United States Patent Palmer Apr. 17, 197.3
[75] Inventor: Gaylord M. Palmer, Castro Valley,
Calif.
[73] Assignee: Foremost-McKesson, Inc., San Francisco, Calif.
[22] Filed: Aug. 18, 1970 [21] Appl. No.: 64,726
[56] References Cited UNITED STA ES PATENTS 3,042,526 7/1962 Spiess et a]. ..99/D]G. 4
3,120,438 2/1964 Mclntire et a1. ..99/D1G. 4 3,300,315 1/1967 Nava et a1. t t ..99/56 3,420,811 1/1969 Van Wieren et al.... ..9/20 X 3,389,131 6/1968 Van Horn ..99/20 X.
Primary Examiner-Raymond N. Jones Atzarney-Flehr, Hohbach, Test, Albritton & Herbert 5 7 1 ABSTRACT A dry instantized sodium. caseinate powder with'essentially all of the particles containing a coating of watersoluble saccharide (e.g., corn syrup solids) in which'a surfactant (e.g., lecithin) is dispersed. A process of forming this product includes the step of dry blending spray-dried sodium caseinate powder saccharide powder, moistening the: blend by subjecting thesame to a moist atmosphere containing finely divided surfactant to form moist aggregates and drying the aggregates. The moist atmosphere may be an atomized aqueous dispersion formed by mixing lecithin, water, and steam.
19 Claims, 12 Drawing Figures and time T PATENTEDAPR 11 3,728,127
SHEET 3 or 4 PATENTE APR] 7 I975 SHEET a, 0F 3 FIG SODIUM CASEINATE-CONTAINING PRODUCT AND METHOD FOR MANUFACTURING BACKGROUND OF THE INVENTION powder, having a high protein content, is used as an ingredient in a large number of food products, such as confections, bakery products, and the like, for nutritional value and also for imparting certain physical characteristics including emulsionstability and properties such as whipping, body, and viscosity A serious deficiency of spray dried caseinate is that, even though soluble, it is difficult to disperse in either cold or hot water without extended high energy agitation. This is attributed to its poor wettability en masse dispersion. Because of such characteristics, spray-dried sodium caseinate is not well suited for many uses where it is to be dispersed in water or other aqueous mediums.
Particularly, it is not well suited for use in blended products such as beverage powders, so-called instant breakfast," instant milk cake powders, and various dietary products, where ease of dispersion in water is desired. I
Many dry food products are instantized for the purpose of facilitating ready dispersion in water or other aqueous mediums. Such instantized products are characterized by granules which are in the form of porous aggregates of high wettability. Particular reference can be made to instantized products such as milk, sucrose, lactose and cereal flour. For example, in the milk industry nonfat dry milk (skim milk) is instantized byprocessing in accordance-with Peebles US. Pat. No. 2,835,586. This involves moistening dispersed spray-dried milk powder to make the individual milk particles sticky, and causing the sticky particles to be brought into random contacts to form moist porous aggregates that are subsequently'dried. Such an instantized milk product has high wettability and when a quantity of the products is deposited upon the surface of cold water, the water quickly penetrates the mass and the powder sinks within a short period of the order of 10 seconds or less. Low level agitation, such as stirring with a spoon, serves to disperse the particles in water to form a stable reconstituted milk. When instan- "reconstituted with water.
Contrary to what might be expected, I have found I that when instantizing as described above is applied to spray-dried sodium caseinate, the resulting product cannot be readily dispersed in water with low level agitation. When a quantity of the product is deposited on the surface of water, it tends to float, and when stirred with a spoon, sticky lumps or masses are formed of gel-like consistency. The use of lecithin as in the instantizing of fat-containing milk serves to provide fair wettability but does not materially improve dispersability. Thus, with low energy agitation the material still forms sticky lumps or masses that resist dispersion.
SUMMARY OF THE INVENTION & OBJECTS This invention relates generally to an instantized sodium cas einate product and method of manufacture;
It is an object of the invention to provide a dry sodium caseinate-containing product which has high wettability incold water and which readily disperses in water by simple stirring to produce a stable reconstituted fluid.
It is a further object of the invention to provide a method for producing a product of the aforementioned type.
