Experimental materials: color-changing flowers, measuring cups (3 pieces), baking soda, citric acid, sampling spoon, stirring rod, boiling water and clear water.
Experimental steps:
1, put the color-changing flower into a measuring cup (1 bag can be used for 2 to 3 times), pour 80 ml of boiling water, stir evenly, brew for 1-2 minutes, and take out the color-changing flower to obtain the blue color-changing flower solution.
2. Use a sampling spoon to add half a spoon of baking soda to one measuring cup, and half a spoon of citric acid to another measuring cup, and then pour 60 ml of clear water into each cup and stir evenly.
3. Pour the color-changing flower liquid into baking soda water and citric acid water respectively, and the color will change obviously.
Brief introduction of anthocyanin
Anthocyanin, also known as anthocyanidin, is a water-soluble natural pigment widely existing in plants in nature, and it is a colored aglycone obtained by hydrolysis of anthocyanins. Most of the main coloring substances in fruits, vegetables and flowers are related to them. Anthocyanins make petals appear colorful at different PH values of plant cell vacuoles.
There are more than 20 kinds of anthocyanins, six of which are very important in food, namely geranium pigment, cornflower pigment, delphinium pigment, peony pigment, morning glory pigment and mallow pigment. Anthocyanins in the natural state exist in the form of glycosides, which are called anthocyanins, and there are few free anthocyanins. Anthocyanins are mainly used for food coloring, dyes, medicines, cosmetics and so on.