In situ pectin engineering as a tool to tailor the consistency and syneresis of carrot puree

摘要

To investigate whether in situ pectin engineering would be a helpful tool in tailoring the consistency and syneresis of vegetable purees, carrot was selected as a plant tissue in which the textural properties are largely influenced by pectin methylesterase-induced pectin changes. The effect of low-temperature and high-temperature blanching, as well as the effect of two types of mechanical disruption, blending and high-pressure homogenisation, on the flow properties of carrot puree was explored. The influence of these different puree preparation steps on pectin was examined via physicochemical analysis of fractionated walls and isolated polymers, and via anti-pectin antibodies entailing in situ and ex situ analyses. Puree prepared by blending non-pretreated carrots showed a rather high consistency and pronounced syneresis. Treatments that solubilise pectin, such as high-pressure homogenisation and, in particular, high-temperature blanching, limited syneresis phenomena. In contrast, when the intercellular adhesion in carrot tissue was strengthened via low-temperature blanching, the degree of syneresis increased. High-pressure homogenisation was useful to reduce the carrot tissue particle size and, consequently, resulted in a lower consistency carrot puree. Low-temperature blanching on the other hand increased the consistency of carrot puree as the higher level of intercellular adhesion presumably led to an increased resistance to particle disintegration upon blending or high-pressure homogenisation.