Home Cosmetic Science Talk Formulating Advanced Questions How to prevent tea/herbal extract from changing color

  • How to prevent tea/herbal extract from changing color

    Posted by suswang8 on October 24, 2021 at 4:50 am
    Hello, all.
    I have an acidic toner with a tea extract as one of its ingredients.  Whether I use a powdered green tea additive or brewed green tea, the product begins to undergo a color change (and I assume oxidation?) after a few days. 
    Even with 0.5% sodium phytate, 0.5% ascorbic acid (as  antioxidant), and 0.5% sodium gluconate, it’s not enough to prevent it.  I am using deionized water.
    Is it correct that my only real options are to use airless packaging/dark glass?  If so, I will look into this, but most options are better suited to more viscous products.
    Thanks very much.

    Pharma replied 2 years, 6 months ago 2 Members · 1 Reply
  • 1 Reply
  • Pharma

    Member
    October 24, 2021 at 2:27 pm
    You have to get rid of oxygen and keep it out of the bottle till the last drop. Reducing/reacting all that enters is an option but certainly not the best one. For that, you might want to try sodium metabisulfite or sodium dithionite. However, you’d best keep ascorbic acid and the airless/darg packaging but also de-gas all liquids (best flush with nitrogen and work/fill under reduced pressure).
    The only thing you might drop is either phytate or gluconate. Maybe adding Redoxol S3 (in addition to all the other antioxidants, not instead of them!) might help somewhat if you have to go with normal packaging…

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