Introduction
Complete lack of ascorbic acid (a.k.a Vitamin C) in the diets of humans and other
primates leads to a classic nutritional disease, scurvy. This disease was widespread in
Europe during the fifteenth and sixteenth centuries, but it is rare today. Ascorbic acid is
widely distributed in nature, but it occurs in extremely high concentrations in citrus and
green plants such as green peppers and spinach. Ascorbic acid can be synthesized by all
plants and animals, with the exception of humans, other primates, and guinea pigs.
Therefore, vitamin C must be present in our dietary substances.
The fundamental role of ascorbic acid in metabolic processes is not very well
understood. There is some evidence that it may be involved in metabolic hydroxylation
reactions of tyrosine, proline, and some steroid hormones, and in the cleavage-oxidation
of homogentisic acid. Its function in these metabolic processes appears to be related to
the ability of vitamin C to act as a reducing agent.
The adult Recommended Daily Allowance f vitamin C is 70 mg per day. Some
scientists and physicians have suggested doses up to 1 to 3 grams per day in order to help
resist the common cold. Deficiency of vitamin C results in swollen joint, abnormal
development and maintenance of tissue structures, and eventually scurvy.
Determination of vitamin C in biological fluids such as bolld and urine is difficult
because only small amounts of the vitamin are present and many interfering reducing
agents are present. Substances containing sulfhydryl groups, sulfite, and thisosufate are
common in biological fluids and react with DCIP, but much more slowly than ascorbic
acid. The interference by sulfhydryl is often minimized by the addition of
p-cholormercuribenzoic acid.
Materials and Supplies
Apple Juice
Metaphosphoric acid/ Acetic acid