Enzymes

Enzymes are protein compounds that, as vital catalysts, can cause favorable or adverse physical and chemical changes in food. They also play an important role in the metabolism of food in the organs of living things. In general, the mechanism of action of enzymes is manifested by a reduction in the energy required to perform many chemical reactions, called energy activation (Figure 1).

The substance that is affected by the enzyme is called a substrate. The enzyme is separated and reused after making the necessary changes to the substrate and creating a new substance. Compared to conventional chemical catalysts, enzymes have two important and significant advantages. One advantage is their speed. Table 1 shows the activity levels of several enzymes. In general, the specific action of enzymes is a great tool for identifying certain substances and is clearly used in scientific studies. | As a side effect, it should also be noted that enzymes act primarily on normal temperatures, which prevents thermal damage to the product; At the same time, it eliminates some of the costly steps, such as using energy or building heat-resistant devices. In some cases, the enzyme can be separated, for example, by chromatographic methods, while all work on a specific substrate. These components, which are structurally different but have the same substrate and unit, are called isozymes or isozymes.

2- Coffect

They are not purely molecular feet

1- Classification and naming

2- Coffect

They are not purely molecular feet

1- Classification and naming

About two decades ago, the International Union of Chemistry and Biochemistry classified enzymes into six groups: Oxidase and reductase: These are involved in the oxidation of biological systems and include enzymes commonly called dehydrogenase, reductase, oxidase 10, oxygenase, hydroxylase, and catalase 13. This co-enzyme is also partially reversible in our WordPress (Saran is and is presented in the Vinamese section). In the next case, Azoser Vera Al-Rarat will be the new state. In these cases, the metals, with their capacity, grow in the form of elixirs, and thus they are enabled to perform the action on the enzyme. Such as iron metal in the enzyme lipoxygenase and copper in phenol oxidases 32 . On the mechanism of action of airborne aerators In the twentieth century, Amrle Fischer codified a particular theory about the effect of the Aes Baha, known as the Assassin's Creed. According to this theory, the enzyme is the national enzyme in which the soil is placed, the soybean, which is the key source. This special place that becomes the place and the way itself is composed of two parts. One part is called the junction and the other is called the catalytic converter [09:53, 01/07/2020] Tanaz: In order for the substrate to be placed at the junction, it must have a shape that fits the location so that the catalytic work and the achievement of the desired product can be done properly at the catalytic converter. Although the active site is a small part of the verse molecule and the rest of the molecule is a catalyst, it should be noted that the latter part creates a structural space that actually supports and elevates the structure and shape suitable for the active site. is. The cofactor is also located near this active site and plays its role. Figure 4 shows the active site of the carboxypeptidase enzyme and how a part of the end of the peptide chain is located in a specific way, along with the proper communication with the amino acids present in this site. Also in Figure D, the state of breaking of amylose molecule and separation of maltose from it in the active site of beta enzyme۔ Amylase has been shown. As shown in the last figure, there are four special points in the active location that break the bond by making the necessary connection. They do amylose in the molecule. There are many substances that form during the action of the enzyme and stop this process in some way. These substances are called inhibitors. One can act in both competitive and non-competitive forms in enzymatic reactions. The inhibitor has a substrate structure, so it can be incorporated into the enzyme and remove it from the substrate. In fact, they have it here and act as a wrong key to murder. In non-boat form, they are retracted and attached to the enzyme in villas other than the active site. So that the substrate can no longer be properly placed in this place for enzymatic action to take place, as described above, inhibitors can block important metabolic pathways. This feature is widely used in pharmaceuticals and Drugs can be produced that can stop harmful metabolic processes. In this regard, the effect and inhibitory properties of some antibiotics are used in food protection. One of the most important inhibitors is trypsin inhibitor, which has been mentioned in previous sections. This inhibitor forms a complex to stable protein with the protein, so it can be released quickly and the problem of protein breakdown from this point of view is not difficult. But the trypsin complex and inhibitor are more stable, thus reducing the effectiveness of trypsin in a specific and highly problematic way.

4- Using enzyme as an indicator of process efficiency

The thermal resistance of enzymes may be used to determine the efficiency or completeness of the desired process. A clear example in this regard is the study of the presence of alkaline nasopharynx in pasteurized milk. The absence of this enzyme indicates good, pasteurization. Because when this enzyme is destroyed, the indicator is that the tuberculosis microbe, which is considered a dangerous and resistant microbe in milk, has also disappeared. Peroxidases and catalase are also used as indicators to destroy other enzymes. Because they have high thermal resistance, their destruction indicates the destruction of other enzymes - which can later have adverse effects on food. Peroxidases, especially plant peroxidases, are very resistant to heat, so even using a temperature of 120 چند C for a few minutes cannot completely destroy resistant peroxidases. In the food industry, there are cases when the inactivated enzyme becomes active again and has its destructive effects. This is the case with peroxidases in milk and vegetables, catalase in vegetables, and lipase in dairy products, and protein-degrading enzymes in citrus extracts. The reason for this is that the thermal process used was not sufficient and did not cause the necessary and sufficient changes in the active site of the enzyme. It is thought that although no enzymatic activity is observed after the end of a heat treatment, after a while the active site regains its original shape and the enzyme can show its adverse effects on the food. However, this return of natural and primary structure in enzymes occurs slowly, despite the enzymatic denaturation of the enzyme over time. This condition usually occurs when rapid desorption is performed. Beta - A non-regenerative amylase that works well when it is present in malt and barley

