If someone had told me when I was younger that I would have fun playing with Ph, I would have laughed at the joke! Yet, I did. I’ll get to the fun part in a moment, right after summing up briefly what I gathered about anthocyanins.
Anthocyanins are water-soluble pigments. They are the red in hibiscus and strawberries, the blue in blue pea flowers and blueberries, the purple in aubergines. They also color young leaves with reddish tints and protect them from UV rays while they are growing.
- Anthocyanins are phytochemicals that belong to the flavonoids group.
- Flavonoids belong to the polyphenols group.
- Polyphenols are secondary metabolites which main functions are to protect the plant against external aggressions.
Which means – as far as cosmetic formulation is concerned – that polyphenols can act to protect the skin from external aggressions, like UV rays. As a matter of fact, anthocyanins have a known antioxidant activity and studies have also demonstrated that they have anti-inflammatory activities. Neat, right?!
Their water solubility means that they can be used to color a product with an infusion or a glycerate. That’s where fun begins.
Anthocyanin’s color depends on many factors such as :
- Metal ions. Hydrangea flowers are the perfect illustration of this kind of variation. In France, they are purple/blue in Brittany where the soil is rich in metal ions and are pink in Provence where the soil is mostly calcareous.
- Copigments such as flavonoids, alcaloids or amino acids. Copigments might not have any color but they will sort of bind with anthocyanins to deepen and stabilise their color.
- pH. Which is what I focused on. Their color ranges from red (acid pH) to blue (neutral pH) to yellow or even colourless (basic pH) but I kept my experiments in a Ph range close to cosmetic formulation.
I played with blue pea flowers and infused 3 dried flowers in 100 ml water during 20 minutes. The result was a pretty turquoise blue that sadly looks green on the picture below.
Then I lowered the pH with lactic acid in 2 beakers. There is undeniable childish amusement and marvel at watching the color tinging with new tones then turning into something new!
I resumed Ph measurements and variations aiming for a 5 – 5,5 this time, which is often my ideal pH. Ladies & gentlemen : pH 5 is a beautiful blue with purple undertones!
Anthocyanins are great additions in a cosmetic formulation where they will both add protective properties and color the product. They are the most prominent compound among flavonoids and are widely available which offers many possibilities. Our flexibility with pH is limited but associations with other ingredients may have many surprises in store.
We’re not done playing!
Anthocyanins: Antioxidant and/or anti-inflammatory activities. Article in Journal of Applied Pharmaceutical Science 1(6):7-15 · August 2011
12/9/15. 1. Anthocyanins – More than. Nature’s Colors! Taylor C. Wallace, PhD, CFS, FACN. George Mason University.
Anthocyanins – Pennington Nutrition Series – 2009 N° 1
Anthocyanes – Wikipedia
Plant extracts 101 – Swettis Beauty Blog