Flavors are widely used in the food industry

Food flavors are substances that can be used to blend food flavors and make food more fragrant. It can not only enhance appetite, favorable digestion and absorption, but also to increase the variety of food colors and improve the quality of food has a very important role.

First, the key point of the role of flavor
Fragrance can play a good role in scented products is the key to volatility control, how to do the head fragrance, body fragrance and the bottom of the balance between the fragrance and coordination.
The first fragrance – volatility is large, is an important factor in determining the “image” and “freshness” of the flavor.
Body fragrance – gives the flavor characteristic aroma, volatility is moderate, is also the main flavor of the flavor.
Base fragrance – volatility is small, accordingly, the molecular structure is relatively large and complex, so that the flavor retains the fragrance for a long time.

Figure source: Creative post
Second, the application of flavor in the food industry
(1) oil flavor is suitable for hard candy, cookies and other baked goods, meat products, instant noodle food, etc., the general dosage of about 0.2%. But the oil flavor with propylene glycol as solvent can also be used in soft drinks, beverages, etc., the general dosage of 0.05-0.1%.

(2) water flavor for soft drinks, beverages, ice cream, other cold drinks, wine, etc., the general dosage of 0.07-0.15%.

(3) Emulsifying flavor for soft drinks, beverages, etc., the general dosage of about 0.1%; turbidity agent dosage of 0.08-0.12%.

(4) slurry flavor is suitable for soft drinks, beverage preparation base with, can also be used directly for soft drinks, beverages, the general dosage of 0.2-0.23% (full-color), 0.05% (non-full-color, another complementary caramel color 0.15-0.18%).

(5) Coconut powder is suitable for cookies, other meat, vegetable and poultry diced powder is suitable for cookies, other diced meat, vegetable and poultry diced powder is suitable for puffed food, convenience food and soup, the general dosage is 0.3-1%.

(6) The dosage of flavor for wine is generally 0.04-0.1%, and the dosage of flavor for tea is about 1%. The dosage of powder flavor for feed is generally 0.5‰, and feed flavor (for additives) (5%-10%).

(7) Powder flavor for instant noodles, puffed small food, meat products, spicy small food, frozen products, etc., the general dosage of 0.1-0.5%.

(8) Paste flavor is suitable for instant noodles, puffed small food, meat products, spicy small food, frozen products, etc. The general dosage is 0.1-0.5%.

The basic introduction of flavors

Flavor, can be divided into two categories: sweet flavor and savory flavor.
Flavor composition: flavor by at least several kinds of raw materials, and even dozens of natural and synthetic spices, or a complex of organic compounds.

Flavor blending can be composed of the following:

• Fragrance base – showing the main body of the fragrance characteristics;
• Synergist – a component that aims to harmonize the aroma of various ingredients;
• Modifiers – components that make the flavor change its tone;
• Fixed fragrance – itself is not volatile, and can inhibit the volatility of other volatile fragrances, so that the volatility of the slowed down;
• Diluent – appropriate to lighten the flavor and the crystalline spices and resinous balsam for dissolution and dilution. It should be odorless, stable, safe and low price.

The first fragrance – volatility, is to determine the flavor “image” and “freshness” of the important factors.
Body fragrance – gives the flavor characteristic aroma, volatility is moderate, is also the main flavor of the flavor.
Base fragrance – volatility is small, accordingly, the molecular structure is relatively large and complex, so that the flavor retains the fragrance for a long time.

A certain type of aroma of the flavor is called fragrance.
The general classification is as follows:
(1) sweet flavor
(1) floral: young people love to stay young, a single floral and composite floral;
② fruity: middle-aged people like light and unique, giving people the effect of honesty and credibility;
③ wood flavor: cool, elegant, quiet and steady;
(iv) Grass flavor: light, fresh aroma with green mood.

(2) savory flavor
① meat flavor flavors: such as pork, chicken, beef and other flavors, can also be divided into barbecue, stewed, braised and other flavors.
② seafood flavor: such as shrimp, crab, sea fish and other flavors. ③ Plant-based flavors: such as cumin, vanilla, cardamom, thyme and other flavors.

