.. *>• ■; X V 22 2 9 37 An alternative means for analyzing particle size distributions involves the use of an image analyzing computer, for example, a QUANTIMET~720 available from Cambridge Institute, U.K.

Another means involves the use of the MICROTRAC*" particle size analyzer. The general aspects of this technique are described in an article entitled "Particle Size Analysis and Characterization Using Laser Light Scattering Applications" by J.W. Stitley, et al. 10 in Food Product Development, December, 1976.

As will be apparent to a man skilled in the art in light of the instant disclosure, sedimentation techniques may also be utilized for the purpose of rendering particle size determinations. It will be appre-15 ciated, however, that gravimetric techniques must take into account the protective colloid effects of, for example, whatever processing aids may have been used during the above-described heat denaturation treatment. One example of a gravimetric determination of the 20 percent "oversized" protein aggregate is summarized hereinbelow: 1. A 5% weight by weight dispersion of the macrocolloid of the present invention is prepared and neutralized to a pH of between 6.5 and 7; 25 2. A high fructose corn syrup having a specific gravity of 1.351, a pH of 3.3, a total nitrogen of 0.006% and a solids concentration of about 71% is added in a 1 to 4 weight by weight ratio to the neutralized 5% macrocolloid dispersion; 30 3. The mixture is then homogenized to dis perse loose associations between the macrocolloid particles ; 4. The mixture is then centrifuged at 478 gravities for 20 minutes at about 15 degrees 35 Centigrade. The oversized protein aggregates, i.e., particles having a diameter substantially greater than 2 microns, can be expressed as a percentage of the weight •.rn. . ' v ' v •- * 22 2 9 37 of the protein contained in the centrifuged pellet divided by the weight of the protein contained in the macrocolloidal dispersion prior to centrifugation.

These tests are applicable in respect of both 5 the macrocolloidal dispersions of the present invention and the protein materials useful as raw materials in the ^ production of said macrocolloids. As will be readily apparent to a man skilled in the art, capacitance based particle size analysis equipment such as, for example, 10 the well known Coulter-Counter1" analyzers will not be suited to the present application, having regard to the charged nature of the macrocolloid particles at certain pH1 s.

In accordance with the preferred processing 15 conditions, however, the aqueous protein solution is subjected to high temperatures for a very short time at shear rates of 7,500 to 10,000 reciprocal seconds or greater. For a one gallon Waring blender drive equipped with a miniaturized (e.g., 1 litre capacity) "Henschel" j 20 mixer, for example, a processing speed of 5000 rpm has been found to provide sufficient shear.

Preferred processing temperatures range from about 80°C to about 120°C with processing times ranging from about 3 seconds to about 15 minutes or longer with 25 times of from about 10 seconds to about 2 minutes being preferred. Processing times are longer at lower temp-eratures, with treatment at 80°C requiring as much as 15 minutes while processing times at temperatures between 90°C and 95°C being about five minutes. By contrast, at 30 120eC the processing time may be only about 3 seconds. High processing temperatures are complemented by increased rates of heat transfer. Where the nature of the processing equipment permits, therefore, processing at high heat transfer rates/high denaturation tempera-35 tures for very short times is preferred. It should be noted, however, that at temperatures higher than 120°C with correspondingly reduced product residence times, <1 i A 22 2 9 37 n the resulting macrocolloid product is "thinner" and may be less desirable.

Processes for the production of the macrocolloids of the present invention utilize an aqueous 5 protein solution characterized by having a protein concentration between about 10% by weight and 20% by weight with protein concentrations between about 15% by weight and 18% by weight being preferred. At protein concen-; trations less than about 10% by weight, stringy masses tend to form which have undesirable organoleptic qualities. Solutions having protein concentrations much in excess of about 20% by weight tend to become extremely viscous rendering impractical the application of requisite rates of shear to the protein solutions. 15 The aqueous protein solutions may further comprise up to 100% by weight or more of a polyhydroxy ^ compound, preferably a mono- or di-saccharide. These compounds may be "naturally" present in the protein starting materials (e.g., lactose present in sweet dairy 20 whey protein concentrates) or added to the solutions prior to denaturation processing. Preferred polyhydroxy j. sr- i 4^ compounds include reducing sugars such as lactose, | glucose, fructose and maltose, with lactose being par ticularly preferred. Suitable non-reducing sugars 25 include sucrose and lactitol.

The high level of shear useful in the prepara-tive processing of the present invention is believed to i prevent the formation of large denatured protein aggre- i gates during denaturation. Aggregate blocking agents i i 30 may optionally be added to the aqueous solutions to | facilitate production of desired products. The aggre- | gate blocking agent be selected or adjusted in concen tration so that it does not in turn alter the pH of the mixture to outside of the optimal processing specifica-35 tions. Suitable aggregate blocking agents include hydrated anionic materials such as xanthan gum (ordinarily included at 0.1% to 1.0% by weight of the protein Vv • 22 2 9 3; o r> concentrate), datem esters (0.5% to 2.0% by weight of the protein concentrate despite the fact that datem esters tend to contribute an off-flavor to the final product) and lecithin (1% to 10% by weight of the pro-5 tein concentrate). Other suitable aggregate blocking agents include carrageenan, alginate and calcium steroyl lactylate.

Malto-dextrins produced by enzymatic or acid hydrolysis of starch provide another chemical aggregate 10 blocking agent useful in practice of the invention. The preferred concentration is from 10% to 50% by weight of the protein concentrate. These materials are believed to have a protein-sparing effect, as does high fructose syrup, although the latter is not as efficient as the 15 former in this regard. It will be appreciated that these blocking agents are carbohydrates and hence are a source of calories, a factor which may mitigate against their selection for use in applications such as reduced calorie foods.

Hydrated lecithin and hydrated xanthan gum exemplify the differing effects of different blocking agents. Both impart lubricity to the mouth feel of the final product. Lecithin, however, being a slightly less effective blocking agent, produces a slightly larger 25 average size macrocolloid particle. Those macrocolloid particles produced with xanthan aggregate blocking agent, however, are smaller and smoother particles.

Both of the foregoing have a whitening effect on the final product in that they seem to assist in creating a 30 more uniformly dispersed system thereby increasing the light scattering effect which is perceived as whiteness.

Combinations of aggregate blocking agents also have been found to have useful attributes. A lecithin-maltrin combination, for example, is particularly suit-35 able for producing macrocolloids useful in low viscosity salad dressings (e.g., French) and with a more reduced solids content, a coffee whitener. A combination of 0 22 2 9 37 A I u xanthan and lecithin aggregate blocking agents is preferred for applications such as the high viscosity salad dressings (e.g., Blue Cheese or Creamy Italian), fruit puddings and confectionery gels.

