Potassium -sorbate

Sorbates are effective against many food spoilage organisms, and have many uses because of a milder taste, greater effectiveness, and broader pH range of inhibitory activity in comparison with either benzoate or 

Sources U.S. Department of Agriculture, Food Safety and Inspection Service. Federal Register 64 732-749, 1999 and U.S. Department of Agriculture, Food Safety and Inspection Service. Federal Register 66 12589-12636, 2001. 

Potassium sorbate has greater solubility in water than sorbic acid and is used accordingly in dipping or spraying fruit and vegetable products. The antimycotic action of potassium sorbate is similar to sorbic acid, but approximately 25% more potassium sorbate is usually needed to secure the same protection. Stock solutions of potassium sorbate can be made in water and concentrated up to 50%, to be mixed later with liquid food products, or diluted in dips and sprays. In foods with very low pH, low sorbate levels have excellent protective activity. Sorbates are applied in beverages, syrups, fruit juices, wines, jellies, jams, salads, pickles, etc. (Barbosa-Canovas et al., 2003). Salts of propionic and sorbic acids are often added to intermediate moisture bakery products (Arroyo, Aldred, and Magan, 2005). 

BP Potassium sorbate PhEur Kalii sorbas USPNF Potassium sorbate 

E202 2,4-hexadienoic acid ( , )-potassium salt potassium ( , )-hexa-2,4-dienoate potassium ( , )-sorbate sorbic acid potassium salt. 

Potassium sorbate is an antimicrobial preservative, with antibacterial and antifungal properties used in pharmaceuticals, foods, enteral preparations, and cosmetics. Generally, it is used at concentrations of 0.1-0.2% in oral and topical formulations, especially those containing nonionic surfactants. Potassium sorbate has been used to enhance the ocular bioavailability of timolol. 

Potassium sorbate is used in approximately twice as many pharmaceutical formulations as is sorbic acid owing to its greater solubility and stability in water. Like sorbic acid, potassium sorbate has minimal antibacterial properties in formulations above pH 6. 

Potassium sorbate occurs as a white crystalline powder with a faint, characteristic odor. 

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Table 2. Solubility of Sorbic Acid and Potassium Sorbate...

The ketene—crotonaldehyde route through polyester with various modifications and improvements is reportedly practiced by Hoechst Celanese, Cheminova, Daicel, Ueno, Chisso, Nippon Gohsei, and Eastman Chemical Company. Differences in thein processes consist mosdy in the methods of polyester splitting and first-stage purification. Production of the potassium salt can be from finished sorbic acid or from a stream in the sorbic acid production route before the final drying step. Several patents on the process for producing sorbic acid and potassium sorbate from this route are given in the hterature. 

Sorbic acid is produced and marketed in the United States in the dust-free powder form. The 1995 tmckload (TL) Hst price was U.S. 8.60— 8.80/kg for food grade and 12.41/kg for National Formulary (NF) grade. Water-soluble potassium sorbate is marketed as a powder or as granules. The 1995 TL Hst price was U.S. 7.90— 8.15/kg for food grade and 11.75/kg for NF grade. In addition to Eastman, the only U.S. producer, there are four Japanese producers and two producers in the European Union. Worldwide consumption in 1994 was approximately 2700—3000 metric tons and the nameplate productive capacity was approximately 2900—3100 metric tons. 

Sorbic acid and its salts are highly refined to obtain the necessary purity for use in foods. The quaUty requirements are defined by the Food Chemicals Codex (Table 3). Codistillation or recrystaUization from water, alcohoHc solutions, or acetone is used to obtain sorbic acid and potassium sorbate of a purity that passes not only the Codex requirements but is sufficient for long-term storage. Measurement of the peroxide content and heat stabiUty can further determine the presence of low amounts of impurities. The presence of isomers, other than the trans,trans form, causes instabiUty and affects the melting point. 

Analytical Techniques. Sorbic acid and potassium sorbate are assayed titrimetricaHy (51). The quantitative analysis of sorbic acid in food or beverages, which may require solvent extraction or steam distillation (52,53), employs various techniques. The two classical methods are both spectrophotometric (54—56). In the ultraviolet method, the prepared sample is acidified and the sorbic acid is measured at 250 260 nm. In the colorimetric method, the sorbic acid in the prepared sample is oxidized and then reacts with thiobarbituric acid the complex is measured at - 530 nm. Chromatographic techniques are also used for the analysis of sorbic acid. High pressure Hquid chromatography with ultraviolet detection is used to separate and quantify sorbic acid from other ultraviolet-absorbing species (57—59). Sorbic acid in food extracts is deterrnined by gas chromatography with flame ionization detection (60—62). 

Seafood. Sorbates are used to extend the shelf life of many seafood products, both fresh and processed (103,104). For smoked or dried fish, an instantaneous dip in 5 wt % potassium sorbate or a 10-minute dip in 1.0 wt % potassium sorbate prior to drying or smoking inhibits the development of yeast and mold (105,106). For fresh fish, sorbates can be incorporated at approximately 0.5 wt % into the ice, refrigerated seawater, or ice-water slush in... 