Microencapsulated flavors are made of spices and wrapping agents (such as modified starch, etc.) through emulsification and spray drying, with the characteristics of preventing oxidation and volatilization loss, mainly used for solid beverages, seasonings and other flavoring.

Water-soluble flavors are made of distilled water or ethanol as diluent and blended with edible spices, mainly used for soft drinks and other flavoring.

Oil-soluble flavors are made of propylene glycol and other edible flavors, mainly used for candy, cookies and other flavoring.

Emulsified flavor is composed of edible spices, edible oil, specific gravity regulator, antioxidants, preservatives and other components of the oil phase and by the emulsifier, coloring agent, preservatives, thickeners, acidulants and distilled water and other components of the water phase, emulsification, high-pressure homogeneity made of soft drinks and cold drinks, mainly used for soft drinks and other aroma, flavoring, coloring, or to make it turbid.

Savory reaction flavor, also called thermal processing flavor, generally refers to the thermal processing reaction between amino acids and reducing sugars, resulting in a mixture with a specific flavor. The amino acids may be derived from the breakdown of proteins or from chemically synthesized products. Sugars are generally monosaccharides and may be derived from natural products or chemically synthesized products.

Image source: creator post

The three values of flavorings and fragrances – Aroma Ratio Strength (ARS), Aroma Quality (AQ), and Aroma Retention (AH).
①Aroma ratio value (expressed as “b”) is a way to express the aroma intensity of a spice or flavor in numerical terms.

Phenylethanol’s aroma intensity is set at 10, a variety of other spices and flavors are compared to him, according to their respective aroma intensity to give a certain value. Such as geraniol aroma intensity is 15 times that of phenylethanol, then it is stronger than the value of the aroma is 150.

② aroma value (“p” said) aroma value is a flavor or spice “taste” of high and low, is a relative concept, by the familiar aroma as a “reference”, by the professional Scoring by professional perfumers, so there is a great deal of subjectivity.

(iii) The value of fragrance retention (expressed as “l”) is an important technical indicator of flavor or spice. Aroma in less than a day on the smell of the spice coefficient is set at “1”, more than 100 days can smell the coefficient of the aroma of the coefficient is set at “100”, this coefficient is known as the “retention value”. This coefficient is called the “retention value”.

Classification of fragrances:
Natural flavors are substances obtained by purely physical means from natural aromatic plants or animal materials. They are generally considered to be safe. They include essential oils, tinctures, infusions, pure oils and spice oleoresins.

Natural equivalents are substances obtained by synthetic methods or separated from natural aromatic raw materials by chemical processes. These substances are chemically identical to those present in natural products (processed or not) intended for human consumption. There are many varieties of these flavors, which make up the majority of food flavors and are very important in the formulation of food flavors.

Artificial flavors are flavor substances that have not yet been found in natural products for human consumption, whether processed or not. There are fewer varieties of these flavors, they are chemically synthesized, and their chemical structures have not been found to exist in nature to date. For this reason, the safety of these flavors is of great concern.

Synthetic spices are usually classified according to the functional groups of organic compounds, mainly hydrocarbons, alcohols, ethers, acids, esters, lactones, aldehydes, ketones, acetal (ketones), nitrile, phenols, heterocyclic and a variety of other sulfur-containing nitrogen compounds. The molecular weight of various synthetic fragrances generally does not exceed 300, volatility and the persistence of its aroma.

Natural flavors: mainly plant and animal two kinds.

Vegetable natural flavors: the most common, such as orange oil, from the peel of sweet oranges, with steam distillation, pressing method or rolling with orange mill extraction. Lemon oil, from lemon peel by pressing or distillation.

A Terpene Series
Terpenes or terpene alcohols are the most abundant terpene series compounds in plant-based essential oils, and such compounds are insoluble in water. They are subdivided into five groups according to the number of isoprenoids comprising C5, the basic substance in biosynthesis: terpenes containing C10 are monoterpenes; terpenes containing C15 are sesquiterpenes; terpenes containing C20 are diterpenes; terpenes containing C30 are triterpenes; and terpenes with more than 20 C5 units are polyterpenes.

