In order to prolong the storage time of fresh fruits, the storage conditions are best .

a Low O2, proper humidity, low temperature above zero and ethylene-free.

Low O2 can reduce aerobic respiration as much as possible, so that the whole respiration effect is relatively low, proper humidity can make the water not lose too much, if the humidity is too high, various microorganisms may multiply more, affecting storage, high temperature above zero, low temperature below zero may lead to freezing, damage to the internal structure.

And ethylene is used for ripening, of course it can't be used.

a Certain conditions - this is more suitable.

Because the cells respire, they also have to exchange water with the outside world, and if the outside world is too dry, then the water evaporated by the cells cannot be replenished - so there must be a certain amount of humidity.

If there is no O2, it will lead to the proliferation of some anaerobic bacteria, which is not suitable for storage.

If there is no oxygen, it will lead to the proliferation of some anaerobic bacteria, which is not suitable for storage, and in addition, the cells will not be able to carry out basic life activities - respiration.

Oxygen levels are best at 4 to 5%.

Anaerobic respiration occurs in fruits without oxygen. Make it deteriorate.

Answer] A Answer Analysis] Test Question Analysis: To store fruits for a long time, it is necessary to reduce their cellular respiration and reduce the consumption of organic matter. Under low temperature conditions, respiratory enzyme activity decreases; In the hypoxic state, the aerobic respiration of the cells is weak, the anaerobic respiration is inhibited, and the respiration intensity of the whole cell is in the lowest state, which can effectively reduce the consumption of nutrients, but if the temperature is below zero, it will frostbite the fruit.

The humidity is moderate, which reduces the loss of water in the fruit and is conducive to freshness. Choose A

Test Points: This question examines the application of cellular respiration and is intended to test the candidate's ability to recognize the knowledge points listed and use the knowledge to make reasonable judgments or draw correct conclusions.

To store fruits for a long time, it is necessary to reduce their cellular respiration and reduce the consumption of organic matter Under low temperature conditions, the activity of respiratory enzymes is reduced; In the hypoxic state, the aerobic respiration of the cells is weak, the anaerobic respiration is inhibited, and the respiration intensity of the whole cell is in the lowest state, which can effectively reduce the consumption of nutrients, but if the temperature is lower than zero degrees, it will frostbite the fruit The humidity is appropriate, reducing the loss of water in the fruit, which is conducive to fresh-keeping Ethylene has the effect of ripening, which is not conducive to fruit storage

Therefore, 8

The storage of fruits and vegetables requires (above zero) low temperature, low oxygen and moderate humidity, which can reduce the rate of cellular respiration, reduce the consumption of organic matter, and achieve the effect of long-term storage and preservation.

Precautions for preserving vegetables at home: vitamins are easy to be destroyed by oxidation in the air at room temperature, and the destruction of vitamins can be delayed by preserving the outer leaves and shells. Therefore, do not peel off the outer leaves of bulbous vegetables, do not peel off the outer skin of onions and garlic, and do not peel off the pods of beans before eating.

Potatoes need to be kept away from light to prevent the sprouts and rind from turning green to produce toxic solanine.

The nitrite content in fresh vegetables is very low, and if it is stored for too long, the nitrite content will increase significantly when it decays and deteriorates. If stored in the refrigerator at low temperature, the respiration intensity of vegetables is relatively weak, not easy to rot, and the contents of vitamin C, total sugar and nitrite do not change much.

Conditions for fruit storage and preservation: low temperature above zero (inhibition of enzyme activity), low oxygen (inhibition of anaerobic respiration), high CO2 concentration (inhibition of 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, which is intended to test students' ability to analyze and solve problems, and 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. In production, this principle is often used to store fruits at low temperatures, inhibit respiration, and reduce the consumption of organic matter.

2. In production, the principle of reducing oxygen concentration to inhibit respiration and reduce organic matter consumption is often used to prolong the preservation time of fruits However, in the case of complete anaerobic, anaerobic respiration is strong, and there are more organic matter decomposed, and alcohol is produced at the same time, which is not conducive to the quality and preservation of fruits, so low oxygen preservation is generally used, and aerobic respiration is weak at this time, and anaerobic respiration is inhibited

3. Grain storage needs a low-temperature, dry, and low-oxygen environment, while fruit and vegetable storage needs (above zero) low temperature, low oxygen, and moderate humidity, which can reduce the rate of cellular respiration, reduce the consumption of organic matter, and achieve the effect of long-term storage and preservation.

