(Picture from the Internet)
Autumn is the taste of persimmons. Since ancient times, persimmons have been given beautiful meanings and are also known as the "holy product of fruits".
According to legend, ancient people in the Song Dynasty would place a kind of li market called "Pepsiji" on the dining table during the Chinese New Year, which means that persimmons, oranges and cypress branches are placed on the same plate, first break the cypress branches, and then break the persimmons and oranges in turn. This is "cypress persimmon orange", which means "all-auspicious".
Nowadays, persimmons are often expressed by people for their good expectations, such as "persimmons are good for their wishes", "good persimmons are in pairs", etc. However, people have different opinions on eating persimmons, and some people even dare not eat persimmons. How about persimmons? We are here to overturn the persimmon!
Why are persimmons astringent and
sweet?
Some persimmons are sweet when they bite, while others make their tongues numb. The ingredient that causes this taste difference is the tannin contained in persimmons, also called tannin .
When the tannins in food touch the tongue, they will feel astringent because tannins will cause proteins in saliva to condense into clusters, thereby increasing surface friction. The lower the ripening fruit, the higher the tannin content and the more astringent it tastes. [1]
Among common fruits, the tannin content of persimmons is the second best.
However, the astringent taste of persimmons is also related to the variety, and it is divided into four categories: sweet persimmons , incomplete sweet persimmons, astringent persimmons, and incomplete astringent persimmons. The soluble tannin content of the latter two is significantly higher than that of the former two. The tannin content of
persimmons can reach more than 4% at the highest, and the lowest is about 0.5%. [2] Sweet persimmons and incomplete sweet persimmons can naturally deafen on the tree as their maturity increases, while astringent persimmons and incomplete astringent persimmons must be artificially deafen after picking. [3] After removing the astringent persimmon, the astringent taste becomes lower and the sweetness is obvious.
How can persimmons become "not astringent" in
?
Most of the persimmon sweet persimmons are bought on the market. Even the astringent persimmons will be manually removed and then sold. But if you buy persimmons at a personal street stall, it is likely that they have not been treated with astringent treatment. The more astringent the taste, the higher the content of tannins. This astringent taste is really difficult to swallow. What should I do?
There are many ways to remove persimmons by themselves.
1, and seal with ripe fruit: some ripe fruits will release ethylene , such as bananas. Because ethylene has small molecules and is a gas at room temperature, it can easily spread to other tissues and the external environment. [4] Ethylene can promote persimmons to produce acetaldehyde . In the hypoxia or anaerobic state, it can also activate ethanol dehydrogenase to produce a large amount of acetaldehyde, which promotes the condensation of soluble low-molecular tannins with astringent taste, forming insoluble polymer condensation tannins, which will disappear and achieve a deafing effect. [5]
2. Soak in warm water: Soak the persimmons in warm water at 40℃, continue to heat, and keep them for 16-18 hours [6], which will produce more acetaldehyde and shorten the deaerating time. However, if the temperature is too high and exceeds 60℃, astringent may occur. [5] After removing the astringent, the persimmon fruit is softer and you should eat it as soon as possible.
3. Deaerating the astringent water: Putting persimmons in cold water for anaerobic respiration can produce ethanol, acetone, and , and then turn into acetaldehyde to deaerate. This method of deaerating astringent takes a long time, but is easier to operate and has a crisper taste than warm water to deaerate astringent. [5]
4, frozen persimmons thawed and deaerated: The purchased persimmons can be placed in the freezer chamber of the refrigerator to be frozen slowly. Studies have found that slowly frozen persimmons can be removed after thawing, while the fast-frozen persimmons cannot be removed after thawing. This may be because slow freezing can destroy cell walls, and cell membranes to produce a large amount of water-soluble pectin and sugar substances, making tannins gel-like and astringent smell disappear. [3]
In addition, northern people often place more astringent persimmons on outdoor windowsills. Over time, the persimmons will naturally become softer and the astringent taste will become lighter.
What nutrition does persimmon have?
Persimmons have a cultivation history of more than 3,000 years in my country, which is enough to show how people love persimmons. This is not only because the persimmons are delicious after being astringent, but also because they are nutritious.