Other optional ingredients such as salts and end product components including suitable flavors, colors and stabilizers may generally be present in or added to the solution without adverse effect. In many cases (i.e., where the nature of the additive and its 10 influence on the protein solution permits), it may be particularly desirable to include such end product components in the protein solution in order to avoid the need for subsequent, additional pasteurization steps following processing.

Protein starting materials may optionally be treated to remove cholesterol, fat and other impurities which may introduce off-tastes to the macrocolloid product. One such procedure comprises an extraction step wherein the protein material is contacted with a 20 food-grade solvent which is preferably ethanol in the presence of a suitable food-grade acid. The protein material is then subjected to several wash and filtra-J tion steps to render the extracted protein product.

! Suitable solvents include lower alkanols, | 25 hexane or the like, with ethanol being particularly ' preferred. Suitable food-grade acids include mineral I © acids such as phosphoric, and food grade organic acids : such as acetic, citric, lactic, and malic with citric j acid being particularly preferred. j 30 The extraction procedure is particularly use- | ful for the removal of cholesterol and fat from protein ! sources such as whey protein concentrate. In preferred extraction procedures providing optimal elimination of fat and cholesterol, the whey protein concentrate is 35 extracted at 52°C for six hours with a mixture of 90-97% alcohol (preferably about 90% ethanol), 3-10% water (preferably about 9%) and about 0.01-0.20% acid (pref- © 22 29 37 n erably about 0.084% citric acid). In alternative practices providing highly desirable flavor and processing characteristics, the whey protein concentrate is extracted at 40°C for four hours with a mixture of 5 ethanol, water and citric acid with respective concentrations of 94.95, 5.0 and 0.05 percent. According to such procedures, whey protein concentrate comprising as - much as 4.0% fat and 0.15% cholesterol prior to the extraction step comprised less than 2% fat and less than 10 0.02% cholesterol after such an extraction step.

Once the heat denaturation process is completed, the product may, optionally, be subjected to a homogenization treatment. Such a treatment is desirable in the case of products which are dilute (i.e., having a 15 lower protein concentration) and/or neutralized, such as coffee whiteners for example. This treatment is useful in disrupting the relatively loose, inter-particle associations which occasionally form during processing. While not aggregated, (i.e., not fused into par-20 tides of substantially larger than 2 microns in diameter) those of the macrocolloids which are asso- /f" 'vL ciated with one another (i.e., usually in doublets or triplets) are nonetheless organoleptically perceived as single composite particles which cannot be differen-25 tiated from aggregates on the basis of their respective mouth feels. The homogenization treatment divides these associations of particles into individual macrocolloidal particles having the desired mouth feel attributes. The homogenization treatment of dilute products having low 30 macrocolloid concentrations (e.g., coffee whiteners) is preferably carried out at about a pH of 6 to 7. At such pHs, the distribution of electrical charges on the surfaces of the macrocolloids helps maintain an even dispersion of the macrocolloids in the aqueous medium. 35 While any of the traditional homogenization treatments known in the art may be employed to this end, reasonable care must be taken to avoid exposing the macrocolloidal 22 2 9 3 7 n particles to such elevated temperatures as may cause them to aggregate to larger particles.

Particle size testing provides a measure of organoleptic quality of the products of the present ' 5 invention. One of the simplest and most rapid of the techniques involves the preparation of an optical slide ^ in a manner which is analogous to the preparation of clinical blood smears. Pursuant to this method, ten (10) grams of a paste-like food sample is weighed into a 10 Waring blender and 190 grams of distilled water is added to make a 5% solution. The solution is then blended at high speed for 2 minutes and then pH-adjusted to 6.75-7.0. The sample is then, subjected to high speed magnetic stirring during sonication for 1 minute using a 15 probe sonicator (Braunsonic Model 2000 Sonicator, Burlingame, CA). This procedure breaks up any weak Xj associations that might exist between the individual I macrocolloid particles. The solution is then diluted ! further with deionized water to between 0.25% and 0.50% i depending on particle concentration. This solution is then placed in an ultrasonic bath (Branson 2200 Ultrasonic Bath, Shelton, CN) for 1 minute immediately before slide preparation.

After shaking by hand for 10 seconds, 20 yl of 25 the sample, as prepared above, is placed on the center of a microscope slide which has been placed in a Corning slide spinner. The slide is spun immediately after the sample has been placed on the slide. As soon as the slide is dry, usually within about 30 seconds, it is 30 ready for microscopic evaluation.

The sample is observed with a Zeiss Axiomat Microscope equipped with a halogen light source (Zeiss, Thornwood, NY) and a Dage MTI video camera (Michigan City, IN) and camera control using a 50X objective and a 35 total magnification ranging between 1000 and 1600. The system is only capable of performing quantitative analysis on particles with diameters greater than about H ,-,v /ttfr ' vV" r> * l2 9 3 7 0.25 microns. For this reason, all statistical measures of particle size herein, unless otherwise noted, refer to particles having major dimensions exceeding 0.25 microns. Nevertheless, particles between about 0.10 5 microns and about 0.25 microns may be viewed by an observer and their presence is routinely noted.

Numerous fields (15 to 25) are scanned to subjectively evaluate the overall size and shape homogeneity/heterogeneity of the sample. Subsequent to qualitative evalu-10 ation of the sample, a field is chosen which appears to be representative of the entire sample. This image is then projected on a high resolution black and white television monitor [Lenco, Jackson, MO) for quantitative analysis.

The image on the television monitor is first digitized and is then translated from the television ^ monitor to the computer monitor. During this digitiza tion/translation step, the image is slightly reduced ! with the side effect that some of the particles that 20 were separate on the original image become fused together and are thus not representative of the true particles. These apparently fused particles are then carefully edited out by comparing the old (television monitor) image to the new (computer monitor) image. 25 Approximately 250 ± 50 particles are typically measured in one field. Initially the number of particles in the image is determined along with their corresponding lengths and breadths. From this data, two additional variables, equivalent spherical (E.S.) diameter and volume, are calculated as follows: E.S. Diameter = (B2 x L)1/3 E.S. Volume = 4/3 n B2L.

Where B equals breadth and L equals length.

When E.S. Diameter and Volume have been determined for the entire distribution of particles in the image, number-weighted (Dn) and volur.e weighted (Dv) mean E.S. diameters are calculated. Dn is a number 5 averaged particle size diameter which is calculated by summing the diameter of all particles in the distribution and dividing by the total number of particles. The Dv (volume weighted mean diameter) weights each particle in relation to its volume and thus provides an indica-10 tion of where the mean diameter lies on the basis of voiume or implicitly of mass. Maximum Diameter (Dmax) is simply the diameter of the largest particle present in the microscopic field.

