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Anthocyanins are water-soluble vacuolar pigments. In the 1664 book Experiments and Considerations Touching Colours by chemist Robert Boyle, various edible plants are reported as visual pH indicators due to pH-responsive mechanisms in their tissues [Boyle, 1664]. Anthocyanin is a kind of natural colorant in food and beverage industry, and has been found to possess anti-inflammatory antioxidant properties [He, 2010]. It has also been researched for use as an indicator for packaging applications to detect spoilage in pork and fish products [Zhang, 2014]. All tissues of vascular plants contain the flavonoid anthocyanin, a pigment that changes colour under varying pH solutions. | Anthocyanins are water-soluble vacuolar pigments. In the 1664 book Experiments and Considerations Touching Colours by chemist Robert Boyle, various edible plants are reported as visual pH indicators due to pH-responsive mechanisms in their tissues [Boyle, 1664]. Anthocyanin is a kind of natural colorant in food and beverage industry, and has been found to possess anti-inflammatory antioxidant properties [He, 2010]. It has also been researched for use as an indicator for packaging applications to detect spoilage in pork and fish products [Zhang, 2014]. All tissues of vascular plants contain the flavonoid anthocyanin, a pigment that changes colour under varying pH solutions. | ||
Under different pH conditions, the hydroxyl (OH) and/or methyl ether (O-CH3) groups attached to the carbon rings (figure 1) undergo reversible structural transformations and ionizations. Restructuring a molecule changes the way it ab- sorbs light, giving rise to colour changes [Kan, 2017]. | Under different pH conditions, the hydroxyl (OH) and/or methyl ether (O-CH3) groups attached to the carbon rings (figure 1) undergo reversible structural transformations and ionizations. Restructuring a molecule changes the way it ab- sorbs light, giving rise to colour changes [Kan, 2017]. | ||
[[File:Screen Shot 2018-01-31 at 12.08.56.png|400px]] | [[File:Screen Shot 2018-01-31 at 12.08.56.png|400px]] Figure 1 Chemical diagram of colour-changing anthocyanin pH reaction [UMass Amherst Department of Chemistry ] | ||
1.2 red cabbage | 1.2 red cabbage | ||
"Red cabbage is rich in a number of bioactive substances, including anthocyanins"[Wiczkowski, 2012]. The method of extracting anthocyanin from red cabbage is easy and convenient. | "Red cabbage is rich in a number of bioactive substances, including anthocyanins"[Wiczkowski, 2012]. The method of extracting anthocyanin from red cabbage is easy and convenient. | ||
'''2. Idea''' | '''2. Idea''' | ||
Coffee always mixed with milk and sugar or curd. We know coffee is a kind of acid drink. When it mixed with water the pH level will change. I want make its pH readable through my experiment. | |||
My first idea is using this chemical reaction as pigments. Like watering the plant which has anthocyanin with different pH solutions to enhance the aesthetic environment. People can monitor and alter the pH of plants to manipulate the way they grow. And I can draw a picture using different pH solutions then spray red cabbage solution on it, colour will change because of the chemical reaction. After discussing with Miga, I think it is a good idea to use red cabbage solution to use red cabbage extract solution to know pH of different drinks and maybe can judge wether it is good to drink. | My first idea is using this chemical reaction as pigments. Like watering the plant which has anthocyanin with different pH solutions to enhance the aesthetic environment. People can monitor and alter the pH of plants to manipulate the way they grow. And I can draw a picture using different pH solutions then spray red cabbage solution on it, colour will change because of the chemical reaction. After discussing with Miga, I think it is a good idea to use red cabbage solution to use red cabbage extract solution to know pH of different drinks and maybe can judge wether it is good to drink. | ||