Home Cosmetic Science Talk Formulating L-Ascorbic Acid and is protein encapsulated????????? Any Input

  • L-Ascorbic Acid and is protein encapsulated????????? Any Input

    Posted by mflick1 on February 6, 2014 at 8:57 am


    I was hoping someone could help shed light on the below for me. I have a customer with a Vit C serum which they claimed was 10% Vit C. I had it tested only to find that 2.2% was actually in there. When I came forward with this information, the below response is what I received. Does this make sense to anyone? Any helpful comments are appreciated :-) I have some thoughts but not sure if they are correct. 
    “One form we use is 7% L-Ascorbic Acid and is protein encapsulated to help stabilize it and prevent oxidation, the second form is 3% pure L-Ascorbic Acid.  What we found from the lab tests is that the protein encapsulated L-Ascorbic Acid will not show up on a test for L-Ascorbic Acid because it’s encapsulated in the protein.  Our lab tests showed Vitamin C levels of 2.9%, so the samples we tested and the samples you had tested are only picking up the L-Ascorbic Acid not encapsulated in protein.”

    Also, isn’t there a test for encapsulated product?
    Bobzchemist replied 10 years, 5 months ago 5 Members · 5 Replies
  • 5 Replies
  • Herbnerd

    February 7, 2014 at 6:53 pm

     I guess the best way would be to speak with the manufacturer to supply an assay method for protein encapsulated vitamin C. Most suppliers would supply this (well, in pharmaceutical fields at least).

    However, I have my doubts - it doesn’t add up to me.

  • gfeldman

    February 8, 2014 at 5:08 pm

    It seems unlikely that bound L-ascorbic acid would not disassociate during HPLC analysis (due to organic solvents involved, ect), but not having worked with bound Vit C in the past I cannot say for sure. What I can say is that if you degrade the proteins with high heat and/or 6M Guanidinium chloride they will unfold, releasing any bound L-ascorbic acid. Assay the solution again after doing so and you should be able to find out for sure.

    (^^ If you want to go through all that trouble, otherwise use a vendor that is more upfront with you about the materials you are working with)

  • Herbnerd

    February 9, 2014 at 3:36 am

    It would probably be easier to use a protease and a low pH  to digest the proteins and release the vitamin C - but there is also the danger of the Ascorbic acid would oxide and disappear anyway.

  • Avick

    February 10, 2014 at 9:35 am

    Perhaps they are referring to DHAA: http://en.wikipedia.org/wiki/Dehydroascorbic_acid

    We run an assay that requires reaction with DL homocysteine to reduce the DHAA to ascorbic acid.

    Free ascorbic acid and “total Vitamin C” can be two different measures, especially if the source is a plant extract.

  • Bobzchemist

    February 10, 2014 at 10:38 am

    If it’s that hard to assay the Vitamin C, how could it possibly have any effect on skin?

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