Lactylates are organic compounds that are FDA approved for use as food additives and cosmetic ingredients, e.g. as food-grade emulsifiers. These additives are non-toxic, biodegradable, and typically manufactured using biorenewable feedstocks. Owing to their safety and versatile functionality, lactylates are used in a wide variety of food and non-food applications. In the United States, the Food Chemicals Codex specifies the labeling requirements for food ingredients including lactylates. In the European Union, lactylates must be labelled in accordance with the requirements of the applicable EU regulation. Lactylates may be labelled as calcium stearoyl lactylate (CSL), sodium stearoyl lactylate (SSL), or lactylic esters of fatty acids (LEFA). CSL, SSL, and food-grade LEFAs are used in a variety of products including baked goods and mixes, pancakes, waffles, cereals, pastas, instant rice, liquid shortenings, egg whites, whipped toppings, icings, fillings, puddings, toppings, frozen desserts, creamers, cream liqueurs, sugar confectionaries, dehydrated fruits and vegetables, dehydrated potatoes, snack dips, chewing gum, dietetic foods, minced and diced canned meats, mostarda di frutta, sauces, gravies, and pet food. In addition, these lactylates are FDA approved for use in food packaging, such as paper, paperboard, and cellophane, and pharmaceuticals. Lactylates are also used in a variety of personal care products including shampoos, skin conditioners, lotions, barrier creams, makeup bases, lipsticks, deodorants, and shaving creams. In addition, lactylates are bio-friendly additives for use in polyolefins, flame retardants, pigments, and PVC.
History Lactylates were developed in the 1950s by the C.J. Patterson Company as non-petrochemical alternatives to Sta-Soft, a polyoxyethylene derivative of stearic acid, for delaying the staling of bread. The research into the development of lactylates led to the first lactylate patent application, filed in 1951, and two issued patents in 1956 and 1957. These patents included lab-scale manufacture and applications of several lactylates, including CSL and SSL. In 1954, the inventors published an article showing that CSL improved mix tolerance, bread volume and overall quality. CSL won FDA approval for use as a food additive in April 1961 and was first used as a commercial bakery additive in the United States in 1962. The research was acknowledged as a major achievement in the baking industry, winning the Food Technology Industrial Achievement Award in 1965. SSL use as a bakery additive followed in 1968.
Manufacturing
The original lab-scale preparation of lactylates involved esterification of lactic acid or poly(lactic acid) with an acid chloride derivative of the desired fatty acid. Current manufacturing practices were patented in January 1956 and combine fatty acids (e.g. naturally derived stearic acid) and lactic acid at elevated temperatures. For CSL and SSL, the stearic acid component is typically produced from vegetable oils such as soybean oil or palm oil. Lactic acid is primarily produced by lactic acid fermentation of sugar with lactic acid bacteria (similar to the bacteria used to produce yogurt). The sugar can be sucrose, fructose, or glucose obtained from corn, sugar beet or sugar cane. Because the lactic acid is derived from plant sources and not from milk or milk products, it does not contain any residual lactose. Therefore, people who are lactose intolerant can consume lactylates without concern. Lactylates, in the free acid form, are not readily water dispersable. To improve the water dispersibility and emulsification properties, the carboxylic acids comprising lactylates can be neutralized using hydroxides or carbonates of group 1 or group 2 metals such as sodium or calcium. At room temperature, lactylates can be viscous liquids or solids depending on the starting fatty acid, the total recoverable lactic acid content, and the degree of neutralization. Solid lactylates are often processed into powders. The traditional method is to solidify the liquid into a flake and grind the resulting flake into a powder. Newer methods utilize spray congealing to directly form beads. The manufacturing process of lactylates is an esterification reaction. The water coproduct is removed by evaporation to drive the reaction towards the desired product composition in accordance with Le Chatelier's principle. Water removal is accomplished either by sparging with a constant stream of dry nitrogen or by vacuum outgassing with the use of a vacuum pump system. Using nitrogen sparging or vacuum outgassing also protects the reaction mixture from undesirable oxidation processes.
The manufacturing process does not produce chemically pure lactylates (e.g. stearoyl-2-lactylate) for two reasons. First, the source fatty acid is not chemically pure since it is typically derived from natural sources. The source fatty acid may contain varying ratios of different fatty acids (e.g. lauric acid (C12:0), myristic acid (C14:0), palmitic acid (C16:0), stearic acid (C18:0), arachidic acid (C20:0), behenic acid (C22:0), etc.). Second, lactic acid readily undergoes self-esterification producing a variety of polylactyls (typically numbering from one to three lactyl groups). Chemically pure lactylates (e.g. stearoyl-1-lactylate, stearoyl-2-lactylate, etc.) can be produced through an intermediate benzyl ether derivative. This synthetic pathway provides a convenient route to the production of analytical standards of the individual lactylate components.
Functionality
Overview
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