Our daily food, clothing, food and shelter are inseparable from chemistry. For example, we have to eat oil and salt sauce vinegar and sugar every day. The manufacture of these commonly used condiments is inseparable from chemistry. Some people think that sugar is extracted from plants such as sugar cane and sugar beet, so that it is not chemical. In fact, the techniques of filtration, evaporation, and crystallization used in the manufacturing process of sugar are common chemical techniques. These technologies are also used in the manufacture of salt. The production of soy sauce and vinegar is mainly based on fermentation, and many biochemical reactions occur. Traditional chemical techniques such as filtration and refining are also used.
Food chemistry is extremely relevant to our diet. Food chemistry is the science of systematically studying the chemical composition, structure, properties of foods, and the chemical changes that occur during food processing and storage. There are many chemical reactions in food processing, and some chemical reactions are very interesting. Braised pork is a favorite dish of the common people of our country. Almost no one does not like to eat braised pork. When making braised pork, it is usually necessary to add white sugar and cooking wine (yellow wine). It is generally believed that the amino acid is esterified with ethanol to form amino acid ethyl ester. This reaction shows the effect of cooking wine to remove cockroaches. The flavor of braised pork is mainly amino acid ethyl ester. Credit. In fact, the smell of braised pork is mainly the credit of white sugar. Today we introduce a chemical reaction that takes place during the process of making braised pork. This chemical reaction is the main factor in the color, aroma and good taste of braised pork.
The Maillard reaction, also known as the "non-enzymatic browning reaction", was proposed by the French chemist LC Maillard in 1912. The Maillard reaction is a non-enzymatic browning that is widespread in the food industry. It is a reaction between a carbonyl compound (reducing sugar) and an amino compound (amino acid and protein). After a complicated process, it eventually produces brown or even black. The macromolecular substance is black essence or called melanin, so it is also called carbonyl ammonia reaction.
Reaction mechanism
The initial stage
1. Schiff base formation (Shiffbase): amino acid and reducing sugar are heated, and amino group is condensed with carbonyl to form Schiff base.
2. Formation of N-substituted glycosylamine: Schiff base is formed by cyclization.
3. Amadori compound formation: N-substituted glycosylamines are rearranged by Amiadori to form Amadori compound (1-amino-1-deoxy-2-ketosaccharide).
Intermediate stage
1. Under acidic conditions: the 1,2-enolization reaction produces carbonylmethylfuran aldehyde.
2. Under alkaline conditions: the 2,3-enolization reaction produces reduced ketones and dehydrogenated ketones. Conducive to Amadori rearrangement products to form 1-deoxysome. It is a precursor to many food flavors.
3. Strecker degradation reaction: The cleavage reaction is continued to form a carbonyl group-containing and biscarbonyl compound for the final stage reaction or a Strecker decomposition reaction with an amino group to produce a Strecker aldehyde.
Final stage
The intermediate stage product reacts with the amino compound to form an aldehyde-amino group, which ultimately produces a melanoid and a series of intermediate reducing ketones and volatile heterocyclic compounds, so that the products of the Maillard reaction are not fragrant components.
Influencing factor
1. The Maillard reaction can occur when the temperature is 20~25°C. Generally, each phase is 10 °C, and the reaction speed is 3 to 5 times different. The speed is higher than 30 ° C. When the temperature is higher than 80 ° C, the reaction speed is less affected by temperature and oxygen.
2. When the moisture content is between 10% and 15%, the reaction is easy to occur, and completely dry food is difficult to occur.
3. pH value When the pH value is above 3, the reaction accelerates as the pH value increases.
4. Chemical reagents Acidic sulfite inhibits browning, and calcium salts and amino acids combine to form insoluble compounds to inhibit the reaction.
The use of precursor materials to prepare meat flavors, mainly based on sugars and sulfur-containing amino acids such as cysteine, through the reaction of heating, including oxidation, decomposition of fatty acids, thermal degradation of sugars and amino acids, carbonyl ammonia reaction And secondary or tertiary reaction of various products. There are hundreds of flavoring ingredients that are formed. Based on these substances, meat flavors having different characteristics can be produced by blending. The meat flavor formed by the Maillard reaction can be regarded as natural regardless of the raw material or the process, so the obtained meat flavor can be regarded as a natural flavor.
Product number
product name
package
characteristic
Market price¥
Discount price¥
D23-RA1030
DL-cysteine
25g
BR, 98%
192
144
C28-A1206
Absolute ethanol
4L
HPLC, 99.9%
600
600
TC49-11665
P-dimethylaminobenzaldehyde
25g
99%
69
25
D23-A0144
Compound amino acid powder
250g
BR, 80%
144
120
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