Results and discussion
The analyses of amino acids were performed on two lots of
the pulp of pear fruits (Pyrus communis L. var. S. Bartolomeu),
corresponding to two sets of experiments. In the
first one, the amino acids present in the free form and
incorporated into proteins were determined on traditionally
processed fruits as well as on the fresh ones. If these amino
acids are involved in Maillard reactions, they should
present variations from fresh to the traditional sun-dried
processing. To evaluate this, samples from two harvests,
2008 and 2009, were used. In the second set of experiments,
the amino acids present in the free form and
incorporated into proteins were determined in fruits processed
according to different methodologies and presenting
different colours (Fig. 1): traditionally sun-dried, processed
in a large glass greenhouse with air convection (GH1),
processed in a small greenhouse with natural convection
(GH2) and processed using a hot air tunnel in the absence
of light (HAT). For these experiments, the fruits used were
harvested in 2009. Having performed analysis to the free
and protein-bound amino acids of the different samples, a
search for Maillard reaction compounds, namely furosine,
CML and CEL, was performed in all samples of 2009
harvest and their possible relationship with the colours of
the samples are discussed.