Grape frosting, also known as fruit powder, is a sugar alcohol substance secreted by grapes themselves, which is harmless to human body and can be eaten. These hoarfrost are not easy to clean because they are natural synthetic substances and insoluble in water. Frosting on the surface of grapes has a good protective effect on grapes, which can not only reduce the evaporation of water, but also avoid the shrinkage of grapes caused by picking. Reduce the probability of grape infection with germs, and also contain yeast.
Cleaning grapes is a technical job. Intelligence army shares small coup!
Beat a basin of water first, add flour (about a spoonful) and mix well. After standing for about 2 minutes, swing the grape handle left and right in the water, paying attention to the gentle movement. Swing until the water becomes turbid and then wash it clean.
The principle of this method is that flour water is sticky, and washing grapes in this water will stick some hidden things to the surface by flour water, so that the grapes will be washed naturally. At this time, rinse the grapes with clear water and you're done. It is a convenient and healthy method without adding detergent. Lycium barbarum, dried dates and raisins at home can be cleaned in this way.
In addition, it is best to wrap the grapes in paper and keep them in the refrigerator. Plastic bags should not cause frosting or even rot on the surface of grapes.
This is correct, because grape skins are rich in nutrition. "Eat grapes without spitting grape skins" is no longer a tongue twister, but the motto of scientific diet. The content of resveratrol in grape skin is the highest, reaching 50- 100 μ g/g, which is the highest among more than 70 kinds of plants for human consumption, such as peanuts. Resveratrol has been found to have a very high anticancer effect. Grape skin, especially purple grape skin, contains a flavonoid that can lower blood pressure. It can promote the increase of high-density lipoprotein in blood, thereby reducing the content of harmful cholesterol in blood, preventing atherosclerosis and protecting the heart. Studies have shown that the darker the color of grape skin, the higher the content of flavonoids. Some grapes are purple, but they actually contain a nutrient-anthocyanin. Anthocyanin is a kind of flavonoid, which is commonly found in the tissues of grapes, purple cabbage, blueberries, eggplant skins, cherries, red oranges, strawberries, mulberries, hawthorn skins, perilla, black (red) rice and other plants. Anthocyanins contained in grape skin have strong anti-oxidation, anti-mutation, relieving liver dysfunction and protecting cardiovascular system. In addition, grape skin is rich in cellulose, pectin and iron, which can supplement the nutrition lacking in modern people's diet. It can be seen that the scientific way to eat grapes should be to eat them with skin, especially for elderly friends. Eating grapes regularly is good for health and longevity. Wash the skin clean when eating. Some nutritionists suggest that the peel should be thoroughly washed before eating grapes, and the whole mouth and even the belt should be eaten together, so that the nutrition will reach "100%".
Hello! From the perspective of pesticide residues, it is better not to eat grape skins. After all, there are still many cases of spraying pesticides on fruits. However, eating grapes will get angry. Then I suggest soaking the skins of the grapes together, so as not to get angry. You can soak the grapes in water for a period of time in advance (if you are not afraid of trouble, it is best to change the water twice). If you eat this way, most pesticide residues can be removed.
Eating grapes without spitting grape skins and not eating grapes without spitting grape skins are tongue twisters that we often talk about. Then, in our daily life, do we have to spit grape skins when eating grapes? This seemingly small problem contains great dietary nutrition and health.
A brief history of grapes
Grape, called grape in ancient times, belongs to Vitaceae and Vitis, is a deciduous vine and an ancient fruit tree. According to research, grapes have spread all over Europe, Asia and North America about millions of years ago. The earliest written record about grapes in China can be found in the Book of Songs, Nan Zhou Polygonum: "There is Polygonum in the south, and Ge hates it, but only a gentleman can get its blessing." [ 1]。 Visible grapes have been loved by people since ancient times.
Nutritional value of grape skin
Grape has good color, fragrance, taste and shape. Grapes have a high sugar content and most of them are easily absorbed by people. Grape contains 0.5- 1.4% organic acid, which is more helpful for digestion. Eating more grapes can strengthen the spleen and stimulate appetite. It contains protein 0. 15-0.9%, minerals such as potassium, calcium, phosphorus and iron 0.3-0.5%, and vitamins.
Eating grapes often is good for neurasthenia and fatigue, and it is also excellent for the general population. Some grape products, such as raisins, red wine and grape juice, are also good products. A proper diet is conducive to a balanced nutrition.
Then, if we eat grapes, what nutrition and efficacy does its skin have? Knock on the blackboard and draw the key points!
1. anthocyanin
The attractive purple color of grapes actually contains an ingredient-anthocyanin. Anthocyanin is one of the main pigments that constitute the color of petals and fruits, mainly distributed in epidermal cells and lower epidermis, so grape skin contains more anthocyanins than pulp.
Anthocyanins can not only color fruits, but also play an important role in scavenging free radicals (when free radicals are uncontrolled, they will destroy the genetic material DNA of human cells). Because anthocyanin is also a polyphenol pigment, it has strong antioxidant capacity, which is 20 times that of vitamin C and 50 times that of vitamin E.