This data can be plotted in the form of a 15 histogram plot with E.S. diameter on the abcissa as a function of the number of particles as well as volume of particles. From these data, the percentage of particle volume over 2 microns as well as the maximum particle size diameter can also be directly determined. 20 Apparatus suitable for use in preparation of products of the invention is described in .

N.2. Patent No. 216684. Alter native apparatus is depicted in the accompanying drawing Figures 1 through 5.

With reference first fo Fig. 1 a presently preferred processor comprises a housing 10, which in this example is supported by a base plate 11 and secured to it by a plurality of bolts 13. The base plate 11 in turn is mounted on a stand 14 which has an annular rim 16 formed on its upper end. An annular recess 17 in the underside of the base plate 11 receives the rim 16. The stand 14 and the base plate 11 have aligned vertically extending passages 18 and 19 through them, and a vertically extending drive shaft 20 extends through the passage 18 and upwardly into the passage 19. The drive shaft 20 is connected to be rotated by a drive mechan^ such as an electric motor (not illustrated) during V c*r; •rty- •I 2; > 2 9 37 operation of the processor. Secured to the upper end of the drive shaft 20 is a blade shaft 21, and a key coupling is provided between the two shafts 20 and 21.

The housing 10 of the processor comprises a 5 lower vessel part 26 and an upper lid part 27, the vessel being supported on an annular bearing support 28. The annular bearing support 28 has threaded holes formed in its underside and the previously mentioned bolts 13 are threaded into the holes in order to rigidly 10 secure the seal support 28 to the base plate 11. A centrally located, vertically extending opening 29 is formed through the seal support 28. The upper end portion of passage 29 is widened and it forms a ledge or seat 33 formed on the inner periphery of the passage 29 15 in order to properly align the seal 39 in the support 28. The blade shaft 21 extends through passage 29.

Above the seal 39, a blade 36 (see also Fig. lb) is positioned on the upper end of the blade shaft 21 and secured thereto by a cap nut 37. The conventional lip 20 seal 39 is provided between the bearing 31, the blade shaft 21 and the washer 38 in order to form a fluid-^ tight seal at this juncture.

The vessel 26 is in this instance double-walled and includes an outer wall 41 and an inner wall 25 42, the two walls being spaced in order to form a flow passage 43 between them. The two walls 41 and 42 are bowl-shaped and at their lower center portions have aligned openings 44 formed through them which receive the seal support 28, the two walls 41 and 42 being 30 secured to the seal support 28 such as by welding. At their upper ends, the two walls 41 and 42 are flared radially outwardly from the axis of the blade shaft 21 and are pressed tightly together to form a sealed connection in the area indicated by the reference 35 numeral 46. A heat exchange medium is passed through the space 43 between the two walls, an inlet tube 47 and an outlet tube 48 being secured to the outer wall 41 and •br.,,/v 2 2 9 37 r> connected to the space 43 in order to flow the heat exchange medium through space 43.

The lid 27 extends across the upper side of the two walls 41 and 42 and overlies the upper sides of 5 the flared portions 46. To secure the lid 27 tightly to the vessel 26, a ring 51 is positioned on the underside of the flared portions 46 and the periphery of the cir-cular lid 27 extends across the upper side of the flared portion 46. A circular clamp 52 encircles the outer 10 peripheries of the ring 51 and the lid 27, the clamp 52, the ring 51 and the lid 27 having mating bevelled surfaces 53 so that the clamp 52 wedges or cams the lid 27 tightly downwardly toward the member 52 when the parts are assembled. A gasket or annular seal 54 is mounted 15 between the adjacent surfaces of the ring 51 and the lid 27 in order to seal the connection.

Formed within the housing 26 is a toroidal or donut shaped cavity 61 which is formed between the inner wall 42 of the housing 26 and the lid 27. The interior 20 wall surface 63 of the vessel is in the shape of a round bowl and forms the lower half of the toroidal cavity. The upper half of the toroidal cavity is formed by an annular concave recess 64 formed in the underside of the lid 27 above the wall 63, the annular recess 64 being 25 coaxial with the axis of rotation of the blade 36 and with the center of curved surface 63 of the vessel 26. At the outer periphery of the cavity 61, the interior surface of the recess 64 extends downwardly in the area indicated by the numeral 66 and is closely adjacent the 30 upper edge surface 67 of the ends of the blade 36. In addition, the lid 27 dips downwardly along the axis of the toroidal cavity 61 to form a center portion 68, and the center of the blade 36 and the cap nut 37 slope up at the center of the toroid, directly under the portion 35 68.

The lid 27 has two holes or passages 71 and 72 formed in it. The passage 71 is on the axis of the c* ' • V " - *> -v *' ~ A'' -'v\. » _ j 22 29 37 cavity 61 and extends from the upper surface of the lid 27 and through the portion 68 and opens on the axis of the cavity 61. A tube 73 is fastened to the upper end of the passage 71 by a threaded fitting 74, and a 5 pressure control device 76, which in the present instance is a weight, is positioned on the upper end of the tube 73. A dead-end hole 77 is formed in the weight 76 and the upper end of the tube 73 extends into the hole 77. During the operation of the processor, 10 internal pressure within the cavity 61 may be vented out of the cavity through the tube 73 if the pressure is above the amount required to lift the weight 76 off of the upper end of the tub^e 73, and the weight 76 thereby maintains pressure within the cavity. The passage 72 is 15 connected to another tube 78 by a fitting 79, and the passage 72 extends to the uppermost portion of the cavity 61. The passage 72 and the tube 78 may be used, for example, for venting air from the cavity 61 when it is filled with a fluid to be processed, and a thermo-20 couple (not shown) may be inserted through the tube 78 and the passage 72 and into the upper surface of the (2^ fluid during the processing in order to monitor the temperature of the fluid.

The blade 36 includes a central thickened 25 portion 81 which has a vertically extending hole 82 formed through it for the blade shaft 21. The cap nut 37 fits across the upper surface of the portion 81. Extending radially outwardly from the portion 81 are two arms 83 and 84 which curve radially outwardly and 30 upwardly and extend closely adjacent (a clearance of about 0.5 to 1.0 nun is preferred) the interior curved surface 63 of the wall 42 of the vessel. The upper end portions of the blade arms 83 and 84 are substantially parallel with the blade axis, and thus the arms extend 35 over the lower half of the toroidal cavity. As shown in Fig. lb, the sides 86 and 87 of the two arms 83 and 84 also taper such that the blade arms narrow adjacent V/w~ « 22 2 9 37 their outer ends. Assuming that the blade 36 and the shaft 21 rotate in the counterclockwise direction as seen in Fig. lb, the two arms 83 and 84 have leading sides 86 and trailing sides 87. With reference to Fig. 4, the two edges 86 and 87 of each arm are relatively blunt but preferably taper downwardly and toward each other.

