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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]] Figure 1 Chemical diagram of colour-changing anthocyanin pH reaction [UMass Amherst Department of Chemistry ] | |||
[[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 | ||
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3.2. Making pH solutions | 3.2. Making pH solutions | ||
'''12.12.2017''' | |||
[[File:Screen Shot 2018-01-31 at 15.12.21.png|400px]] | [[File:Screen Shot 2018-01-31 at 15.12.21.png|400px]] | ||
3.3. Process of experiment | 3.3. Process of experiment | ||
'''17.1.2018''' | |||
'''17.1.2018''' | |||
However, there’s a problem which I’m not sure: | However, there’s a problem which I’m not sure: | ||
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And also, this is a website of Acid/Alkaline Food Chart: http://www.phmiracleliving.com/t-food-chart.aspx | And also, this is a website of Acid/Alkaline Food Chart: http://www.phmiracleliving.com/t-food-chart.aspx | ||
And I find some healthy medicines which are used to adjust pH, the main ingredients are moderately or highly alkaline food. | And I find some healthy medicines which are used to adjust pH, the main ingredients are moderately or highly alkaline food. | ||
What I will do on 17th: | What I will do on 17th: | ||
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[[File:4591516359873_.pic_hd.jpg|400px]] | [[File:4591516359873_.pic_hd.jpg|400px]] | ||
'''19.1.2018''' | '''19.1.2018''' | ||
I did the experiment of reversibility of colour change. | I did the experiment of reversibility of colour change. | ||
[[File:Reversibility of Color Change.jpg|400px]] | |||
And then I use reversibility of colour change to make the colour of coffee more obviously. | And then I use reversibility of colour change to make the colour of coffee more obviously. | ||
pH of expresso coffee is around 6, I add solution (pH= | pH of expresso coffee is around 6, I add the solution (pH=8) into the original solution 1/2/3, the colour changing is more obviously. | ||
[[File:4581516359845_.pic_hd.jpg|400px]] | [[File:4581516359845_.pic_hd.jpg|400px]] | ||
[[File:result.jpg|400px]] | |||
'''4. Discussion''' | |||
'''5. References''' | '''5. References''' | ||
[] Robert Boyle. 1664. Experiments and Considerations Touching Colours. Project Gutenberg. 1–157 pages. | [1] Robert Boyle. 1664. Experiments and Considerations Touching Colours. Project Gutenberg. 1–157 pages. | ||
[] Jian He and M Monica Giusti. 2010. Anthocyanins: Natural Colorants with Health-Promoting Properties. | [2] Jian He and M Monica Giusti. 2010. Anthocyanins: Natural Colorants with Health-Promoting Properties. | ||
[] Xiahong Zhang, Sisi Lu, and Xi Chen. 2014. A visual pH sensing film using natural dyes from Bauhinia blakeana Dunn. Sensors and Actuators B: Chemical 198 (2014), 268–273. | [3] Xiahong Zhang, Sisi Lu, and Xi Chen. 2014. A visual pH sensing film using natural dyes from Bauhinia blakeana Dunn. Sensors and Actuators B: Chemical 198 (2014), 268–273. | ||
[] UMass Amherst Department of Chemistry Lecture Demonstrations. | [4] UMass Amherst Department of Chemistry Lecture Demonstrations. | ||
[] Viirj Kan. 2017. Organic Primitives: Synthesis and Design of pH-Reactive Materials using Molecular I/O for Sensing, Actuation, and Interaction. Proceedings of the 2017 CHI Conference on Human Factors in Computing Systems | [5] Viirj Kan. 2017. Organic Primitives: Synthesis and Design of pH-Reactive Materials using Molecular I/O for Sensing, Actuation, and Interaction. Proceedings of the 2017 CHI Conference on Human Factors in Computing Systems Pages 989-1000. | ||
Pages 989-1000. | |||