1: Because in a high temperature environment, the respiration of cells will be more violent, so it should be stored in a low temperature environment! (Temperature requirement -1 0).

2: It should be placed in an environment with moderate humidity (humidity requirements of 85% 95%)

3: Hypoxia, (3% 5% of the modified atmosphere index).

Of course, it is dry and low oxygen, and the most important thing is low temperature, in a low temperature, low oxygen and dry environment, the metabolism of microorganisms around fruits and vegetables or on the surface will be inhibited, and the metabolism of fruits and vegetables will also slow down, which can be conducive to the long-term preservation of fruits and vegetables.

To say that the preservation of vegetables and fruits should be very particular, first of all, fresh and undamaged vegetables and fruits should be placed on special shelves, and the temperature should be set to a specific temperature range for storage.

It's best not to pick, it's good to keep it fresh for the longest time, hehehe.

There are still many ways to fruit insurance, which can be roughly summarized into three conditions: leakage type.

Low temperature: This is easy to understand, generally speaking, we will put perishable fruits in the refrigerator, because low temperature can inhibit the respiration of fruits.

Reduce the consumption inside them.

Low oxygen: This return to the ear is generally carried out at the same time as low temperature, low oxygen is to reduce the concentration of oxygen, what we often do is to use plastic wrap.

Wrap the fruits, so that they and the air contact with the plastic wrap is reduced, it should be noted that low oxygen is not anaerobic, and the anaerobic conditions are not conducive to fruit insurance, which will make the fruit more perishable.

Comfortable and dry temperature: In addition to low temperature and low oxygen, the storage of fruits also needs a suitable relatively dry environment, and at the same time, it should be noted that the storage temperature of fruits needs to be above zero, not below zero, and the temperature above zero is just the environment where the fruit is just threatened but will not feel oppressed, if the temperature is too high or too low for the fruit is fatal.

Respiration.

Respiration is one of the most basic physiological processes in the harvesting of vegetables. Fruits and vegetables need to undergo respiration to maintain normal life activities; But on the other hand, if the respiration is too strong, the stored organic matter will be consumed too much, the content will be rapidly reduced, the quality of fruits and vegetables will decline, and the excessive respiration will also accelerate the aging of fruits and vegetables and shorten the storage life.

In addition, respiration produces many intermediate products in the process of decomposing organic matter, which are the material basis for the further synthesis of new organic matter in the plant.

How to keep fruits fresh.

Broadly speaking, there are two ways to keep it fresh:

1. The main physical methods are: low-temperature storage, controlled atmosphere storage, decompression storage, electromagnetic radiation storage, etc. Among them, the more advanced preservation technologies mainly include critical low temperature and high humidity preservation, intercellular water structured modified atmosphere preservation, ozone preservation, etc., although these preservations are widely used, but they require special equipment, complex operation, high cost, and have certain difficulties in large-scale use.

2. The chemical methods mainly include preservatives to keep fresh. Common preservatives include: paint applicators, ethylene treatment agents (absorbents), bactericidal and antiseptic preservatives, etc.

If it is used for household preservation, it is recommended that chemical preservatives be used sparingly, and most of them generally use physical methods, such as low-temperature storage (refrigerator), cellar, exhaust sealing or placement in water (low temperature and high humidity), and often need to be assisted by fresh-keeping cold storage.

It mainly inhibits cell growth, controls temperature, humidity, germs, and oxygen consumption.

1.Wrap in plastic wrap and put in the refrigerator.

2.Many common fruits, such as pears and apples, if these fruits are ripe when they are purchased, then we can roll them straight into a bag or plastic wrap and put them in the refrigerator to store Dahui.

3.If it is a fruit with a relatively low moisture content, then we can wrap them well, then tie a few holes in the bag and put them in the refrigerator.

4.This is done to avoid losing water from the fruit too quickly.

5.Put it in a plastic box.

6.Fruits that are easy to spoil, such as strawberries, can be put in a plastic box first, and then put in the refrigerator for storage, eat as much as you want, wash as much as you want, and avoid spoilage.

