Are Misshapen Fruits Carcinogenic? Are They Actually Edible?
Are misshapen fruits actually edible? This is the season when all kinds of fruits are coming to market. Among the dazzling array of fresh and tender fruits, there are some with strange, bumpy, and deformed shapes. When people pick fruits, they naturally choose those with smooth and fresh skins, leaving the ugly-looking ones behind.
In Chinese folklore, there's a saying that misshapen fruits taste better; another, contrary view, claims that these deformed fruits are like "plant cancer" and should not be eaten.
There are many factors that can cause a plant's fruit to become deformed, including radiation. Scientists have conducted experiments by taking crop seeds (such as peppers) on artificial satellites, where they were exposed to space rays. The fruits cultivated from these seeds not only grew larger but also had brighter colors. However, the specific reasons for the fruit mutations require further study.
Besides radiation, other physical stresses like water deficit, low temperatures, high temperatures, and strong light, as well as various factors such as saline-alkali conditions, environmental pollution, diseases, pests, and weeds, can cause changes in fruit shape. In professional terms, these factors are all called "adverse stress," which refers to environmental factors that exert a harmful influence on plants, preventing the fruit from growing under normal conditions. Since these are all harmful factors, does that mean eating such fruits is harmful to human health?
Not necessarily. For example, there is currently no evidence that radiation from such sources harms human health. On the contrary, some foods irradiated with rays are beneficial to people's lives. For instance, chestnuts irradiated with γ-rays can be stored for a longer time. Fruits cultivated after exposure to space rays not only grow larger and have brighter colors but are also rich in nutrients and beneficial to the human body.
Therefore, to some extent, the folk saying that misshapen fruits taste better has some merit. Additionally, there is another folk saying: "A worm-eaten peach or a rotten plum is incredibly delicious."
Why Are Misshapen Fruits Tastier?
Why do misshapen fruits like these反而 (on the contrary) taste better? Could it be that plants, too, produce "talents through adversity"?
Fruits grown under appropriate adverse stress tend to ripen more easily because such stress often stimulates the faster release of ethylene in the fruit, and ethylene is a substance that promotes fruit ripening. The main ingredient in commonly used fruit ripening agents is this substance.
Ethylene can promote the conversion of accumulated starch in the fruit into disaccharides (like sucrose) or monosaccharides (like glucose, fructose, etc.), and it can also reduce the fruit's acidity. Some special fruits, such as persimmons, bananas, and kiwis, cannot be eaten immediately after harvesting but need to be stored for a period of time. A freshly picked persimmon is astringent because it contains soluble tannins. The release of ethylene can promote the conversion of soluble tannins into insoluble ones, reducing the astringent taste. By the same logic, during the post-harvest storage of bananas and kiwis, ethylene also induces an increase in soluble sugar content, a decrease in acidity, and the synthesis of aromatic substances, allowing their unique flavors to develop.
For "worm-eaten peaches and rotten plums" that have been "bitten" by pests or "misshapen fruits" caused by physical adversity, the stress before maturity can accelerate ethylene synthesis within the fruit, promoting an increase in soluble sugar content and earlier ripening. Therefore, compared to fruits that are not yet ripe, they have already matured, and the expected flavor of the fruit has begun to appear. So, from this perspective, the folk saying also has some truth to it. However, since the mid-1990s, China's fruit cultivation area and output have ranked first in the world and remain so today. People no longer worry about not having enough to eat. The once "incredibly delicious" "worm-eaten peaches and rotten plums" are now considered substandard products, unsuitable for dining tables and even less for major markets.
As early as the 1980s in Japan, someone cultivated square watermelons for sale. These watermelons were sought after by many as soon as they hit the market because they were so novel and strange. If the saying about misshapen fruits being tastier holds true, these watermelons should be even more delicious. Is this the case? And how were they cultivated?
Are Misshapen Fruits More Nutritious?