References

5 - Investigation of the properties

Investigation of the properties of different enzymes of amylase alpha amylase, this enzyme is abundant in plants and animals and each molecule has one gram of calcium. Alpha amylase is an internal and randomized enzyme It should be noted that gluco amylase glucose does this. In this way, it can reduce the viscosity created by the location and dilute the environment. That is why it is also called enzyme 38. This enzyme can be greatly increased by performing malting on grains such as barley. Such a malt, which is rich in this enzyme, can be used for bread production [09:54, 01/07/2020] Tanaz: Alpha-amylase activity is required to provide sugars that can be used for yeast. Of course, in the case of wheat, the production or presence of high alpha amylase is undesirable because it causes large amounts of gas during bread production. But for wheat, which, like North American wheat, is essentially low in alpha-amylase, using this enzyme can be beneficial. Alpha - The amylase used in industry is mostly obtained from Bacillus le Chani Formis or Aspergillus aries 40. Beta-amylase. This enzyme is an external 41 or end enzyme. This means that from the non-regenerative end of the starch, it separates the glucose molecules into two, namely maltose. But its operation stops when it reaches the 9-1 connection. This enzyme is only found in excellent plants. The resulting product can be used for yeast. In this regard, barley malt and wheat, which have significant amounts of this enzyme, can be used. It should be noted here that during this conversion, the alpha-maltose shape becomes the beta shape. Clogramylase. Glucose amylase is a foreign enzyme that secretes glucose from the non-regenerative end of the molecule. This enzyme is also able to break down the 9-1-1 bond, except that it does so faster than breaking the 4-1-a bond. In this sense, the end product is glucose. The sources of this enzyme are Sporgilus Niger and Spirgilus Aries. This enzyme is used to produce corn syrup and flowers. One problem with the conversion of corn starch to glucose is the enzyme trans glucosidase 42, which is produced by alpha amylase and glucose amylase. Because this enzyme from glucose produces oligosaccharides, it reduces the way it works. In general, it should be noted that in order for starch to be completely degraded, it must have been gelatinized beforehand. Beta-galactosidase 44. This enzyme is found in plants, animals, bacteria and yeasts. One The important function of this enzyme is to break down lactose; And that's why it's known as lactase. As mentioned earlier, milk consumption is associated with digestive problems for some people due to the presence of lactose in it. The reason for this is the lack of the same enzyme lactase in these people. This enzyme can also be obtained from Aspergillus niger, Aspergillus erythema, and some Saccharomyces. Its stabilized form is also used successfully today.

