Performance characteristics and applications of commonly used food additives

Food additives are an important factor in the modern food industry. They play an extremely important role in improving the color, aroma, and taste of food, increasing food nutrition, improving food quality, improving processing conditions, preventing food deterioration, and extending the shelf life of food. Therefore, the food additive industry occupies an important position in the modern food industry.

01 Definition and function of Food Additives

1. Definition of food additives

Food additives refer to synthetic or natural substances added to food for the purpose of improving the quality and color, aroma and taste of food, as well as for the needs of anti-corrosion and processing technology.

2. The role and development trend of food additives

1) The main role of food additives
a) It can improve the quality of food, improve the quality of food, and meet people's requirements for food flavor, color and taste;
b) It can make the food processing and manufacturing technology more reasonable, more hygienic and more convenient, which is conducive to the mechanization, automation and scale of the food industry;
c) It can enable the food industry to save resources and reduce costs. While greatly improving the quality and grade of food, it also increases its added value, resulting in obvious economic and social benefits.

2) Development trend of food additives
a) Develop natural, nutritious and multifunctional food additives;
b) Committed to the development of diversified and dedicated additives.

02 Types of food additives

Food additives can be divided into natural food additives and synthetic food additives according to their sources. Classified by function, they mainly include: nutrition enhancer, antiseptic and antifungal agent, anti-oxidation preservative, thickener, emulsifier, chelating agent (including stabilizer and coagulant), quality improver, flavoring agent, color treatment agent , Food flavors, spices, etc.

1. Food preservatives

Food preservatives are a class of additives used to inhibit food spoilage and deterioration, and extend the storage period and preservation period. Currently commonly used food preservatives mainly include four categories: benzoic acid and its salts, sorbic acid and its salts, propionic acid and its salts, and parabens.

1) Benzoic acid and its sodium salt
Benzoic acid, also known as benzoic acid, is a commonly used organic fungicide. In a low pH environment, benzoic acid is effective against a wide range of microorganisms, but has a weak effect on acid producing bacteria. When the pH is higher than 5.5, it has no effect on many molds and yeasts. The optimum pH value for benzoic acid for bacteriostasis is 2.5-4, and the minimum mass fraction for complete inhibition of general microorganisms is 0.05% to 0.1%.

2) Sorbic acid and its salts
The chemical name of sorbic acid is 2,4-hexadienoic acid, which is a broad-spectrum food preservative.

3) Propionic acid and its salts
Propionic acid is a liquid with a stimulating acid fragrance similar to acetic acid. Because it is a normal intermediate of human metabolism, it is non-toxic and its ADI value is not limited. Propionic acid is effective against molds, aerobic bacteria, and gram-negative bacteria, especially E. coli, which makes bread produce filamentous mucus, and can prevent the production of aflatoxins, so it is often used in the production of bread and pastries. Propionate has the same antiseptic effect, and calcium and sodium salts are commonly used.

4) p-Hydroxybenzoic acid and its esters
Parabens, also known as parabens, are colorless crystals or white crystalline powder, tasteless and odorless. Mainly used in soy sauce, jam, refreshing drinks, etc. The antiseptic effect is better than that of benzoic acid and its sodium salt, the usage amount is about 1/10 of sodium benzoate, and the suitable pH value is 4-8. The toxicity of paraben is lower than that of benzoic acid, and its Water solubility is poor. Commonly used alcohols are dissolved before use, and the price is higher.

5) Natural food preservatives
Natural preservatives have the advantages of strong antibacterial properties, safety and non-toxicity, good water solubility, good thermal stability, and wide range of action. Not only are they harmless to human health, but they also have certain nutritional value. The natural preservatives researched and developed in recent years include: natamycin, glucose oxidase, protamine, lysozyme, polylysine, chitosan, pectin decomposition products, propolis, tea polyphenols, etc.

2. Food emulsifier and thickener

Food emulsifiers and thickeners are additives that improve and stabilize the physical properties of food components or improve the state of food tissue, and play an important role in the "shape" and "quality" of food and the performance of food processing technology.

1) Emulsifier
Any food additive that can make incompatible liquids (such as oil and water) form a stable emulsion when added in a small amount is called an emulsifier.

①Fatty acid glycerides
The reaction of glycerol and fatty acids can produce mono-, di- and tri-esters. Mono-fatty acid glycerides, abbreviated as monoglycerides, is an important food emulsifier, widely used in shortening, cakes, bread, candy, ice cream, emulsification, foaming, anti-crystallization and anti-aging effects.

②Sucrose fatty acid ester
Sucrose fatty acid ester is an emulsifier with excellent performance, high efficiency and safety. Sucrose fatty acid esters use sucrose as a hydrophilic group and long carbon chain fatty acids as a lipophilic group, which can be digested into sucrose and fatty acids in the body and absorbed. Sucrose fatty acid esters are non-toxic, non-irritating, and easily biodegradable, so there is no restriction on their use in food.

③Sorbitan fatty acid ester
The trade name of sorbitan fatty acid ester is span. Span-type emulsifiers undergo an addition reaction with ethylene oxide under alkali catalysis to obtain Tween-type emulsifiers.

