Based on their functions in food production, processing, and storage, food additives are generally classified into 23 major categories: acidity regulators, anticaking agents, defoaming agents, antioxidants, bleaching agents, leavening agents, colorants, color preservatives, emulsifiers, enzyme preparations, flavor enhancers, flour treatment agents, coating agents, moisture retainers, nutritional fortifiers, preservatives, stabilizers and coagulants, sweeteners, thickeners, food flavorings, food processing aids, base substances for gum-based candies, and others. Depending on the needs, one or more food additives may be used as the primary ingredient, and carriers, solvents, preservatives, antioxidants, or other substances may be added to facilitate storage, distribution, standardization, dilution, or dispersion. The following briefly describes the main functions of each category for reference only.
- Acidity Regulators
Acidity regulators, also known as pH adjusters, are substances used to maintain or change the pH of food. They primarily include acidifiers, alkali agents, and salts with a buffering effect. Acidifiers, also known as acidulants, are additives that generate excess hydrogen ions in food to control pH and impart a sour flavor. They have various functions, including flavoring, preservatives, buffering, gas production, chelation, gelling, coagulation, and fermentation. Commonly used acidifiers include citric acid, lactic acid, and phosphoric acid. Alkali agents primarily regulate pH and act as buffers. For example, in cheese production, alkali agents such as trisodium phosphate are added to increase pH, thereby dispersing proteins and improving casein’s emulsification and water-binding capacity. Buffering salts are added to maintain a relatively stable pH during the food manufacturing process or in the final product. Their use prevents significant changes in the hydrogen ion concentration of the final product caused by the addition of small amounts of acid or alkali. - Anticaking Agents
Anticaking agents, also known as anti-caking agents, are substances used to prevent granular or powdered foods from clumping and maintaining their loose or free-flowing state. Their fine, loose, porous particles possess strong adsorption properties, absorbing moisture, oil, and other factors that can cause clumping, thereby maintaining the food in a powdery or granular state. Commonly used anticaking agents include silicon dioxide, calcium silicate, and calcium stearate. - Defoaming Agents
Defoaming agents are substances that reduce surface tension and eliminate foam during food processing. Foam is a dispersion of gas in a liquid, with the gas as the dispersed phase and the liquid as the dispersion medium. Foam is typically formed by external forces at the interface between a surfactant-containing aqueous solution and air, where bubbles of air form and accumulate and rise to the surface. During food processing operations such as fermentation, mixing, boiling, and concentration, large amounts of foam can be generated. This foam not only affects the smooth operation of production but also the final product quality. In severe cases, it can reduce the usable capacity of equipment, increase energy consumption, and reduce production efficiency. Therefore, it is essential to prevent or eliminate foam promptly. Defoamers can be roughly divided into two categories: one that eliminates existing bubbles, such as sucrose fatty acid esters; the other that inhibits bubble formation, such as polydimethylsiloxane and its emulsions. - Antioxidants
Antioxidants are substances that prevent or delay the oxidative decomposition and deterioration of fats and oils or food ingredients, thereby improving food stability. Symptoms of oxidative deterioration of food ingredients include rancidity of fats and oil-rich foods, discoloration and browning, and the loss of vitamins. Antioxidants can be divided into two categories based on their solubility: oil-soluble and water-soluble. Oil-soluble antioxidants include butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), tertiary butylhydroquinone (TBHQ), and propyl gallate (PG); water-soluble antioxidants include D-isoascorbic acid and its sodium salt. The oxidative rancidity of fats in oils and fat-rich foods is not only related to the properties of the fat itself, but also directly linked to storage conditions such as temperature, humidity, air, and catalytic oxidation-causing light, enzymes, and metal ions such as copper and iron. To prevent fat oxidation, appropriate countermeasures must be taken to address these factors. Antioxidants act by blocking the oxidation reaction chain, preempting oxidation themselves, inhibiting the activity of oxidases, and complexing metal ions such as copper and iron to eliminate their catalytic activity. Antioxidants work by preventing or delaying oxidation reactions in foods, but they cannot reverse oxidation reactions once they occur. Therefore, antioxidants must be added before oxidation occurs. - Bleaching Agents
Bleaching agents are substances that destroy or inhibit coloring factors in food, causing it to fade or preventing it from browning. They are categorized into two types: oxidizing bleaching agents and reducing bleaching agents. Oxidizing bleaching agents achieve their bleaching purpose by oxidizing and destroying coloring substances through their own strong oxidizing action. Reducing bleaching agents, primarily sulfite and its salts, discolor food through the reducing action of the sulfur dioxide they produce, while also having antibacterial and antioxidant effects. Reducing bleaching agents are effective only when present in food. Once removed, the food can be oxidized by the presence of oxygen in the air, causing it to recolor.