Not necessarily. In fact, they are not much different from regular fruits, only in shape. The texture of a fruit is mainly judged by its sweetness, sourness, aroma, and moisture content.
The accumulation of sugar in fruit generally follows a process. In the early stages of growth and development, the fruit mainly accumulates polysaccharides like starch. At this point, the fruit is not sweet at all because these substances have no sweetness. However, as the fruit ripens, polysaccharides slowly convert into monosaccharides or disaccharides, which are sweet. When the polysaccharides are almost converted and the monosaccharides or disaccharides have accumulated to a certain level, the fruit enters the ripening stage. Many fruits have the best taste when they are 80-90% ripe, and such fruits can be stored for a period of time. When the sugar in the fruit further converts, and the polysaccharides are completely converted into monosaccharides, which then gradually break down, the fruit becomes fully ripe (100% ripe). At this stage, although the fruit is sweet, it often lacks sourness and is not suitable for long-term storage; it needs to be eaten immediately after picking. If the fruit is overripe, its texture is no longer good because the fruit continues to respire. At this point, the monosaccharides are consumed by respiration, the cellular structure begins to break down, and some original characteristics, such as the fruit's crispness, are completely lost. The tissue becomes soft, mealy, and its water content decreases, making it unpalatable.
Whether the fruit is normally shaped or strangely shaped, it goes through this same growth process. Therefore, the texture of square watermelons or apples with characters on them is essentially not much different from that of ordinary fruits.
Although the texture of these fruits hasn't changed, what about their nutritional value? Has it changed in some way? The nutrition we talk about in fruit mainly includes sugars, proteins, fats, minerals, vitamins, fiber, etc. Among the nutrients we care about, such as minerals and vitamins, their proportion in the fruit is less than 1%, with the rest being mostly water. Therefore, fruits under adverse stress are not significantly affected in terms of nutrition. They don't become particularly good for the human body just because they are deformed.
Moreover, not all adverse stress is beneficial to fruits; sometimes it has the opposite effect. So, which types of adverse stress are actually harmful to fruits?
Can Bizarrely Shaped Fruits be Man-Made?
Cultivating such peculiar fruits is actually quite simple. For square watermelons, all you have to do is place a square box around the fruit as it begins to form, then replace it with a larger square box as the watermelon grows, until it is fully mature. This way, the watermelon that grows will be square.
Besides square watermelons, heart-shaped pomelos and apples with auspicious characters have also appeared on the market.
Cultivating these peculiar fruits is also simple. The heart-shaped pomelo is just like the square watermelon: a mold is placed around the fruit to shape its growth. As for making characters grow on fruit, it's easy too. A simple method is to stick a paper-cut on the fruit before it starts to change color. To create characters with a depressed (indented) look on the fruit, the method is actually the same as for the square watermelon: a mold is placed on the outside, but this time the mold is engraved with the desired characters. When the fruit is fully grown, the mold is removed, revealing a fruit with a raised and indented pattern.
It is said that these bizarrely shaped fruits are not cheap; they can be several times or even dozens of times more expensive than ordinary fruits. So, are these unique fruits better in terms of taste and nutrition than regular fruits?
How Did a Pumpkin Turn into "Wood"?
First, the method of using stones or molds to press and shape the fruit has certain drawbacks. Plants have a certain ability to resist pressure, just like humans, but there is a limit. Someone once conducted an experiment with a pumpkin, placing a stone on it as it began to grow. The weight of the stone was within what the fruit could bear, and as the pumpkin grew larger, heavier stones were used until it was mature. When people cut open this pumpkin, they found it was incredibly hard, and the flesh inside had become woody and inedible. Wang Liangju explained that this was because the fruit was under continuously increasing pressure, causing its cell walls to thicken, the cells to arrange themselves densely, the fibers to coarsen, and the tissue to harden. Such a pumpkin becomes as hard as a stone, and from a texture perspective, it is certainly not good to eat.