7.Store at room temperature.

8.If the fruit you buy back is not ripe, it needs to be stored at room temperature, and there is no way to get ripe if you avoid putting it in the refrigerator.

9.Tropical fruits, such as durian and mango, should not be put in the refrigerator, but should be kept in a cool, ventilated place.

10.If we buy too many fruits, we can wash them first, wash the skin, wrap them one by one in plastic wrap, and then put them in the refrigerator.

11.Raw fruits can be stored in the refrigerator after they are ripe at room temperature and cannot be eaten within a few days.

Generally, temperate fruits such as grapes, apples, pears, etc. , it can also be kept fresh in the refrigerator。Bananas and mangoes, on the other hand, turn black at 10 times of storage.

When pineapples are stored at 6 -10 years, not only will the skin change color, but the flesh will also be soaked in water. There are also lychees, longans, rambutans, etc. When stored at 1 -2 o'clock Celsius, the exocarp will become darker and the endocarp will appear with scalded spots.

Such fruit can no longer be eaten. Fruits should also be classified for preservation, and they should not be blindly stuffed into the refrigerator. The first category should not be put in the refrigerator, otherwise it will get frostbitten.

Such as bananas, star fruit, loquat, etc. The second can be kept in the refrigerator, but it must be ripe first (i.e., unripe fruits cannot be kept in the refrigerator). Such as durian, mango, Shakyamuni, passion fruit, persimmon, papaya, etc.

The third type must be put in the refrigerator to last a long time. Such as: peach, mulberry, plum, lychee, longan, rambutan, cherry, chestnut, guava, grape, pear, strawberry, mangosteen, dragon fruit, sweet melon, grapefruit, etc.

The fourth can be stored at room temperature or refrigerated. Such as: lemon, pineapple, grape, orange, olive, jujube, apple, watermelon, orange, coconut, grapefruit, sugarcane, etc.

Peaches, mulberries, plums, lychees, longans, rambutans, cherries, chestnuts, guavas, grapes, pears, strawberries, mangosteen, dragon fruit, melons, grapefruits, lemons, pineapples, grapes, oranges, olives, dates, apples, watermelons, oranges, coconut, grapefruit, sugarcane, etc. Temperate fruits can be kept fresh in the refrigerator. <

Peaches, mulberries, plums, lychees, longans, rambutans, cherries, chestnuts, guavas, grape backbones, pears, strawberries, mangosteens, dragon fruits, melons, grapefruits, lemons, pineapples, grapes, oranges, olives, dates, apples, watermelons, dregs oranges, coconut, grapefruit, sugarcane, etc. Temperate fruits can be kept fresh in the refrigerator.

Fruit refers to the edible plant fruit that is juicy and has a predominantly sweet and sour taste. Fruits are not only rich in vitamins and nutrients, but also can promote digestion.

Answer] B Answer Analysis] Test Question Analysis: The new coarse He Yun fresh fruit is wrapped in a fresh-keeping rock beam bag, and the fruit cells are weakened due to the reduction of oxygen, the respiration is weakened, and the organic matter that decomposes and trembles is reduced, which can prolong the storage time, the main principle is not to reduce water loss, nor is it to reduce the damage to the peel and maintain the temperature, so A, C, D are wrong, B is correct, choose B

Test Center: This question examines the application of respiration and is intended to test the candidate's ability to apply what he has learned.

a. Under hypoxic conditions, the intensity of aerobic respiration is weak, and anaerobic respiration is inhibited; The preservation of the fruit requires proper humidity to maintain sufficient moisture in the fruit; Moreover, the low temperature above zero is conducive to reducing the enzyme activity, and then reducing the intensity of respiration, a is correct;

b. Sub-zero low temperature is easy to frostbite plant tissue cells, so that the quality of fruits decreases, B error;

c. In the absence of oxygen, plant tissues will carry out anaerobic respiration to produce alcohol, which will reduce the quality of fruits, and fruits need a certain water content and cannot be stored under dry conditions, c is wrong;

d. Under the condition of no carbon dioxide, aerobic respiration may be enhanced, and a certain humidity is required for fruit preservation, and the moisture content of the fruit will decrease under dry conditions

Therefore, a