B Phenolics
Phenolics have a variety of biological functions, the most important of which is defense against herbivores, insects, and microorganisms. The phenolic analogs of fisetinone are strong insecticides, while the isomeric flavonoids have anti-estrogenic effects and cause infertility in domestic animals. Flavonoids are found in many flowers and green plant leaves and function to protect the plant by absorbing excess ultraviolet light and allowing only visible light to pass through. When UV light is increased, the synthesis of flavonoids and flavonols in the plant increases. In addition, phytoantitoxins in the plant also have an inhibitory effect on the invasion of pathogens and an antibacterial effect.

C Alkaloid Series
Alkaloids are nitrogenous organic compounds found in many plants, their growth regulating effects in plants are not well known, but humans show toxicity when they ingest large quantities of alkaloids. For example, strychnine, atropine and toxaphene are toxic, but have medical effects when taken in small amounts. Morphine, codeine, atropine, and ephedrine are medicinal plant alkaloids, and cocaine, caffeine, and nicotine are used as over-the-counter stimulants or tranquilizers.

Botanical Flavor Manufacturing:
Plant-based natural flavors are produced from the flowers, branches, leaves, grasses, roots, skins, stems, seeds or fruits of aromatic plants as raw materials, using methods such as steam distillation, maceration, pressing, absorption, etc., to produce essential oils, extracts, tinctures, balsams, balsam resins and net oils, such as rose oil, jasmine extract, tincture of vanilla, balsam resin, daffodil net oils, and so on. Plant-based natural flavors are the most widely used, there are many types, the main form of goods are essential oils, net oils, extracts, tinctures and so on. These are flowers, leaves, branches, skin, roots, stems, fruits, seeds and other raw materials produced by a variety of components of the mixture.

Animal Natural Flavors:
The most commonly used commercialized varieties of animal-based natural fragrances are musk, spirit cat incense, beaver incense, ambergris and musk rat incense 5, they are all very good scent fixing agent, widely used in perfume or high-level cosmetics.

A musk (Musk)
Source: musk is living in southwestern China, northwestern plateau and North India, Nepal, Siberia cold zone of male musk deer secretion of the genital glands. 2 years old male musk deer began to secrete musk, 10 years old for the best secretion period, each musk deer can be secreted about 50g.

Ingredients: black-brown musk powder, most of the animal resins and animal pigments and other components, its main aromatic component is only about 2% of the saturated macrocyclic ketone – musk ketone. 1906 Walbaum from the natural musk will be the macrocyclic ketone single isolated, in 1926 Ruzicka determined its chemical structure for the 3-methyl cyclopentadecanone. -methylcyclopentadecanone. Later, Mookherjee and other natural musk composition for further study, identified its fragrance components and 5-ring pentadecenone, 3-methyl ring thirteen ketone, ring fourteen ketone, 5-ring fourteen ketone, musk pyran, musk pyridine and other more than a dozen kinds of macrocyclic compounds.

B Ling cat incense (Civer)
Source: There are two kinds of civet: big civet and small civet. It lives in the middle and lower reaches of the Yangtze River in China and in India, the Philippines, Myanmar, Malaysia and Ethiopia. Both male and female civets have 2 sac-like secretion glands, which are located between the anus and genitals, and take the sticky substance secreted by the scent sacs, which is known as civet incense.

Ingredients: Ling cat incense in most of the animal mucus, animal resin and pigment. Its main component is only about 3% of the unsaturated macrocyclic ketone – ling cat ketone. 1915 Sack single from the success of the 1926 Ruqi card to determine its chemical structure for the 9-ring heptadecenone, and later, Mookherjee, Wan Dorp and other components of the natural ling cat incense was further analyzed to identify the fragrance of its constituents and dihydrolingcat. Mookherjee, Wan Dorp and others further analyzed the composition of natural lingcats incense, identified its fragrance components are also dihydro lingcats ketone, 6-cycloheptadecenone, cyclohexadecadienone and other eight macrocyclic ketones.

