Скачать или смотреть Red Cabbage Juice-pH

Turn red cabbage into a natural pH indicator! In this experiment, we use red cabbage juice to test common household substances and classify them as acids or bases. Watch how the juice changes color based on pH, revealing the hidden chemistry behind everyday items. A fun and colorful way to explore acid-base reactions at home!

Red cabbage contains Anthocyanins, which are a group of flavonoid pigments responsible for the red, purple, and blue colors in many plants, berries, and flowers.
They are amphoteric compounds, meaning they can act as both acids and bases, depending on the environment. This is why they are pH-sensitive.
The structure of anthocyanins contains a chromophore, a part of the molecule responsible for absorbing certain wavelengths of light, which changes depending on the pH. The color change of anthocyanins occurs due to the molecular rearrangement of their structure when exposed to different pH levels: In acidic solutions, it exhibits pink or red color. Neutral pH gives it a purple color and alkaline pH gives it Green to yellowish green.
Red cabbage is ideal for home based science experiments since it contains a high concentration of anthocyanins, making its pH sensitivity more noticeable. Anthocyanins easily dissolve in water, so they can be extracted by boiling or blending the cabbage in water. Anthocyanins in red cabbage exhibit a broader range of colors across the pH spectrum compared to some other natural indicators.

Several fruits, vegetables, and flowers contain anthocyanins, which are responsible for their vibrant red, purple, blue, and sometimes black hues. These natural pigments are also powerful antioxidants and are widely distributed in nature. Here's a list of common foods rich in anthocyanins:
Berries:
Blueberries
Blackberries
Raspberries (red or black varieties)
Strawberries (lower amounts compared to darker berries)
Cranberries
Elderberries

Grapes: Red grapes and Purple/black grapes
Found in grape juice and red wine.
Cherries: Especially dark red or black cherries.
Plums: Especially purple-skinned varieties.
Pomegranates: Rich in anthocyanins in both the arils and juice.
Other Fruits:
Blackcurrants
Red apples (in the skin)
Blood oranges
Acai berries

Vegetables:
Red Cabbage: A standout source of anthocyanins.
Purple Carrots: An ancient variety of carrot rich in anthocyanins.
Beetroot: While its red pigment comes mainly from betalains, beets contain some anthocyanins.
Eggplant: Found in the purple skin.
Purple Sweet Potatoes: Particularly varieties like Okinawan or Stokes purple sweet potatoes.
Red Onions:The red/purple outer layers are rich in anthocyanins.
Purple Cauliflower:A colorful variant of cauliflower.
Kale and Lettuce (Purple Varieties):Anthocyanins are found in purple-leafed varieties.

Grains and Legumes:
Black Rice (Forbidden Rice): Anthocyanins are concentrated in the outer husk.
Purple Corn: Used traditionally in South American cultures.
Black Beans: Anthocyanins are present in their dark seed coat.

Flowers and Other Plants
Hibiscus Flowers: Used in teas, they change color based on pH.
Butterfly Pea Flowers: Deep blue in neutral conditions, but turn pink in acidic solutions.
Black Elderflower: A source of anthocyanins, used in syrups and extracts.
The intensity and type of anthocyanins vary based on environmental factors like soil pH, light exposure, and temperature. This is why the same plant may have slightly different colors depending on where it's grown.

Hydrangea is another great example for the effect of pH on Anthocyanin. In acidic soils they have blue flowers, red or pink flowers in alkaline soils and lavender to purple flowers in neutral soil.