2. resveratrol
In addition to anthocyanins, grape skins also contain another antioxidant: resveratrol, which is a plant antitoxin produced by vines to resist mold invasion. This substance was first discovered in grapes in the 1970s, and it still remained in grape skins after the plant antitoxin was produced, so the content of resveratrol in grape skins was the highest, reaching 50 100mg/kg.
With the deepening of research, it is found that it has the functions of antioxidation, scavenging free radicals, anticancer, reducing blood lipid, preventing cardiovascular diseases and delaying aging [3].
In addition, grape skin is rich in cellulose, pectin and iron, which can supplement the nutrition lacking in modern people's diet.
The correct way to eat grapes
Described the benefits of so many grape skins, then, when we eat grapes, do we swallow them together to get the protection of these powerful antioxidants?
First of all, we should know that the solubility of anthocyanins, resveratrol and other antioxidants in grape skin is not high [3], which means that most nutrients are difficult to be absorbed by our bodies.
The Nutrition Society of China suggests that everyone should eat 200-350g of fruit every day (if you eat too much, you can't absorb it, which is equivalent to eating it from the intestine). For a balanced nutrition, eat 1 to 3 kinds.
This means that even if we eat grapes and skins every day, it doesn't mean how many doses of antioxidants our bodies will absorb, and we can't achieve the expected results.
Secondly, at present, in China, the prevention and control of diseases and insect pests in grape planting needs to take targeted prevention and control measures according to different diseases and insect pests and different growth periods of grapes. The main means is usually chemical spraying [4]. Therefore, some grapes sold in the market have pesticide residues.
But how much residue will there be? The Standards for Safe Use of Pesticides and Guidelines for Rational Use of Pesticides clearly stipulate the standards for pesticide residues in food [5]. When our intake is calculated according to the average weight of people, and the total amount of food per day is within the safety valve, then the pesticide residue on grape skin will not affect our health.
So how to ensure that the pesticide residues in grapes remain in the safety valve?
1. Consumers are advised to choose large supermarkets and markets to buy vegetables and fruits, because China has vigorously promoted the market access system for agricultural products in recent years, requiring that agricultural products that meet the quality requirements must be listed for sale.
2. At the same time, after sufficient washing, there is little pesticide residue, let alone any threat.
Considering these circumstances, two conclusions can be drawn:
1. If the quality of grapes is guaranteed and washed adequately, of course we can eat grape skins;
2. When eating grapes, most people will think that the grape skin is astringent and will choose to spit it out. According to their personal preference, or if they are too lazy to wash, it is still recommended to remove the grape skin before eating. They can't absorb much anyway. What is more important is good health or a balanced diet.
References:
[1] Gong. Talking about grapes. [J]。 Low carbon life, 20 1 1, 1 (9): 34-35.
[2] Guo Yuying. Nutritional value of grapes [J]. Northern horticulture, 1992, (4):5 1.
[3] Song Yu. Function and application of resveratrol extracted from grape skin [J]. Gansu Agriculture, 2006, (6):347.
[4] Lu Yuhong. Discussion on the main points of prevention and control of grape planting diseases and insect pests in East China [J]. Agriculture and science and technology, 20 12:87.
Liu Chunhong, Liu Liegang. Food hygiene. [M]。 Beijing: Science Press, 20 15:40-45. ..
The author of this question is Zhao.
From a nutritional point of view, grape skins and seeds contain polyphenols such as resveratrol, proanthocyanidins and flavonoids, which have antioxidant and cardiovascular effects, but because they account for too little of the whole fruit, they will not have much effect.
In terms of taste, the tannins in grape skins and seeds are astringent, which will make people feel astringent at the entrance, and the acid content of grape skins is higher than that of pulp, so it is inevitable that they will be sour when eaten together, which will affect the taste and make people feel that they cannot fully enjoy the sweetness of pulp ~
Many grapes are covered with hoarfrost, which is difficult to wash off. Frost is a sugar alcohol substance, and its main component is a kind of fruit powder called "oleanolic acid", accounting for 60%~70% of frost. In addition, the cream also contains alcohols and esters.
Wine is brewed all over the world. Grapes can be brewed directly at suitable temperature and humidity without adding yeast or base wine. The reason lies in this layer of frost, which is the natural yeast of grape skin. Of course, the pulp is rich in glucose, fructose and sucrose, which can also make grapes naturally form wine without obstacles. The history of wine is as long as that of grape cultivation.
This kind of frost can also protect pulp from germs and reduce water evaporation. In Xinjiang, you can see that many grapes are hung on vines and naturally dried.
Now let's talk about grape skins. I believe many people have heard of the famous Australian health care product: grape seed capsule.
The following is taken from the encyclopedia:
"Chinese name grape seed
Grape seed
The main raw materials are grape seed extract and proanthocyanidins.
The main nutrients are OPC and VE.