C beaver incense (Castoreum)
Source: Beaver inhabits the banks of small rivers or lakes and marshes. It lives mainly in Siberia, Russia and Canada. Both male and female beavers, in the genitals near the two pear-shaped glandular sacs, containing a white milky viscous liquid, that is, beaver scent.

Composition: most of the beaver incense for animal resin, in addition to containing traces of salicin (C17H18O7), benzoic acid, benzyl alcohol, p-ethyl phenol, its main component is the content of 4% to 5% of the structure is still unknown to the crystalline civet vanillin (Castorin). 1977, a Swiss chemist analyzed and identified in the civet incense civet vanillin was employed, quinoline derivatives, trimethyl pyrazine and tetramethyl pyrazine and other nitrogen-containing incense components. In 1977, a Swiss chemist analyzed and identified a nitrogen-containing aromatic components in civet incense, including quinoline derivatives, trimethylpyrazine and tetramethylpyrazine.

Ambergris
Source: Ambergris is produced in the intestines of sperm whales. The cause of ambergris has been described in different ways, but it is generally believed that it is a kind of stone that is discharged from the whale’s body and floats on the surface of the sea or washes up on the coast when the sperm whale swallows a lot of animal bodies in the sea. The main origin is southern China, India, South America and Africa and other tropical coasts.

Ingredients: In addition to the ambergris has been identified as containing small amounts of benzoic acid, succinic acid, calcium phosphate, calcium carbonate, but also contains organic oxides, ketones, hydroxyl aldehydes and cholesterol and other organic compounds. Ambergris alcohol is said to be the main component of ambergris gas, and its molecular formula is C30H52O.

E Muskrat (Muskrat)
Source: Artificially reared adult male muskrat (Ondatra zibethica) secretion from the scent sac.

Ingredients: musk ketone, descending musk ketone, cyclic seventeen ketone and so on. In recent years, Switzerland, the United States, Germany, Japan and South Korea and other countries on the application of natural flavors research is very active, the main tendency is to study the functionality of natural flavors, such as immunity, nervous system calming, anti-carcinogenic, anti-aging, anti-inflammatory and antibacterial properties. At present, there are a lot of researches on the extraction of natural flavors in China.

Introduction of Flavoring

The basic process of flavor blending:

• Design of flavor formulations;
• Skillful formulation of flavors;
• Inspection of flavor formulations
• Verification between flavors and flavored products.

Requirements for designing formulations
High olfactory quotient, balanced development of left and right brain;
Solid knowledge of chemical chemistry;
Familiarity with production processes and formulation characteristics in various industries;
Fraternity.

I. Design the composition of the formula
① aroma base – show the main body of the fragrance characteristics;
② Hop aroma agent – to harmonize the aroma of various ingredients for the purpose of the composition;
③ modifier – so that the flavor changes the tone of the ingredients;
④ fixed aroma – itself is not volatile, and can inhibit the volatility of other volatile spices to slow down the volatility;
⑤ Diluent – appropriate to lighten the fragrance and the crystalline spices and resinous balsam for dissolution and dilution. It should be odorless, stable, safe and low price.

The composition of the flavor by volatility
Head fragrance – volatility, is to determine the flavor “image” and “freshness” of the important factors.
Body fragrance – gives the flavor characteristics of the aroma, volatility is moderate, but also the main flavor of the flavor type.
Base fragrance – volatility is small, accordingly, the molecular structure is relatively large and complex, so that the fragrance of the essence to stay a long time.

Example:
“Rose flavor”
Head fragrance – bitter almond oil, lemon oil, lemon oil, nutmeg oil, basil oil, rosehip oil; body fragrance – guaiac wood oil, orris net oil, deodorant wood oil, clove oil, incense leaf oil, rose oil, ylang ylang oil, etc.; base fragrance The base fragrance — ling cat incense net oil, patchouli oil, vetiver oil, sandalwood oil and so on.

Second, the perfume is the art of creation
The so-called perfume, is a variety of fragrant, smelly, difficult to say is fragrant or smelly things blended into a pleasant smell, most people like, can be used in a certain range of more valuable mixtures.

Fragrance blending is a conscious act that adds (sometimes dramatically) material value, and is a creative, artistic action that cannot be equated with the work of an artist.