Another object of the invention is to provide a dry sodium caseinate-containing product which may be dry blended with other'ingredients to provide formulated products of desired protein levels.
In carrying out the present method, spray-dried sodium caseinate powder is uniformly dry blended with highly water-soluble saccharide powder, e.g., in a ratio of from between 40 and percent to between 5 and 60 percent. Thereafter, the blend is moistened by subjection to a moist atmosphere containing a finely dispersed surfactant so that a substantial portion of the saccharide powder dissolves and the sodium caseinate particles are caused to become: sticky and adhere together in the form of moist aggregates with saccharide and surfactant incorporated thereon. The' amount of surfactant may be such as to provide a surfactant content of from 0.1 to 2.0 percentv in the final product. The moist porous aggregates are then dried to remove excess moisture. Suitable-surfactants include lecithin, polyoxyethylene sorbitanesters of fatty acids, monoand di-glycerides, and combinations thereof. Suitable water-soluble" saccharide powders include corn syrup solids, monosaccharide's such as glucose;
disaccharides such as sucrose and lactose, and watersoluble polysaccharides such as dextrins. a i
The instantized dry sodium caseinate product produced according to the invention consists of particles containing sodium caseinate, water-soluble saccharide, and a surfactant. These particles are bonded together to form porous aggregates of a size substantially greater than the original-particles, with a substantial portion of the saccharide and surfactant forming a generally uniform coating over the surfaces of essentially all of the sodium caseinate particles. The product is characterized by high wettability and its ability to readily disperse in water by simple stirring to form a stable dispersion.
Additional objects and features of the invention will appear from the following description in which the preferred embodiments of the invention havebeen set forth indetail in conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 a flow diagram illustrating one procedure for carrying out the method of the present invention.
7 FIGS. 2 12 are photomicrographs at three different magnifications serving to illustrate the uniform distribution of saccharide and lecithin on the sodium caseinate of my product by comparison with sodium caseinate, my product without lecithin, and my product without saccharide.
DETAILED DESCRIPTION OFJI-IE PREFERRED EMBODIMENTS In accordance with the procedures shown in the drawings, spray-dried sodium caseinate powder is dryblended with a predetermined quantity of a water-soluble saccharide powder to form a substantially homogeneous blend. This blend is then moistened in step 12 by contact with moisture-containing a surfactant to form moist porous aggregates. The aggregated material from step 12 passes to step 13, where excess moisture is removed by drying to form the final product.
The sodium caseinate powder, supplied to step 11, may be spray dried by conventional methods from a sodium caseinate solution typically prepared by dissolving high-quality isoelectric casein in sodium hydroxide solution. Such a powder typically has a relatively small particle size (e.g., essentially all of the powder passing through a 100 mesh screen) and includes up to about 90 percent protein and percent total moisture.
To impart the desired characteristics to the final product, the saccharide powder supplied to step 11 is water-soluble. For example, it may include monosaccharides, such as glucose, di-saccharides such as sucrose and lactose, water soluble polysaccharides such as dextrins, or corn syrup solids of various compositions. In order to facilitate coating of the saccharide homogeneously onto substantially all of the sodium caseinate particles, for the purpose explained herein, the average particle size is not larger than that of the sodium caseinate.
Corn syrup solids are an economical saccharide for my process. They are typically producedby the partial hydrolysis of starch to form a hydrolysate product which is then dried. One method of drying corn syrup solution to form corn solids is disclosed in Peebles US. Pat. No. 2,317,479 and includes atomizing the solution in a high temperature zone and then cooling the liquid particles to form a solid product of a partially crystalline and partially glass structure. This product is then comminuted to form a powder of the desired size. By way of example, a particularly suitable ingredient is sold under the trademark Frodex 24" by the Americ'an Maize Products Co. It has a dextrose equivalent in the range of 24-28 percent and a typical sieve analysis in which 99 percent of the product passes through a 200 mesh screen. For convenient, the process will be described herein with a corn syrup solids powder of this type as the water soluble saccharide powder.
The amount of water soluble saccharide powder blended with the sodium caseinate should be sufficient to impart the desired instant" properties. For this purpose, as low as 5 percent by weight of saccharide may be blended. However, better results are obtained for most saccharides by employing at least to percent. Although not necessary for instantizing according to the invention, the saccharide may be increased to 60 percent or higher, if desired for a particular food product.
