The effect of high pressure homogenization and endogenous pectin-related enzymes on tomato purée consistency and serum pectin structure

- Stimulation of endogenous pectin-related enzymes in tomato purée results in high serum yield and pectin content.
- High pressure homogenization influences the molecular weight of tomato serum pectin.
- Intense high pressure homogenization restores tomato purée consistency loss due to enzymatic pectin degradation.

The influence of mechanical tissue disintegration techniques (i.e. blending and high pressure homogenization) and the stimulation of endogenous pectin-related enzymes (i.e. pectin methyl-esterase and polygalacturonase) on tomato purée consistency, serum composition and serum pectin structure were investigated. Serum pectin structure was characterized in terms of degree of methyl-esterification, acetylation, neutral sugar composition and molecular weight (Mw) distribution.Endogenous pectin methyl-esterase and polygalacturonase stimulation resulted in the lowest purée consistency and highest serum yield. However, when such purée was homogenized, a higher purée consistency and a low serum yield were observed. Moreover, the Mw of serum pectin was exceptionally high for the homogenized purées. The low methyl-esterified, linear and remarkably high Mw tomato serum pectin of the homogenized purées partly explains their increased consistency. This work demonstrated that high pressure homogenization can at least partially restore the consistency of tomato purée despite an initial consistency loss ascribed to enzymatic pectin degradation.Industrial relevanceThe synergistic action of endogenous pectin-related enzymes causes serum pectin de-polymerization that consequently results in consistency loss of tomato purée. Nevertheless, intense high pressure homogenization showed to influence serum pectin molecular weight and at least restore the consistency loss. This means that a high tomato purée consistency can still be achieved regardless of the initial action of endogenous enzymes in the tomato pieces or puréed tomato food system using high pressure homogenization. This offers an additional processing alternative in the production of tomato-based dispersions with a targeted functionality.