V Considering the operation of the processor illustrated in Fig. la, assume that the composite shaft 10 20, 21 is coupled to be rotated by a suitable drive motor and that the lid 27 is initially removed from the vessel 26. The cavity 61 is filled with a batch of fluid which is substantially equal in volume to the volume of the cavity 61 with the lid on the vessel.

With this batch of fluid in the vessel portion of the cavity, the lid 27 is positioned over the vessel with the annular portion 66 of the lid extending downwardly into the vessel cavity. The clamp 52 is then attached to the adjoining outer peripheral parts of the vessel 20 and the lid, in order to tightly secure the lid to the vessel. As the lid 27 is moved downwardly onto the '■""T vessel, air in the upper portion of the concave recess 64 may escape through the passage 72, along with any excess amount of the fluid within the cavity 61. Elimi-25 nation of the air from the cavity may be assisted by slowly turning the composite drive shaft 20, 21 and the blade 36 in order to eliminate any air pockets in ® fluid and remove any air from the cavity. In this manner, air is eliminated from the cavity 61 prior to 30 processing.

To process the fluid, the composite shaft 20, 21 and the blade 36 are rapidly rotated, and the high speed rotation of the arms 83 and 84 creates high shear forces within the fluid. Subsonic pulses are formed at 35 the leading edges 86 of the arms and cavitation occurs at the trailing edges 87. The rapid rotation of the arms causes the fluid to assume the shape of a natural 22 29 3; r- " s 1 if: toroid 91 or donut as illustrated in Fig. 5. By a natural toroid, it is meant that the fluid naturally assumes the toroidal shape in the absence of the lid 27 on the vessel. In other words, if the lid 27 were 5 removed and the blade rotated at a sufficient speed, the fluid will assume the shape of the toroid 91. The annular concave recess 64 in the underside of the lid 27 is shaped to conform to the surface of the toroid 91, thereby disallowing presence of "dead zones" wherein 10 fluid flow is much less intense.

With reference to Figure 5, it is theorized that the surface fluid of the toroid 91 flows upwardly and radially inwardly from the outer ends of the blade arms, and the fluid circles along the path indicated by 15 the arrows 92. In addition, the fluid moves in the circumferential direction and follows the direction of movement of the blade, thereby forming a helical path. Further, it is theorized that a number of concentric layers are formed in the fluid (the layers being 20 represented by the concentric arrows 93), and the layers follow similar helical paths. There is also, however, movement of the liquid between the layers so that homo-geniety is rapidly produced within the fluid. The movement of the blade through the fluid and the movement of 25 the various fluid layers against each other is so intense that there is a high degree of conversion of mechanical energy to heat.

When the blade is rotated at about 5,000 rpm, the blade causes the fluid to undergo the described 30 rapid toroidal flow and significant cavitation and turbulence are created, particularly in front of the leading edges 86. The flow of the fluid permits rapid heat transfer from the wall 42 and the heat exchange medium. The agitation or high shear force produced by 35 the blade quickly mixes and heats the fluid. The conversion of mechanical energy to heat is estimated by measuring the temperature rise in the fluid above the ySi . ".\f " v > 22 2 9 3 r- temperature of the heat exchange medium per unit of time and per unit of mass. The intensity of work input to the fluid by rotating blade 36 is sufficiently high (as reflected by the magnitude of temperature rise due 5 solely to mechanical effects) to prevent the aggregation of, e.g., protein molecules, larger than a particle size of about 1 to 2 microns.

The blade 36 is particularly effective in heating and mixing the fluid. The relatively blunt 10 leading edges 86 of the blade at 5,000 rpm produce subsonic pulses in the fluid, whereas cavitation occurs at the trailing edges 87. The slight downward and inward taper of the sides 86 anjd 87 (shown in Fig. 4) moves the fluid in front of the blade arms toward the bottom of 15 the cavity and against the wall. This action produces great agitation of the fluid and also effectively eliminates accumulation of product on the cavity wall. The blade produces a natural torus and the chamber or cavity is shaped to match the natural torus during mixing, 20 thereby avoiding dead space in the cavity, preventing caking or buildup of the product in low flow spaces, and ■-T • promoting uniformity of the mix.

In an instance where the fluid in the cavity is to be prevented from becoming too hot, a cooling 25 medium is flowed through the tubes 47 and 48 and the space 43 in order to restrain the fluid in the cavity 61 from rising beyond a desired temperature. On the other hand, if the fluid is to be heated, a hot medium may be flowed through the space 43. After the fluid has been 30 sufficiently agitated by the blade and the temperature of the fluid is at the desired level, the blade rotation is stopped, the lid 27 is removed, and the batch of the mixed fluid is removed from the cavity 61.

Figs. 2 and 3 illustrate a preferred embodi-35 ment of the apparatus which is designed for a continuous flow operation as contrasted with the batch operation of the embodiment shown in Fig. la. The embodiments of • * r- x 22 2 9 3 7 f Pig. la and Fig. 2 include corresponding parts and the same reference numerals are used in the two figures for corresponding parts, except that the numerical value of 100 is added to the numerals in Figs. 2 and 3.

With specific reference to Fig, 2, the processor includes a vessel 126 and a lid 127 which are similar to those of Fig. la except that the lid 127 has a larger vertical thickness. The vessel and the lid in Fig. 2 are fastened together by a clamp 152 with seal 10 154 and O-ring 155 located between them. The vessel and the lid form a toroidal cavity 161 between them and a blade 136 is mounted within the cavity 161. In this specific example, the vessel 126 also has double walls similar to the vessel of Fig. la and inlet and outlet 15 tubes 147 and 148 are also provided. However, the tubes 147 and 148 are sealed by plugs 201 in order to form a j dead air space 143 between the two walls, this space acting as insulation around the vessel. The lid 127 has the passage 172 formed in it which may be used for a 20 thermocouple sensor, and the passage 171 which, in this instance, forms an outlet for the continuous flow of the ! CD' fluid product after processing as it leaves the cavity ! 161. j The vessel 126 is mounted on the base plate ; 25 111 by a base 128 which in this embodiment of the inven tion also includes a passage for the flow of the fluid into the processor cavity. A product inlet tube 203 is connected to a source (not shown) of the fluid product and to an annular seal ring 204 which fits tightly 30 around the outer periphery of the base 128. The inner end of the tube 203 connects with a diagonal passage 206 in the base 128, which is sealed at its outer end by an O-ring 207. The passage 206 angles radially inwardly and upwardly as seen in Fig. 2 to the interior surface 35 of the base 128 and to a spacer bushing 208. A circular recess or groove 209 is formed in the outer surface of the bushing 208 and the passage 206 is in flow communi v .V, / I ! ^ i i . i 22 2 9 37 cation with the groove 209. Consequently, product flowing into the processor through the tube 203 flows through the passage 206 and into the annular groove 209. A plurality of feed or inlet ports 211 angle 5 upwardly and radially inwardly from the groove 209 and the upper ends of the ports 211 appear on the upper surface of the bushing 208 below the lower surface of the blade 136. Due to the angles of the inlet ports 211, the fluid product entering the cavity first flows 10 radially inwardly and upwardly and then flows radially outwardly and upwardly past the sides of the blade 136.

