The
unraveling of crushed grapes by maceration enzymes during winemaking
is difficult to study because of the complex and rather undefined
nature of both the substrate and the enzyme preparations. In this
study we simplified both the substrate, by using isolated grape skin
cell walls, and the enzyme preparations, by using purified enzymes
in buffered conditions, to carefully follow the impact of the individual
and combined enzymes on the grape skin cell walls. By using cell wall
profiling techniques we could monitor the compositional changes in
the grape cell wall polymers due to enzyme activity. Extensive enzymatic
hydrolysis, achieved with a preparation of pectinases or pectinases
combined with cellulase or hemicellulase enzymes, completely removed
or drastically reduced levels of pectin polymers, whereas less extensive
hydrolysis only opened up the cell wall structure and allowed extraction
of polymers from within the cell wall layers. Synergistic enzyme activity
was detectable as well as indications of specific cell wall polymer
associations