Patent Application
20090208603
The disclosure relates generally to producing super dispersible gums, starches, powder ingredients, and blends thereof, that disperse readily in water using spoon mixing or under low shear of around 400 RPM, as well as, the process for making the same. These poorly-dispersing or low dispersible substrates include xanthan gum, various cellulose derivatives, various seed gums, carrageenans, pectin, various alginates, gum Arabic and other tree exudates, larch gum, konjac, blends of gums, various instant starches, gum-starch blends and other powder ingredients that suffer the same dispersion and clumping problems, such as, soy protein, egg solids, non-fat dry milk, certain flours, cocoa and others.
Many techniques to improve dispersion of gums, instant starches and hard-to-disperse powders have been developed, such as, batch and continuous agglomeration with water and wet granulation. However, straight agglomeration or granulation with water only works with a few non-viscous gums, such as, gum arabic, inulin, larch, etc. All cold water soluble and viscous gums, starches, protein powders and blends thereof, still clump up badly when they are dissolved in water at normal mixing conditions or when the end users put the powder mix containing these gums in water with spoon mixing. Various wetting agents and surfactants as disclosed in the patents below have been tried to improve gum dispersion. Hydrophilic sprays of, for example, glycols, sugar alcohols, and cold water soluble gums, such as, gum Arabic, have been used to create what was accepted as “readily dispersible” agglomerates. However, these techniques work only with non-viscous gums that by nature are much easier to disperse or dissolve in water. When viscous gums are added to water, they start building viscosity immediately during addition which makes it extremely difficult to disperse the remaining, un-added material without creating lumps. When non-viscous gums are being added, the water remains thin until all of the material is wetted and mixed in the water.
There have been attempts in the past to improve dispersion of gums in water; however, while significant improvements in powder dispersion have been observed, the current techniques leave significant room for improvement.
The present disclosure includes, in one embodiment, spraying a crosslinkable alginate solution or a solution of any crosslinkable anionic sugar acid monomer, followed by spraying a solution of a calcium salt to induce polymerization and forming an insoluble, thin hydrogel coat of crosslinked calcium-alginate gel on the surface of the agglomerates or granulates; which delays swelling of the particles for ease of dispersion in water. In another embodiment, a surface coating with pre-activated cold-water insoluble or slow swelling gum, cook up starch, or a combination thereof, is used to achieve the same effect.
None of the previous attempts to improve dispersion have been based on this principle or disclose a similar process to make super dispersible gums, instant starches, powders, and blends thereof. The disclosed super dispersible gums and powders will disperse with spoon mixing or under low shear of around 400 RPM and will not leave the finished product with an off taste or oil-soluble residual.
The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description serve to explain the principles of the disclosure. In the drawings:
The disclosure relates generally to producing super dispersible gums, starches, powder ingredients, and blends thereof, that disperse readily in water with spoon mixing or under low shear of around 400 RPM, as well as, a process for making the same.
Viscous anionic hydrocolloids, such as, xanthan, CMC, alginate, carrageenans, and pectins; viscous non-ionic gums, such as, konjac, guar, fenugreek, tara gum, hydroxypropylcellulose, methylcellulose, HPMC; and other similar materials all swell too rapidly in water and tend to clump up when added to water under normal mixing conditions. Additionally, instant starches used for thickening soups, sauces, gravies, and dips; and cocoa and protein ingredients, such as, soy isolate and milk protein isolates tend to form lumps when added to water or the liquid portion of a batch, and their dispersion problems become worse when they are blended with the gums. When these materials are used in most manufacturing processes a special high-shear mixer or an eductor/disperser is needed to dissolve these ingredients without lumping. However, the tradeoff is an excessive entrainment of air, which requires additional steps and time to remove. Even low viscosity gums tend to clump up during the dissolution process if preparing a stock solution at high concentrations. This problem is exacerbated using high viscosity gums and instant starches because of the compounding effect of instantaneous swelling of the particles upon contact with water resulting in the formation of “fish eyes” or gum lumps. Standard agglomeration with water creates interstitial voids that help in dispersion and hydration; however, this seems to work only with low viscosity gums at low and non-viscous concentrations.
Coating and agglomeration techniques using surfactants and wetting agents with a wide range of HLB (hydrophilic and lipophilic balance) have been tried with “hard-to-disperse” gums. The techniques improved dispersion of viscous, fast-swelling gums only to a certain extent; however, it was not possible to spoon-mix these products without forming lumps. Many wetting agents and surfactants also change the clarity of the gum solution, which is critical in many end uses for the clear gums. Additionally, others impart an off taste or are insoluble and float in water, which discourages their use.
