Effect of Storage on Rheology of Water-Soluble, Chelate-Soluble and Diluted Alkali-Soluble Pectin in Carrot Cell Walls

Joanna Mierczyńska,Piotr M Pieczywek,Justyna Cybulska,Artur Zdunek

doi:10.1007/s11947-014-1392-9

Joanna Mierczyńska, Piotr M Pieczywek + Show 2 more

Open Access

https://doi.org/10.1007/s11947-014-1392-9

Copy DOI

Abstract

The properties and functionality of pectins from plant cell walls depend on their structure. Therefore, the objective of this work was to determine the rheological properties of pectins extracted from plant cell walls with different solvents in relation to postharvest storage time. Water (WSP), chelate (CSP) and diluted alkali (DASP) soluble pectins were studied, taken from carrot cell walls (‘Nerac’ variety), at harvest and at five time points during storage. The rheology of pectins was studied in relation to flow properties and viscosity, and the storage effect was studied in relation to enzyme activity. The results showed that rheology of pectins depend on the solvent used for extraction. The viscosity of each pectin fraction increased during storage. WSP had the highest viscosity (maximum 0.045 Pas) compared to CSP (0.023 Pas) and DASP (0.011 Pas). DASP revealed thixotropic properties that increased from 3 % at harvest to 14 % after 5 months of storage. Flow behaviour of DASP did not change with storage time, whereas WSP and CSP showed a change from dilatant to pseudoplastic flow. The changes in rheological properties may be related to an enzymatic-induced molecular transformation, which promotes a gelling ability.

Highlights

Pectins are a heterogeneous group of polysaccharides abundant in cell walls and the middle lamella of higher plants
Enzyme activity and degradation of pectin in carrot cell walls were examined during 5 months of storage in a cold atmosphere
The degree of methylation in WSP was at a relatively high level and varied in the range of 71.8–78.8 %, which may be explained by the formation of new high-methoxyl pectin due to the increase of the total galacturonic acid (GalA) content during storage between 228 and 329 μm/ mg alcohol insoluble residues (AIR)

Summary

Introduction

Pectins are a heterogeneous group of polysaccharides abundant in cell walls and the middle lamella of higher plants. Pectins and rheology have been widely studied, since they determine the properties of cell walls, and are used in the food industry as a functional food ingredient (E440 in the European Union) and as a stabilizer for gelling properties in the production of fruit juice, jams, jellies, drinks, sauces, syrups, sugar confectionery, pastries, products and yogurts (Jayani et al 2005; Mesbahi et al 2005; Arancibia and Motsenbocker 2006; Cybulska et al 2011). Pectinases are widespread in higher plants and can be produced by phytopathogenic microorganisms. The enzymes are widely used in the food industry as clarification agents for fruit juices, coffee and tea fermentations (Cybulska et al 2012). Pectinolytic enzymes are involved in maintaining a balanced ecosystem, decomposing organic material from plants (Jayani et al 2005; AlimardaniTheuil et al 2011)

Objectives

Results

Conclusion