The homogeneous blend of sodium caseinate powder and corn syrup solids powder is supplied to agglomerating chamber in which it is moistened by subjecting the same to a moist atmosphere containing a finely dispersed surfactant, such as lecithin. In one embodiment, the atmosphere is formed by homogeneously mixing atomized liquid lecithin with wet steam as dis closed in Nava US Pat. No. 3,300,315. The dry blend is conveyed through a duct suitably by forced air to the top of the chamber. To avoid fouling of the duct with moist product, the air is suitably at a temperature of 70-80F and at a relative humidity of 30-35 percent. The wet steam-liquid lecithin mixture may be supplied to the agglomerating chamber through a nozzle. The apparatus and general processing conditions may be of a type disclosed in Nava US. Pat. No. 3,300,315, or in Hutton US. Pat. No. 3,331,306. The dry blend feed is rapidly heated by. contact with the steam and hot atomized droplets whereby the temperature is elevated to a range of about l20-160F. Under these conditions, the particles of divided sodium caseinate are caused to become sticky and are intermingled whereby they are brought into random contact. As a result, random porous aggregates are formed firmly bonded together at points of contact.
In conjunction with the formation of these aggregates, a substantial portion of the corn syrup solids dissolves and is homogeneously distributed over the surfaces of the individual sodium caseinate particles of the aggregates formed therefrom. The dispersed atomized lecithin is also deposited in a homogeneous manner on the individual particles of the aggregates.
For a final product of the desired instantized character, the moist aggregates leaving the agglomeration chamber of step 12 may have a total moisture content on the order of 16-22 percent optimally 18-20 percent. Below about 16 percent moisture, it is found that the sodium caseinate particles do not agglomerat'e sufficiently and so tend to break down into fines, which do not possess instant properties: above about 22 percent moisture, the aggregates tend to become too firm and so require increased time for dispersion in cold water.
Moistening of the blend in step 12 may be carried out by subjecting the blend to an atmosphere at conditions other than the aforementioned ones of homogeneously mixed atomized liquid lecithin, water, and wet steam. For example, the lecithin may be dispersed, in warm water at, say, ambient temperature and, at line pressures on the order of 500 2,500 psia, supplied to a high-pressure nozzle of a conventional spray-drying type for spraying into the agglomeration chamber.
Following the formation of moist porous aggregates excess moisture is removed in step 13 to produce the final dried product. The handling of the aggregates following step 12, and .the equipment used for removing excess moisture, should be such as to minimize crushing or grinding, thereby avoiding the breaking up or crushing of the aggregates. In a typical instance, the aggregates fall through the agglomeration chamber onto a transfer conveyor and from there to a series of tray dryers. The upstream dryers are suitably at a relatively high temperature (e.g., 270F inlet temperature) methods. For example, material under 100 mesh screen size may be returned to the process, and oversized material greater than, e.g., 20 mesh, may be subdivided by crushing. The moisture content of the final product may range from about 1.5 to 4 percent.
The surfactant is of a type that will impart wettability to the aggregated product when deposited upon cold water. Surfactants which provide this property include lecithin, polyoxyethylene sorbitan esters of fatty acids, monoand di-glycerine and combinations of the same. Particularly effective surfactants are lecithin .base compositions sold under the trade name ofClearate F" or Clearate WDF by the W. A. Cleary Corporation or polyoxyethylene sorbitan mono-oleate sold under the trade name Tween 80.
As is well known, lecithin is the commercial or popular name for a crude mixture of compounds which may be more accurately designated as phosphatides or phospholipids. The phosphatides are complex organic compounds which are similar to fats or lipids, but differ from fats radically enough to give them unique properties. Lecithins of vegetable oil origin are mixtures of phosphatides produced from such raw materials as cottonseed oil, corn oil, or soybean oil. Products from current commercial treatments modifying natural lecithin to emphasize either the lipophilic groups or the hydrophilic groups, may be used for our purpose. Commercially, available soya lecithin has been used with good results. It is commercially available as a liquid material with lecithin dispersed in a soybean oil carrier. Assuming that the liquid lecithin product contains about'60 percent lecithin(s), to obtain a final product containing from, say, 0.17 to 0.6 percent lecithin, from 0.25 to 1.0 percent of the lecithin product canbe employed.