A mechanical seal 216 is provided to seal the connection between the spacer bushing 208 and the blade 136. The mechanical seal 216 is annular and is sealed 15 to the bushing 208 by O-rings 217, 217b and an upwardly projecting seal face 218 on the upper end of the seal 216 engages the underside of the blade 136. With reference to Fig. lb, the seal face 218 is shown in dashed lines and it will be noted that it is entirely within 20 the outer contour of the blade. To obtain a good seal, the underside of the blade 136 in the area of the seal face 218 is preferably lap ground. Another rotary lip seal 221 is provided between the base 128 and the shaft 121 in order to seal this connection. The seal 221 is 25 nonrotatably mounted at its outer periphery on the base 128 and its inner periphery slidingly engages the outer surface of the shaft 121. An annular spring 222 such as a garter spring holds the lip seal tightly against the shaft 121.

A chamber 223 is thus formed between the lip seal 221, the mechanical seal 216, the outer surface of the shaft 121 and the bushing 208. This chamber 223 is flushed by cooling water which enters the processor through a tube 226 and leaves the processor through 35 another tube 227, the two tubes being located at opposite sides of the processor as shown in Fig. 3. The two tubes 226 and 227 are also mounted on the seal ring 204 22 2 9 3 r^ A\ and extend radially through the ring 204. Flow passages 228 and 229 are formed through the base 128, the inner ends of the two passages connecting with opposite sides of the chamber 223. The outer ends of the passages 228 5 and 229 respectively connect with the tubes 226 and 227, and O-rings are provided around these connections. Consequently, during operation of the processor, coolant water flows into the processor through the tube 226, into the chamber 223 and around the internal surfaces in 10 the area where the mechanical seal 216 meets the lower surface of the blade 136, and then out of the chamber through the tube 227.

During the operation of the processor, the lid 127 is fastened to the vessel 126, the blade 136 is 15 rotated within the cavity 161, and the coolant water is flowed through the chamber 223. The product mix is then introduced into the cavity 161 by being flowed through the inlet tube 203, through the passage 206 and the inlet ports 211, and into the cavity 161 from the under-20 side of the rotating blade 136. The fluid product fills the cavity 161 and air initially filling the cavity is flushed by fluid flow through the tubes 172. The fluid assumes its natural toroidal shape within the cavity 161 as previously described and the walls of the vessel 126 25 and the lid 127 conform to the shape of the natural toroid. The product within the cavity is held under pressure because pressure is required in the tube 203 in order to force the fluid product through the cavity and out of the passage 171. The outlet tube 231 connected 30 to the passage 171 may contain a restriction or valve in order to form a back pressure and thereby increase the pressure within the cavity 161.

The described mixing and heating of the fluid in the cavity 161 is similar to that in the cavity 61. 35 The fluid entering the cavity flows directly into a high shear area below the blade. Further, the upward and inward angle of the ports 211 causes the incoming fluid to form a turbulent flow and wash against the seal 216, and thereby prevent any buildup or caking of the fluid in this area. Further, the inward flow and proximity to the center ensures that all of the fluid flows under the blade and that some of the fluid will not be shunted out at the sides of the arms immediately after leaving the ports 211. The coolant flow within the chamber 223 prevents the bearing 216 and the blade from overheating and burning the fluid product being processed. The port 211 opposite inlet 206 is preferably slightly enlarged to provide uniform flow through the three ports.

According to a procedure for operating the apparatus of Figure la, the empty vessel is aligned, the shaft segments are mated, the vessel is secured to the base plate and the blade is mounted on the shaft and secured. Three hundred forty (340) grams of deaerated protein premix is charged into the vessel, care being taken to avoid the formation of bubbles or voids.

The lid is fitted into the well formed by the upper walls of the vessel and is slid down into place over the gasket with care being taken to position the empty thermocouple-port so that entrapped air can be vented through this port. Removal of any trapped air may be facilitated by slowly rotating the blade. When this has been accomplished, the lid is seated securely, excess premix which may have been forced out of the port is removed, and the thermocouple is inserted and secured. The lid is then secured by clamping means and the counter-weight is seated on the vent-tube.

Heating fluid is then circulated through the vessel, the drive means is switched on; and the speed of the blade is set at the desired rotational speed, which is typically greater than about 5000 rpm. The blade rotating at this speed causes the contained protein premix to undergo rapid toroidal flow with the consequence that significant cavitation and turbulence are created, particularly in the areas immediately in front •-,W a £ 22 29 37 of the impact-edges of the blade). The swirling flow of the premix is adequate to permit rapid heat-transfer from the heating fluid through the inner vessel wall, into the premix. As the temperature of the premix 5 passes through about 80°C, the viscosity of the mix begins to increase but the blade is maintained at a constant speed by the motor.

The unabated high work-input (coupled with the increasing viscosity) imparts considerable mechanically-10 induced heat to the product. Typically, this drives the product temperature about 20 to 40*C above the temperature of the "heating" fluid in a period of from about one to two minutes. When the targeted temperature and dwell-time have been achieved, the externally-mounted 15 valves which control the flow of heat-exchange fluids are aligned so that the heating fluid is displaced by cooling fluid. Product temperature is seen to begin to decrease immediately. When the product is cooled to 80°C, the blade speed is reduced to about 1000 rpm in 20 order to avoid imparting further mechanical energy and thus to reduce cooling time. When the product has been cooled to about 35°C, the drive means is turned off, the lid is removed, and the product is collected from the vessel and the lid.

The following examples relate to preferred methods and procedures according to the present invention. Example 1 relates to a preferred method for the production of macrocolloid material according to the invention from the extracted whey materials. Example 2 30 relates to the production of macrocolloid material from bovine serum albumin. Example 3 relates to the production of macrocolloid material from egg white albumin while Example 4 relates to the use of soy protein to form macrocolloid materials according to the invention.

I s,;.*" Jjm " -<■ ai» ■ "-.^.nt- T 22 2 9 37 Example 1 An extraction procedure was carried out for the removal of fat and cholesterol from the whey protein concentrate (WPC) protein source prior to denaturation 5 processing. More specifically, a reactor was charged with 181 kg of absolute ethanol (Lot Nos. 16468x, 16995x, Aaper Alcohol & Chemical Co., Shelbyville, KY). Water (8.58 kg) and 10% citric acid solution (954 grams, Miles, Elkhart, IN) were then added and the solu-10 tion was agitated for about two minutes. The pH of the solution was then measured to confirm that it was pH 5.0±0.5.