- Raising Agents
Raising agents are substances added during food processing to cause products to rise, forming a dense, porous structure, thus imparting a fluffy, tender, or crispy quality. They are added to wheat flour, the primary raw material for steaming, baking, and frying foods. During processing, they decompose upon heating, producing carbon dioxide gas, which causes the dough to rise again, forming a dense, porous structure, thus imparting a fluffy, tender, or crispy quality to noodle products. Chemical raising agents include alkaline and acidic types. Acidic raising agents often use acidic phosphates, which provide the hydrogen required for the reaction; alkaline raising agents often use carbonates and bicarbonates, which provide CO2. - Colorants
Colorants are substances that impart and enhance the color of food. They improve the sensory properties of food, enhance its color, and stimulate appetite. Colorants, also known as pigments, generally fall into two categories: synthetic edible pigments and natural edible pigments. Synthetic edible pigments are primarily produced through artificial chemical synthesis. Synthetic pigments, such as Allura Red and Tartrazine, offer advantages such as bright color, strong tinting power, resistance to fading, relatively low usage levels, and relatively stable performance. Approved edible synthetic pigments also include their respective lakes. Lakes are special colorants made by precipitating water-soluble pigments onto an approved insoluble matrix (usually aluminum oxide). Aluminum lakes are virtually insoluble in water, making them suitable for powdered foods, oily foods, icings, and pastries. Natural edible pigments are derived from natural, mostly edible, sources and processed using specific processing methods. They are primarily extracted from plant tissues, but also include some pigments from animals and microorganisms. Examples include natural carotene, bayberry red, and lutein. - Base Substances in Gum-Based Candies Base substances in gum-based candies, also known as gum base, are the substances that give gum-based candies their foaming, plasticizing, and chewability properties. Gum base is regulated as a food additive in my country, but because it only contributes to chewability and foaming, it is a relatively specialized food additive present as a skeletal structure in gum-based candies.
- Nutritional Fortifiers
In my country, food nutritional fortifiers are a type of food additive. According to GB 14880-2012, “National Food Safety Standard – Standard for the Use of Food Nutritional Fortifiers,” nutritional fortifiers refer to natural or synthetic nutrients and other nutritional ingredients added to food to increase its nutritional content (value). Common nutritional fortifiers currently approved for use in my country include vitamins, minerals, and other nutrients (such as DHA, amino acids, carnitine, taurine, nucleotides, choline, and inositol). Adding food nutritional fortifiers can improve the nutritional composition and ratio of nutrients in food, helping people consume specific nutrients they need, especially those that are often deficient in the diet. Food nutritional fortifiers are widely used in the food industry and are an effective means of improving public health. However, the consumption of nutritional fortifiers is not necessarily better. For example, excessive intake of fat-soluble vitamins can cause toxicity. Therefore, national standards set upper and lower limits for fortification to ensure both effectiveness and safety. - Sweeteners
Sweeteners are substances that impart a sweet taste to food. Sweeteners can be divided into nutritive and non-nutritive sweeteners. Nutritive sweeteners are those with the same sweetness as sucrose and a caloric value equivalent to more than 2% of the caloric value of sucrose. They mainly refer to some sugar alcohols with a polyhydric alcohol structure, such as xylitol, lactitol, sorbitol, maltitol, erythritol, D-mannitol, etc. Non-nutritive sweeteners are those with the same sweetness as sucrose but a caloric value less than 2% of the caloric value of sucrose. They include sodium saccharin, sodium cyclamate, aspartame, acesulfame potassium, isomaltulose, etc. Their relative sweetness is much higher than that of sucrose, and their dosage is extremely small. Their caloric value is very low and they are generally not involved in the metabolic process. They are usually called high-intensity sweeteners.
