How do vegetables stay fresh for a long time at room temperature?

It is easy to age, and in order to maintain the delicate quality of the meat and not cause rough aging, it will be made into barrel bamboo shoots immediately. Arrow bamboo shoots - similar to cinnamon bamboo shoots, they are unearthed young bamboo branches, but their bamboo shoots are more small, and they are also marketed in the way of product processing. Bamboo shoots will age rapidly after harvesting, except for the processed cinnamon bamboo shoots and arrow bamboo shoots, other bamboo shoots are extremely difficult to preserve, so try to eat them while they are fresh.

Radish: It is better to have no voids on the surface, elastic and shiny, and if the root is straight and not bent, it is the best choice. It is best to bring mud and place it in a cool and ventilated place.

If the radish you buy has been washed, you can wrap it in dry newspaper and put it in a plastic bag, and put it in the refrigerator upright in the vegetable and fruit fresh-keeping room, but the leaves will accelerate the root shrinkage, it is best to cut off the leaves after buying, and then wrap them in plastic wrap and put them in the refrigerator. Asparagus: Buy asparagus, with straight shape, tight bud at the tip of the bamboo shoot, no water wound and rancid smell, bright and not atrophied skin, delicate and coarse, the base is not aged, and it is folded by hand.

Tomatoes: Choose medium and large tomatoes with a round fruit shape and green fruit color, if the fruit color is all red, it will lose its crispness. Small and medium-sized tomatoes are round or long in shape, and the fruit color is bright red, and the sweetness of yellow and red is not enough.

When storing tomatoes, they should be placed separately with the stems facing down, and if the tomatoes are placed on top of each other, the overlapping parts will rot faster. Gherkins: Fresh cucumbers have wart-like protrusions, and there will be a stinging sensation when rubbing them with your hands.

If the head part is soft, then there will often be small holes in it, so it is best not to buy it. Gherkins will slowly dry out at room temperature. Before refrigeration, the cucumber must be wiped dry and put into a sealed fresh-keeping bag, and the bag mouth should be sealed and refrigerated.

Bitter gourd: When choosing bitter gourd, it has a hard body, a sense of weight, a bright and crystalline skin, and the larger the warts on the surface, the better, so that the bitter gourd is not so bitter. If the inside of the melon is red, it means that the melon is overripe.

The ripening effect of bitter gourd is quite fast, it is not resistant to storage, and it should not be stored in the refrigerator for more than 2 days. Shiitake mushrooms: The flesh of the mushroom umbrella is thick and elastic, and there are no markings, showing a tender brown color.

Freshly harvested shiitake mushrooms will have a thin film on the inside of the mushroom umbrella, and if there are brown spots here, it means that they are not very fresh. If you buy too much at once, you can store it in the freezer of the refrigerator. Potato:

The quality on the market is not bad, but if the surface is too uneven, avoid buying. Round potatoes are powdery potatoes and are suitable for salads or baked potatoes; On the other hand, the slender May Queen variety is slimy and does not boil easily, making it suitable for curry. In the principle of room temperature storage, without washing, potatoes and apples can be placed together and stored in a cool place, because apples will release an ethylene gas that ages other fruits and vegetables, which can inhibit potato germination.

Green beans: Avoid obvious protruding beans, and preferably those with bright green and elastic color. Green beans are usually stored directly in a plastic bag for 5 to 7 days, but after a long time, coffee-colored spots will gradually appear, if you want to keep them longer, it is best to wash the green beans, blanch them with salt water, drain them, and then put them in the refrigerator to freeze, you can keep them for a long time.

Remember to drain the water so that the frozen green beans don't stick together. Green peppers: Choose those with a firm, shiny skin and pointed ends.

If you refrigerate it directly, the green pepper will slowly soften. It is best to store it in a sealed plastic bag, or make a small hole in the plastic bag to avoid condensation. Cabbage:

The surface should be dry, the leaf flesh is thick, the leaf veins are thin (the thick is an old vein), the touch is hard and the weight is crispy. The cut of the chopped cabbage will slowly turn black, and if left at room temperature, it will only stay fresh for about 2 to 3 days. The cabbage that is bought is usually wrapped in a layer of plastic wrap, which must be peeled off and then put in a dense layer.

