This wonderful material is available in powder and liquid forms. Both forms are useful in gumoil, because the commercially available liquid tends to be a bit thin but can be thickened up a bit with the powder. Not only does gum work as a medium for suspending the sensitizer (potassium bichromate) for hand-coating on paper, but the liquid gum alone can be used as a masking agent in manipulating the oil print.
Since the ninteenth century, gum arabic has been combined with a sensitizer and a soluble pigment, applied to paper, and exposed through a negative under a powderful light source. This can produce beautiful prints only surpassed by addign further layers of gum pigments in registration. It is also possible to print color separated black-white negatives to produce gorgeous true color prints, but precise registration is required
Gum Arabic can be using in the melting yarn chips process. Gum Arabic is added to make the yarn stronger and increase its tensile strength. These days, many textile manufacturers use a modified starch mixed with Gum Arabic.
Gum Arabic can be added to the painting formula to fix the pigment in the fabric, thus saving printing costs.
The essential ingredients in watercolors are pigments, a binding agent (usually gum arabic), and water. When combined these three components create transparent watercolor. Gum arabic acts as the binder for both watercolor and gouache paints. Pigments are ground up and a liquid gum arabic solution is added to produce paint that is more opaque and which imparts a dusty quality to the surface. Gum arabic is resoluble once it has dried, therefore it can be stored in cakes. Occasionally oxgall (a wetting agent) is added to water color to aid the even dispersion of pigment.
In the past, Gum Arabic was used in the aluminium plate process. Normally, after printing was finished, the plate would have to be cleaned with chemicals and covered by a gum arabic solution before re-using the plate.
Planographic Printing (Lithography):
The planographic method of offset lithography is “by far the most common form of printing nowadays” according to Alan Pipes, author of "Products for Graphic Designers". The process works by sensitizing a part of the printing plate so that it will accept grease, oil, printing ink. An image is drawn or transferred on to an aluminum or zinc plate and ‘etched’ with a solution of gum arabic, water, and nitric acid. This area is known as the oleophylic area, and the nonsensitized area is called hydrophilic. Offset lithography continues to be the most economical and reasonable printing process because of its low up-front costs for film preparation and press operation.
Moldings have to be covered with paraphin wax before the injection process to make it easy to remove the mold, but parafin wax is difficult to clean out. Manufacturers must mix gum arabic with the parafin and then when they put the mold into hot water overnight the Gum Arabic dissolves the wax out easily.
Gum Arabic liquid should be mixed into paint before use, especially water-based paint. Gum Arabic makes the colors brighter and lighter.
INK MAKING USING GUM ARABIC
Prepare gum arabic solution, scrape lampblack(carbon collected on a spoon held over flame) from spoon enough times to get a goodly quantity of it(takes about an hour). Add water one drop at a time until water is inky black. Add small amount of gum arabic to thicken for writing. Store in airtight jar. INVISIBLE INK : 1 part linseed oil, 20 parts ammonia water, 100 parts water. Agitate mixture before using. To view writing, dip paper in water. SCENTED TNK : Add a few drops of essential oil to ink. Shake well before use.
Basic Permanent Black Ink:
Mix 1 egg yolk, 1 tsp gum arabic and ? cup honey in a small bowl. Add ? tsp lamp black (buy in a tube or make by holding a plate over a lit candle) to make a thick paste. Store in jar. To use, mix a little paste w/a little water to make a fluid.
Gum arabic imparts the lowest viscosity to water of then normal, unhydrolyzed industrial gums, A comparison of its solution viscosity with tragacacanth karaya, ghatti, and corn fiber gums is shown in figure 1. Gum arabic mixes well with other industrial gums, and at high concentrations has suspending, stabilizing, and emulsifying properties. Gum arabic solutions exhibit Newtonian viscosity at concentrations up to 40%; but at higher concentrations, they acquire pseudoplastic character. Normally, gum arabic solutions are of pH about 4.5-5.5, which is near pH 6, where maximum viscosity is displayed. Solution viscosity decreases with age, following a zero rate order. This decrease is commonly due to hydrolysis; but gum arabic solutions are affected, as are solutions of other gums, by ultraviolet radiation and other glycosidic bond-breaking phenomena. Viscosity rises with increases in pH to about 6 then gradually falls to about pH 12 , where it again levels off. However, a more or less broad maximum viscosity is displayed over the range pH 2-10. As expected, when the pH is lowered to 3 or less, the ionization of the carboxyl groups is repressed, and the polymer tends to gel and lose solubility.
Gum arabic is effective in preparation of oil-in-water emulsions. The emulsions are stable in the presence of electrolytes; in fact, some emulsions develop improved stable in the presence of electrolytes. Thus, an emulsion produced by 10% gum arabic can be duplicated in stability by a 0.5% gum solution to which a sodium salt has been added. Stable emulsions are produced by gum arabic over a range of pH values. Gum collects at the emulsion interface in the form of a visible film that prevents coalescence of the oil microspheres. The viscosity of the emulsion differs with the type of oil and film thickness.
