Sorbic acid applications

Sorbic acid Acidity regulators. The main applications of E201-E203 are... 

Sorbic acid and its potassium salt, collectively called sorbates, are used primarily in a wide range of food and feed products (63) and to a lesser extent in certain cosmetics (64), pharmaceuticals, and tobacco products. There are limited applications of the calcium and sodium salts, but the acid and its potassium salt are used almost exclusively. 

The inhibitory activity of sorbates is attributed to the undissociated acid molecule. The activity, therefore, depends on the pH of the substrate. The upper limit for activity is approximately pH 6.5 in moist applications the degree of activity increases as the pH decreases. The upper pH limit can be increased in low water activity systems. The following indicates the effect of pH on the dissociation of sorbic acid, ie, percentage of undissociated sorbic acid at various pH levels (76,77). 

Benzoic acid and its derivatives are among the most widely used antimicrobial agents these, together with the propionates, sulfur dioxide, nitrates, nitrites and sorbic acid, account for the bulk of food preservatives. A number of other compounds find use, however, in various miscellaneous applications, including 3-acetyl-6-methyl-3//-pyran-2,4-dione (67)... 

The bacteriological stability of guar gum dispersions may be improved by the addition of a mixture of 0.15% methylpar-aben and 0.02% propylparaben as a preservative. In food applications, benzoic acid, citric acid, sodium benzoate, or sorbic acid may be used. 

In the field of food analysis, a number of successful applications of analytical isotachophoresis have been reported (e.g. determination or organic acids in juices 9,76,99,112-114) yoghouTts wincs , and tea . The short time required for the separation and the minimum necessary treatment of the samples are the main advantages of these analyses. Thus both preservatives (sorbic acid and benzoic acid) and the initial components of the samples (ascorbic, isoascorbic, citric, lactic, aconitic, aspartic and glutamic acids, theanine etc.) may be determined. 

With this scenario in mind, the development of lesser known organic acids and acid blends, such as lactic acid and sorbic acid, to ensure product differentiation is expected to be boosted. Furthermore, novel applications, in the form of blends with non-acid ingredients, represent other potential growth sectors. 

Occasionally, confusion arises regarding the applicability and expectations surrounding the use of sterilants and preservatives. Properly administered in correct amounts, a sterilant can be expected to kill 100% of the viable cell population regardless of species. Preservatives, on the other hand, may cause cell death, but, in general, function to inhibit specific populations of microorganisms. Thus, the use of preservative such as SO2 and sorbic and benzoic acids should not be expected to be a carte blanche remedy for control of microorganisms present in the wine at bottling. Other distinctions between the two classes of compounds may also be drawn. The antimicrobial properties of compounds like sorbic acid and sulfur dioxide resides in the undissociated, rather than the ionized, molecule. Thus, inhibitory activity is enhanced at lower pH (Zoecklein et al., 1995). A sterilant, such as DMDC, does not rely on pH for enhanced/diminished activity. 

Sorbic acid is a short-chained (a-p-unsaturated fatty acid) which is widely used in food industries as a fungistatic agent. In the wine industry, it finds application at bottling in the prevention of refermentation in sweetened wines by Saccharomyces cerevisiae. 

Sorbic acid has a more suitable fat-water distribution than methylparaben, which makes it better applicable in emulsions. For solubilisates there is however a problem to overcome because sorbic acid adsorbs onto polysorbate, which is often used as a solubilising agent. Therefore the processed quantity of sorbic acid should be larger than the solubility of sorbic acid in water. Potassium sorbate is used to achieve this. Potassium sorbate is dissolved in water and then converted to sorbic acid using citric acid. Part of the sorbic acid dissolves in the lipid phase and adsorbs to the polysorbate. The free sorbic acid serves to preserve the aqueous phase [33]. See further Sect. 23.8.6. 

Applications. Sorbic acid and its salts are permitted as preservative in all countries of the world in a very broad spectrum of food, pet-food, feed, pharmaceutical and cosmetic products. The permissible quantities are between 0.1 and 0.2%, depending on the application. In the US sorbates can be used in many foods according to GMP without an upper limit. Thus sorbates are some of the most widely used food preservatives in the world. 

Formic acid exhibits its antimicrobial activity primarily in the undissociated state, i.e. at pH below 3.5 and therefore partly as an acidulant. The efficacy covers especially yeasts and some bacteria lactic acid bacteria and moulds are relatively resistant. Ethyl formate (9.1.), a generator of formic acid may also be applicated for preservation purposes. Sodium formate (CAS-no. 141-53-7, EC-no. 205-488-0) and potassium formate (CAS-no. 590-29-4, EC-no. 209-677-9) - both are crystalline white powders which are highly soluble in water- are used for the preservation of acid foods (addition rates 0.1 0.4%), frequently in combination with benzoic acid (8.1.9.) or sorbic acid (8.1.5.). In the EC list of preservatives permitted for the incorporation into cosmetic products formic acid and its sodium salt are mentioned with a maximum authorized concentration of 0.5% (add). 

Further examples of applications of SPE prior to TLC analysis include isolation of organophos-phorus pesticides from water (82) and benzoic and sorbic acid preservatives from beverages (83). 

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