In accordance with the present invention, the instant" properties'can be generally obtained to a substantial extent by incorporating lecithin in an amount as low as'Q. l 5 percent. However, best results were obtained with the lecithin content at a level of at least about'O.3 percent. The desired rang is from about 0.3 to 0.5 percent although greater percentages can be used if desired.
The product produced by the foregoing method consists of particles of sodium caseinate bonded together in the form of aggregates of a size substantially greater than the original individual particles. The surfaces of substantially all of these individual particles are coated in a generally uniform layer including both a watersoluble saccharide and extraneous lecithin. For good instantizationythese particles should contain at least 5 percent saccharide and 0.3 percent surfactant. A desirable range of ingredients in the final product on a dry weight basis is from 40 percent to 95 percent sodium caseinate, 60 percent to 5 percent saccharide, and
- 0.3 percent to 0.6 percent surfactant.
The photomicrographs of FIGS, 2 12, inclusive, taken with an electromicroscope, serve to illustrate the uniform distribution in my product of saccha'ride and lecithin in a coating on sodium caseinate aggregates by comparison with (a) sodium caseinate powder, (b) sodium caseinate aggregates coated with saccharide, and (c) sodium caseinate aggregates coated with lecithin.
It should be noted that, under normal conditions, the particles illustrated in FIGS. 2 12 are of a generally spherical nature. The collapsed form of such particles is caused by the application of an extremely high vacuum preparatory to the taking of the photomicrographs by the electron microscope.
FIGS. 2-4 are photomicrographs of spray-dried sodium caseinate at 300, 1,000, and 3,000X magnification, respectively. These figures illustrate the general size distribution of, and typical form of, untreated sodium caseinate particles.
FIGS. 5-7, inclusive, are photomicrographs of sodium caseinate particles aggregated in a process accord- I ing to the invention using lecithin but no saccharide, at
300, 1,000 and 3,000X magnification, respectively. it is apparent from these photomicrographs that the lecithin forms small clusters or groupings in a distinctive form rather than a uniform coating on the sodium caseinate particles; Furthermore, they suggest that the lecithin clusters are not present on all particles which would result in improved wettability of only a portion of the particles.
FIGS. 8 and 9 are photomicrographs of aggregated product of percent sodium caseinate and 20 percent corn syrup solids formed according to the invention, but with no lecithin, at 300 and 1,000X magnification, respectively. It is apparent by a comparison of these photomicrographs with those of FIGS. 2 and 3 that the particle distributions and types are similar and so that no individual corn syrup solids are either dispersed separately from, or incorporated as distinct particles upon, the sodium caseinate. It is concluded from this that the corn syrup solids are dissolved in the water and then coated in a generally uniform layer upon the sodium caseinate particles.
FIGS. 10 12 are photomicrographs of an embodiment of my product including about 80 percent sodium caseinate, 20 percent corn syrup solids and ,3 percent lecithin, at 300, 1,000 and 3,000X magnification, respectively. It is apparent that there is essentially no physical distinction between my product as illustrated in FIGS. 10 e 12 and the same product without lecithin as illustrated in FIGS. 8 and 9. The physical appearance in FIGS. 10 12 indicates that there is a uniform coating of lecithin dispersed in the corn syrup solids which coating is apparently as uniform as that of corn syrup solids alone. In contrast, as previously discussed, the lecithin of FIGS. 5 7, without corn syrup solids, seems to form in small clusters on the surface of some, but not all, of the sodium caseinate, rather than a uniform coating on all particles. From a composite of these two comparisons, it is seen that the lecithin which would otherwise cluster on some individual sodium caseinate particles is dispersed within the saccharide coating upon essentially all of the particles. Since the lecithin is in a finely divided state during coating, presumably the dispersion is homogeneous.
The final product of the above type has the desired instant" properties. When a quantity of this powder is deposited upon the surface of either cold or warm water, the water quickly penetrates the mass and the individual porous aggregates, without blocking, whereby the entire mass quickly wets and sinks. Thereafter, simple stirring serves to effectively disperse the particles to form a stable dispersion withoutformation of lumps. As an example of the instantized nature of my product,
five grams of my product with approximately 80 percent sodium caseinate, 20 percent corn syrup solids and 0.3 percent lecithin in the form illustrated in FIGS. 10- 12 when deposited upon an 8 02. glass of water at 68F, wetted and sank within 4 seconds and dissolved within a minute with gentle manual stirring.
