Home Cosmetic Science Talk Formulating Formation of Sorbic acid?

  • Formation of Sorbic acid?

    Posted by NeilL on September 23, 2020 at 1:46 pm

    Hi all,

    I realise that this technically isn’t a cosmetic question but feel it could apply to cosmetics as well.

    Currently I’m formulating a nutraceutical drink rough formulation below (sorry can’t give specifics).

    Water 98.00%
    Citric acid 0.08-0.24%
    Sodium Chloride 0.8%-1.2%
    Sodium ascorbyl phosphate 0.2%-0.5%
    Potassium Sorbate 0.2-0.3%
    Sodium Hyaluronate 0.3-0.6%

    When I’m blending this formulation I add the water then citric acid, sodium chloride, sodium ascorbyl phosphate and then potassium sorbate.

    At this stage a white solid appears, it is ‘stringy’ in nature. I have tried altering the addition but it seems whenever either the potassium sorbate or citric acid is added this solid forms.

    The pH of the solution at this stage is 4.5, I’m wondering if this is too low and the potassium sorbate is forming sorbic acid which has a poor solubility in water and so forming the aforementioned solid. Would the level of potassium sorbate have an affect on this as well? Would reducing it to maybe 0.2% help?

    Any help with this would be greatly appreciated.
    Cheers
    Neil

    belassi replied 3 years, 6 months ago 3 Members · 5 Replies
  • 5 Replies
  • belassi

    Member
    September 24, 2020 at 10:02 pm

    Seems unlikely to me. That is quite a low usage level. You can easily test your idea by replacing it with sodium benzoate which is commonly used in soft drinks and will not discolour your product over time. Actually one of my MBA students is responsible for a major brand of sports drink over here, so I am well aware of the typical formula. And why is sodium chloride in there without potassium chloride?

  • Herbnerd

    Member
    September 24, 2020 at 11:03 pm

    I suspect you are dropping the hyaluronic acid below the isoelectric point and precipitating the proteins.

    For general stability, you ideally need a pH of between 3.6-4.2

  • NeilL

    Member
    September 25, 2020 at 8:15 am

    Herbnerd said:

    I suspect you are dropping the hyaluronic acid below the isoelectric point and precipitating the proteins.

    For general stability, you ideally need a pH of between 3.6-4.2

    Thanks for this however I had a similar idea so ran a knockout experiment without the sodium Hyaluronate and the solids still formed. Thanks for the suggestion though its really appreciated!!

  • NeilL

    Member
    September 25, 2020 at 8:16 am

    Belassi said:

    Seems unlikely to me. That is quite a low usage level. You can easily test your idea by replacing it with sodium benzoate which is commonly used in soft drinks and will not discolour your product over time. Actually one of my MBA students is responsible for a major brand of sports drink over here, so I am well aware of the typical formula. And why is sodium chloride in there without potassium chloride?

    Why would I require Potassium Chloride in there as well? Thanks for the suggestion I shall replace it for now but I know the customer doesn’t want Benzoate in there due to some concern over the formation of benzene with vitamin C present.

  • belassi

    Member
    September 25, 2020 at 3:02 pm

    You would use potassium chloride in order to maintain the correct electrolyte balance. 1% sodium chloride in one litre is 10g of salt!! I assume you don’t want to give your customers high blood pressure or palpitations?

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