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Clinical pharmacy PharmD program Third level Phytochemistry-1 (PG-504)

I) Pentoses

• They are unfermentable by yeast.

• Identification: By some color tests based on the reaction of some reagents

with furfural, which is produced on warming pentose with dilute acid.

a) Aniline acetate paper Brilliant red stain

b) Phloroglucin Red color, then brown ppt.

c) Orcinol (Bial’s test ) Dark green color.

• The most common examples: L-Arabinose, D-Apiose, D-Xylose and D-Ribose.

1) L-Arabinose: (Pectin sugar)

• It is found in gum, hemicelluloses, pectin and in some glycosides.

• It can be prepared by partial hydrolysis of gum.

Acid hydrolysis
Araban L-Arabinose

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