16
B
3
Forms, Chemistry, and Stability
i
i i
id i h i ll
idi
3 b li
N cot n c ac s c em ca y pyr ne ‐car oxy c
acid, and nicotinamide is pyridine 3‐carboxcylic
acid amide.
In unprocessed foods niacin is mostly present in
the form of the pyridine coenzymes nicotinamide
adenine dinucleotide (NAD) and nicotinamide
adenine dinucleotide phosphate (NADP)
Nicotinamide is considerably more water soluble
than nicotinic acid and therefore the general
choice for fortification in liquid products.
Nicotinic acid is a powerful vasodilator
which can be used to lower serum
cholesterol.
Both free forms of B
3
have an absorbance
maximum at 260nm and do not fluoresce.
Niacin is the most stable water soluble
d
ff
d b h l h
vitamin, an is not a ecte y eat, ig t,
acid alkali, or oxidation.
Acid or alkali hydrolysis free the niacin from
coenzyme structures.
