Question

For pH differential method, how to convert anthocyanin content (mg/L to mg/g) ? Show the calculation for example

28mg/L to mg/g.

What usually would be the total anthocyanin content (TAC) from butterfly pea ?

Answer 1

First of all we need to know the quantity of the sample which was used for the determination of anthocyanins and, optionally, its dry matter content. Let's assume that you used 1 g of some plant material and dry matter content of that plant material was 0,20 g d.m./g. You used 10 ml of some solvent. After diluting your extracts you continued the analysis and determined that there was 28mg of anthocyanins per 1 litre of your original extract. Now you have to carry out the following calculations:

28 mg of anthocyanins ----------------- 1000 ml of the crude extract

                    x                   ----------------- 10 ml of the crude extract

x = .28 mg of anthocyanins

You used 1 g of the plant material for the preparation of 10 ml of the crude extract, so:

0.28 mg of anthocyanins ------------------- 1 g of the plant material

You can finish here (so the result is 0.28mg/g) but if you want express your results as mg in dry matter then you need to do the following calculations:

0.28 mg of anthocyanins ------------- 1 g of the plant material ----------- 0,20 g of d.m,

                        x             --------------------------------------------------------- 1 g of d.m.

x = 1.4mg of anthocyanins/1 g d.m.