1 and vitamin C: 100 grams of persimmons contain 30 mg of vitamin C[7], which is similar to the vitamin C content of oranges. The weight of a large persimmon is generally more than 200 grams. Eating one can meet the average adult's vitamin C needs throughout the day.
2, β-carotene : The β-carotene content in persimmons is 2210 micrograms/100 grams [8], which is similar to the β-carotene content in carrots (the carrot content is 2653 micrograms/100 grams [7]). Beta-carotene can be converted into vitamin A in the body, which is good for eye health.
3. Dietary fiber: The dietary fiber in persimmons is mainly pectin, accounting for about 5%-8%. [2] It is a type of water-soluble dietary fiber . It can absorb water and expand, and is fermented and utilized by microorganisms in large intestine to promote gastrointestinal motility, prevent constipation, and is beneficial to intestinal health. Pectin also has the effects of lowering blood lipids, preventing arteriosclerosis, and preventing coronary heart disease.
4, flavonoids : Persimmons are rich in flavonoid components, and have antioxidant, anti-tumor, removal of free radicals , and anti-aging.
Rumors about persimmons
1. Eat persimmons on an empty stomach?
cannot be generalized.
Eating persimmons with high tannin content on an empty stomach will increase the risk of gastric persimmon stones.
tannins can form difficult-to-digestible complexes with dietary proteins and sugars in the digestive tract, reducing nutritional value and affecting the effect of gastric enzymes. Under the action of gastric acid, it will also mix with protein, pectin, etc. to form gastric persimmon stones, resulting in stomach discomfort. [9]
If you eat ripe sweet persimmons or persimmons that have been treated with deafness, don’t worry too much. But for children and people with poor gastrointestinal function, it is best not to eat persimmons on an empty stomach.
2. Can’t persimmons be eaten with yogurt? The reason why
has such rumors is because of the tannins in persimmons. It is believed that tannins in persimmons react with proteins in yogurt to produce precipitation, resulting in stones.
In fact, as long as it is a persimmon with low tannin content, you can feel free to match it. Not to mention yogurt, even milk, chicken, beef, etc. are fine.
3. Can’t persimmons be eaten with seafood?
There are rumors that eating persimmons with seafood will lead to poisoning. In addition to tannins, it also means that vitamin C in persimmons will convert pentavalent arsenic in seafood into toxic trivalent arsenic, producing arsenic.
In fact, it is not reliable to talk about toxicity aside. If you want to get poisoned by the combination of persimmons and seafood, you need to eat about hundreds of kilograms of seafood. The normal stomach really can't do it.
4. Can’t you eat persimmons when you are anemia?
Persimmons contain tannins. Under the action of gastric acid, the polymerized persimmon tannins will be redissolved, forming greater insoluble substances with macromolecular sugars and proteins, affecting the absorption of iron, calcium, and other factors and the effective utilization of vitamins A and vitamin B12. [3]
So, friends with anemia are worried that eating persimmons will make them more anemia. In fact, there is no need to worry too much. First, you can choose sweet persimmons with low tannin content. Secondly, you can add iron-rich foods to your diet, such as animal liver, lean meat, razor clams, , etc.
5. Can’t you eat persimmons if you lose weight?
Most of the friends who are in the weight loss period are more concerned about their calorie intake, and the calories of persimmons are higher than those of the apples, grapes, peaches, pears, oranges, etc. we often eat. Therefore, many weight loss friends are discouraged by persimmons.
In fact, even if you are losing weight, you can eat persimmons. As long as the calories consumed > the calories consumed will be beneficial to weight loss. The calories of persimmons are 74 kcal/100 grams, which is similar to pomegranate . [7] According to the recommendations of the "HTM3 Dietary Guidelines for Chinese Residents ", the fruit intake must be controlled at 200-350 grams persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon persimmon
However, the sweet persimmon cake has a high calories, with 2 persimmon cakes about 100 grams and a calories of up to 255 kcal. [7] The calories are higher than a bowl of rice, and eating more will make you fat.
6, Diabetic Can't eat persimmons?
