What Are Food Additives? What Are Their Functions?

Given the rapid development of the food industry, food additives have become an indispensable part of food production and processing. They not only improve the color, aroma, taste, and appearance of food, but also extend shelf life, enhance nutritional value, and meet consumers' diverse and high-quality demands.

Food additives often do not exist naturally in a specific form; they require a carrier and may involve multiple industrial processing steps. They are easily misunderstood and labeled as "harmful and 

useless." However, in fact, food additives that meet national standards undergo rigorous safety assessments, and when used appropriately, they do not pose a threat to human health.

This article will introduce six core categories of food additives: acidity regulators, preservatives, sweeteners, amino acids, vitamins, and nutritional supplements. It will detail their types and specific functions and uses, helping readers gain a correct understanding of food additives.

1. What are food additives? What kinds are there?

（1）Definition of Food Additives

Food additives are artificial or natural substances added to food to improve its quality, color, aroma, and flavor, as well as for preservation, freshness, and processing needs. These include nutritional fortifiers.

（2）The Basic Role of Food Additives

China currently has over 2,300 approved food additives, categorized into 23 classes based on their function. They play an irreplaceable role in the food industry:

• Maintain or enhance the nutritional value of food itself

Food fortifiers can compensate for nutrient loss during food processing and storage, and improve the nutritional status of specific populations.

• Improve the sensory properties of food

Colorants give food an appealing color, flavorings bring a pleasant aroma, and thickeners create a suitable texture.

• Improving food quality and stability

Preservatives and antioxidants can extend the shelf life of food and prevent it from spoiling.

• Increase the variety and convenience of food

Sweeteners satisfy sweetness requirements while reducing the use of sucrose, and emulsifiers make it possible for oil and water to mix.

2. Acidity regulators: Control the acidity of food to create a superior taste and stability

（1）Definition of Acidity Additives

Acidity regulators, also known as acidulants, are food additives that adjust the pH value of food, improve its acidity and flavor, and are one of the most widely used categories in food production. Currently, 35 acidity regulators are approved in China, the most common being citric acid, malic acid, fumaric acid, tartaric acid, lactic acid, acetic acid, and phosphoric acid. Among these, citric acid, due to its natural presence in fruits such as lemons and oranges and its high safety profile, has become the most widely used acidity regulator.

（2）The core function of acidity regulators

• Adjusting the acidity and texture of food

Citric acid can impart a refreshing sour taste to beverages, candies, jams, and other foods, balancing sweetness and enhancing the flavor profile. For example, adding citric acid to carbonated drinks and fruit juices can neutralize the sweetness and make the taste more refreshing.

• Improve food stability

By regulating the pH value of food, the growth and reproduction of microorganisms can be inhibited, thus helping to extend the shelf life of food. At the same time, it can also prevent the loss of nutrients in food. For example, adding acidity regulators to canned foods can prevent the ingredients from spoiling due to unsuitable pH values.

• Improve the processing characteristics of food

In flour products, acidity regulators can adjust the gluten content of the dough, improving the texture of the products; in meat products, they can promote tenderization and enhance the eating experience. Furthermore, some natural acidity regulators, such as citric acid, can also act as chelating agents in food, binding metal ions to prevent oxidation and discoloration.

• Promote nutrient absorption

Acidity regulators can also promote the digestion and absorption of calcium and phosphorus in food.

（3）Core application areas of acidity regulators

• Beverage industry (most widespread application)

Citric acid, malic acid, and phosphoric acid are commonly used in soft drinks, fruit juices, and tea beverages to adjust sourness, harmonize taste (e.g., to make refreshing drinks more thirst-quenching), inhibit microbial growth, and prevent browning.

• Food seasoning and preservation

It increases the acidity of food, improving its flavor. As a preservative, it limits bacterial growth by lowering the pH value of food. It is commonly used in jams, gummies, and pastry fillings.

• Meat Products and Processing

Adjusting the pH of cheese and meat products increases emulsifying ability, improves stability, and enhances texture and color.

• Frozen Foods and Canned Goods

Used to prevent frozen foods from spoiling and to stabilize the color and flavor of canned products.

• Fermented foods

Adjusting the fermentation environment enhances the sensory characteristics of the food.

