Which dragon fruit is better, red or white? Here's how to choose the right one!

Pitaya, also known as red dragon fruit or fairy honey fruit, is a very familiar fruit. After it was introduced to my country, people thought that the scales on its surface resembled the outer scales of a dragon, and it was bright red in color, so it got a new name - pitaya.

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There are two common colors of dragon fruit, white dragon fruit and red dragon fruit. In fact, there is also a yellow dragon fruit, also called bird's nest fruit, with yellow skin and white flesh, but it is still relatively rare on the market. In this article, we will mainly talk about the common red and white dragon fruits on the market, so that everyone can understand how to eat them.

01

Why are the two types of dragon fruit so different in color?

Red pitaya and white pitaya look similar in appearance, but they are very different inside. When you cut open the red pitaya, you'll see a full red color, which is much brighter than the white pitaya. They're both pitaya, so why is there such a big color difference? This is mainly due to the effects of betacyanin and anthocyanin , with betacyanin being the dominant color.

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An experiment was conducted to test the anthocyanin content of two colors of pitaya, and the results are shown in the following table:

The betacyanin content of red pitaya pulp is 10-29 mg/100 g, [2] which is several times higher than the anthocyanin content.

Therefore, through data comparison, we know that the reason why red pitaya is red is mainly due to the effect of betacyanin. Some people may wonder: anthocyanin has an antioxidant effect, so can betacyanin also have an antioxidant effect? ​​Some studies have mentioned that betacyanin has good antioxidant activity and free radical scavenging ability. [2] Animal studies have also shown that betacyanin has an immunomodulatory effect and can enhance the immunity of mice. [3] Whether it has a good antioxidant and immunity-enhancing effect on the human body requires further research to confirm. Betacyanin is also a natural colorant. If a large amount of betacyanin is ingested at one time, the body cannot absorb it, and the excess will be excreted from the body with urine and feces, causing the urine and feces to turn red. Don't worry, this phenomenon is only temporary and will return to normal in a day or two.

02

What are the nutritional differences between the two?

Although they are both dragon fruits, they are different varieties after all, so there are naturally some differences in nutrition. ① Dietary fiber: The average dietary fiber content of red pitaya and white pitaya is 2.77% and 3.14% respectively, [4]. In comparison, the dietary fiber content of white pitaya is higher. This nutrition can enhance satiety, promote gastrointestinal motility, prevent constipation, and is very beneficial to intestinal health. The dietary fiber content of pitaya is higher than that of apples, tangerines, oranges, peaches, etc. that we often eat. In particular, the small black seeds in pitaya are the main contributors to dietary fiber. For friends who want to prevent constipation, you can choose a large white pitaya and show off one directly. ② Sugar content: The sugar content of red pitaya is higher than that of white pitaya, [4] so it tastes sweeter and the calories of red pitaya are also higher. Other nutrients such as vitamin C, calcium, magnesium, potassium, phosphorus, iron, zinc, etc. are similar between the two, and the difference is not big.

03

How to store dragon fruit?

If pitaya is stored at room temperature, it can generally be kept for 12 days, but the quality will deteriorate. After 3 days, the scales will turn yellow and become stale; after 7 days, the skin will become wrinkled; after 12 days, some of the scale bases and the navel will begin to rot, gradually losing its edible value. [5] If it is placed in direct sunlight, the betacyanin in it will undergo photodegradation and oxidation reactions, and the content will decrease. [2]

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Studies have shown that pitaya is best stored at low temperatures, with the optimal storage temperature being 3°C to 5°C. Compared with storage at room temperature, low-temperature storage can extend the shelf life by 16 to 20 days. [6] Therefore, when buying pitaya, it is best to choose pitaya whose scales have not turned yellow and whose surface has not wilted. After buying it, put it in the refrigerator immediately for storage. Be careful not to place it too close to the inside of the refrigerator, as the temperature inside the refrigerator is too low and it is easy to get frostbite.

04

How to keep the red color when cooking dragon fruit?

The red pitaya has bright colors, and many people fantasize about using it to make pleasing delicacies, such as pitaya steamed buns, pitaya flower rolls, red dumplings, and red glutinous rice balls.

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But reality is always disappointing. We clearly used red dragon fruit juice and the dough was also red, but why did it turn yellow after cooking? What went wrong? In fact, this is a normal phenomenon. After all, the red color of dragon fruit is mainly due to betacyanin, but this ingredient is less stable at high temperatures. When the temperature exceeds 50°C, betacyanin will change from purple-red to orange-red; when the temperature exceeds 85°C, it will turn yellow. [2] We basically cook food at temperatures above this temperature, so it is naturally yellow! However, there are some ways to keep it red. You can add some vinegar or lemon juice to the dragon fruit juice, because betacyanin is more stable under acidic conditions and can maintain its purple-red color. [2] But be careful not to add too much, as it will become less stable under strong acid conditions.

Summary: Red pitaya tastes sweeter than white pitaya and has a certain antioxidant effect, but its dietary fiber content is not as high as white pitaya and its calories are relatively higher. If you are losing weight, you should eat red pitaya slowly!

Little knowledge: Pitaya is a member of the cactus family. You never thought of that, did you?

References:

[1] Li Ruizhen, Wu Li, Liu Meiran, Ji Yueyun, Zhou Qiaoming, Yang Yuxia, Fu Xinyu. Determination of anthocyanin content in pitaya by spectrophotometry[J]. Journal of Hainan Tropical Ocean University, 2023, 30(2): 115-121

[2] Lv Yawen, Zhu Wenxian, Liao Hongmei. Research and application progress of betalain from pitaya[J/OL]. Food and Fermentation Industries: 1-11[2023-05-24]. DOI:10.13995/j.cnki.11-1802/ts.034586.

[3] Bao Xiaowei, Han Haixia, Du Guangming, Wei Chenye, Zhu Xuan, Ren Wei, Zeng Lanjun, Zhang Yatao. Antioxidant and immunomodulatory effects of betalain on mice[J]. Food Science, 2019, 40(17): 196-201

[4] Deng Aini, Ye Haihui, He Xiufen, Wang Xiaogang, Su Bingxia, Li Qiong. Analysis of nutritional content of red and white pitaya in Hainan[J]. Preservation and Processing, 2020, 20(3): 177-182

[5] Pan Xujie. Study on storage quality deterioration and flavor of pitaya[D]. Zhejiang Ocean University, 2021.DOI:10.27747/d.cnki.gzjhy.2021.000129.

[6] Ma Feiyue, Shuai Xixiang, Zhang Ming, Du Liqing, Li Ya, Tang Xinming. Research progress on postharvest storage and preservation of pitaya[J]. Preservation and Processing, 2021, 21(11): 136-143

[7] 2011-04-04 Health Times: "Small movements in the shower can relieve discomfort"

Author: Xue Qingxin, one of the first nutrition instructors of the National Health Commission, and a registered nutritionist in China

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