- Sahaana V
Dose of STEM: Black Rice and Blueberries
Are these thoughts running in your mind?
"Why are we comparing two completely different things?
"Yes, Blueberries and black rice... What about them?"
The title may seem odd to some of the readers, but it actually makes sense.
What's with the title? Blueberries and black rice contain anthocyanins. These are compounds similar to pigments. This is what gives red cabbage, blueberries, raspberries and black rice bright and rich colors. Anthocyanins produce various colors, but their molecular structures are similar. So, what is so special about them? Their color depends on the pH value. If the substance becomes more acidic or basic, the molecules will change their shape and take on a different hue. Do you remember the red cabbage acidity/basicity indicator experiment? You can also try it with blueberries!
The combination of red and mixed colors in autumn leaves is provided by anthocyanins. Isn't it Carotenoids that give fall leaves their color? That's true, but Carotenoids give mostly the yellowish hue, while anthocyanins give the red color, as mentioned above. A combination of anthocyanins and carotenoids gives orange leaves.
What are the health benefits of anthocyanins?
Scientists are still trying to determine whether or not a high dose of anthocyanins can cure a specific disease. However, so far, they have found that anthocyanins are excellent for keeping your heart healthy. They improve cholesterol levels and prevent hypertension or high blood pressure. The main health benefit is the fight against oxidative stress. Oxidative stress is the imbalance between free radicals and antioxidants in our bodies. Oxidative stress is a major risk factor for many chronic diseases and conditions such as heart disease, cancer, glaucoma, stroke, Parkinson's disease and Alzheimer's disease. In fact, according to a 2010 study published in Phytotherapy Research, anthocyanins can prevent breast cancer!
The Tale of Two Anthocyanins
Here are two examples of common foods that contain anthocyanins.
1. Pomegranates
The ruby red color of pomegranate is due to its anthocyanins. It is a good source of fiber, tannins (antioxidants) and vitamins A, C and E. One study showed that drinking at least 50 ml of pomegranate juice a day reduced artery damage and cholesterol build-up in people with narrowed arteries. Pomegranate also helps fight prostate and breast cancer, hypertension, arthritis and joint pain. The main anthocyanin in pomegranates is cyanidin-3,5-diglucoside.
2. Aubergine
Eggplant, as the Americans call it, is not a vegetable, but a fruit! Eggplant is rich in antioxidants which are provided by an anthocyanin called nasunin. It is effective in protecting cells from free radical damage. It is also rich in fiber which helps control blood sugar, as well as manganese. Since it is low in calories, it can also help with weight loss.
Fun Facts #1: In the photosynthetic tissues of plants, anthocyanins act as a "sunscreen" to protect the plant from damage caused by high-frequency radiation such as UV light.
#2: There are over 600 structurally different anthocyanins that have been found in nature.
P.S. Take a look at the picture of purple cauliflower on the internet. They also contain anthocyanins, and they are beautiful!
Do you know of any other plants that contain anthocyanins? Comment on them below!
Sources:
Some health benefits: www.healthline.com
Image Sources:
Aubergine photo by Nina Luong on Unsplash
Pomegranate photo by Steve Buissinne from Pixabay
Chemical composition of anthocyanin: Science Direct
