This paper briefly describes the color change mechanism of fresh pork from bright red to tan when it

After animal slaughter, hemoglobin.

Stop the supply of oxygen to the muscles, myoglobin in fresh meat.

Maintaining its reduced state, the muscle color is burnt dark purple, and when the ketone body is segmented, the reduced myoglobin changes in two different directions as the muscle comes into contact with the air.

One part of myoglobin reacts with oxygen to form bright red, and the other part reacts with oxygen to form tan. As the meat is left in the air for a long time, the color of the meat turns and maroon.

The color of good pork is light red or bright red, and the color of unsafe pork is often dark red or purplish-red, and the color of healthy pork is white or light white, and the cut surface is shiny, brown or pink, without any liquid flowing out; The meat muscles of the dead pigs are inelastic, the cut surface is smooth and dark purple, and the flat section has a pale yellow or pink liquid. Second, the smell is healthy, and the pork has no peculiar smell; Sick and dead pork smells of blood, urine, and spoilage. 3. Touch elasticity and healthy pork is elastic; Sick and dead pork is dark red, and the capillaries between the muscles are congested and inelastic.

Here's how you can hopefully help you:

1. Wrap the fresh meat with a damp cloth soaked in vinegar, which can be kept fresh for about 24 hours.

2. Put the fresh meat into the pressure cooker, steam it on the heat until the exhaust hole is bubbling, and then buckle the pressure reducing valve to remove from the fire, which can be stored for about 48 hours.

3. Put the mustard in a small dish, put it together with the fresh meat, and store it for 4 to 5 days.

4. Cut the fresh meat into about 500 grams and put it in a clean basin. Put the soy sauce in a pot and boil it to sterilize, wait for it to cool and then put it in a basin, the soy sauce should be able to submerge the pork, and then cover the basin with a lid, and there will be no peculiar smell after 3 months.

The first thing to mention is the refrigerator that is closely related to meat food, because the nutritional value of food is not only the innate growth factors, but also the acquired preservation environment, if the refrigerator preservation function does not reach a certain index, the nutritional value of the food will accelerate the loss. Therefore, when buying a refrigerator, we should pay attention to ecological indicators such as temperature, humidity, gaseous, and antibacterial, which is also the first step in meat preservation.

Secondly, some traditional meat preservation methods can be used. One is low-temperature refrigeration, so that the meat will remain below 0 degrees Celsius for a short time without spoiling, but the frozen meat will lose moisture and become coarse and not delicious enough. So you can add small options, such as soaking the meat in the gravy and freezing it at the same time, or wrapping it in a double-walled plastic or aluminum tissue paper bag or aluminum tissue paper for storage.

The second is heat treatment, which plays a role in inhibiting bacteria and enzymes, such as cutting fresh meat into pieces and frying or boiling fresh meat, and putting it in freshly boiled lard while hot. In some cases, fermentation can also be performed.

In addition, there are many new ways to preserve meat food, one of which is to increase preservatives, such as various organic acids and salts, such as soaking fresh meat in boiled and cooled brine can keep fresh for two or three days, spraying fresh meat with glucose solution, which can keep fresh for more than a month. Here's another method that I've experimentally proven: soak the meat in a preserving solution to form a film that sticks to the surface of the meat, usually for a week at a temperature of 40 degrees.

The formula of this fresh-keeping solution is: 24 kg of water, kg of salt, kg of glucose, kg of maltodextrin, and the pH value can be adjusted into a mixture with citric acid.

In the future, the development trend of preservatives is natural preservatives, such as using the antioxidant and deteriorating properties in tea to preserve freshness, or extracting active ingredients from spices to sterilize and inhibit bacteria, which is safe and effective. Allicin and alliin in garlic, volatile oil in cinnamon, and clove oil in cloves all have bactericidal effects.

According to the family situation, vacuum packaging technology can be used, and its main functions are: inhibiting the growth of microorganisms, preventing secondary pollution, and slowing down the rate of fat oxidation.

In fact, the preservation of meat is a big problem for families and even society, with the change of people's lifestyle and rhythm, the exploration of this aspect will continue to deepen, I believe that there will be more and more ingenious and simple methods continue to appear.