Main edible effects:
Antioxidant, free radical scavenging, beauty and health care
Suitable crowd
People with low immunity and skin problems
No side effects. "
Anthocyanin contained in grape skin has the effects of protecting microvessels and anti-inflammation; Resveratrol is a polyhydroxyphenol compound, which can prevent cardiovascular and cerebrovascular diseases and has strong anticancer ability. In addition, it is rich in cellulose, pectin and iron.
Seeing this, do you still spit grape skins when you eat grapes?
The best way to eat grapes is recommended: after washing, the seeds are broken and drunk.
Of course, you can also try your mouth, chew and swallow it.
Off-topic: Into the Wild's high class is to grow grapes and make wine.
In Li Bai's Xiangyang Song, there are:
When people asked them what they were laughing at, they laughed and killed the mountain man.
Cormorant, parrot cup.
36,000 days in a hundred years, 300 cups a day.
Looking at the duck head green in Hanshui from a distance is like the beginning of grapes.
There was no liquor before, and fine wine was wine.
It's best not to throw up, just wash.
1, grape skin contains more anthocyanins than pulp, which has the effects of protecting microvessels and anti-inflammation. It is suggested that the washed hairy meat and seeds should be made into juice so that the nutrition can be completely absorbed. Anthocyanin in grape skin is a strong antioxidant, which can not only effectively remove free radicals and delay aging, but also enhance immunity, inhibit inflammation, resist allergy, prevent eye fatigue and enhance vision.
2. The natural pigment in grape skin can actively promote the decomposition of sugar in human body, effectively resist hyperglycemia and avoid the problem of indigestion caused by eating too many grapes.
3. Improve sleep. Grape skin can stimulate the pineal gland in the brain and secrete melatonin, which helps to regulate the sleep cycle and improve sleep.
Let me ask you a question. Do you spit grape skins when you eat grapes? Some people say that eating grapes does not spit out grape skins, and some people say that grape skins are too dirty to eat. It's troublesome to spit grape skins, but it's unsanitary not to spit. This is really a world problem of eating goods. Today, this article may give you a choice.
First, let's look at the nutritional value of grapes. Looking up the food composition table, we can know that 100g grape contains 0.2g of protein, 0.4g of dietary fiber, 0.04mg of potassium/kloc-0.3mg of phosphorus, and vitamin A, vitamin C, vitamin E, carotene and other nutrients.
To say that the main ingredient of grapes is water, of course it is. In addition, the dietary fiber and polyphenols in it have a great promoting effect on human health. Dietary fiber can improve intestinal function, regulate the metabolism of blood sugar and blood lipid, and prevent some cancers.
So where does dietary fiber mainly exist? Experiments show that the dietary fiber in grapes is mainly located in grape skins and grape seeds. Grape seed is believed that most people will spit it out directly. If you don't even eat the skin, you really waste a lot of nutrition. In addition, the polyphenols in grape skin and grape seed account for 25-50% and 50-70% respectively, which can be said to be a "treasure house of nutrition".
What are the benefits of polyphenols in grape skins and grape seeds? 1, antioxidant
The formation of arteriosclerosis is largely due to the oxidation of low density lipoprotein. Resveratrol can inhibit this oxidation process and play an antioxidant role.
2. Protect the cardiovascular system
Besides antioxidation, the protective effect of resveratrol on cardiovascular system should not be underestimated, especially for patients after bypass surgery, which can relax great saphenous vein and internal thoracic artery.
In addition, grape skin also contains anthocyanins, the role of anthocyanins is mainly reflected in lowering cholesterol and low-density lipoprotein, thus improving platelet function.
3. Reduce the risk of cancer
Eating more grapes can reduce the risk of some cancers, including intestinal cancer, gastric cancer and pancreatic cancer. This is only for healthy people. If you are already a cancer patient, it will have no effect, and you need a series of treatments such as surgery and chemotherapy.
In short, grape skins and grape seeds are healthy and can be eaten after cleaning, but if it is really unacceptable, there is no need to force it. Other foods can also supplement dietary fiber and polyphenols.
As can be seen from the above, don't spit out grape skins and grape seeds, which will waste most of the nutrition of grapes. However, many people are worried about pesticide residues and planting pollution. There is another fundamental reason. Grape skins and grape seeds are not delicious, and they will all be spit out. It doesn't matter if you spit them out because they are not delicious, but if you feel polluted, then I have to say something. You've already chewed in your mouth. You think spitting grape skins and grape seeds will be all right? Actually, you've already eaten.
The best solution is to find farmers to buy directly and buy the kind they eat. Absolutely no problem. My mother-in-law's family specially planted 3 mu of grapes, which were not sprayed with chemicals. The granules were not big, but they sold well and the price was high. Dried raisins are also more delicious than those with medicine.
Most of the polyphenols in grapes exist in the peel (not to mention seeds and stems), and polyphenols are good antioxidants (anti-aging) and resveratrol and other anticancer substances.
But! The body can't absorb much. Therefore, from the perspective of nutrition and health care, it is really a "natural egg" not to spit skin. But its mouth feels the influence of tannin, which is astringent and not delicious. There are also thin-skinned varieties, which do not affect the taste.
Therefore, it is up to you to decide whether to spit or not.