ACIDULANTS AND ALKALIZERS.
Taste is only one of several qualities of a process or product which is affected by an excess of either of these ions. Some raw materials are naturally too acidic, others too alkaline-so that neutralizers must be added to adjust the pH within an acceptable range. In the dairy industry, for example, the acid in sour cream must be adjusted by the addition of alkaline compounds in order that satisfactory butter can be churned. Quite often, the pH may be difficult to adjust or to maintain after adjustment. Stability of pH can be accomplished by the addition of buffering agents which, within limits, effectively maintain the desired pH even when additional acid or alkali is added. For example, orange-flavored instant breakfast drink has just enough "bite" from the addition of potassium citrate (a buffering agent) to regulate the tart flavor imparted by another ingredient, citric acid. In some instances, the presence of acids or alkalies assist mechanical processing operations in food preparation. Acids, for example, make it easier to peel fruits and tubers. Alkaline solutions are widely used in dehairing animal carcasses.
The pH values of various food substances cover a wide range. Plant tissues and fluids (about 5.2); animal tissues and fluids (about 7.0 to 7.5); lemon juice (2.0 to 2.2); acid fruits (3.0 to 4.5); fruit jellies (3.0 to 3.5).
Acidulants commonly used in food processing include: Acetic acid (glacial), citric acid, fumaric acid, glucono delta-lactone, hydrochloric acid, lactic acid, malic acid, phosphoric acid, potassium acid tartrate, sulfuric acid, and tartaric acid. Alkalies commonly used include: Ammonium bicarbonate, ammonium hydroxide, calcium carbonate, calcium oxide, magnesium carbonate, magnesium hydroxide, magnesium oxide, potassium bicarbonate, potassium carbonate, potassium hydroxide, sodium bicarbonate, sodium carbonate, sodium hydroxide, and sodium sesquicarbonate. Among the buffers and neutralizing agents favored are: Adipic acid, aluminum ammonium sulfate, ammonium phosphate (di- or monobasic), calcium citrate, calcium gluconate, sodium acid pyrophosphate, sodium phosphate (di-, mono-, and tri-basic), sodium pyrophosphate, and succinic acid.
Functions of Acidulants.
In the baking industry, acidulants and their salts control pH to inhibit spoilage by microbial actions to enhance the stability of foams (such as whipped egg albumin), to assist in leavening in order to achieve desired volume and flavoring, and to maximize the performance of artificial preservatives. A variety of the food acids previously mentioned is used. For example, citric acid traditionally has been favored by bakers for pie fillings. Baking powders (leavening agents) frequently will contain adipic acid, fumaric acid, and cream of tartar. Fumaric acid, in particular, has been the choice for leavening systems of cakes, pancakes, biscuits, waffles, crackers, cookies, and doughnuts. This acid also provides the desired characteristic flavor for sour rye bread-this eliminating fermentation of the dough to achieve desired flavor. Lactic acid and its salts sometimes are used as dough conditioners.
Acidulants are used in the soft drink beverage industry for producing a tart taste, improving flavor balance, modifying the "sweetness" provided by sugar and other sweeteners, extending shelf life by reducing pH value of final product, and improving the performance of antimicrobial agents. Specific acidulants preferred vary with the type of beverage- i.e. carbonated, noncarbonated, dry (reconstituted by addition of water), and low-calorie products.
In the production of confections and gelatin desserts, acidulants are used mainly for enhancing flavor, maintaining viscosity, and controlling gel formation. In confections, such as hard candies, acidulants are used to increase tartness and to enhance fruit flavors. Acidulants also contribute to the ease of manufacturing.
In dairy products, acidulants, in addition to achieving many of the foregoing functions, also help to process the products. As an example, adipic acid improves the texture and melting characteristics of processed cheese and cheese foods, where pH control is very important.
In fruit and vegetable processing, acidulants play somewhat different roles than previously described. These would include reducing process heating requirements through pH control, inactivating certain enzymes that reduce shelf life, and chelation of trace metals that may be present (through catalytic enzymatic oxidation). Citric acid is used widely in canned fruits, such as apricots, peaches, pears, cherries, apple-sauce, and grapes, to retain the firmness of the products during processing. The acid also provides a desirable tartness in the final products.
In the processed meat field, citric acid, along with oxidants, is used to prevent rancidity in frankfurters and sausages. Sodium citrate is used in processing livestock blood, which is used to manufacture some sausages and pet foods.
Acidulants and alkalizers, like other food additives, are controlled by regulatory bodies in most industrial nations. Some of the additives mentioned in this article are considered to be "Generally Regarded as Safe," having a GRAS classification. These include acetic, adipic, citric, glucone delta lactone, lactic, malic, phosphoric, and tartaric acids. Others are covered by the Code of Federal Registration (FDA) in the United States.
In "Van Nostrand's Scientific Encyclopedia", Douglas M. Considine, editor; Glenn D. Considine, managing editor; Springer Science+Business Media New York, USA, 1995; excerpts p.20-21. Adapted and illustrated to be posted by Leopoldo Costa.
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