Image source: Creative Post

A high olfactory quotient is essential for perfumery
IQ and EQ are well known, but this is the first time you’ve heard of olfactory quotient. Simply put, IQ determines whether you can be a scientist or not, EQ determines whether you are suitable to be a politician or not, but what about olfactory quotient? It has a lot to do with whether you live a happy and meaningful life.

SQ (smell quotient) is the ability of the nose to smell and recognize aromas.
How is SQ tested? Never received special training on the personnel, the use of A props, let you smell and then scored, scored 0-100 points; on the general management and workers in the factory, the use of B props, scored 100-150 points; on the perfumers and perfume evaluators, the use of C props, scored 150-200 points.

“Props” is a series of (10-20 bottles) scented things: A are natural fragrances, B is synthetic fragrances and flavors, C is a brand-name perfume and a variety of scented products. The main method of assessment looks at the ability to differentiate.

Take a practical example:
Mixing a coffee flavor, the sample of the roasted flavor is relatively heavy, how to do? The main characteristic flavor of coffee flavor is furfuryl alcohol and furfuryl thiopropionate.
The flavor can be blended on the basis of coffee extract or coffee tincture.
Roasted flavor: I personally think it may be pyrazine, pyridine substances added more, consider the queue range, adjust it, there will be no burnt taste.

Third, the flavor formula check
Flavor formulations in the fragrance raw materials must be nationally permitted to use!

Pay attention to the essentials
First of all, we must pay attention to the flavor of the fragrance and aroma quality, which means that both to be able to evoke and to stay long-lasting, before and after the aroma of consistency without the emergence of foreign flavors. So in the selection of single spices should pay attention to the quality of pure, so as to maintain the overall flavor of the head, base and tail of the aroma of the three aroma levels, as far as possible to maintain the stability of the fragrance before and after the dispersal of the tail can not be left with a single odor.

In the mixing of flavors can also add the right amount of natural spices or essential oils, which is conducive to highlighting the temperament of the aroma.
The creation of any kind of flavor, stereotypes, is to go through the formulation of flavor formulations and detailed inspection, and finally to carry out the trial matching and verification of the flavor, and so on.

Edible flavor use

First, the use of meat flavor
(A) Western-style meat sausage, Western-style ham products
According to the meat manufacturer’s equipment, process conditions are different, the use of flavor additions will be different, there are three main methods:
The use of injection (or not), kneading process to produce Western ham meat products, such as brine ham, manor ham, beer ham, baked meat, roasted through the spine, sandwich ham and other products, can be dissolved in the curing solution of flavors with the injection or kneading added to the meat;
The use of fine grinding and mixing process to produce semi-emulsified sausage products, can be added during the mixing process;
The use of chopping machine processing emulsified sausage, it is appropriate to add in the chopping.

(ii) Chinese products (sauce and marinade)
China’s vast geographical area, Chinese products processing technology and materials used in the characteristics of the obvious differences. Whether it is white brine or sauce brine products can be combined with local flavor characteristics of the selection of appropriate flavoring essences to add flavor to the products.
Western-style injection, tumbling process for the production of marinated products, it is appropriate to add flavor in the marinade when injecting;
Sauce cooking broth can also be supplemented by adding the appropriate amount of flavoring. Such as: (soy sauce beef, poultry products)
For the prior use of marinade processing products (wet marinade), can be dissolved in the flavor of marinade liquid, static marinade for more than six hours.

(iii) Directly added to marinade (old broth)
Meat products with the amount of flavors added to the total amount of ingredients in the meat products formula, exactly to the weight of the final product (the actual yield) calculated. In general:

Yield (%)

100-200

200-300

Dosage (%)

0.15-0.2

0.2-0.3

When the flavor is compounded and used, the amount of single-species flavor used should be no higher than the recommended amount of added flavor. Sauce and marinated products are generally added at the rate of 0.3% -0.6% of the amount of marinade (old broth).

Second, the use of meat products with flavor compounding knowledge introduction
Meat products with the use of flavor compounding not only to meet the diversified needs of consumers on the flavor of meat products, but also meat processing enterprises to achieve one of the important means of self-protection.