One hundred and forty pounds (63.5 kg) of whey protein concentrate WPC-50 (lot 6302-2 Fieldgate, 15 Litchfield, MI) was then added to the reactor and the reactor was sealed. Steam was then admitted to the reactor jacket and the reactor temperature was maintained at 40°-42#C for 4 hours. The protein slurry was removed from the reactor and filtered on a continuous 20 belt filter allowing the cake thickness to reach 1 inch. The collected cake weighed 116 kg. The reactor was charged with 127 kg of 95% ethanol and the wet cake was added to the reactor to form a slurry which was mixed for 20 minutes. The slurry was then removed, 25 filtered as before, and the collected cake was again added to the reactor charged with 127 kg of 95% ethanol. The slurry was mixed for 20 minutes and was then filtered with care taken to remove as much liquid as possible. The wet cake weighed 104.5 kg. 30 The wet cake was then placed in trays to a uniform depth of 1 inch or less. The material was then dried under vacuum for 12 hours at temperature of 45° ± 1°C, providing 51.5 kg of WPC material for a yield of 80.9%. Calculating that approximately 3.5 kg of 35 material had been lost in the dryer, the percentage of volatiles in the initial wet cake was calculated to be 47.4%. n A 22 2 9 3 / The resulting material had a protein concentration of 56.91% and a solubility of 93% measured according to the solubility determination method described above. The protein was then employed to make up 5 a formulation which included lecithin ("Lecigran F", Riceland, Little Rock, AR), 37% Food Grade hydrochloric acid {J.T. Baker, Phillipsburg, NJ), xanthan ("Keltrol T", Kelco, San Diego, CA) and water.

Table 2 Whey Protein Formulation Inqredient % cr • V WPC-50 34.500 690.00 Lecithin 0.932 18.64 Hydrochloric Acid 1.590 31.80 Xanthan 0.186 3.72 Water 62.792 1255.00 100.000 2000.00 I The components of the formulation listed in Table 2 above were added to a high shear mixer and ! deaerator (Kady Hill, Scarborough, HE) in the following i 25 order: water, hydrochloric acid, lecithin, xanthan and J whey protein concentrate. The mixture was deaerated j (2) before being introduced into the apparatus of Figure 1, J with care taken to minimize the conversion of mechanical I energy to heat. The processing vessel was then filled with the premix which had a pH of 4.15, sealed and the temperature recorder was turned on. The motor was activated, and the speed of the blade was adjusted to 5,080 rpm. After a few seconds, heating fluid with a temperature of 100°C was circulated through the jacket of the 35 vessel. The product reached a temperature of 122°C in 4.3 minutes, at which time the heating fluid was displaced by a flow of cold water which cooled the product to 40°C within 2 minutes. i ->22937 ft s~\ The product obtained from the above process was then evaluated for its organoleptic and physical characteristics. The product, which may be seen at lOOOx in FIG.6 , had a smooth and creamy consistency 5 with 64% of the protein converted to macrocolloid particles with 0% of the produced particles having dimensions exceeding 3 microns. The spherical particles had a volume-weighted mean diameter (Dv) of 0.99 microns, a mean particle size diameter (Dn) of 0.78 microns and a 10 maximum diameter (Dmax) of 1.50 microns.

Example 2 In this example, bovine serum albumin (BSA) was used to produce a protein macrocolloid product 15 according to the invention. Bovine serum albumin identified as "Bovine Albumin, Fraction VH was obtained from U.S. Biochemical Corp. (Cleveland, OH). The material was a lyophilized powder with a 97% protein content and a solubility of 99% according to the solubility deter-20 mination method described above. Other formulation ingredients included lecithin ("Lecigran F", Riceland, Little Rock, AR), 37% Food Grade hydrochloric acid (J.T. Baker, Phillipsburg, NJ), Xanthan ("Keltrol T", Kelco, San Diego, CA), lactose (alpha-lactose monohydrate, 25 Sigma St. Louis, MO) and water.

Jy* 1 tl DEC 1989 $] - -A,-. 22 29 37 n Table 3 Bovine Serum Albumin Formulation Ingredient % Wt. (g) BSA 13.080 121.64 Lecithin 2.100 19.53 Hydrochloric Acid 0.770 7.16 Xanthan 0.200 VD CD • H Lactose 7.560 70.31 Water 76.290 709.50 100.000 930.00 The formulation listed in Table 3 above was prepared in a high shear mixer and deaerator (Kady Mill, 15 Scarborough, ME) with the xanthan gum having been pre-hydrated. In order, water, hydrochloric acid, lecithin, ^ xanthan, lactose and BSA were added to the mixer and the mix was deaerated before being introduced into the apparatus of Figure 1. The processing vessel was filled 20 with the premix which had a pH of 4.19, sealed and the J ^ temperature recorder was turned on. The motor was acti- "w vated, and the speed of the blade was adjusted to 5,080 rpm. After a few seconds, heating fluid with a temperature of 80°C was circulated through the jacket of the 25 vessel.

The product reached a temperature of 126°C in 4.8 minutes, at which time the heating fluid was displaced by a flow of cold water. The product was cooled to 40°C within 2 minutes. The shear rate of this pro-30 cessor is reflected in the 46°C difference between the temperature of the product and the temperature of the heating fluid. This additional heat had been derived from the conversion of mechanical energy to heat at the rate of about 380 J/sec.

The product obtained from the above process was then evaluated for its organoleptic and physical characteristics. The product had a thick consistency r* o o I 222937 similar to the macrocolloid material produced from whey protein concentrate, and a creamy texture with high lubricity. 71% of the protein had been converted to macrocolloidal particles. The particles were dominantly spheroidal although some rod-like and fibrous particles persisted, as may be seen in FIG. 7. These rods and fibers having dimensions exceeding 3 microns accounted for 2.25% of the particles by number. When the rods and fibres were excluded from the microscopy-image analysis, the spheroidal particles had a volume-weighted mean diameter (Dy) of 1.03 microns, a mean particle size diameter (Dn) of 0.66 microns and a maximum diameter (Djnax) of 1.75 microns. , Example 3 In this example, egg white albumin was used to produce a protein macrocolloid product according to the invention. It was determined that a combination of fresh egg white and spray dried egg white would produce the desired product. Fresh egg white was separated manually on the day the premix was prepared from fresh eggs purchased locally. This egg white was determined to include 98% soluble protein but the protein concentration was less than 10%. Due to the initial protein concentration, processing of fresh egg white alone, can give rise to stringy masses of denatured protein product. Spray dried egg white was obtained from Henningsen Foods (White Plains, NY) (Type P-110 egg white solids) with 80% minimum protein. The protein solubility of the spray dried egg white powder was only 83% and processing of this material alone can generate an unacceptable number of oversize particles. In order to avoid the limitations of using each of the materials alone, the fresh and spray dried egg white materials were combined to provide a suitable egg albumin prote* source for practice of the invention.