The persimmons after deafness have a sweet taste, but diabetics dare not eat them, for fear that they will increase blood sugar after eating them.
Persimmon blood sugar generation index GI is 61. [10] Although it belongs to foods with medium GI, if you want to know the effect of a certain food on blood sugar after consumption, you cannot just look at GI, but also the blood sugar load GL. GL <>
GL=Food GI×The available carbohydrate content in this food (g)/100
The average carbohydrate in persimmon is 15 grams/100 grams [10]. If you only eat 100 grams of persimmons, the GL will be 9 after calculation. However, this is close to the upper limit of the hypoglycemia load value, so you should try to eat as little as possible. It is recommended to choose smaller persimmons, such as eating only 50 grams.
7. Is the white cream on the persimmon cake a preservative?
persimmon cake tastes very sweet. It is a food after drying persimmons, with a moisture content of 33.8%, [7] or even lower.
The persimmon cake dried has a layer of white powder on the outer crust. This is not a preservative added manually, but a precipitated frosting.
Because the moisture content of persimmon cakes is lower than that of fresh persimmons and has a higher sugar content, it limits the reproduction of microorganisms, so the shelf life is longer, which can reach more than half a year.
Summary:
is now in the persimmon season, soft, sweet and sweet should not be missed! It is recommended to buy sweet persimmons directly, which are convenient to eat and delicious. The amount of persimmon tannin can be judged by just peeling the skin and licking it with your tongue. If it is very astringent, take it off and then eat it!
Finally, I wish you all "thinking of persimmons"!
References:
[1] Harold Maji[Mei]. Translated by Cai Chengzhi. Food and Cooking. Vegetables, Fruits, Spices, Cereals. Beijing Fine Art Photography Press. 2013.8
[2] Chen Pei, Li Ping, Hao Yanbin, Qi Jianxun, Dai Shengjie, Wang Canlei, Leng Ping. Changes in soluble pectin and tannins during the ripening of persimmon fruits [J]. Journal of China Agricultural University, 2012, 17(01): 88-92.
[3] Zhang Baoshan, Wu Xiaohong, Chen Jinping. Research progress on tannins [J]. Journal of Shaanxi Normal University (Natural Science Edition), 2008(01): 99-105.
[4]. Research progress on changes in tannin substances during persimmon fruit development and drying process [C]//. Proceedings of the 3rd National Academic Symposium on the Progress of Dried Fruit Production and Scientific Research., 2003:286-289.
[5] Chai Xiong, Jiang Xibing, Gong Bangchu. Research progress on deaf and storage methods of persimmon fruit [J]. Hubei Agricultural Sciences, 2012, 51(07):1297-1302.DOI:10.14088/j.cnki. issn0439-8114.2012.07.053.
[6] Liu Tao, Zhu Wei, Li Chunmei. Current situation and countermeasures of my country's persimmon processing industry[J]. Food Industry Science and Technology, 2016, 37(24):369-375.DOI:10.13386/j.issn1002-0306.2016.24.064.
[7] Yang Yuexin. Chinese Food Generation Sub-table 6th edition Volume 1 [M]. Peking University Medical Press, 2018
[8] Liu Tao, Sun Rongrong, Zhao Chunping, Li Chunmei. Research on the contribution of different ingredients in persimmon fruit to their antioxidant activity and their synergistic/dissonance effects [J]. Food Science and Technology, 2015, 40(01): 63-67.DOI: 10.13684/j.cnki.spkj.2015.01.014.
[9]Zhao Beita, Liu Linwei, Li Xuan, Wang Xiaoyong. Research on the flocculation characteristics of tannins in simulated gastric juice [J]. Journal of Northwest Agricultural Sciences, 2014, 23(01):177-182.
[10] University of Sydney blood glucose generation index http://www.glycemicindex.com/foodSearch.phph
Author | Xue Qingxin Member of the Chinese Nutrition Society Registered nutritionist Registered nutrition technician Health manager Public nutritionist review｜Song Shuang Associate Researcher of the Institute of Nutrition and Health of the Chinese Center for Disease Control and Prevention
(Popular Science China)
