Thickening agent Thickening agents , or thickeners , is the term applied to substances which increase the viscosity of a solution or liquid / solid mixture without substantially modifying its other properties ; although most frequently applied to foods where the target property is taste , the term also is applicable to paints , inks , explosive s , etc . Thickeners may also improve the suspension of other ingredients or emulsion s which increases the stability of the product . Thickening agents are often regulated as food additive s and as cosmetics and personal hygiene product ingredients . Some thickening agents are gelling agents ( gellants ) , forming a gel , dissolving in the liquid phase as a colloid mixture that forms a weakly cohesive internal structure . Others act as mechanical thixotropic additives with discrete particles adhering or interlocking to resist strain . Thickening agents can also be used when medical condition such as Dysphagia cause individuals difficulty when swallowing . Thickened liquids play a vital role in reducing risk of aspiration for dysphagia patients . Food . Food thickeners frequently are based on either polysaccharide s ( starch es , vegetable gum s , and pectin ) , or protein s . A flavorless powdered starch used for this purpose is a fecula ( from the Latin " faecula " , diminutive of " faex " meaning " dregs " ) . This category includes starches as arrowroot , cornstarch , katakuri starch , potato starch , sago , tapioca and their starch derivatives . Vegetable gum s used as food thickeners include alginin , guar gum , locust bean gum , and xanthan gum . Proteins used as food thickeners include collagen , egg white s , furcellaran , and gelatin . Sugars include agar and carrageenan . Other thickening agents act on the proteins already present in a food . One example is sodium pyrophosphate , which acts on casein in milk during the preparation of instant pudding . Different thickeners may be more or less suitable in a given application , due to differences in taste , clarity , and their responses to chemical and physical conditions . For example , for acidic foods , arrowroot is a better choice than cornstarch , which loses thickening potency in acidic mixtures . At ( acidic ) pH levels below 4 . 5 , guar gum has sharply reduced aqueous solubility , thus also reducing its thickening capability . If the food is to be frozen , tapioca or arrowroot are preferable over cornstarch , which becomes spongy when frozen . Many other food ingredients are used as thickeners , usually in the final stages of preparation of specific foods . These thickeners have a flavor and are not markedly stable , thus are not suitable for general use . However , they are very convenient and effective , and hence are widely used . Functional flours are produced from specific cereal variety ( wheat , maize , rice or other ) conjugated to specific heat treatment able to increase stability , consistency and general functionalities . These functional flours are resistance to industrial stresses such as acidic pH , sterilisation , freeze conditions , and can help food industries to formulate with natural ingredients . For the final consumer , these ingredients are more accepted because they are shown as " flour " in the ingredient list . Flour is often used for thickening gravies , gumbo s , and stews . It must be cooked in thoroughly to avoid the taste of uncooked flour . Roux , a mixture of flour and fat ( usually butter ) cooked into a paste , is used for gravies , sauce s and stews . Cereal grains ( oatmeal , couscous , farina , etc . ) are used to thicken soup s . Yogurt is popular in Eastern Europe and Middle East for thickening soups . Soups can also be thickened by adding grated starchy vegetables before cooking , though these will add their own flavour . Tomato puree also adds thickness as well as flavour . Egg yolk s are a traditional sauce thickener in professional cooking ; they have rich flavor and offer a velvety smooth texture but achieve the desired thickening effect only in a narrow temperature range . Overheating easily ruins such a sauce , which can make egg yolk difficult to use as a thickener for amateur cooks . Other thickeners used by cooks are nuts ( including rehan ) or glaces made of meat or fish . Many thickening agents require extra care in cooking . Some starches lose their thickening quality when cooked for too long or at too high a temperature ; on the other hand , cooking starches too short or not hot enough might lead to an unpleasant starchy taste or cause water to seep out of the finished product after cooling . Also , higher viscosity causes foods to burn more easily during cooking . As an alternative to adding more thickener , recipes may call for reduction of the food ' s water content by lengthy simmering . When cooking , it is generally better