The aforementioned instant" properties of my product are in marked contrast to those possessed by a spray-dried powder of essentially sodium caseinate as in FIGS. 2 4, of sodium caseinatewith extraneous lecithin incorporated thereon as in FIGS. 5 7, or of an aggregate product formed from a blend of sodium caseinate and a water-soluble saccharide as in FIGS. 8 and 9.
The first of these other products floats on the surface of .water and when stirred with a spoon forms lumps or masses. The second product tends to form a coalesced gel-like mass which cannot be completely dispersed and dissolved without vigorous mechanical agitation for at least several minutes. The third product with 80 percent sodium caseinate and 20 percent corn syrup solids, floats on the surface of the water and requires at least several minutes of low energy stirring for dissolution.
It is not completely understood why the aforementioned synergistic instant" properties of sodium caseinate are obtained with both a surfactant and a water-soluble saccharide. One possible explanation is that, as'illustrated in FIGS. 2 12, the uniform coating of saccharide upon each particle of the sodium caseinate aggregates decreases the rate of moisture penetration sufficiently to allowwater to percolate among and break apart the individual particles of the agglomerates. Furthermore, it is believed that the individual particles each contain lecithin uniformly dispersed in the saccharide coating for improved wettability so that they are readily hydrated in a separated state. It is believed that, by omitting the saccharide from a lecithin-treated aggregate, the particles tend to fusetogether into a gel-like mass because the particles are wetted at an excessive rate. It is believed that I without lecithin, the particles do not possess sufficient wettability to overcome the interspacial tension. Furthermore, the saccharide performs an additional carrier function by spreading the lecithin homogeneously to coat substantially all of the sodium caseinate particles, as seen in FIGS. 10 12, rather than a portion of the particles in a product without saccharide, as suggested in FIG. 5.
An unexpected benefit in the use of lecithin with the sodium caseinate in the aforementioned manner provides an unexpected processing advantage. The aggregates in which lecithin is incorporated are of a generally discrete fairly uniform size in comparison to the aggregates produced without the lecithin which tend to fuse into large pieces of material upon leaving the agglomerater unit. Thus, my product requires limited crushing, if any, to produce a product of the desired size as a dry blend additive ,(e.g., passing through a mesh screen). As a consequence, the fines that would otherwise be produced during crushing, as well as the cost of crushing, are substantially reduced.
In order more clearly to disclose the nature of the present invention, specific examples of the practice of the invention are hereinafter given. It should be un- EXAMPLE 1 Spray-dried sodium caseinate powder was blended with Frodex-24 corn syrup solids powder having a dextrose equivalent of 24 percent and a sieve analysis of at least 99 percent passing through a 200 mesh screen. The ratio was parts by weight of sodium caseinate to 20 parts by weight of corn syrup solids. This blend was fed by means of forced air stream through a conduit through the top of an agglomerator chamber. A commercial lecithin product (Clearate F was supplied at a uniform rate to a spray nozzle concentric at the outlet of the conduit. The amount of the product used was such that it amounted to about 0.4 percent of the final dried product (i.e., about 0.4 percent lecithin). Wet steam at a pressure of 135 p.s.i.g. was used to atomize the lecithin and form a homogeneous mixture therewith which was sprayed from the nozzle. The temperature within the agglomeration chamber was maintained at about 1 10 to 130F. Under these conditions, the feed particles formed aggregates which left the agglomeration chamber at'a total moisture content of from 19 to 19.4 percent. These particles were conveyed on a transfer conveyor to a series of tray dryers having successive inlet air temperatures of 260270F, 250-265F, 245-26lF and 7779F. The resulting dried product with a total moisture content of about 2 percent was then sized through a sifter in which material retained on the four mesh screen was rejected and that retained on a 20 mesh screen was crushed to pass through a 20 mesh screen in a secondary sifter. The resulting product was instantized sodium caseinate with excel-, lent wettability and dispersibilityin cold water. When deposited upon the surface of -a glass of cold water (e.g.,- 50- 60F.) it almost instantaneously-sank and with gentle stirring formed a stable dispersion free of floating material in less than 1 minute.