A broad use of gum arabic has been to spray-dry a solution or emulsion of the gum-flavor mixture to produce a fixed or encapsulated flavor in the dry powder form that can be packaged in dry mixes of desserts puddings, beverages, cakes, and soups. Many industrial gums have been examined for flavor entrapment and preservation, but so far, bum arabic has been the polymer of choice for citrus oils. It has the advantage of rapid dissolution with rapid release of flavor, without affecting product viscosity. A common ratio of gum to flavor oil is 4:1, but on occastions where more protection is required, the ratio may increase to 9:1.
A large part of gum arabic is used in confectionery products to prevent sucrose crystallization and evenly distribute lipid components. Sizable applications are in jujubes and pastilles that have high sucrose content and relatively low moisture. Another large application is in caramels and toffees where gum arabic maintains uniform distribution of fat and retards fat accumulation on the surface that would produce a greasy or, under certain conditions, a whitening effect.
Candy jellies such as jujubes, fruit bums, fruit pastilles, gum drops, and cough drops have been made with gum arabic for many years. These depositors or moguls may have been invented by Venetian candy markers in the beginning of the 19th century. The process involves crushing and sifting the gum, followed by dissolving it in water to 50% concentration, skimming and decanting the solution, and mixing it with sucrose and corn syrup. This mixture is cooked to about 102O and a solids content of 65-68%. The cooled mixture is then mixed with required acid, color, and flavor, deposited in starch-coated molds, and dried at a selected temperature. After several days, the gum candies are unmounted, depowdered on screens, brushed to remove starch, and glazed with wax or oil and, if desired, sugared. Such candies are soft but firm and long-lasting in the mouth. They contain 50% less sugar than hard candies. The gum gives a cleaner, finer taste. Pectins, gelatin-gum arabic mixtures, and thin-boiling starches can be used as replacements for gum arabic.
Sugar-coated confections made by the panning process employ gum arabic solutions to provide an adhesive and film coating for nuts, candy corn, jelly beans, bridge mixes, and others. The gum also serves as a whipping and stabilizing agent for aerated confections like angel kisses, marshmallows, soft caramels, nougats, and meringues, especially those made with hydrolyzed soy protein. Reduced-calorie nougats contain about 27% each of gum arabic and microcrystalline cellulose. Calorie reduction to more than 50% in toffee is obtained by using higher levels of these nonmetabolizable polysaccharides.
Gum arabic has been used in dietetic foods as a noncaloric bulking agent and has been used in the preparation of special-purpose foods such as those for diabetics. A mixture of gum arabic and xanthan (10%) has been used in the preparation of stabilized whipped or aerated low-calorie products such as butter, margarine, toppings, spreads and frozen desserts.
Gum arabic's water solubility, low viscosity, and adhesiveness gives it value as a glaze for buns to provide gloss and flexibility and also makes it useful as a component in toppings and icing bases and in applications where its emulsifying power is important. It can be used to encapsulate baking flavors, such as cinnamon oil, for dispersal in vegetable fats and for use where flavor release is wanted at specific melting temperatures.
Gum arabic's effectiveness as an emulsifier has given it broad application in foods; it has an especially strong position in the soft drink industry as stabilizer of citrus oil emulsion concentrates. It fills an important application in beverages as cloud-producing agent and in dry mixed where a spray dried emulsion of gum arabic and hydrogenated vegetable oil produces a stable, free-flowing powder that, on dispersal in water, provides a cloudiness or turbidity typical of citrus or other juices. This procedure, with modifications, is used in the formulation of several dry beverage mixes. The foam-stabilizing ability of gum arabic gives it use in beer and certain soft drinks to stabilize the foam "lace" on the side of the glass.
Only small quantities of gum arabic are used in pharmaceuticals. These uses depend upon its emulsifying, suspending, demulcent or coating characteristics. The gum maintains suspensions of insoluble when use in rather high concentrations. Owing to its mild ability to complex heavy metal ions, it brings about better suspension of these salts when needed, as for example, in the suspension of calamine lotion, and in certain instances in the emulsification of liquid petrolatum and of cod liver oil. Its demulcent property has given it some application in pharmaceutical syrups where it also masks unpleasant tastes.
Gum arabic stabilizes lotions, protective creams, and emulsion. It increases the viscosity, assists in imparting spreading, adds a smooth feel to the skin, and forms a protective coating. It is also a binding agent in the formulation of compact cakes and rouges and acts as an adhesive in the preparation of facial masks. A typical compact cake is composed chiefly of a color vehicle, a mineral oil, and an aqueous solution of gum arabic. The gum is also used as a foam stabilizer in liquid soap. Gum arabic has been recommended use as a fixative and binder in hair creams and as a stabilizer and film former in protective creams.
Adhesives Powdered gum arabic is a simple adhesive for paper products and may be used directly after dissolution in two or three times its weight of water. A 40% aqueous solution has been made as a mucilage for general office purpose.
Miscellaneous Gum arabic acts as a colloid protective agent in the suspension of carbon black in inks and printing pastes. In lithography, gum arabic has found special application because of its easy wettability and spreadability, viscosity control, stabilization of lithography chemicals, and ready removability through simple washing.
Various gums are used in the textile industry as sizes, finishes, and suspending and spread-control agents in printing pastes. Gum arabia has been used in all aspects with different textile fibers and under different conditions, but its increasing cost and somwhat variable supply has induced the development and modificatio of other polysaccharides as replacements.