3. Preservatives: Inhibit microbial growth and protect food freshness

（1）Definition and mechanism of action of preservatives

Food preservatives are additives that prevent spoilage caused by microorganisms and extend the shelf life of food; they are also known as antimicrobial agents. Their main function is to inhibit the reproduction of microorganisms in food.

The mechanisms of action of preservatives include: coagulating or denaturing microbial proteins; disrupting microbial cell walls or cell membranes; acting on genetic material, interfering with replication and transcription; and inhibiting the activity of enzymes within microorganisms.

Preservatives are broadly classified into two categories: natural preservatives and chemically synthesized preservatives. Natural preservatives include natamycin, nisin, ε-polylysine, and plant extracts, while chemically synthesized preservatives include potassium sorbate, sodium benzoate, and sodium dehydroacetate. Currently, China regulates the use of 30 preservatives, including benzoic acid, sodium benzoate, sorbic acid, potassium sorbate, and calcium propionate. Other countries' national standards have strict regulations on the dosage and scope of application of preservatives to ensure their safety.

（2）The core role of preservatives

Inhibits the growth and reproduction of microorganisms such as bacteria, mold, and yeast in food: prevents food from spoiling and deteriorating, thereby extending the shelf life of food and reducing food waste.

（3）Different preservatives are suitable for different scenarios.

• Organic chemical preservatives

These mainly include benzoic acid and its salts, sorbic acid and its salts, and esters of p-hydroxybenzoic acid. They all require an acidic environment to exert their antibacterial effect through undissociated molecules, hence the name acidic preservatives.

• Benzoic acid and its sodium salt

Effective against a wide range of microorganisms in low pH environments, with the optimal pH for inhibition being 2.5-4. Commonly used in carbonated beverages, low-salt pickles, preserved fruits, soy sauce, and vinegar.

• Sorbic acid and its salts

Broad-spectrum food preservatives with relatively high safety. Suitable for preserving fish, meat, eggs, poultry products, fruits and vegetables, pastries, bread, etc.

• Propionic acid and its salts

Effective against molds and aerobic bacteria, especially against Bacillus subtilis that causes bread to develop a filamentous, slimy texture, and can prevent the production of aflatoxin, therefore it is commonly used in bread and pastry making.

• Inorganic chemical preservatives

These mainly include sulfur dioxide, sulfites, and nitrites. Nitrites can inhibit Clostridium botulinum and prevent botulism, but are primarily used as colorants.

• Natural Preservatives

In recent years, natural preservatives developed and researched include nisin, natamycin, lysozyme, chitosan, and tea polyphenols. These preservatives possess advantages such as strong antibacterial properties, safety and non-toxicity, and certain nutritional value.

It is important to note that preservatives are not "the more the better." Excessive use can actually negatively impact food quality. Food companies must strictly adhere to the dosages specified in national standards.

（4）Core Application Areas of Preservatives

• Food Industry

Used to prevent food spoilage and maintain taste and appearance. Commonly used preservatives include sodium benzoate (soy sauce, vinegar), potassium sorbate (beverages, pastries), nisin, and nitrites (meat products).

• Cosmetics Industry

Prevents discoloration, separation, odor, and infection risks caused by microbial growth, ensuring product safety after multiple uses.

• Pharmaceutical Industry

Ensuring the sterility of multi-dose containerized drugs (such as eye drops) during long-term storage and use.

• Other fields

Green preservatives are used in funeral, animal husbandry and bio-industry.

The future development trend of preservatives is from chemical synthesis to natural preservatives, from single-purpose preservatives to broad-spectrum preservatives, and from harsh usage environments to convenient use.

4. Sweeteners: a substitute for sucrose, balancing sweetness and health needs

（1）What are food sweeteners?

Sweeteners are substances that impart a sweet taste to food and belong to the category of food additives. Compared with added sugars such as sucrose and fructose, sweeteners have the characteristics of high sweetness, low energy, and good stability. Only a very small amount is needed to obtain a suitable sweetness.

（2）What are the types of food sweeteners?

Currently, commonly used sweeteners can be mainly divided into three types:

• Sugar alcohols are nutritional sweeteners.

Sugar derivatives, similar in structure and sweetness to sugars, but with lower energy content, do not cause a significant glycemic response, and can significantly reduce the risk of tooth decay.

A: Xylitol: With a sweetness of 65%–100% that of sucrose, it has a refreshing sweet taste and can be absorbed by the body through cell walls without the need for insulin. It has functions such as lowering blood lipids and inhibiting ketone bodies.