The present disclosure includes two distinct processes for producing super dispersible gums, starches, powder ingredients, and blends thereof, using surface coating and agglomeration/granulation technique with either 1) a crosslinked hydrogel coat, or 2) an insoluble, slow-swelling coat of hydrocolloid.
In the first embodiment, the crosslinked hydrogel coat is created by spraying an alginate solution (or a solution of any sugar acid polymer) over the substrate, which is then followed by a calcium spray (or any divalent ion that induces crosslinking).
In the second embodiment, the coat of a slow-swelling hydrocolloid is created by first activating and hydrating a cold-water insoluble gum, such as, agar, locust bean gum, kappa-carrageenan, gellan, cook-up starches, or slow swelling gums, such as, guar gum, tara gum and others, and spraying it on the substrate in single or multiple dose.
When the coated substrate is dried, the coating produced in either embodiment delays the swelling of low dispersible substrates causing the particles to sink, wet and disperse without lumping even on low shear. In short, the present disclosure will produce super dispersible gums, starches, powder ingredients, and blends thereof, by coating the substrate with a thin layer of an insoluble or slow swelling hydrogel crosslinked gum or with another hydrocolloid that meets the swelling criteria. The materials to be coated or used as substrate include xanthan gum, various cellulose derivatives, various seed gums, carrageenans, pectin, various alginates, gum Arabic and other tree exudates, larch gum, konjac, blends of gums, various instant starches, gum-starch blends and other powder ingredients that suffer the same dispersibility problems, such as, soy protein, egg solids, non-fat dry milk, flour, cocoa and others.
The disclosure includes:
In a first embodiment, the coating process is achieved by using two spray coatings, such as, an alginate solution spray and calcium solution spray to form a crosslinked calcium-alginate hydrogel. The calcium-alginate coat on the surface of the particle modifies the swelling behavior of the coated particles and causes delay in the swelling of the agglomerated product making the particles disperse in water with minimal shear. The delay in the swelling could be a few seconds to 10-15 minutes depending the dose of the spray coats. Alternatively, a spray solution of pectic acid, very low methoxy pectin or any sugar acid polymer, in place of the alginate, and any divalent ion, in place of Ca2+, for crosslinking may be used in this process. This coating process can be done in a fluid bed agglomerator, either in a continuous or batch mode; fluidized spray dryer; or any wet granulation or pelletizing machine that is suitable for spraying and mixing powder material.
The process includes:
Step 100. In step 100, the gum substrate or blend to be agglomerated is fed into a mixing, agglomerating or granulating unit, and while the powder is being fluidized or mixed it is sprayed with a dilute solution of sodium alginate or another sugar acid polymer ranging, preferably, from approximately 0.1% to approximately 10% by weight in water. The amount of alginate spray or sugar acid polymer spray varies for each substrate used.
Step 200. In step 200, a second coat of a solution of a calcium salt is sprayed to react the alginate with the calcium ions to form an insoluble calcium-alginate hydrogel. Cross linking salts include, for example, calcium chloride, calcium lactate, calcium acetate and other suitable calcium salts ranging in concentration preferably from, approximately 0.1 to approximately 10%. Alternatively, any divalent salt, such as, a magnesium salt can be used. In this embodiment, step 100 and step 200 may be interchanged to achieve the same effect. The dose of the crosslinked hydrogel coating may be modified to achieve synergy between the coat and the substrate, wherein synergy is defined as increased viscosity, stability or process tolerance of the coated product in water or in the end application.
Step 300. In step 300, as applicable for fluffy and light substrates, a finishing spray of: a wetting agent, such as, lecithin/glycerin, sugar alcohols; weighting agents comprising of solution of calcium salts, magnesium salts, sodium salts, potassium salts; disintegrant, such as, cellulose powder, MCC, croscarmellose sodium, starch glycolate; or a mixture thereof; is applied to make the coated particles sink faster and disintegrate more readily.
Step 400. In step 400, the coated product is dried to the moisture specification of the substrate in the same fluid bed unit or in a separate drying unit, such as, a tunnel dryer, drum dryer or other suitable drying equipment. If applicable, the sprayed material may be extruded and pelletized or flaked first prior to drying.
Step 500. In step 500, the dried coated substrate is sifted and/or milled to the desired particle size distribution depending on the substrate.