EXAMPLES 2, 3, and 4 The procedure of Example 1 is followed with the substitution for the dry blend therein with the following blends: parts sodium caseinate and 10 parts corn syrup solids and 60 parts sodium caseinate to 40 parts of sucrose.
The resulting dried products have similar excellent dispersibility and wettability characteristics to those of Example I.
In general, I have provided a sodium caseinate product having desired instant" properties and a process for forming the same. Various modifications can be made within the scope of this disclosure. For example, while particular reference has been made to a dry mixture of sodium caseinate and saccharide supplied to the agglomeration chamber, it is apparent that if either blend component is available in a moist form that it may be employed without predrying.
I claim:
1. In a method for the manufacture of instantized sodium caseinate, the steps of uniformly dry blending 40 to 95 percent spray-dried sodium caseinate powder with to 60 percent highly water-soluble saccharide powder, moistening the blend by subjecting the same to a moist atmosphere containing a finely dispersed surfactant, whereby a substantial portion of the saccharide powder dissolves the sodium caseinate particles are caused to become sticky and adhere together in the form of moist aggregates with saccharide and surfactant incorporated thereon, the amount of surfactant used being such as to provide a surfactant content of from 0.1 to 2.0 percent in the final product, the moistening being sufficient to impart to said aggregates a total moisture content on the order of l622 percent, and removing excess moisture from the aggregates.
, 2. A method as in claim 1 in which the surfactant is selected from the group consisting of lecithin, polyox yethylene sorbitan esters of fatty acids, mono-and diglycerides, and combinations thereof.
3. A method as'in claim 2 in which the surfactant is lecithin.
4. A method as in claim 1 in which from about 80 to 95 percent sodium caseinate powder is dry blended with from about 5 to percent of saccharide powder. '5. A method as in claim 1 in which the moist atmosphere is formed by homogeneously mixing liquid lecithin with wet steam.
6. A method as in claim 1 in which the moist atmosphere is formed by atomizing an aqueous dispersion of lecithin.
7. A method as in claim 1 in which the saccharide powder is selected from the group consisting of corn syrup solids, monosaccharide, disaccharides, and water-soluble polysaccharide. I
8. A method as in claim 1 in which the saccharide powder is a corn syrup solids powder having a dextrose equivalent ofl at least 24 percent.
9. A method as in claim 1 in which the saccharide powder has an average size no greater than that of the spray-dried sodium caseinate 10. A method as in claim 7 monosaccharide is glucose.
1 l. A method as in claim 7 in which the disaccharide is selected from the group consisting of sucrose and lactose.
12. A method as in claim 7 polysaccharide is dextrin.
13. An instantized dry sodium caseinate product consisting of particles containing about 40 to percent spray-dried sodium caseinate, about 5 to 60 percent water-soluble saccharide and about 0.1 to 2.0 percent surfactant, said particles being boncled together to form aggregates of a size substantially greater than the original particles, a substantial portion of said saccharide and surfactant forming a generally uniform coating over the surfaces of essentially all of the sodium caseinate particles, said product being characterized by high wettability and its ability to readily disperse in water by simple stirring to form a stable dispersion.
14. An instantized dry sodium caseinate product as in claim 13 in which the surfactant is selected from the group consisting of lecithin, polyoxyethylene sorbitan in which the in which the esters of fatty acids, monoand di-glycerides, and combinations thereof.
15. An instantized dry sodiumcaseinate product as in claim l3 in which the saccharide is selected from the group consisting of corn syrup SOlldS, monosaccharide,
disaccharides, and water-soluble polysaccharide.
16. An instantized dry sodium caseinate product as in claim 13 in which said lecithin is homogeneously dispersed in said saccharide coating.
17. An instantized dry sodium caseinate product as in claim 15 in which the monosaccharide is glucose.
18. An instantized dry sodium caseinateprocluct as in claim 15 in which the disaccharide is selected from the group consisting of sucrose andlactojse. y
19. An instantized dry sodium caseinate product as in claim 15 in which the polysaccharide is dextrin.