(1) meat flavor flavor compounding according to the meat products with flavor in the aroma product function, can be carried out between the flavor compounding use. Enhance the head flavor of the product. The specific ratio can be determined according to the flavor of the product. Flavoring essences that provide mainly head flavors and provide mainly bottom flavors can be compounded for use, which can overcome the limitations of using a single flavor for flavoring. In order to achieve the flavor requirements of meat products, pork flavorings can be used in combination with chicken flavorings. Pork flavor can also be used in combination with beef flavor.

(2) Meat flavor and spice flavor compounding
Users can according to the flavor characteristics of their own products, meat flavor and spice flavor compound use.

Third, the use of flavors need to pay attention to the problem
(1) liquid flavor or paste flavor should be shaken well when used, in order to facilitate the use of paste flavor, warm water (about 50 ℃) can be preheated. When adding flavor, it is best to dilute the flavor (mainly powder and paste) with the right amount of water and then add it to make sure that the flavor is evenly distributed in the sausage filling.

(2) The product should be kept in a cool place away from light. After opening the package, the product should be used as soon as possible. If the product is not used up, if it is liquid or paste flavor, the lid should be tightened and sealed after each use; if it is powdered flavor, the mouth of the bag should be sealed to prevent the loss of aroma, moisture absorption or deterioration.

Safety of flavors

The key factor affecting the safety of food flavors is its raw materials, there are three main categories:

1, spices food flavor flavoring can only be used after the toxicological evaluation test proved safe for human spices. The safety assurance of any food flavor is based on the quality of its products and the amount of use. Food flavor producers, distributors and users must strictly guarantee the quality of food flavors. The user must ensure that the flavorings are used within the permitted use levels.

In fact, people do not have to worry about the use of spices due to the excessive use of food safety hazards, because the use of food flavors in the use of “self-limiting” characteristics, that is, any kind of food flavors when its use of more than a certain range of its flavor will be unpleasant, the user has to reduce the amount of its use to the appropriate range, and the additional The effect is counterproductive.

2、Thermal Reaction Raw Materials There are many varieties of thermal reaction raw materials, mainly including various amino acids, reducing sugar, HVP, HAP, yeast, spices, vegetable juice and so on. These raw materials must be allowed to be used in food, not contaminated, not spoiled, quality qualified raw materials. The temperature and time of the thermal reaction must meet the requirements.

3, solvent and carrier food flavor auxiliary raw materials such as solvents, solid carriers, etc. must be allowed to use in food varieties, their quality must meet the requirements.

Food flavors used in the production of spices, thermal reaction of raw materials and other auxiliary materials must be allowed to use in food, the quality of qualified products, the amount of which must be within the permitted range, the production process and product packaging must be in line with the relevant provisions of food hygiene. Savory food flavors that meet the above conditions will not affect the safety of food.

Instrumental Analysis

The independent creation of a certain aroma by a flavorist must be based on an in-depth knowledge of the aroma of existing substances. Instrumental analysis is the most basic course for flavorists.

First, gas chromatography (Gas chromatogram a GC)
Gas chromatography refers to the use of gas as the mobile phase of the chromatographic method. Because the sample in the gas phase transfer speed, so the sample components in the mobile phase and the stationary phase between the equilibrium can be instantaneous. In addition, there are many substances that can be used as stationary phases, so gas chromatography is a separation and analysis method with high analytical speed and separation efficiency. In recent years, the use of highly sensitive selective detector, making it also has the advantages of high analytical sensitivity and wide range of applications.

Second, mass spectrometry (Mass Spectrum a MS)
Mass spectrometer types, different instruments have different application characteristics, in general, in 300C or so can be vaporized samples, you can give priority to the analysis of GC-MS, because the GC-MS using EI source, get the mass spectral information, can be library search. The separation effect of capillary column is also good. If it can not be vaporized at about 300℃, it needs to be analyzed by LC-MS, at this time, the main molecular weight information, and if it is a tandem mass spectrometry, it can also get some structural information. If it is a biomolecule, it is mainly analyzed by LC-MS and MALDI-TOF, and the main molecular weight information is obtained.