Lecithin, xanthan, hydrochloric acid and lactose were obtained from the sources cited in Example 1 and were utilized in the amounts listed in Table 4 below.

Table 4 Egg White Albumin Formulation Ingredient % Wt. (g) Fresh Egg white 70.21 1168.92 Spray Dried Egg White 13.44 223.72 Lecithin 2.97 49.54 Xanthan 0.30 4.95 Hydrochloric Acid 2.37 39.43 Lactose .71 178.35 100.00 1664.91 Fresh egg white, lecithin, xanthan, lactose, spray dried egg white and hydrochloric acid were added in sequence and in the amounts specified in Table 4 to a high shear mixer where they were mixed and deaerated. The resulting premix had a pH of 3.6 and was introduced into the processing apparatus of Figure 1. The processing was carried out with a bath temperature of 80°C and was continued for 4.33 minutes with the blade speed set at 5,080 rpm. The maximum product temperature was 125°C.

The product obtained from the above procedure was thick and creamy. 88.9% of the protein had been converted to macrocolloidal particles which had a pronounced tendency to loosely aggregate. Particle size analysis showed that the particles were within the desired size range with a Dv = 1.22 microns and with 4% of the particles over 2 microns. Substantially all particles were spheroidal as may be seen in FIG. ®. i\ f< V*. r> 2 9 37 Example 4 In this example, soy protein was used to produce a protein macrocolloid product according to the invention. Soy protein was obtained from Ralston Purina (SN 1631-32-1, St. Louis, MO) which had a protein content of 61.4% and a solubility of 81% according to the method cited above. Lecithin, xanthan, hydrochloric acid and lactose were obtained from the sources cited in Example 1 and were utilized in the amounts listed in Table 5 below.

Table 5 Soy Protein Formulation i Inqredient % Wt. (q) Soy Protein 22.036 99.16 Lecithin 3.000 13.50 Xanthan 0.100 0.45 — Hydrochloric Acid 2.196 9.88 * ,-T Lactose .800 48.60 Water 61.868 278.41 100.000 450.00 The mix was prepared by adding water, hydro-chloric acid, lecithin, xanthan, lactose and soy protein in sequence to a high shear mixer where they were mixed and deaerated. The resulting premix had a pH of 3.74 30 and was introduced into the processing apparatus of Figure 1. The bath temperature was kept at 110°C. Heating was continued for 4.30 minutes with the speed set at 5,080 rpm. The maximum temperature reached by the product was 119°C.

The product developed a light tan color during cooking and was smooth, creamy, and thick with a somewhat beany taste typical of soy products. 71% of the ._w,^ _ -» ' 1 r 922937 protein was converted to macrocolloidal particles. Particle size analysis showed that the particles were within the desired size range, with a Dv of 1.46 microns and a Dmax of 2.5 microns. Substantially all particles 5 were spheroidal as may be seen in PIG. 9.

The foregoing illustrative examples are believed to provide an ample demonstration of the generic nature of the discoveries constituting the present invention. In one of its broadest aspects, the 10 invention resides in the discovery that virtually any source of animal or vegetable protein can be employed to generate proteinaceous water-dispersible macrocolloid particles which in hydrated form possess the substantially smooth (i.e., non-powdery, chalky or gritty) 15 organoleptic character of an oil-in-water emulsion. In general, hydrated macrocolloid products of the invention have relatively high viscosities (on the order of 25,000 cps), are non-dilatant, and possess the lubricity (i.e., absence of adhesiveness) of fat emulsions. Such 20 products are conspicuously useful as partial or total /T replacements for fats and fat-like materials in a wide variety of foods wherein fats ordinarily are present in amounts sufficient to make an organoleptic contribution.

The proteinaceous products of the invention are rather readily prepared through controlled denatura-^ tion processing of previously substantially undenatured proteins to provide a relatively homogeneously sized and shaped population of hydrated protein particles wherein 30 the particle size distribution is effective to impart the substantially smooth organoleptic character ordinarily only provided by oil-in-water type fat emulsions.

As demonstrated in the illustrative example, 35 the controlled denaturation processing required to ff^ generate the desired populations of proteinaceous par tides is most readily provided by concurrent applica -t V. m ■ * 2 29 37 n tion of heat and high shear forces to solutions of protein. In order to optimally attain the benefits of the invention, the starting material protein solutions should be formulated from, e.g., dried protein source 5 materials wherein in excess of about 80% of the dry protein is soluble in water or dilute salt solutions. Alternately stated, the use of source materials which comprise substantial amounts of insoluble protein or provide any substantial quantity of insoluble, 10 particulate, non-proteinaceous materials, is unlikely to provide desired products because application of heat and high shear is usually ineffective to reduce particle size of oversized material during processing. Where it is desired to make use of protein preparations 15 containing oversized materials which are not reduced during processing, it is within the contemplation of the invention to pretreat the preparations by known size reduction processes effective to reduce existing particles to within or below the desired size range 20 prior to controlled heat/shear processing. An example of such pretreatment would include processing the preparation in an attrition mill such as is commonly employed in the field of paint and pigment preparation.

The chemical complexity of proteins, the amphoteric character of protein in solution and the general heterogeneity of most natural protein source materials all dictate that the controlled denaturing processes of the invention take into account the pH of 30 the solutions heated and subjected to high shear. At present, optimal results are provided by carrying out heat denaturation at any pH below the midpoint of the isoelectric curve of the proteins in solution, with care being taken to avoid those pH values so low as to give 35 rise to hydrolytic degradataion of the proteins. Consistent with these considerations, many protein solutions will require adjustment of pH (with any suitable food grade acid) prior to denaturation.

The ability to generate desired substantially homogeneously sized and shaped populations oE protein particles can, in many instances, be favorably or unfavorably affected by the presence or absence of soluble, non-proteinaceous components in the solutions subjected to denaturation. Among the more significant of these components are the "aggregate blocking agents" previously described. While the term is aptly descriptive of one of the potential functions served by these compounds (i.e., prevention of the formation of aggregation of protein molecules to larger than desired size ranges), they serve other functions such as enhancing the overall lubricity of the macrocolloid products. Significantly, these compounds can also significantly increase the extent of conversion of protein to particulate form, most likely through charge-based effects or protein complex formation. The combination of effects on enhancement of coagulum-formation and prevention of particle formation results in an overall "focusing" of formation of protein particles in the desired size range. In preliminary studies directed toward ascertaining more precisely the effects of aggregate blocking agents, it was observed that upon the addition at room temperature of acidified, substantially pure protein solutions to hydrated aggregate blocking agents, a coagulum appeared which could be dissolved by increasing pH toward neutrality. The coagulum displayed a variety of macroscopic forms including a single massive gel, an abundance of fibers ranging into the microscopic region and/or small globular, disaggregated particles. The configuration of the coagulum can be used to guide the choice of the concentration of added materials and their order of addition.

