Development of an immunological toolbox to detect endogenous and exogenous pectin methylesterase in plant-based food products

Abstract

An immunological toolbox consisting of five monoclonal antibodies (MA) was developed for the detection of endogenous as well as exogenous pectin methylesterase (PME) in plant-based food products. Based on cross-reactivity with plant PME, the MA were subdivided into two groups. MA of group one recognise exclusively PME from Aspergillus aculeatus (fPME), which could be visualised upon infusion. Three different infusion techniques were compared for three different types of plant tissue, revealing a homogenous distribution of exogenous PME upon pressure-and vacuum-assisted infusion. The MA of group two recognise fPME as well as PME from different plant sources like tomato, carrot, strawberry, broccoli and apple. The use of these antibodies allowed detection of endogenous PME in tomato which revealed an overall presence of PME in the pericarp of tomato fruit. Moreover, the PME detected by the MA of group two in the plant cell wall of tomato coincided with the localisation of two isoenzymes of tomato PME, as detected by isoenzyme-specific MA. The obtained results highlight the versatility of the developed antibodies as probes to detect PME in the context of food processing.