④Soy lecithin
Soy lecithin, also known as soybean lecithin or phospholipid, is a light yellow or brown transparent, translucent viscous substance. It is a by-product of soybean oil production and a natural surfactant. Its main components are lecithin, cephalin and inositol phospholipids. As an emulsifier, soybean lecithin has excellent emulsification, anti-oxidation, dispersibility and moisturizing properties, and has been widely used in food, instant milk, margarine, granular beverages, and nutritional emulsifiers.

2) Thickener
Thickeners are a kind of food additives that can increase food viscosity and change performance.

① Gelatin
Gelatin is white or light yellow, translucent, slightly shiny flakes or fine particles. Its main component is protein. It is a polymer peptide obtained by partial hydrolysis of collagen contained in animal skin, bone, cartilage, etc. polymer. Gelatin gel is tough, flexible, and has good pressure-bearing properties. It dissolves in water at 30°C and condenses into a colloid after cooling.

②Maltdextrin
Maltodextrin, also known as water-soluble dextrin or enzymatic dextrin, is made from various starches as raw materials, and is produced by low-level control hydrolysis conversion, purification and drying by enzymatic technology. Maltodextrin is widely used in candy, malted milk extract, fruit tea, milk powder, ice cream, beverages, canned food and other foods. It is a filler and thickener for various foods.

③Pectin
Pectin is a polysaccharide substance widely found in plant tissues. Its main component is galacturonic acid. It is recommended by the FAO/WHO Food Additives Joint Committee and is a recognized safe food additive that is not restricted by the amount of addition. At present, the main raw material for the production of pectin is citrus peel.

④Carrageenan
Carrageenan is a natural vegetable gum extracted from red algae. It is the youngest of the three seaweeds: algin, agar, and carrageenan. Its main components are D-galactose and L-galactose. Carrageenan is extracted from raw materials such as Eucheuma, Salsa and Carrageenan. The carrageenan used in the food industry mainly has the characteristics of gelling, viscosity, stability, emulsification and suspension, and is widely used in dairy products, ice cream, fruit drinks, bread, hydrogels (such as gels, etc.), Meat products, canned food and other foods.

⑤Xanthan Gum
Xanthan gum is a safe, non-toxic and tasteless new food additive with excellent thickening, suspending, emulsifying and stabilizing functions. Xanthan gum is produced by Xanthomonas with starch as the main raw material through a series of biochemical reactions. Its main components are glucose, mannose, glucuronic acid, etc. The molecular weight is as high as millions. At present, the product with the most commercial value, the largest output and the widest market coverage among domestic and foreign microbial polysaccharide products. Xanthan gum has excellent thickening properties, and the required viscosity can be achieved at a very low concentration. Xanthan gum can form a stable thickening system when coexisting with high concentration of sugar or multiple salts.

3. Flavoring agent

Flavoring agents mainly include sour agents, sweeteners, salty agents and bitter agents. Among them, bitter agents are rarely used, and salty agents (commonly used salt) are not managed as food additives in my country. The following mainly introduces sour and sweeteners.

1) Sour agent
Food additives whose main purpose is to impart acidity to food are called sour agents. Sour taste can promote the secretion of saliva, gastric juice, bile and other digestive juices, has the effect of promoting appetite and assisting digestion. Its main role is to adjust the pH value of food, as an antioxidant synergist, prevent food rancidity or browning, and inhibit microorganisms Growth and prevention of food corruption, etc. Sour agents mainly include organic acids: citric acid, lactic acid, tartaric acid, malic acid, fumaric acid and adipic acid; inorganic acids: edible phosphoric acid, carbonic acid, etc.

①Citrate
Citric acid is a colorless transparent crystal or white powder with a mild and refreshing sour taste. It is commonly used in the manufacture of various beverages, sodas, wines, candies, snacks, biscuits, canned juices, dairy products and other foods.

② Malic acid
The chemical name of malic acid is carboxysuccinic acid or hydroxysuccinic acid. It is a white or fluorescent white solid. It has a special malic acid scent, which is widely used in yogurt, soda, ice cream, chewing gum, tomato sauce, jam, vinegar, fruit wine, margarine, etc. The effect of malic acid is better than that of citric acid. It has a strong acidity, tastes close to natural juice, and has a good pH adjustment effect. Using it instead of citric acid as a sour agent can save 20% of the amount and can mask the peculiar smell produced by some sucrose substitutes.

2) Sweetener
Sweeteners are food additives whose main purpose is to impart sweetness to food. According to its source, it can be divided into natural sweeteners and synthetic sweeteners. Natural sweeteners are further divided into sugar and sugar derivatives and non-sugar natural sweeteners. Synthetic sweeteners are mainly chemical substances with sweet taste. The sweetness is generally tens to hundreds of times higher than that of sucrose, and most of them have no nutritional value.

①Saccharin and sodium saccharin
The chemical name of saccharin is saccharin, it has no calories and high sweetness. Sodium saccharin has a sweetness of 300-500 times that of sucrose. It is a chemically synthesized sweetener developed early. It has been used in food since the beginning of the 20th century. my country has a history of more than 60 years of production and use, with a production capacity of 40,000 t/year, and is a major exporter in the world.

