A new laboratory method is discussed
for monitoring phenolic quality
in grape during maturation in the
vineyard. Spectroscopy on whipped
grapes was used to determine an index
of phenolic maturity (Phenolic Maturity
Trend - PMT) derived from the elaboration
of the reflectance signals from
six light emitting diodes in the spectral
range 525-880 nm. The PMT index allows
the trend of the overall maturity
of polyphenols in grape berries to be
qualitatively defined in laboratory and supplies information equivalent to that
obtained with the traditional methods
used to identify polyphenols. Since the
method does not require polyphenol extraction,
many more analyses can be
done daily.
