A MODIFIED TITRIMETRIC METHOD FOR THE QUANTITATIVE DETERMINATION OF VITAMIN C IN COLORED PLANT EXTRACTS
Vitamin C (ascorbic acid) is an irreplaceable food component. It takes an active part in various metabolic reactions, participates in the synthesis of collagen, regulates blood clotting and normalizes vascular permeability, enhances immunity, and helps to eliminate toxins and heavy metals from the body. Ascorbic acid is not synthesized by the human body and therefore must be consumed daily with food. There are many different methods for determining vitamin C in foods, usually of plant origin. However, the proposed methods for the determination of ascorbic acid in colored extracts are either insufficiently reliable and convenient for implementation, or require special equipment and reagents. We have developed a simple, reliable and affordable method for the determination of vitamin C in colored plant extracts, based on the titrimetric method with visual titration with 2,6-dichlorophenolindophenol with preliminary sorption of colored compounds that interfere with the analysis. The method uses the property of kaolin (white clay) to absorb anthocyanins from extracts, the main coloring pigments of many fruits and berries (black, red currants, cherries, sweet cherries, irga, plums, grapes, etc.). Also, based on the analysis of uncolored fruit and berry crops with and without sorbent, a coefficient was calculated that takes into account the loss of vitamin C during the sorption of colored compounds. Currently, great importance is attached to methods for determining the content of important biochemical components that increase their nutritional and biological value. The proposed method will make it possible to identify new interesting breeding material; it can be used in the mass analysis of fruit and berry and vegetable crops that produce colored extracts.