In the second embodiment, the coating process is achieved using a single or multiple sprays of a dilute hydrocolloid solution, such as, agar, locust bean gum, gellan gum, cook up starch and other cold-water insoluble or slow-swelling polysaccharides, such as, guar gum, tara gum, or a combination thereof, without crosslinking. The requirement for insoluble or slow-swelling hydrocolloids for use in the second embodiment is based on the principle that, when these polymers are activated and used as a coating, they revert to their cold-water insoluble state or slow-swelling state upon drying. On the surface of the substrate, the coat delays the swelling of “hard-to-disperse” substrates which makes the particles sink and disperse in water without lumping. Therefore, an insoluble or slow-swelling thin coat on the surface of the substrate will enable “hard-to-disperse” gums, instant starches, clumpy ingredients, and blends thereof, to sink and disperse in the water before starting to swell, even under low shear.
The process includes:
Step 100. In step 100, the substrate (e.g., gums, instant starches, powder ingredients or blends) to be agglomerated is fed into the agglomerating or granulating unit and sprayed with, preferably, approximately 0.1 to approximately 10% of the hydrocolloid, or combination of hydrocolloids, in single spray or multiple spray coats. The dose of the slow-swelling hydrocolloid coating may be modified—to achieve synergy between the coat and the substrate, wherein synergy is defined as increased viscosity, stability or process tolerance of the coated product in water or in the end application.
Step 200. In step 200, as applicable for the fluffy and light substrates, a finishing spray of: a wetting agent, such as, lecithin, glycerin, sugar alcohols; a weighting agent, such as, a solution of a calcium salt, magnesium salt, sodium salt, potassium salt; disintegrant, such as, cellulose powder, MCC, croscarmellose sodium, starch glycolate; or a mixture thereof; is applied to make the coated particles sink faster and disintegrate more readily.
Step 300. In step 300, the coated substrate is dried to its moisture specification in the same fluid bed unit or in a separate drying unit, such as, a tunnel dryer, drum dryer and other suitable drying equipment. If applicable, the sprayed material may be extruded and pelletized, or flaked first prior to drying.
Step 400. In step 400, the dried coated substrate is sifted and/or milled to the desired particle size distribution depending on the substrate.
The finished product produced using the coating and agglomeration/granulation technique as described in the two embodiments possess fast dispersion and hydration characteristics under low shear of 400 RPM mixing speed, as shown in Tables 1, 2, 3 and 4, as compared to the standard agglomerated and non-agglomerated substrates. The finished products using the present disclosure sink and disperse in water without lumping, and thus thicken much faster as soon as the water penetrates the surface coating.
The dispersion of the finished product in water was tested using spoon mixing in a beaker or cup. However, the above data were obtained using the test procedure for dispersion and hydration described below:
Gum polysaccharides are capable of showing unexpected synergy with the coating and the present invention includes a discovery of dramatic synergy between the various coatings listed in the two embodiments and xanthan gum. However, the scope of these synergies is not limited to xanthan alone or to the types of coating disclosed in this invention as other substrates and coatings will show synergy as well. The principle of uniformly coating, wetting and intermingling the coating polymers and gum polymers and then drying, using coat-agglomeration or other methods, such as, film casting or sheeting, slurring and drum drying, etc., can give the coated substrate improved functionality. The product features to be considered are the type of coating type, level of coating, and final moisture content.
The coating synergy was best seen with xanthan gum, which scientifically can be explained by xanthan's molecular structure and water binding property. Xanthan has an unusually low viscosity compared to its high molecular weight gum counterparts, such as, guar gum and konjac glucomannan. The reason is because of its unique structure—a linear glucose backbone with a trisaccharide substitution. Unlike guar gum, which is also a linear substituted polysaccharide, xanthan assumes a double helical conformation when it is hydrated in water. Inside the helices, water is tightly bound and viscosity is high, but between the helices or between polymer chains, the intermolecular hydrogen bonds are weaker and viscosity is low. Therefore, compared to guar gum and konjac, the measured viscosity for xanthan is low because these inter-polymer bonds are the ones broken during the shear test. The highly pseudoplastic flow of xanthan is attributed to these low and high viscosity zones, which is also responsible for xanthan's superior suspending property. It seems that the coating, which are linear hydrocolloids, are able to induce or form micelles with the xanthan gum strengthening the inter-polymer chain association and causing a dramatic increase in viscosity. Standard xanthan grade has a 1% viscosity of about 1200-1600 cP and the high viscosity xanthan grade has about 2400-3300 cP. The synergy between the xanthan and the coating boosted the viscosity of these xanthan grades around ten-fold.
Although the disclosure has been described and illustrated with a certain degree of particularity, it is understood that the disclosure has been made only by way of example, and that numerous changes in the conditions and order of steps can be resorted to by those skilled in the art without departing from the spirit and scope of the disclosure.
This application claims priority to U.S. Provisional Patent Application 60/972,573 (filed Sep. 14, 2007), of which is expressly incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 60972573 | Sep 2007 | US |