B: Maltitol: With a sweetness 0.8–0.9 times that of sucrose, it does not produce calories after ingestion, does not synthesize fat or stimulate cholesterol formation, and is chemically stable.

• Natural Non-Nutritional Sweeteners

Extracted from natural plants, these sweeteners are high in sweetness and low in calories.

A: Stevia glycosides: Extracted from stevia, they are about 300 times sweeter than sucrose, but have only 1/300 the calories. They are also very stable to heat, acids, and alkalis.

B: Monk fruit glycosides: Extracted from monk fruit, they are about 240 times sweeter than sucrose, but only 1/50th the calories of sucrose, and have a fragrant and delicious taste.

• Artificial Non-Nutritional Sweeteners

Chemically synthesized sweeteners with extremely high sweetness.

A: Aspartame: Synthesized from aspartic acid and phenylalanine, it is 100-200 times sweeter than sucrose. It can be used in carbonated beverages, bread, pastries, chewing gum, etc. It is not suitable for people with phenylketonuria.

B: Sucralose: The only sweetener synthesized from sucrose, it is 600 times sweeter than sucrose, has good heat stability, and a pure sweet taste. It is currently the closest artificial sweetener to sucrose.

C: Acesulfame K (AK sugar): A calorie-free sweetener, approximately 200 times sweeter than sucrose, widely used in candies, beverages, baked goods, etc.

D: Cyclamate: Approximately 30 times sweeter than sucrose, with a good flavor, it can mask the bitterness of other sweeteners.

（3）The Core Role of Sweeteners

The key role of sweeteners is to impart sweetness to food while simultaneously meeting the health needs of different consumers.

A: They replace sucrose to reduce the calories in food, making them suitable for special groups such as obese individuals and diabetics. For example, adding steviol glycosides and sucralose to sugar-free beverages and sugar-free biscuits ensures sweetness while reducing calorie intake.

B: Some sweeteners are more stable and less prone to decomposition during high-temperature processing, meeting the processing requirements of baked and fried foods. For example, maltitol, used in pastry baking, does not lose its sweetness at high temperatures and can even improve the moisture retention of pastries. Furthermore, sweeteners can reduce food production costs. High-sweetness non-nutritive sweeteners only require a small amount to achieve the desired sweetness, effectively reducing the amount of sucrose used.

（4）Scientific Use of Sweeteners

In food processing, non-nutritive sweeteners are often combined with sugar alcohols to complement each other's advantages, harmonize taste, and enhance flavor.

It should be noted that different people have significantly different tolerances to sugar alcohols, and consuming large amounts in a short period of time may cause diarrhea. It is recommended to consume them in moderation according to your own situation.风味。

5. Amino Acids: Improving Food Flavor and Supplementing Essential Nutrients

（1）What are amino acids?

As the building blocks of proteins, amino acids are essential nutrients for the human body. Some amino acids, such as lysine, threonine, and tryptophan, cannot be synthesized by the human body and must be obtained from food; these are called essential amino acids. Fortifying food with these amino acids is of great significance for improving the nutritional status of specific populations.

（2）Functions of Amino Acid Food Additives

• Improving Food Flavor

Monosodium glutamate (MSG) enhances the umami flavor of food and is an indispensable ingredient in seasonings. It is widely used in dishes, soups, meat products, and condiments to enhance the umami flavor profile. Glycine and alanine have sweet and umami flavors and can harmonize the taste of food and mask off-flavors. For example, adding them to meat and seafood products can reduce fishy smells and enhance flavor.

• Supplementing Essential Nutrients

Lysine is an essential amino acid that the human body cannot synthesize and must obtain from food. Adding lysine to grains and pastries can enhance the nutritional value of the food and meet the body's nutritional needs. In addition, some amino acids can improve the processing characteristics of food. For example, adding amino acids to flour products can enhance the elasticity and extensibility of the dough, improving the taste of the flour products.

6. Vitamins: Fortifying Food Nutrition and Filling Dietary Nutritional Gaps

（1）Why Supplement Vitamins?

Vitamins are essential nutrients for maintaining normal physiological functions in the human body. They are also a core category of food fortifiers, used to supplement vitamin deficiency symptoms.

