Produce Degradation Pathways and Prevention

472 Produce Degradation: Reaction Pathways and their Prevention

FIGURE 15.5

Pectin degradation by pectin methyl esterase, polygalacturonase, and pectin lyase. (From Agrios, 1997. With permission.)

O

O

O

...

O

O

...

O

O

O

HH

O

OH HO

O

...

O

...

O

O

...

...

...

COOH

COOH

COOH

O

COOH

+

CH

OH 3

Methanol

H OH

COCH

3

O

C

H

OCH

3

O

++

O

O

O

O

O

...

O

O

O

O

O

COOH

COOH

O

COOH

COCH

3

O

O

COOO

CH

3

O

O

COCH

3

O

COCH

3

O

COCH

3

O

(PME)

(PG)

(PL)

Pectin methyl esterase

Pectin lyase (PL)−H

2 O

Polygalac-turonase(PG)

+ H

O 2

+ H

O 2

(PME)