Proteases

Proteases, such as amylase, include two main groups, external and internal. There are two types of external types. One is carboxy peptidases, which break down peptide bonds of amino acids at the C-end of the peptide chain, and the other is amino peptidases, which separate the amino acids at the N-terminus. Internal proteases break down various bonds within the peptide chain and have a specific function in this regard. Which peptide bond is broken down by a particular internal enzyme depends on the R group of amino acids on either side of the bond. Because to break the bond, the amino acids on both sides of the enzyme site must be properly aligned to do this. In this regard, it is necessary that the R groups of these amino acids have a specific structure. Proteases are very important in metabolic and nutritional processes, some of the most important of which are discussed below. Food industries are becoming increasingly important. 48 Renin is a pure form of the enzyme found in rent 4 or cheese yeast that is given in cheese making. This enzyme is extracted from the fourth stomach of the infant calf - as long as it feeds on grass. After the calf begins to consume grass, it releases 50 instead of renin. This enzyme is secreted in an inactive state, called proprinandine. The extract extracted from the dried stomach contains both renin and perineum. The conversion of proline to renin is accelerated by the addition of acid. This process is autocatalytic, meaning that by producing some renin, it converts the rest of the renin into active renin. Pepsin can also convert porphyrin to renin. The process of converting proprinine to renin is accompanied by the release of peptides from the N-terminus part of the precursor molecule, during which the molecular weight is reduced from 36,000 to 31,000. The three disulfide bonds bind the different parts of the proline together, which remain unchanged after conversion to renin. PH is suitable for action - Ernin is 3.5, but its maximum stability in PH 5 can be seen. Cheese production is done at a pH of 5.5. Renin is coagulated by milk during two stages. In the first step, which is an enzyme, the enzyme caffeine-casein, which contains 199 amino acids, breaks down the bond between phenylephrine and methionine, which are the 105 and 101 amino acids in the protein, respectively. As a result, the protective effect of capa-casein zinc-casein is eliminated. In the second phase, which is non-enzymatic, the altered casein deposits under the influence of calcium ions. Other proteins that break down protein, such as pepsin [09:54, 01/07/2020] Tanaz: Microbial proteases can also break the same bond. Pepsin. Pepsin is produced in the lining of the stomach. This enzyme is also inactivated, called pepsinogen, which is converted to active pepsin in the lower pH of the stomach. These small peptides, which are now inextricably linked to pepsinogen, act as a inhibitor of its activity. But in PH 1-2 In the stomach, they are separated from pepsinogen and pepsin is produced. Pepsin consists of 321 amino acids. In postsynaptic to pepsin conversion, isoelectric pH of 3 / 7 is reduced to 1. The third type of building in Pepsin has been stabilized by three disulfide bonds and one phosphate bond. Pepsin becomes denatured at pH more than 5 and loses its activity. This enzyme Preferably breaks the adjacent connections of phenylalanine, tyrosine and tryptophan. And in general, some of the proteases that act at low pH and acidity (e.g. Pepsin) is used in the production of cheese. But the quality of the cheese produced is not as good as the cheese produced by Renin, and the bitter-tasting peptides may form and be problematic. These proteases are also obtained from some microorganisms, such as Mokurpousilos 53. In recent years, significant progress has been made in the use of microbial proteases in cheese production. Microbial protease (Aspergillus arise) is also used in the preparation of soy sauce and miso (fermented soy food from East Asia). Trypsin and chymotrypsin head. These two enzymes are secreted by the pancreas in the intestine. Trypsin breaks down the peptide bond formed by the carboxylic amino acid lysine or arginine group with other amino acids. Kimo trypsin actually contains several relatively similar enzymes that are identified by the prefix alpha, beta, gamma, delta, and p. They break the bonds adjacent to the amino acids tyrosine, phenylalanine and tryptophan, and have a good pH of about 8. This group includes several types of enzymes that differ from each other in terms of protein breakdown. These are located in cell lysosomes and can be distinguished from other proteases, such as trypsin, which are secreted by the cell. These enzymes do not play a significant role in animal life and can be said to have a inhibitory effect on lysosomes. However, after death, they show a certain activity and, as mentioned in the topic of protein, they take part in the operation of crushing the meat after slaughter and coagulation. These enzymes are likely to be released from lysosomes after death, causing myofibrils to break down inside muscle cells, as well as protein in connective tissues (such as collagen). Papain 7 AH, Fisine And bromelain 59. These enzymes have plant roots and are obtained from the fruit of the papaya tree (which is not fully ripe), from the latex "fig" (white sap secreted from the tree) and from the fruit and stem of the pineapple tree, respectively. The active site of these enzymes has a cysteine. And is a histidine that is essential for their activity. PII is suitable for these 5.7-1. These enzymes hydrolyze peptide, ester, and amide bonds. Papain is made up of a single polypeptide chain with 212 amino acids. Catalytic action of this enzyme takes place in two stages. In the first stage, milling, during which an intermediate enzyme-asyl compound is produced.

- Approved colors

The colors used in food can be divided into two groups. The first group are natural dyes that may be derived from natural sources or are made from synthesized materials. All the color materials that have been discussed so far. They are part of this group of colors. In general, adding these new and colored materials to food and food products is completely permissible and free. In this regard, these are called approved colors. in place. But 3 of these colors and their consumption limits are clear. It should be noted that although in most cases there is no legal restriction on the use of these substances, the issue of high prices or the emergence of certain grayness in food actually limits the consumption of some of them. The second group includes those dyes that do not exist in nature. But they are made through synthesis. Consumption of this group of substances requires the approval of the relevant organs and health laws. For this reason, these materials are the colors that need to be approved, or in other words, the approved colors. The history of production and consumption of these paints dates back to the middle of the last century. The material used to produce these is coal tar, and due to the high power of color, their consumption spread rapidly and replaced the natural colors used. At the beginning of this century, there were about 700 different types of this color group in the US market. Over the past decades, extensive research has shown the potential use of these dyes in unlicensed foods, as well as the potential dangers to health, especially the development of cancer in laboratory animals. Was. The chemical structure of the colors approved for food use in the United States is shown in Figure 17. Today, however, the petrochemical industry provides the raw materials needed to produce approved dyes. However, due to the historical background mentioned above, these colors are still often referred to as coal tar colors, which is not correct.

References

Food Chemistry, Dr. Hassan Fatemi

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