The selection of one or more aggregate blocking agents for incorporation in protein solutions to be treated by controlled heat denaturation according to the invention can suitably be based on examination of room s. ¥ n ^ 22 2 9 37 temperature coagulum-forming effects as noted above.

The formation of a large globular coagulum or massive gel upon mixture of an acidified protein solution to the aggregate blocking agent is generally predictive of poor 5 prospects for obtaining a dispersion of particles within the desired size range. Likewise, formation of a fibrous coagulum is predictive of denaturation products having substantial numbers of non-spherical and threadlike protein particles unless positive steps are taken 10 to disperse the coagulum prior to application of heat and high shear conditions. The formation of small, globular, disaggregated coagulum particles at room temperature is correspondingly generally predictive of denaturation processability to provide the desired 15 macrocolloid product.

Other solution components which can play a j significant role in processes of the invention are J naturally-occurring polyhydroxy compounds such as mono- I and di-saccharide sugars, especially lactose. It will be apparent from the illustrative examples that whey protein concentrate solutions which contain on the order of 50 percent by weight lactose are readily subjected to heat and high shear to provide products of the invention. In preliminary studies of the effects of lactose 25 concentrations on the ability to use controlled heat denaturation for large scale production of products, it was found that chromatographic purification pretreatment of whey protein concentrates to remove substantially all lactose did not preclude preparation of useful 30 products. On the other hand, however, adding lactose to the lactose-free whey protein solutions did improve efficiency of production, especially when aggregate blocking agents are employed. Moreover, as indicated in the above illustrative examples, the preparation of 35 macrocolloids of the invention by heat/shear treatment of bovine serum albumin, egg albumin and soy protein was benefited substantially by addition of lactose to the ii n 22 29 37 solutions. While reducing sugars such as lactose would appear to be the most suitable additives, non-reducing sugars can also be effectively employed as additives.

Numerous modifications and variations in practice of the invention are expected to occur to those skilled in the art upon consideration of the foregoing descriptions of preferred embodiments thereof. Consequently, only such limitations should be placed upon the scope of the invention as appear in the appended claims.

I

Claims (7)

WHAT WE CLAIM IS:

1- A proteinaceous, water-dispersible, macrocolloid comprising substantially non-aggregated particles of denatured protein (as hereinbefore defined on page la) having in a d state a mean diameter particle size distribution ranging from 0.1 microns to 2.0 microns, with less than 2 percent of the total number of particles exceeding 3.0 microns in diameter, and wherein the majority of the said particles are generally spheroidal as viewed at 800 power magnification under a standard light microscope, the particles in a hydrated state form said macrocolloid having substantially smooth, emulsion-like organoleptic character.

2. The macrocolloid of claim 1 wherein the protein is derived from undenatured substantially soluble protein.

3. The macrocolloid of claim 1 wherein the protein is bovine serum albumin.

4. The macrocolloid of claim 1 wherein the protein is egg white albumin. 5. The macrocolloid of claim 1 wherein the protein is soy protein. 6. The macrocolloid of claims 1, 2, 3, 4 or 5 wherein said particles are hydrated. 7. An aqueous dispersion of the macrocollo of claim 1. 8. The dispersion of claim 7 wherein said-particles of denatured protein are obtained from an undenatured protein which is substantially soluble. ®V' 1'-'" ' \\VyE3£V"' ftf - . 222937 - 5

5 - a cr 9. The dispersion of claim 8 wherein said particles of denatured protein are obtained from an undenatured protein which is greater than 90% soluble. 10. The dispersion of claim 7 wherein said particles are produced from an aqueous solution charac- O terized by having a protein concentration between 10% and 20%, and a pH less than the midpoint of 10 the isoelectric curve of the protein as defined on page 8. 11. The dispersion of claim 10 wherein the aqueous solution has a pH about 1 pH unit below the midpoint of the isoelectric curve of the protein. 15 12. The dispersion of claim 10 wherein said aqueous solution is established to contain from 0 to 100 percent by weight of a sugar per unit weight of protein. 20 13. The dispersion of claim 10 wherein said sugar is lactose. 14. The dispersion of claim 11 wherein said particles are produced from an aqueous solution charac- 25 terized by having between 15% and . 18% by weight protein. 15. The dispersion of claim 11 wherein said solution is modified by the addition of one or more 30 aggregate blocking agents. 16. The dispersion of claim 15 wherein said aggregate blocking agent is an anionic blocking agent. 35 17. The dispersion of claim 16 wherein saic anionic aggregate blocking agents are selected from tj group consisting of xanthan, datem esters, lecithin, carrageenan, alginate and calcium steroyl lactylate. ■r-ik'..:-. SV ' ■ \ v- 1 «*\ - 5

6 - 222937 18. The dispersion of claim 15 wherein said aggregate blocking agent is a malto-dextrin. 19. A process comprising heating undenatured substantially soluble and coagulable proteins other than denatured dairy whey protein at heat denaturing temperatures in an aqueous solution at a pH less than the isoelectric point of said proteins, under shear conditions selected and carried out for a time sufficient so as to avoid the formation of any substantial amounts of fused particulate proteinaceous aggregates having diameters in excess of 2 microns while also forming denatured proteinaceous macrocolloid particles which are greater than 0.1 microns in diameter. 20. The process according to claim 19 wherein the proteins are selected from the group consisting of bovine serum albumin, egg white albumin and soy protein. 20 21. The process according to claim 19 wherein 1 said pH is about 1 pH unit below the midpoint of the j isoelectric curve of the protein as defined on page 8. | 25 22. The process according to claim 19 wherein 1 O said heat denaturation is carried out at temperatures of j between 80 degrees Centigrade and 120 ] degrees Centigrade. ! 30 23. The process according to claim 19 wherein said shear rate is greater than 7,500 reciprocal seconds. ( 24. The process according to claim 19 wherein ^ j^(j\990 35 said time is between 10 seconds and 120 seconds. 23 r\ -» •4 i Q \ C v ^ 222937 - 5

7 - 25. The product of the process according to Claim 19. 2ga A proteinaceous, water-dispersible, macro-colloid as claimed in any one of Claims 1-18 and substantially as hereinbefore described with reference to any one of the fore-going Examples. 27. The process as claimed in claim 19 and substantially as hereinbefore described with reference to any one of the foregoing Examples. ,'~N JOHN LABATT LIMITED By their authorised Agents P.L. BERRY & ASSOCIATES Per