②Xylitol
Xylitol is a sugar alcohol made by reducing xylose or polyxylose in wood, corn cobs and other materials. Xylitol is a white crystal or crystalline powder with a refreshing and sweet taste. The sweetness is 65% to 100% of sugar. The calorific value is 12.5kJ/g, which is higher than other sugar alcohols. It can inhibit the formation of dental caries Proteus activity The effect of. In addition to the common properties of sucrose and glucose, xylitol also has special biochemical properties. It can be absorbed by the human body through the cell wall without insulin, and has the functions of reducing blood lipids and anti-ketone bodies. It can be used to make beverages and candy , Canned food and other foods.

③Stevioside
Steviol glycosides are colorless or light yellow needle-like crystals with a melting point of 196°C to 198°C. They are a mixture of various glycosides extracted from plant stevia. It is relatively safe and has a sweetness of about 300 times that of sugar. Its taste is similar to that of sucrose, with pure sweetness, long-lasting time, delicious aftertaste, stable to heat, acid and alkali, and is an ideal low-energy sweetener.

④Maltitol
The sweetness of maltitol is 0.8 to 0.9 times that of sucrose. After ingestion, it does not produce calories, synthesize fat and stimulate the formation of cholesterol. The pure maltitol has very stable chemical properties. It has better heat resistance and acid resistance than sucrose, sorbitol and xylitol. Maltitol can resist the digestion of gastric juice, the hydrolysis of small intestinal enzymes and the large intestine during human digestion. Decomposition of microorganisms. This special physiological property makes maltitol a high-end health-care sweetener with excellent taste and no calories.

⑤Aspartame
The chemical name is aspartame and the relative molecular mass is 294.31. Aspartame is a new type of amino acid sweetener, with the appearance of white crystals or crystalline powder, pH: 4.5-6.0. Aspartame has a pure sweetness like granulated sugar, 200 times the sweetness of sucrose, no peculiar smell, and has a synergistic effect on food flavor. It has good safety performance. It does not need insulin to be metabolized in the body. It can be digested and absorbed quickly without causing dental caries.

⑥Acesulfame
The chemical name is acesulfame potassium and the molecular weight is 201.24. Acesulfame K is a white crystalline powder with high sweetness, and its sweetness is about 200 times that of sucrose (3% mass fraction solution).

⑦Other sweeteners
There are mainly oligofructose, erythritol, cyclamate, thaumatin and so on.

4. Food coloring

The additives used in food coloring are called food colorings, and their purpose is to increase the taste for food and stimulate appetite. Food colorings are divided into synthetic colorings and natural colorings according to their sources.

1) Artificially synthesized pigment
Synthetic pigments include amaranth, carmine, erythrosine, new red, lemon yellow, sunset yellow, indigo yellow, brilliant blue, and aluminum lakes for enhancing the dispersibility of the above-mentioned water-soluble acid pigments in oils. 

①Carmine
Carmine is a red to deep red powder. It is characterized by good acid resistance and light resistance, but poor heat resistance and reduction resistance. It turns brown when exposed to alkali. It is mostly used in the processing of cakes, beverages, agricultural, livestock and aquatic products.

②Lemon yellow
Lemon yellow is an orange-yellow powder that is allowed to be widely used in various countries. It is mainly used in cakes, beverages, processing of agricultural, livestock and aquatic products, medicines and cosmetics. It is characterized by good heat resistance, acid resistance, light resistance and salt resistance, and poor oxidation resistance. It turns red when exposed to alkali and fades when reduced.

2) Natural pigments
Natural pigments are obtained by solvent extraction from animal and plant tissues. Although natural pigments are slightly inferior in color and have relatively poor stability to light, heat, pH, etc., they are safer than synthetic pigments and have abundant sources. Some natural pigments also have vitamin activity or certain pharmacological functions, and are increasingly People are paying attention, and production and sales are growing rapidly. The main products of natural edible pigments in my country are: caramel, red yeast rice and red yeast rice noodles, red yeast red, chili oleoresin and chili red, mast yellow, mast blue, beet red, shellac red and so on.

03 General requirements and safe use of food additives

With the development of food toxicology, food additives previously considered harmless have been found to have chronic toxicity, teratogenic, mutagenic, and carcinogenic hazards in recent years. Therefore, all countries have paid full attention to this.

At present, both the international and domestic treatment of food additives have adopted strict management, strengthened evaluation and restricted use attitudes. In order to ensure the safety of food additives, food additives should follow the following principles:

① Safety evaluation. The primary criterion for evaluating the toxicity (or safety) of food additives is the ADI value (human body intake per day), and the second commonly used index for evaluating the safety of food additives is the LD50 value (half lethal dose, also known as lethal medium dose) .

② Use regulations. GB2760—2014 National Food Safety Standard and Food Additives Use Standards stipulate the principles of use of food additives, the types of food additives that are allowed to be used, the scope of use, and the maximum use or residual amount.