to add thickener cautiously ; if over - thickened , more water may be added but loss of flavour and texture may result . Gelling agents are food additive s used to thicken and stabilize various foods , like jellies , desserts and candies . The agents provide the foods with texture through formation of a gel . Some stabilizer s and thickening agents are gelling agents . Typical gelling agents include natural gum s , starch es , pectin s , agar - agar and gelatin . Often they are based on polysaccharides or proteins . Examples are : Commercial jellies used in East Asian cuisine s include the glucomannan polysaccharide gum used to make " lychee cups " from the konjac plant , and aiyu or ice jelly from the " Ficus pumila " climbing fig plant . Food thickening can be important for people facing medical issues with chewing or swallowing , as foods with a thicker consistency can reduce the chances of choking , or of inhalation of liquids or food particles , which can lead to aspiration pneumonia . Mechanical and thixotropic agents . Fumed silica and similar products form stiff microscopic chains or fibers which interlock or agglomerate into a mass , holding the associated liquid by surface tension , but which can separate or slide when sufficient force is applied . This causes the thixotropic or shear - thinning property ( also frequently exhibited by gels ) , where the viscosity is non - newtonian and becomes lower as the shearing force or time increases ; their usefulness is primarily that the resulting increase in viscosity is large compared to the quantity of silica added . Fumed silica is generally accepted as safe as a food additive and is frequently used in cosmetics . Additives such as precipitated silica , fine talc , or chalk also meet the definition of " thickening agent " in that they increase viscosity and body while not affecting the target property of a mixture . Cosmetics . Thickening agents used in cosmetics or personal hygiene products include viscous liquids such as polyethylene glycol , synthetic polymers such as carbomer ( a trade name for polyacrylic acid ) and vegetable gum s . Some thickening agents may also function as stabilizers when they are used to maintain the stability of an emulsion . Some emollient s , such as petroleum jelly and various waxes may also function as thickening agents in an emulsion . Paint and printing thickeners . One of the main use of thickeners is in the paint and printing industries , which depend heavily on rheology modifiers , without which paints would be oil based , with shellac added to help the surface not crack on drying , but without thickeners , pigments would settle to the bottom of the can , and inconsistent results would be common . Water based formulas would be nearly impossible with the exception of India ink and the few other water soluble pigments , but these would have very little coverage and at best would stain wood slightly . All modern paints and inks will have some " pigment " added at the factory for opacity and to control the specularity of the finish , from matte to high gloss , dependent on thickener used , but more so on the size of the particles added as opacity modifier . One micron particle sizes and below will be the limit of high gloss , probably confined to luxury automotive coatings , and about 100 micron particulates will make a bumpy surface on the microscopic scale , which scatters light and makes the surface appear matte . There are dozens or hundreds of other performance additives used in paints and inks , for example wetting surfactants , binders , flocculants , dispersants , leveling compounds , antifoam , aerators , surface tension modifiers , film formers , plasticizers , pore formers , water repellents , corrosion inhibitors , bittering agents to deter rodents . . . Rheology modifiers in common use : All of the above rheology modifiers are used in the 0 . 2 % to 2 . 0 % range Petrochemistry . In petrochemistry , gelling agents , also called solidifiers , are chemicals capable of reacting with oil spills and forming rubber - like solids . The gelled coagulated oil then can be removed from the water surface by skimming , suction devices , or nets . Calm or only moderately rough sea is required . Explosives and incendiaries . Various materials are used to convert liquid explosive s to a gel form . Nitrocellulose and other nitro esters are often used . Other possibilities include nitrated guar gum . Many fuels used in incendiary device s require thickening for increased performance . Aluminium salts of fatty acid s are frequently used . Some formulations ( e . g . Napalm - B ) use polymeric thickeners , namely polystyrene . Hydroxyl aluminium bis ( 2 - ethylhexanoate ) is also used . Thickened pyrophoric agent , a pyrophoric replacement of napalm , is a triethylaluminium thickened with polyisobutylene .