Pectin is one of the main components of plant cell wall, which is divided into water-soluble pectin and
insoluble pectin. Insoluble pectin is protopectin. Raw pectin is insoluble in water, but it can be
decomposed into water-soluble pectin by adding water under the action of acid, alkali, salt and other
chemical reagents and enzymes. It is widely used in food, textile, printing and dyeing, tobacco, metallurgy
and other fields.
The protopectin is hydrolyzed to soluble pectin under alkaline condition, and further converted to
galacturonic acid. The product condensed with carbazole in strong acid to form purplish red compound,
with characteristic absorption peak at 530 nm.
Reagents and Equipment Required but Not Provided.
Spectrophotometer, desktop centrifuge, water bath, 1 mL glass cuvette, adjustable pipette,
mortar/homogenizer, acetone, concentrated sulfuric acid (H2SO4), anhydrous ethanol and distilled water.
