Chapter 1 Pectin

1-1  Structure and Terminology

1-2  Production

1-3  Characterization of pectin gel

1-4  Factors affecting gelation

1-5  Chemical properties

1-6  Pectic enzymes

1-7  Structure and mechanisms of gel formation

1-8  Application

1-1  Structure and Terminology

Pectin is heterogeneous complex polysaccharide

Its composition varies with the source and the conditions applied during isolation

All pectin molecules contain linear segments of (1à4)-linked a-D-galactopyranosyluronic acid with some of the carboxyl groups esterified with methanol.

Some of the hydroxyl groups of the galacturonosyl unit (O-2 and O-3) are esterified with acetic acid.

Pectin molecule with methyl esterified or nonesterified carboxyl groups

Amidated pectin has commercial importance

Terminology

Protopectin

Pectinic acids

Pectic acids

Pectins

Degree of esterification (DE) > 50

High-methoxyl pectins (HM-pectins)

High concentration of soluble solids, low pH

DE < 50

LM-pectins

Divalent cations

1-2  Production

1-2-1 Raw materials

Citrus peel (20-30%), apple pomace(10-15%)

Sugarbeet waste, sunflower heads, mango waste

Sugarbeet pectin is inferior to citrus or apple pectin

Presence of  acetate esterification

A relatively low molecular mass

Presence of large amount of neutral sugar side chain

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