Food additives are used in food processing in order not to affect the taste, to ensure the quality of the food and its transportation. Phosphate in food additives is a meat product moisture retention agent that effectively activates meat protein. In meat products, it has the functions of maintaining the water retention of meat and enhancing the binding force. In the process of freezing, refrigerating, thawing and heating, the meat will lose a certain amount of water, which will make the meat hard, and lose some soluble protein and other nutrients due to the loss of water. At present, there are several phosphates approved for use in food additives in our country, including sodium tripolyphosphate, sodium hexametaphosphate, sodium pyrophosphate, trisodium phosphate, disodium hydrogen phosphate, sodium dihydrogen phosphate, and sodium acid pyrophosphate and more.

Adding these substances to food helps to diversify food varieties, improve its color, aroma, taste, and shape, maintain the freshness and quality of food, and meet the needs of processing technology. They are very important quality improvers. For example, when phosphate is added to meat, it can improve the water-holding capacity of the meat, so that the meat can still retain its water during processing, so that the nutrient content of the meat is less lost, and the tenderness of the meat is also preserved.

1. During the processing of meat products, adding phosphate has the following effects:

(1) Increase the PH value of meat;

(2) Chelate metal ions in meat;

(3) Increase the ionic strength of meat;

(4) Dissociation of actomyosin.

Therefore, after adding phosphate, the water retention and yield of products can be improved. However, the ability of phosphate to improve the water retention of meat and the texture of meat depends on the type of phosphate used, the conditions of the phosphate system and the amount of phosphate added.

2. Application in improving muscle protein water retention and gel strength

The primary and secondary order of factors affecting the water retention of chest muscle protein gel is: sodium pyrophosphate, sodium tripolyphosphate, sodium hexametaphosphate, and the order of factors affecting the water retention of thigh protein gel is: sodium hexametaphosphate, sodium pyrophosphate ,sodium tripolyphosphate. The different effects of the two muscle types are mainly due to the different muscle types and the different mechanisms of phosphate action.

Tests have shown that pyrophosphate has a significant effect on the water retention of breast meat. The reason is that the pyrophosphate increases the PH value and improves the water retention of the gel through hydration. At the same time, the actomyosin is dissociated into myosin and actin, and the protein molecules bind water to improve the water retention. Tripolyphosphate has no obvious effect on the water retention of thigh protein gel. At this time, it is the structure of the gel that affects the water retention of the gel. The good water retention of the gel indicates that the gel network is relatively fine. A large number of tiny holes are evenly distributed in the gel network, with the help of capillary force to retain some moisture.

In terms of heat-induced gel strength for muscle proteins, phosphate has a lowering effect on the gel strength. Foreign literature reports that sodium pyrophosphate will make myosin unstable, reduce gel strength, and interact with myofibril gel. Sodium tripolyphosphate will also make myosin unstable. When 0.3 mol/L and 0.4 mol/L sodium chloride are applied, the gelation of myofibrillar protein is improved, but when 0.6 mol/L sodium chloride is used, the gel capacity is reduced. Sodium hexametaphosphate has no effect on myosin degeneration, but it improves gel strength. The effect of phosphate on muscle protein is mostly attributed to the changes in ionic strength and PH.

3. Application in improving water retention and yield of meat products

Adding phosphate to meat products can improve the texture of the product, increase the water retention and product yield of the product, and improve the texture of the meat product, thereby reducing the cost of the product without reducing the quality of the product. The principle that phosphate improves the water retention of meat products is that tripolyphosphate and pyrophosphate can increase the ionic strength of the meat system by changing the electric potential of the protein charge, and make it deviate from the isoelectric point, so that the charges repel each other. There is a larger space between them, that is, the "swelling" of protein, so that the meat tissue can contain more water and improve water retention. The hexametaphosphate can chelate metal ions, reduce the combination of metal ions and water, and make proteins bind more water and improve water retention. Practice has proved that the mixed use of multiple phosphates is better than the single use, so mixed phosphates are usually used to increase the effect. The best ratio of compound phosphate in most meat products (such as pork ham, beef, surimi) is 2:2:1 (sodium tripolyphosphate: sodium pyrophosphate: sodium hexametaphosphate), but the best use The amount varies greatly from product to product. For ham, the optimal amount is 0.4%, but for fish, the optimal amount is 0.5%. The water retention effect of compound phosphate on surimi products is better than that of single phosphate, and the color, taste and texture of the products are better; but in chicken products, the optimal phosphate ratio for obtaining the maximum yield is six partial Sodium phosphate 32.6%, sodium tripolyphosphate 45.6%, sodium pyrophosphate 21.8%. The greater the amount of compound phosphate added, the higher the yield, that is, the greater the positive effect on the water retention of the product. However, when the dosage is greater than 0.4% for chicken meat and 0.5% for fish meat, the upward trend of the finished product rate will slow down.

4. Application in improving the tenderness of meat products

The compound phosphate is alkaline, which can increase the PH value of meat and promote the tenderization effect of calcium activating enzyme on meat. At the same time, the complex phosphate has more negative charges, and a lower concentration of the complex phosphate can significantly increase the ionic strength of the solution, and thus can chelate metal ions, such as magnesium, zinc, etc., and expose the protein-COO- end Enhances the electrostatic repulsion of the meat, relaxes the meat, and increases the tenderness of the meat. Since the tenderness of meat is related to the content of connective tissue and myofibril, the more collagen cross-links in connective tissue, the worse the tenderness of meat. After adding complex phosphate, it can increase the solubility of collagen, reduce the cross-linking of collagen in connective tissue, and improve the tenderness of meat. Compound phosphate can also dissociate actomyosin, relieve muscle stiffness, and improve meat tenderness. The ratio of compound phosphate is: tripolyphosphate: pyrophosphate: hexametaphosphate: 2:2:1, and when the addition amount is 0.5%, the tenderization effect on beef and rabbit meat is the best. Use injection marinating for 16 hours.