The conditions for long-term preservation of vegetables, vegetables are the food that we must ingest in our daily life, it is rich in vitamins and different vegetables have different effects, but if you accidentally buy too many vegetables and cannot eat them at one time, how to preserve and ensure the taste of vegetables, let's take a look at the conditions for long-term preservation of vegetables.

Conditions for storing and preserving fruits:

Hypoxia (inhibits enzyme activity), hypoxia (inhibits anaerobic respiration.

high CO2 concentration (inhibits aerobic respiration); Sub-zero low temperatures cause fruit cells to freeze due to freezing;

When there is no oxygen, the anaerobic respiration of the fruit accumulates more alcohol and damages the cells, so that the quality of the fruit decreases.

This question examines the method of storing vegetables and fruits, and is intended to test students' ability to analyze problems and solve problems by splitting the wheel, which is a mid-range question.

When storing grains, fruits and vegetables, it is necessary to reduce the rate of cellular respiration and reduce the consumption of organic matter The main factors affecting cellular respiration are temperature (which affects the activity of enzymes), oxygen concentration, moisture, etc.

1. Vegetables with thick skin of yams, potatoes, lotus roots, radishes, and water chestnuts. These vegetables are shelf-stable and only need to be placed in a cool place for about 1 week and are not suitable for refrigeration. Refrigeration is easy to sprout, but there is no way to eat it after germination.

Potatoes: Apples and potatoes can be stored together to inhibit potato germination, not with sweet potatoes, otherwise it is easy to spoil, and sprouted potatoes cannot be eaten. Lotus Root:

Submerged in cold water and changed every two days, it can keep it fresh for more than 1 month.

2. Cauliflower: Cauliflower can be stored for about 3-4 weeks, and it can be wrapped in celery-type plastic wrap and placed in the refrigerator to keep the temperature at about 0 degrees. If the storage temperature is too high, the surface is prone to black spots.

3. Pumpkin Winter melon: If you don't cut the whole thing, you can store it for a long time if you put it directly in a ventilated, cool and dry place. After cutting, wrap it in plastic wrap and put it in the refrigerator for about 2-3 days.

4. Mushrooms: After buying normal mushrooms, they should not be wet, and at the same time keep them slightly dry and put them in the refrigerator, which can be stored for 1-2 days. During the epidemic period, it is recommended that you can buy dried goods, soak them directly when you want to eat them, and dried shiitake mushrooms, tea tree mushrooms, deer antler mushrooms, etc. can be stored for a long time.

5. Eggplant: It cannot be washed with water, wrapped in plastic wrap and placed in a ventilated place for ventilation, and can be stored for 3-4 days.

6. Onion: Put it in a cool, dry and ventilated place, it can be stored for a long time, if you put it in the refrigerator, it is more likely to be soft and deteriorate.

7. Tomatoes: Put them in a fresh-keeping bag, tie the mouth of the bag tightly, put them in a cool place, open them once a day, ventilate them for 5 minutes, pay attention to wipe the water vapor in the bag, and keep them for a longer time.

Do not wash when not ready to eat. It is difficult to dry the washed dishes thoroughly, and it is easy for bacteria to grow when it is wet. Instead of wrapping the vegetables tightly, put them in a plastic bag and use a pin to prick about 10 holes around the plastic bag to keep the vegetables fresh for a longer time.

"Leafy greens" are very important in the refrigerator, and the roots are stored in the refrigerator to effectively prolong the storage time and retain freshness. <

1. Keep green vegetables dry and shivering: do not wash them when they are not ready to eat. It is difficult to dry the washed dishes thoroughly, and it is easy for bacteria to grow when it is wet.

2. Give enough space for vegetables: Don't wrap vegetables tightly, you can put vegetables in plastic bags, and then use a pin to pierce about 10 holes around the plastic bag, so that the vegetables can be kept fresh for a longer time.