Bakery Products. Sorbates are used in and/or on yeast-raised and chemically leavened bakery products. The internal use of sorbates in yeast-raised products at one-fourth the amount of calcium—sodium propionate that is normally added provides a shelf life equal to that of propionate without adversely affecting the yeast fermentation. Sorbates added at one-tenth the propionate level reduce the mix time by 30% (126). This internal treatment combined with an external spray of potassium sorbate can provide the same or an increased shelf life of pan breads, hamburger and hot-dog buns, English muffins, brown-and-serve roUs, and tortillas. The total sorbate useful in or on these baked goods ranges from 0.03 wt % for pan breads to 0.5 wt % for tortillas 0.2—0.3 wt % sorbic acid protects chemically leavened yellow and chocolate cakes (127). Emit-pie fillings and icings can be protected with 0.03—0.1 wt % sorbates. 

Eor fresh poultry, a potassium sorbate dip significantly reduces total viable bacteria and doubles the refrigerated shelf life of ice-packed broilers (133). In cooked, uncured, vacuum-packaged turkey and poultry stored at 4°C, 0.2—0.25 wt % potassium sorbate suppresses microbial growth for up to 10 days (134). Sorbic acid at 0.5% in a marinade mixture for chicken dmmmettes extends refrigerator shelf life (135). Country-cured hams sprayed with a 10 wt % potassium sorbate solution showed no mold growth for up to 30 days (136). A review of sorbate use in meat and fish products has been pubHshed (137). 

Potassium sorbate, but not sorbic acid, is generally recognized as safe for use in animal feeds (154) and in paper and paperboard products for food packaging (155). 

Potassium sorbate may also be used in meat and poultry food products under USDA regulations (156,157). The USDA regulations allow its use only to retard mold growth in sausage, including beef jerky, when appHed from a 10% water solution to casings before or after stuffing. 

Both sorbic acid and potassium sorbate may be used under U.S. Department of Treasury, Bureau of Alcohol, Tobacco, and Firearms regulations as sterilizing and preservative agents for treatment of wine and juice at up to 300 ppm/L (158). 

Canada. Sorbic acid and potassium sorbate are cleared in Canada as Class II and Class III preservatives (Table XI, Parts II and III, Food and Dmg Regulations) (162). They are cleared for use in the same food types. As in the United States, their lawful use is predicated upon conformity with pubHshed food standards. Otherwise they may be used in bread and unstandardized foods, except meat (Divisions 14 and 21 of the regulations), fish, and poultry, at levels up to 1000 ppm, in cider and wine at 500 ppm, and in cheeses at 3000 ppm in accordance with the food standards for cheese (Section B of the regulations). 

Japan. The Japanese StandardsforFood idditives allow sorbic acid and potassium sorbate to be used as antimicrobial agents in a variety of foods specific limitations depend on the food (163). 

Literature reports iadicate that sodium sorbate causes weak genotoxic effects such as chromosomal aberrations and mutations ia mammalian cells (172,173). This effect is thought to be caused by oxidative products of sodium sorbate ia stored solutions (173—175). The main oxidation product of sodium sorbate, 4,5-oxohexenoate, is mutagenic ia a Salmonella mammahan-microsome test (176). Sorbic acid and potassium sorbate were not genotoxic under the same test procedures (167,172,174—177). 

Sorbic dcid and Potassium Sorbate JorPreservingFoodFreshness, Eastman Chemical Co. Publication ZS-IC, Kingsport, Term., 1995. 

Sorbic Acid and Potassium Sorbate for Use in Cottage Cheese, Pubhcation No. IC/PI-20, Monsanto, Co., St. Louis, Mo., 1977. 

M. S. Pey, Ph.D. dissertation. Extending the She/fEfe of Fresh Fish by Potassium Sorbate and Modified Atmospheres at 0—1 ° Ce/sius, Cornell University, Ithaca, N.Y., 1980. 

She/fEfe Sensoy, Cooking, and Physica/ Characteristics of Bacon Cured with VayingEeve/s of Sodium Mitrate and Potassium Sorbate, U.S. Dept, of Agriculture, Washington, D.C., July 1979. 

Sodium or potassium benzoate at a concentration of 0.05% is a universally used preservative agent active against yeast and mold. At higher concentrations benzoate is also effective against bacteria. It is most effective at a pH between 2.0 and 4.0. Sodium or potassium sorbate inhibits the growth of yeast and mold and is most effective below pH 6.5. 

Potassium sorbate is a polyunsaturated fatty acid salt. It is used to inhibit molds, yeasts, and fungi in many foods, including cheese, wine, and baked goods. It is the potassium salt of sorbic acid. 

Potassium sorbate is added to inhibit yeasts and fungi. Ascorbic acid (vitamin C) is used as an antioxidant. 

The effect of various types of inhibitors with respect to structure and solubility on the formation of N-Nitrosodiethanolamine was studied in a prototype oil in water anionic emulsion, Nitrosation resulted from the action of nitrite on diethanolamine at pH 5.2-5.A, Among the water soluble inhibitors incorporated into the aqueous phase, sodium bisulfite and ascorbic acid were effective. Potassium sorbate was much less so. The oil soluble inhibitors were incorporated into the oil phase of the emulsion. 

Recently, Robach et al. ( ) investigated the effects of various concentrations of sodium nitrite and potassium sorbate on N-nitrosamine formation in commercially prepared bacon. 

Vareltzis, K.R and Buck, E.M., Color stability and sensory attributes of chicken frankfurters made with betalains and potassium sorbate versus sodium nitrite, J. Food Protect., 47, 41, 1984. 

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