Unravelling process-induced pectin changes in the tomato cell wall: An integrated approach

Area of Science:

• Food Science
• Biochemistry
• Plant Biology

Background:

• Pectin modification by enzymes like pectin methylesterase (PME) and polygalacturonase (PG) is crucial for fruit texture and processing.
• Understanding how processing affects these enzymes and pectin structure is key to controlling tomato product quality.

Purpose of the Study:

• To investigate the impact of different processing methods on PME and PG activity in tomato fruit.
• To elucidate the relationship between process-induced pectin changes and cell-cell adhesion in tomato tissue suspensions.

Main Methods:

• Tomatoes were subjected to various pretreatments: no pretreatment, high-temperature blanching (inactivating PME and PG), or high-pressure pretreatment (selectively inactivating PG).
• Mechanical disruption (blending or high-pressure homogenization) was used to create tomato tissue particle suspensions.
• In situ pectin visualization using anti-pectin antibodies and physicochemical analysis of cell walls were employed.

Main Results:

• In intact tomatoes, PME activity is endogenously regulated within the cell wall matrix.
• Processing, particularly high-pressure treatment, led to intensive PME activity and pectin de-esterification, increasing Ca2+-cross-linked pectin and intercellular adhesion.
• High-temperature blanching inactivated both PME and PG, resulting in minimal pectin cross-linking and significant cell separation.

Conclusions:

• Processing significantly alters pectin structure and enzyme activity in tomatoes, directly impacting cell-cell adhesion.
• Selective inactivation of PG, combined with PME activity, enhances pectin cross-linking and strengthens intercellular adhesion.
• These findings provide insights into controlling tomato tissue properties through targeted processing for desired product characteristics.