3. Storage location: The position of "green leafy greens" in the refrigerator is very important, and the roots are placed in the refrigerator room with the roots facing down, which can effectively extend the storage time and retain the freshness.

Vegetables need a dry environment and enough space for a long time, and there are certain requirements for storage location, first keep the storage environment dry to avoid breeding bacteria, and then place the vegetables in plastic bags, prick some small holes to ensure ventilation, and then excite the root of the vegetable after the key is down, put it in the refrigerator, which can prolong the preservation time of vegetables.

1. Dry environment

Vegetables need a dry environment to prolong the preservation time, because in a humid environment, it is easy to breed bacteria, so that the vegetable leaves rot and deteriorate, therefore, when the vegetables are to be kept fresh, they can not be cleaned, keep the vegetable body dry, and the storage environment is dry.

2. Enough space

Vegetables need enough space to prolong the preservation time, because a large number of vegetables are tightly put together, which will make ethylene gas gather, so that the vegetables will ripen and finally rot and deteriorate, the vegetables should be placed in a slightly larger plastic bag, and some small holes should be pierced to ensure that the vegetables are breathable, which is conducive to maintaining the freshness of the vegetables.

3. Storage location

It is best to put the roots of vegetables facing down, and then put them in a higher position in the refrigerator room, so as not to be too low in temperature and stored for too long to make vegetables frostbite and lose their nutritional value.

1. When buying vegetables, choose fresh vegetables, select and store leafy vegetables, including blind vegetables: vegetables such as spinach or chrysanthemum, with no yellow spots on the leaves, fresh and bright, and the roots are plump and straight;

2. Vertical placement of vegetables is more conducive to freshness;

3. Freezing can retain the vitamins of vegetables, and the fresh vegetables after buying back are frozen immediately, which can be stored for about 1 month. The most important thing for freezing is vacuum preservation, and it is better to use a special fresh-keeping bag for freezing;

4. Put the vegetables into a plastic bag and blow and seal the bag tightly to preserve. Because the carbon dioxide contained in respiration can keep the vegetables longer;

5. Wrap the vegetables in wet old newspapers, and then put them in the refrigerator for storage, which can not only keep the rock wet, but also avoid too wet and rotten, and then put the roots facing down upright in the refrigerator vegetable and fruit storage room.

1. Low temperature storage. Low-temperature storage in constant temperature storage is a simple, universal and effective preservation method. Vegetables should be pre-cooled after picking, and the heat in the field (referring to the heat brought into the storage room from the field, flowers, fruits, etc.), the faster they are sent to the right refrigeration temperature, the longer the shelf life.

Depending on the type of vegetables, take effective temperature control and try to keep the temperature as constant as possible. Generally speaking, most vegetables are more suitable for low-temperature storage, but melons and fruits that are susceptible to frost damage are not suitable for low-temperature storage.

2. Modified atmosphere preservation. Modified atmosphere preservation is a method to adjust the corresponding oxygen and carbon dioxide concentrations according to different leafy vegetable varieties under low temperature conditions, and consider comprehensive factors such as temperature and humidity, so as to reduce the respiration of vegetables, reduce nutrient consumption, slow down the aging process after ripening, maintain better quality and prolong storage life. Some leafy vegetables cannot be stored under cold storage, such as bok choy, coriander, leeks, etc., and the storage period under modified atmosphere packaging can reach 7 to 10 months.

3. Decompression storage. Vacuum storage is to reduce the air pressure of the storage environment, generally to 1 10 of the atmospheric pressure, reduce the oxygen and carbon dioxide in the storage environment, cause a certain vacuum, to achieve the purpose of oxygen reduction, is the further development of modified atmosphere refrigeration. Vegetables such as spinach and lettuce have a better effect under decompression storage, and the best storage effect is tomato with the best storage effect by this method, and the shelf life can reach more than 3 months.

4. Store at ice temperature. Ice temperature storage refers to storage at a temperature below 0 and above freezing. Ice storage does not destroy the cell tissue of vegetables, which can effectively inhibit the activity of microorganisms and the activity of various enzymes, prolong the shelf life of vegetables, and improve the quality of vegetables.