However,
it is unclear if the increase of these compounds is really biosynthesis
or simply the result of an easier extraction. In viticulture, cell
wall degradation is considered to be another potential index of
berry maturity, as are technological and phenol maturities. This
is because the extraction of important enological compounds, such
as anthocyanins, or polyphenols in general, is easier when the berry’s
cell wall is broken. Cell wall enzymes, mainly PME (PG is
almost undetectable), are responsible for cell wall degradation
and these enzymes are strongly activated during berry ripening