Thinking Pink—How Can the Color Pink Be Obtained From Organisms?

The pink color in some organisms can be the engine of their lives. The color pink can be present in ocean organisms such as bacteria, microalgae, and seaweed, especially in red algae. In these organisms, the pink color comes from a protein called phycoerythrin, which is part of their photosynthetic system [1]. Phycoerythrin is a pigment that helps capture green light, similar to the way that the green pigment chlorophyll, found in trees and other plants, captures red light. In microalgae, phycoerythrin teams up with other pigment proteins, such as a blue pigment called phycocyanin, to form a structure called the phycobilisome, which is found in the photosynthetic structures inside the cell (Figure 1). Chlorophyll drives life on land, while pigments like phycoerythrin help drive life in the sea. Phycoerythrin in pink/red organisms captures light and generates the energy necessary for the organisms to perform their vital functions, like growth and reproduction. Being pink is very important for these organisms!

Pink organisms can be found in the ocean, but they are not present in large numbers, so they are not visible if you look at a typical seawater sample. However, they can be grown in a laboratory and viewed with a microscope.

Scientists have learned how to obtain the pink pigment from these organisms, and they have discovered that these pigments can have interesting properties, which you will learn about as you keep reading.

Eating Pink—Phycoerythrin Can Be Added to Foods

Scientists are exploring whether phycoerythrin could be added to foods such as yogurts, jellies, and drinks in the future. You might think it would taste like seaweed or the ocean, but in reality, it does not. When scientists extract (remove) phycoerythrin from living sources, they remove everything that smells or tastes like the sea, leaving only the bright red color. So, if you tasted phycoerythrin, it would taste almost like plain water.

So, is it healthy to consume this pink color? Phycoerythrin is a natural pigment that laboratory studies suggest is not toxic and could potentially be used safely in foods. But scientists are interested in it for many other reasons, as well [1]. Early laboratory studies indicate that it might help reduce the risk of suffering from Alzheimer’s disease and other age-related diseases [2].

This protective effect may be due to phycoerythrin’s high activity as an antioxidant—a substance that helps control unstable molecules that can damage healthy cells in the human body. These unstable substances can build up when we are exposed to pollution or too much sunlight, for example. Furthermore, phycoerythrin consumption may help control other diseases, such as diabetes [1]. This is important because diabetes is one of the most common diseases worldwide. Take a look at Figure 2 to learn more about the potential effects of this amazing color!

Sounds great, right? However, creating pink foods still requires some industrial and food processing innovations, as phycoerythrin can be damaged if exposed to light for too long or to large temperature changes. These are key problems that scientists must solve, as phycoerythrin-containing products must survive long periods of transportation and storage, and in some cases even be cooked, without losing their color or their benefits. Researchers around the world are developing new methods of extraction and purification, along with ways to maintain the stability of phycoerythrin so it can be used more widely, similar to adding vitamin C or calcium to foods.

Phycoerythrin can also act as a food preservative, meaning it can be added to foods to extend their shelf lives, especially for seafood. Studies suggest that its use can help preserve the flavor, aroma, and texture of these foods for longer [3]. It is fascinating to see how the color pink can have many benefits in food and can even help reduce food waste.

Discovering in Pink—How Can the Color Pink Be Part of New Things?

The color pink can be part of new technologies and discoveries, too. Phycoerythrin has great potential as an antibacterial compound [4]. You have probably heard of antibacterial substances used to control bacteria, such as chlorine or alcohol. Well, phycoerythrin can also reduce bacterial populations.

This is important because many current antibiotics have lost their effectiveness against some bacteria. Before the discovery of the first antibiotic, people died from infections that developed after a simple cut, for example. Bacterial infections were much harder to control before antibiotics existed. Now, bacteria are developing resistance to the antibiotics commonly used in hospitals, meaning these infections are becoming harder to treat. This could be a huge global public health problem in the future. Therefore, scientists around the world are in a race to find molecules that might have antibiotic properties. Phycoerythrin could help solve this problem. Laboratory studies suggest that it can slow the growth of certain bacteria, including some that cause diarrhea [5]. The results obtained so far are very interesting and scientists are still investigating all the uses that phycoerythrin may have as an antibacterial agent.

Healing in Pink—How Might the Color Pink Help Scientists Fight Cancer?

Considering all you have learned about phycoerythrin so far, you might be thinking that the pink color has many interesting properties. Well, in addition to everything else, this pink color has shown potential in laboratory studies related to cancer research. Colon cancer is the second most common cancer worldwide, which makes the search for new treatments very important. Scientists have found that phycoerythrin can slow the growth of colon cancer cells in laboratory experiments [5]. Laboratory studies suggest that this protein can trigger signals in cancer cells, telling them to begin a process called programmed cell death. In addition, other laboratory studies have shown that phycoerythrin sends the message to begin programmed cell death in human lung cancer, too [6]. These results have encouraged scientists to continue exploring whether phycoerythrin could contribute to new treatments for these and other types of cancer.

Even though phycoerythrin has many interesting properties, scientists are still studying how it behaves in the body and how much can be used safely. Like any substance used in foods or medicines, careful studies are needed to understand its safety. For example, experiments in animals such as rats have shown that certain amounts of this pigment can be consumed without harmful effects [7]. These results help scientists learn whether phycoerythrin could be used safely in the future.

Painting a World in Pink

As you have seen, the color pink can be very interesting and surprising! New applications for phycoerythrin are being discovered, with the most promising being its possible health benefits and how it might contribute to future ways of preventing diseases that affect a large portion of the population. This pink pigment also joins a vibrant palette of beneficial pigments from the sea: the yellows and oranges of fucoxanthin and carotenes, which are associated with benefits for the eyes and skin; the green of chlorophyll, which helps keep blood cells healthy and working properly, and the protective purple pigments, which support the brain and heart with their antioxidants [8].

So next time you see the color pink, remember the amazing science behind it!

Glossary

Phycoerythrin: ↑ A pink pigment that helps cells capture sunlight for photosynthesis. It helps collect sunlight that chlorophyll cannot absorb efficiently.

Pigment: ↑ A substance that gives color to things, for example, blue pigment is used to give blue color to jeans, and chlorophyll is the pigment that gives the green color to plants.

Phycobilisome: ↑ A structure in photosynthetic organisms made of many pigments that function as a light-collecting antenna.

Chlorophyll: ↑ The green pigment that makes plants green and participates in photosynthesis.

Chloroplasts: ↑ Structures in plants and other organisms that convert carbon into glucose. They are part of the photosynthetic system.

Alzheimer’s Disease: ↑ A disease that mainly affects older people. It affects the brain and causes people to forget things or have trouble thinking.

Antioxidant: ↑ Substance that helps protect cells from damage caused by harmful unstable molecules that originate from pollution, stress, and unhealthy food.

Antibiotic: ↑ Medicine or substance that kills bacteria or stops them from growing. Doctors commonly use antibiotics to treat infections.

Conflict of Interest

The author(s) declared that this work was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Acknowledgments

This work was supported by UAM-funded project 106 S264-24, awarded under the Call for Research Proposals Addressing Current Challenges, and by SECTEI (grant SECTEI/044/2024).

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