Vitamins are divided into two main categories: fat-soluble and water-soluble. Fat-soluble vitamins include vitamins A, D, E, and K; water-soluble vitamins include B vitamins (VB1, VB2, niacin, VB6, VB12, folic acid, pantothenic acid, biotin, choline, etc.) and vitamin C.

（2）The Core Role of Vitamins

• Enhancing the Nutritional Value of Food

Addressing nutritional gaps in daily diets and preventing vitamin deficiencies. For example, adding vitamin D to milk promotes calcium absorption, making it suitable for children and the elderly; adding B vitamins to grains and bread supplements the body's need for water-soluble vitamins, enhancing the nutritional value of staple foods; adding vitamin C to fruit juices and canned goods prevents oxidation and discoloration while also providing the body with necessary vitamin C.

• Antioxidant Properties

Some vitamins also possess antioxidant properties. For example, vitamin E and vitamin C can inhibit the oxidation of fats in food, extending shelf life and protecting other nutrients from degradation.

Vitamins can be used as food additives, but must meet national standards. For substances that are both food additives and nutritional fortifiers, such as vitamin B2, vitamin C, and vitamin E, the relevant standards must be followed depending on their intended use.

7. Nutritional Supplements: Enriching the Nutritional Dimensions of Food and Meeting Personalized Nutritional Needs

（1）What are Nutritional Supplements?

Nutritional supplements,also known as food fortifiers, are food additives that, in addition to vitamins and amino acids, supplement food with minerals, dietary fiber, probiotics, and other nutrients. Common examples include minerals such as calcium, iron, zinc, and selenium; dietary fibers such as inulin and dietary fiber; and probiotics such as bifidobacteria and lactic acid bacteria. These additives can provide targeted nutritional fortification to food according to the nutritional needs of different population groups.

（2）The Core Role of Nutritional Supplements

Enriching the nutritional dimensions of food to meet the personalized nutritional needs of different groups:

• Minerals

Calcium added to milk, yogurt, and soy products increases the calcium content of these foods, supporting bone development. Iron and zinc added to infant formula and cereals can prevent iron and zinc deficiencies in children and promote growth and development.

• Dietary Fiber

Supplements such as inulin and konjac flour added to pastries, beverages, and dairy products increase the dietary fiber content of these foods, promoting intestinal motility and improving gut health.

• Probiotics

Added to yogurt and lactic acid bacteria beverages, they can regulate the balance of gut microbiota and enhance intestinal digestion and absorption.

Regarding the use of nutritional supplements, Polifar recommends transforming ordinary foods into "functional foods" to better meet the nutritional needs of special populations such as children, the elderly, and pregnant women.

（3）Requirements for the Use of Nutritional Fortifiers

The use of nutritional fortifiers should adhere to strict regulations:

It should not lead to excessive or unbalanced nutrient intake;

It should not cause any abnormal metabolism of nutrients;

It should maintain stable quality under storage, transportation, and consumption conditions;

It should not cause significant adverse changes in the color, taste, or odor of the food;

It should not exaggerate the content or function of a particular nutrient.

（4）Scientific Selection of Vitamin Foods

When purchasing vitamin foods, consumers should pay attention to:

Understanding vitamin health foods scientifically; health foods are not drugs and cannot replace medication for treating diseases;

Choosing based on individual nutritional needs, such as the elderly needing additional vitamin D supplementation, and women preparing for pregnancy needing folic acid supplementation;

Adhering to the principles of appropriate amount, timing, and moderation; more vitamins are not necessarily better, and exceeding the tolerable upper intake level may pose health risks.

Conclusion

Food additives are a product of the food industry's development. Acidity regulators, preservatives, sweeteners, amino acids, vitamins, nutritional supplements, and various other food additives each play a specific role in food production, comprehensively improving food quality and usability by enhancing flavor, extending shelf life, and fortifying nutrition. We don't need to be overly alarmed by food additives; what we truly need to be wary of is the excessive or unauthorized use of them.

Consumers should view food additives rationally, checking ingredient lists and nutrition facts labels when purchasing food, and choosing products from reputable manufacturers. Food companies must strictly adhere to national standards, using food additives rationally and in a standardized manner to ensure food safety and quality. In the future, with the continuous development of the food industry, natural, healthy, and functional food additives will become a trend, and Polifar will bring consumers more high-quality and diverse food choices.