The fruit shop owner will never tell you the secrets of choosing fruits. I will tell you all today!

In the hot summer, eating a piece of icy cold watermelon, a sweet lychee, or a refreshing mangosteen is a pleasure. So, how can you choose the fruit you like? There are various tips circulating on the Internet, such as pinching the mangosteen to see the freshness, and tapping the watermelon to listen to the sound. Are these tips reliable? Do you have to choose a soft mangosteen? Can a good watermelon really be tapped?

01

Soft-shelled mangosteen is the best mangosteen

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1. Pick the big one;

2. Choose the ones with purple-red shell and green leaves;

3. Choose the ones with soft shells;

4. Look at the number of petals on the mangosteen's "butt" flower petals, which correspond to the number of petals on the flesh .

I once had a painful experience, that is, I bought a lot of hard-shelled mangosteens at a very low price, and tried to open the shells with a kitchen knife at home. After opening, the flesh was already brown and oozing with pungent juice, which was completely inedible.

From an anatomical point of view, the shell of mangosteen is a complete peel, which is equivalent to the "skin and flesh" of the apple we usually eat. The usable "flesh" of mangosteen is actually some appendages (aril) wrapped around the seeds. For the sake of convenience, we still call them "shell" and "flesh".

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The shell of fresh mangosteen is actually relatively soft. As the shell cells metabolize, the shell will dehydrate and gradually produce more and more lignin, becoming harder and harder. The dehydrated and hardened shell can no longer protect the white flesh. Air rushes in from the gaps above, and the mangosteen fruit has a very strong respiration, which consumes sugar very quickly. At the same time, it produces acids, aldehydes and other substances that affect the taste, and the deteriorated flesh is unfit for consumption.

When choosing mangosteen, first look at the size. Choose a large one, as the flesh inside is full. Then look at the color. Make sure to choose a mangosteen with a purple-red shell and bright green sepals . Then look at the texture of the shell. If it can still be scratched by a fingernail, it means the mangosteen is fresh . If the shell of the mangosteen has turned brown and hard, it means that the mangosteen is no longer edible.

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In addition, there is another trick to choosing mangosteen, which is to look at the mangosteen's "butt". At the bottom of each mangosteen, there is a flower-shaped umbilical pedicle. Carefully count the number of "petals" on the umbilical pedicle, and you can guess the number of lobes in the flesh . This is because the umbilical pedicle is the remains of the stigma, and the number of stigmas is consistent with the number of mangosteen ovaries. Therefore, in this way, you can guess how many lobes there are in the mangosteen flesh without peeling it. Generally speaking, the number of lobes will be maintained at 4 to 7.

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02

How to choose watermelon

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1. Choose watermelons with small "navels" and thin skins;

2. Choose the ones with green vines, which means the watermelon is fresh;

3. The melon vines with fewer prickles are more mature;

4. Melon sorting method: raw melons have a crisp sound, while ripe melons have a low tone.

There are many tips circulating on the Internet, such as looking at the grain, looking at the vines, and listening to the sounds. Are these methods effective?

Let’s talk about the vine first. Generally speaking, a small “navel” of a watermelon means that the skin is thin; a green vine means that the watermelon is fresh and has not been stored for too long after being picked; and fewer thorns on the vine mean that the watermelon is more mature and can be eaten sweeter .

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Let's talk about the rind texture. This does make sense, because different varieties of watermelon do have some differences in rind texture. But now the variety is clearly written on the product label, so looking at the rind texture is not very meaningful.

Finally, let’s talk about the method of tapping the watermelon and listening to the sound. Although the “tap the watermelon method” sounds mysterious, it is actually a very reliable method (you can refer to the article published by Science Popularization China, “No need to ask the “watermelon tapper”, you can tell whether the watermelon is sweet by looking here!”). There are two criteria for tapping the watermelon:

The raw melon eggs sound crisp when slapped;

When you tap a ripe melon, it makes a low-pitched sound .

The principle of this method is that the cells of unripe watermelons are tightly connected, and when they are tapped, the sound frequency is high, so it sounds crisp; in the late stage of ripening, the cell walls of watermelons will be degraded in large quantities, the water content of the cells will also decrease, and some loose structures will be formed , so the tone of the sound after tapping is relatively low. However, in order to select individuals with appropriate maturity, it takes a lot of experience.

In fact, any tricks are not as good as a reliable supermarket or a reliable fruit stall, and the owner of the watermelon seller. Because the growth period of watermelons is fixed, the owner knows when the watermelons are ripe and which batch of watermelons is the most suitable time to pick.

If you really don't know how to choose a watermelon, it's a good idea to get along well with the owner of the fruit stall...

03

Choose lychees with pointed mouths and monkey cheeks

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1. Choose lychee shells that are elastic;

2. Choose lychees that are bright in color and not dull;

3. Choose the one with fragrance;

4. Choose the one with a sharp-nosed and monkey-faced appearance .

Bai Juyi commented on litchi in his “Preface to the Lychee Picture”: “If it is separated from the branch, its color will change in one day, its fragrance will change in two days, its taste will change in three days, and after four or five days, its color, fragrance and taste will all be gone.” This characteristic is determined by the structure and physiological characteristics of the litchi fruit.

Like mangosteen, the edible part of lychee is not the peel like peach, but the "aril". And when the peel loses water, it cannot be replenished from the lychee flesh. Therefore, after picking, lychees will quickly dehydrate and change color, which will affect the taste.

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Criteria for identifying fresh lychees: First, the lychee shell should be elastic . If it is stuck to the fruit, it is no longer fresh. Second, the color should be bright and not dull. If it is dull, it means it has been picked too long ago. Third, fresh lychees have a fragrance . If you can't smell it, it means it is not the freshest lychee.

There is another little trick to choosing lychees: don’t choose those that are round and plump, choose those with pointed noses and monkey cheeks . Because the seeds of the latter are small enough and the flesh is thick enough. Of course, the fruit with well-developed seeds is more beautiful. When the seeds secrete enough hormones, the shape of the lychee fruit is round and full, and the color will be beautiful, but the large seeds inside cannot be eaten. Although the pointed nose and monkey cheek lychees don’t look good, the flesh is fuller and more satisfying to eat.

Finally, I wish everyone can choose good fruits.

Author: Shi Jun

Reviewer: Wang Kang, Director of the Science Museum of the National Botanical Garden

Na Zhang, Associate Researcher, Peking University School of Public Health, Doctoral Supervisor

Planning Editor: Cui Yinghao

Editor-in-charge: Cui Yinghao