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

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 puree 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 (M-w) distribution. Endogenous pectin methyl-esterase and polygalacturonase stimulation resulted in the lowest puree consistency and highest serum yield. However, when such puree was homogenized, a higher pure consistency and a low serum yield were observed. Moreover, the M-w of serum pectin was exceptionally high for the homogenized pures. The low methyl-esterifled, linear and remarkably high M-w tomato serum pectin of the homogenized pur es partly explains their increased consistency. This work demonstrated that high pressure homogenization can at least partially restore the consistency of tomato pur e despite an initial consistency loss ascribed to enzymatic pectin degradation. Industrial relevance: The synergistic action of endogenous pectin-related enzymes causes serum pectin de-polymerization that consequently results in consistency loss of tomato puree. 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 puree consistency can still be achieved regardless of the initial action of endogenous enzymes in the tomato pieces or pureed tomato food system using high pressure homogenization. This offers an additional processing alternative in the production of tomato-based dispersions with a targeted functionality.