Yeast sorbic acid

Sorbates. The sodium and potassium salts of sorbic acid [110-44-1], ate used as mold and yeast inhibitors in dairy products, chemically... 

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. 

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. 

Sorbic acid, a yeast inhibitor, is used sometimes in conjunction with membrane filtration as an extra safety factor. However, excessive amounts of sorbic acid may affect the wine s aroma, and most North Coast winemakers avoid its use. 

Sorbic acid and sorbates are effective against yeasts and molds. Sorbates inhibit yeast growth in a variety of foods including wine, fruit juice, dried fruit, cottage cheese, meat, and fish products. Sorbates are most effective in products of low pH including salad dressings, tomato products, carbonated beverages, and a variety of other foods. 

Sorbic acid (pK 4.8) is more effective in acid foods, best below pH 6.0 and is generally ineffective above pH 6.5. The sorbates work better than sodium benzoate between pH 4.0 - pH 6.0 and are primarily effective against yeasts and moulds. For information on sorbate - nitrite combinations in meat products including bacon see... 

This compound is relatively stable during food processing and in food products. It was proposed in 1875 by H. Fleck as a replacer for salicylic acid and can be considered as one of the first safe food preservatives. Like sorbic acid, it is mainly active against yeast and molds, but the growth of micrococci, Escherichia coli, and many other bacteria is retarded as well. 

Steels, H., James, S.A., Roberts, I.N., and Stratford, M. 2000. Sorbic acid resistance The inoculum effect. Yeast 16 1173-1183. 

Derivative benzoates and parabenzoates have been used primarily in fruit juices, chocolate syrup, pie fillings, pickled vegetables, relishes, horseradish, and cheese (Barbosa-Canovas et al., 2003). Other foodstuffs where sodium benzoate is used include soft drinks, baked goods, and lollipops (Poulter, 2007). Benzaldehyde and benzoic alcohol are better known to be yeast inhibitors. Benzoic acid has been found to release fewer protons than sulphite, nitrite, or acetic acid and it may be speculated that benzoic acid is not a classic weak-acid preservative. However, due to a lower pKa value, benzoic acid releases three to four times more protons than sorbic acid. This is a sizable concentration of protons although not as much as other weak-acid preservatives (Stratford and Anslow, 1998). Inhibition of growth is strongly pH-dependent and most effective under acidic conditions. Under these conditions the protonated form of the acid is predominantly found (Visti, Viljakainen, and Laakso, 2003). Another unexpected discovery was that benzoic acid appears to be a pro-oxidant. This was unexpected as it is a well-known fact 2-hydroxybenzoic acid (or salicylic acid) acts as a scavenger of free radicals in vivo (Piper, 1999). 

Some organic acids, such as sorbic acid and benzoic acid, are widely regarded as the most active against yeasts and molds, and not against... 

Papadimitriou, M.N., Resende, C., Kuchler, K., and Brul, S. 2007. High Pdrl2 levels in spoilage yeast (Saccharomyces cerevisiae) correlate directly with sorbic acid levels in the culture medium but are not sufficient to provide cells with acquired resistance to the food preservative. International Journal of Food Microbiology 113 173-179. 

Stratford, M. and Anslow, P.A. 1998. Evidence that sorbic acid does not inhibit yeast as a classic weak acid preservative. Letters in Applied Microbiology 27 203-206. 

Naturally occurring organic acids, such as sorbic acid, benzoic acid, and acetic acid, are the most commonly used chemical preservatives in food and all have a broad antimicrobial spectrum (Plumridge et al., 2004). Benzoic acid, in particular, although mainly associated with fruit preservation, is used in many types of acidic food products (Suhr and Nielsen, 2004). Sorbic acid inhibits both molds and yeasts, and is used in a broad variety of food products (Sofos and Busta, 1981), including fine bakery products, confectionery, and bread (Suhr and Nielsen, 2004). 

In vegetables, natural microflora may consist of various genera of bacteria, yeasts, and molds. The organic acid content of a tomato is responsible for the low pH of between 4.0 and 4.6 (Gutheil, Price, and Swanson, 1980 Sajur, Saguir, and Manca de Nadra, 2007). Sorbic acid and perbenzoic acid are found in particularly high levels in several wild berries (Piper, 1999). 

De Nobel, H., Lawrie, L., Brul, S., et al. 2001. Parallel and comparative analysis of the proteome and transcriptome of sorbic acid stressed Saccharomyces cerevisiae. Yeast 18 1413-1428. 

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