Sorbic acid, also known as rowan acid, is the most widely used highly efficient and non-toxic food mold inhibitor in the world. It has a structural formula of CH3CH=CH-CH=CHCOOH and a molecular formula of C6H8O2 with a relative molecular mass of 112.12. It exists as colorless needle-like crystals or white crystalline powder that is stable to light and heat but prone to oxidation and discoloration. Its melting point is 134.5 ℃, boiling point is 228 ℃ (decomposition), and its saturated aqueous solution has a pH of 3.6. Sorbic acid is slightly soluble in water but soluble in methanol, ethanol, glacial acetic acid, acetone, acetone benzene, and carbon tetrachloride. Sorbic acid exhibits an acidic odor yet it is non-toxic. Chemically active, it readily undergoes addition reactions to form saturated compounds. It effectively inhibits molds, yeasts, and aerobic bacteria but shows little effectiveness against anaerobic Clostridium spp and Lactobacillus acidophilus. Suitable for use within the pH range of 4.5-6., sorbic acid and its potassium salt function by binding to sulfhydryl groups in microbial enzymes which disrupts their activity leading to impaired reproduction. As an unsaturated fatty acid participating in normal metabolism within the body oxidizing ultimately into carbon dioxide and water; sorbic acid poses no harm to humans. The acceptable daily intake (ADI) for sorbic acid stands at 0～25mg/kg for human consumption making it suitable as a preservative (dosage: 0.2～2g/kg) for various foods including soy sauce vinegar jam juice fruit juice wine pickles preserves cakes salami cheese canned foods.
The sorbic acid and its sodium salt have long been used as food preservatives, particularly in low pH conditions where the undissociated acid form plays a role in inhibiting mold growth. In acidic environments (pH 5 ~ 6 or lower), they exhibit inhibitory effects on molds, yeast, and aerobic bacteria, but are almost ineffective against aerobic spore-forming bacteria and Lactobacillus acidophilus. The recommended dosage should not exceed 2g/kg for fruit and vegetable juice concentrate packed in plastic drums for the food industry. For soy sauce, vinegar, jam type products, hydrogenated vegetable oil, fudge, dried fish products, ready-to-eat soybean products, pastry fillings, breads, cakes mooncakes,and ready-to-eat jellyfish lactobacillus beverages,the maximum dosage is 110g/kg. For wine and fruit wine it is 0.6g/kg; for gelatinized salted protein enteric coats and low-salt pickles it is also 0.6g/kg; while for gelatin salt protein sausage,preserves ,fruit juice (flavor) drinks,and jelly,it is limited to a maximum of 0.5g/kg;for fruit and vegetable preservation as well as carbonated beverages,the limit is set at 0.2g/kg.In the meat,fish,eggs,and poultry product industries,the maximum usage allowed is up to 0.075 g / kg.Sorbic acid possesses unique characteristics that distinguish it from other preservatives: strong selective preservation capabilities that inhibit harmful bacteria growth while allowing beneficial bacterial growth without hindrance.For example,it can inhibit cheese molds while having no impact on bacteria responsible for cheese ripening.As such,sorbic acid finds extensive use in the food industry as a preservative in cheese,cakes,and other confectionery items.Tests have determined that the permitted level of sorbic acid in food should not exceed 0.1%. It finds primary application in cheese,pickled vegetables,dried fruits,and fruit-based products.
Sorbic acid is commonly added to various beverages, including wine, for specific reasons. Its addition helps inhibit the growth of yeast during winemaking and enhances the wine's ability to prevent air isolation. When combined with sulfur dioxide, sorbic acid effectively controls acetic and lactic acid bacteria without eliminating them entirely, thereby influencing the quality of the wine. The appropriate amount of sorbic acid ensures minimal exposure to air and prevents excessive oxidation, which can negatively impact the wine's taste and overall quality. Furthermore, it also suppresses the proliferation of yeast, lactic acid bacteria, and acetic acid bacteria. However, it is important to note that excessive consumption of sorbic acid may have certain implications on human health.
If the amount of sorbic acid added exceeds the national standard or if a significant quantity of food containing sorbic acid is consumed in daily life, it may exacerbate gastrointestinal burden and potentially elevate the risk of cancer. However, when added within compliance with national safety standards, its impact on the body is generally minimal.
