Impact of PEF treatment on quality parameters of white asparagus (Asparagus officinalis L.)

Pulsed Electric Field (PEF) application on white asparagus (Asparagus officinalis L) was exercised to examine influence of electroporation on spear characteristics as composition and texture. PEF treated spears showed altered storage behaviour, which was noticed by increased mass transfer as higher water loss as well as the decrease of the Maillard reaction substrate glucose. Cell disintegration measurement revealed significant influence of electric field orientation on electroporation. Since the anisotropy of asparagus tissue, PEF processing in longitudinal direction of the spear axis resulted in 9.06% higher cell membrane permeabilization than treatment in transverse direction. Furthermore, total solids inclusive lignin content were measured to obtain textural improvements of asparagus spears. It could be shown that dry weight as well as the amount of lignin was reduced after PEF implementation. Lignin degradation (-2.4%) might be attributed to the PEF induced interference of electrostatic dipole-dipole interactions between lignin and cellulose and subsequent delignification. Industrial relevance: Since three decades the technology of Pulsed Electric Fields (PM received considerable relevance in food and bioengineering as well as in medicine. Besides the use of PEF to inactivate microorganisms main focus is put on the disintegration of biological cell material to enhance mass transfer in drying or extraction processes. Although the effects of PEF on various plant cell materials are well studied only scarce knowledge exists concerning the impact of PEF on white asparagus. In the study undertaken the PEF-induced changes in asparagus texture and composition were examined. The investigations shall help to reduce unfavored intra- and extracellular components to gain food safety as well as softer spear texture. (C) 2011 Elsevier Ltd. All rights reserved.