Editor's note: From the deep sea to the mountains, from deserts to rainforests, plant imprints are found everywhere on earth. A world of changing years, climate change, geological movement, habitat change, plants that have endured and remain diverse in evolution. Voice of the Chinese Academy of Sciences and the Wuhan Botanical Garden of the Chinese Academy of Sciences jointly opened "Flowers and Flowers of All Things", where we pay attention to the survival, competition, reproduction and death of plants, display the strange and colorful nature of the natural world, interpret the thousands of meteorological phenomena of life, explore the magical secret of life, and pay tribute to this silent and vigorous world.
In the landscape greenhouse of the Wuhan Botanical Garden of the Chinese Academy of Sciences, there are several humble evergreen shrubs, half a person tall, with many short and dense twigs, leathery leaves, and flowers that grow alone or in clusters between the axils of fruit branches and leaves or on old branches. If you happen to come in early summer or mid-summer, you may see several orange-red peanut-like fruits hanging from its branches, with a smooth appearance and only a thin layer of flesh. This seemingly unremarkable oval fruit, sour and sweet to eat, seems to have nothing magical. However, just eat a little bit of this pulp, and then eat the lemon after about half an hour, and you will be surprised to find that the lemon becomes sweeter!
This magical little fruit is the mysterious fruit Synsepalum dulcificum, also known as the flavored fruit, belonging to the family Shanlanaceae, native to tropical West Africa, and was introduced to China in the 1960s. The mysterious fruit itself does not have a sweet taste, but it can modify the sense of taste, such as eating sour fruits to taste sweet.
Mystery Fruit Synsepalum dulcificum (Image: Flora of China)
Why can the mysterious fruit change people's sense of taste?
The mysterious fruit in the pulp of the mysterious fruit is a kind of flavor change protease, which can regulate people's taste, make people eat sour and feel sweet, and this flavor change function is very sensitive, only a small dose can show a high degree of taste change function.
There are currently several explanations for the mechanism of this taste change: some studies believe that after eating the mysterious fruit, the acidic substance is reduced by the sweet substance; some people think that the flavor change function of the mysterious fruit is because the taste change after encountering acid changes its own conformation and bonds with the sweet taste receptor, making people feel the sweetness; and the researcher Yamamoto believes that after eating the mysterious fruit, the taste caused by the acid substance is processed during transmission, and only the sweet signal reaches the central system.
So the question is, why do many people feel sour when it comes to lemons?
Sour taste is caused by the sensation caused by the stimulation of hydrogen ions in the mucous membrane of the tongue, so the substances that can ionize hydrogen ions in solution are sour substances. Vinegar is acidic, its main ingredient is acetic acid, but also rich in calcium, amino acids, succinic acid, grape acid, malic acid and so on. Many fruits have a sour taste, which is caused by citric acid, malic acid, acetic acid, tartaric acid, etc. in plants, such as citric acid in lemons, malic acid in apples, and tartaric acid in sour grapes.
In addition to the lemons and plums that everyone is familiar with, today I will introduce two special sour plants to you.
Sour horns that are more acidic than lemons
Acid horn (Tamarindus indica), also known as capers and tamarind seeds, is native to the savannah of Africa and is an evergreen tree that is used for medicinal and food purposes. Sour horn trees grow slowly, growing for ten years, flowering for ten years, fruiting in ten years, and have a lifespan of up to 200 years, of which the economic lifespan is about 100 years. Acid horn is drought tolerant and prefers light, suitable for dry and hot river valley cultivation, and is very common in Yunnan, Hainan and Liangguang. Its trunk is tall, stout, sparsely leafed, and perennially green, with bunches of tan curved hook-shaped pods hanging from the branches, which often shrink irregularly and look a bit like dry laurel balls.
Acid corner Tamiridus indica (Image source: Flora of China)
People who have eaten sour horns must remember the sweet and sour taste, eat the tongue, the root of the teeth are almost sour, it is even more sour than lemon. Studies have shown that the pulp of the horned fruit is rich in a variety of organic acids, sugars, vitamins, amino acids, proteins and mineral elements. Among them, organic acids are mainly tartaric acid, which is much higher than the content in lemons and plums, which can be described as the preferred object of "hoping for plums to quench thirst".
Sour horn seeds are rich in tamarind polysaccharides, which are similar to pectin but have higher performance in food thickeners and stabilizers. The flesh of the sour horn is rich in multi-purpose nutrients, and in addition to raw food, it is often used to make various flavor snacks, such as the sour horn cake of "Yunnan Eighteen Monsters". The leaves, flowers and fruits of the sour horn tree all contain acidic substances that can be used as dyes. In addition, the wood material of the sour horn tree is hard and dense, and it is known as the "Oriental Sacred Tree".
Sea buckthorn in an ant forest
Well, you read that right, it's that ant forest in some software.
Hippophae rhamnoides, a genus of sea buckthorn in the family Cyprinidae, is a thorny deciduous shrub that often grows on dry riverbeds or hillsides of the Loess Plateau. Sea buckthorn is extremely drought tolerant, extremely barren, extremely resistant to heat and cold, can be described as a very skinny plant, so it is often widely used for soil and water conservation, rapid restoration of vegetation. The data shows that a sea buckthorn tree can stabilize 4 cubic meters of land, purifying itself 40 times more air.
Hippophae rhamnoides of sea buckthorn (Image: Flora of China)
Sea buckthorn, also known as vinegar willow, sour willow, you can hear the sour taste from the name. Sea buckthorn orange yellow or orange red fruit eats very sour, the sour taste in the fruit is because it contains a large number of carboxylic acid, phenolic acid and fatty acids, of which the carboxylic acid content is 3.5% to 4.49%, mainly malic acid, succinic acid, ascorbic acid (vitamin C), oxalic acid, citric acid, tartaric acid, etc., the sour taste is better than lemon.
The content of vitamin C in sea buckthorn is very high, up to 950mg/100g. In addition, sea buckthorn fruit is also rich in bioactive substances, which can be widely used in food, medicine, light industry, aerospace and other fields. In addition to fresh food, sea buckthorn fruit has been processed into juices, fruit wines, jams, preserved fruits and other foods.
So how many sea buckthorn trees have you planted in the ant forest?
bibliography:
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Source: Wuhan Botanical Garden, Chinese Academy of Sciences