For protein samples, the amino acid sequence can also be determined. The resolution of mass spectrometer is an important technical index, high resolution mass spectrometer can provide the composition of compounds, which is very important for structure determination. Double focus mass spectrometers, Fourier transform mass spectrometers, and time-of-flight mass spectrometers with reflectors all have high resolution capabilities.

Mass spectrometry has certain requirements for samples. GC-MS analysis of the sample should be an organic solution, aqueous solution of organic matter generally can not be measured, must be extracted and separated into organic solution, or the use of headspace injection technology. Some compounds are too polar, easy to decompose during the heating process, such as organic acid compounds, at this time can be esterified, the acid into an ester and then GC-MS analysis, the results can be inferred from the structure of the acid. If the sample cannot be vaporized or esterified, it can only be analyzed by LC-MS. The sample for LC-MS analysis should preferably be an aqueous or methanol solution, and the LC mobile phase should not contain non-volatile salts. For polar samples, an ESI source is generally used, and for non-polar samples, an APCI source is used.

Electronic nose
Electronic nose is a simulation of human olfactory system, the design and development of an intelligent electronic instrument, which can be applied to many systems to measure one or more kinds of odorant gas-sensitive systems. Its basic structure includes the following three parts:

(1) gas sensor array, which consists of gas-sensitive elements with broad-spectrum response characteristics, large cross-sensitivity and different sensitivity to different gases. When working, the gas-sensitive element can respond to the contacted gas and produce a certain response pattern. It is equivalent to the olfactory receptor cells of human nose.

(2) Signal pre-processing unit, he is the response mode of the sensor pre-processing, in order to achieve drift compensation, information compression and reduce the signal (with the sample) the purpose of the ups and downs, to complete the task of feature extraction.

(3) Pattern recognition unit, the signal pre-processing unit of the signal issued by the further processing, to complete the qualitative and quantitative identification of gas signals. It includes data processing analyzer, intelligent interpreter and knowledge base. He is equivalent to the human brain.

Fourth, high performance liquid chromatography
High-performance liquid chromatography can be divided into “high-pressure infusion pump”, “column”, “injector”, “detector “, “fraction collector” and “data acquisition and processing system” and other parts.

Under the selected conditions, inject the test solution or the internal standard substance solution specified under each species, record the chromatogram, measure the retention time t(R) and the half-peak width W(h/2) of the peaks of the main component of the test or the internal standard substance, and calculate the theoretical number of plates of the column according to n=5.54[t(R)/W(h/2)]^2, if the measured theoretical number of plates is lower than the minimum theoretical number of plates specified under each species. If the measured theoretical plate number is lower than the minimum theoretical plate number specified under each species, some conditions of the column should be changed (such as column length, performance of the carrier, advantages and disadvantages of the column filling, etc.), so that the theoretical plate number can meet the requirements.

Some related books are attached at the end of this article:
Experiments on Flavor Blending Technology (Edible/Daily Chemicals), Shanghai Institute of Applied Technology.
“Introduction to flavor”, Sun Baoguo, He Jian edited, Chemical Industry Press, March 2006, 2nd edition
Chemistry and Technology of Fragrance, He Jian, Sun Baoguo, China Science and Technology Press, 1996.
Notes on Flavor Blending, D.P. Anonis, China Light Industry Press, 2000.
Food Flavor Preparation Technology, Zhou Yaohua and Xiao Zubing, Light Industry Press, 2007.
Practical Flavor Formulation, Wang Jianxin, Wang Jiaxing, Zhou Yaohua, China Light Industry Press, October 1990
Experiments on Preparation of Synthetic Fragrance Products, Shanghai Institute of Applied Technology.
Natural Spice Processing Technology, Mao Haifang, China Light Industry Press, 2006
Terpene Spice Chemistry, Huang Zhixi, China Light Industry Press, 1999.
Savory Flavor Blending Manual, Tian Huaixiang
Food Flavor Blending (Edible Flavor Technology), Xiao Zuobing
Principles of Flavor Blending Technology (Xiao Zuobing)