DESENVOLVIMENTO E CARACTERIZAÇÃO FÍSICO ... - UFSM

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The first principal component (PC1) explains 69.0% of the variance in the initial data set
and the second principal component (PC2) explain 6.9%. The projections of the samples along the
directions identified by the first two PC’s, is reported in Fig. 1. First principal component (PC1)
of wine treatments (scores) is plotted against the second principal component (PC2) in Fig.1.a. The
separation of the different treatments applied to the wine is showed clearly through the scatter point
plot. This figure shows that wines from the treatments fermented at 10 ºC were separeted by the
first component analysis from those fermented at 20 ºC. Apparently treatments M7T10 and M2T20
were not separated, however the completely separation were visualized with the aid of the third
component (PC3) that explains 4.9% of the variance (data no showed). Fig. 1b shows the
corresponding loadings plot that establishes the relative importance of each variable to discriminate
the treatments. This figure shows that most of volatile compounds may be seen in the upper part of
the plot, where PC1 and PC2 are positive and are strongly correlated to treatment (M7T20). The
first component (PC1) was characterized by major concentration of the volatile compounds,
including, ethyl hexanoate, methyl hexanoate, hexanoic acid and butyric acid. The esters and their
corresponding acids, ethyl hexanoate and hexanoic acid and ethyl butyrate and butyric acid, are
showing a positively correlation with the increases of temperature indicating a possible equilibrium
hydrolyses reaction among these compounds (RAMEY & OUGH, 1980). The volatile compounds
located in the negative PC2 are highly correlated to treatment (D2T10) that presented the lowers
concentrations for the compounds. The upper part of the PC2 (positive) shows some volatile
compounds that did not followed the same behavior of the most volatiles. 2-nonanol and methyl
lavander ketone had its concentration not differing statistically to the treatments at 10 and 20 ºC,
the same was observed for isoamyl acetate and 1-octanol. Therefore, it’s possible to conclude that,
different temperatures had influenced the concentration of the volatile compounds in jelly palm
wine and that a high fermentation temperature increases the volatile concentration. In general, the
dilution of the must may be cause a dilution of the volatile compounds reducing its concentrations
in the headspace of the wine. The influence of the treatments will be discussed for each chemical
class of compounds in separate.
3.3 Esters
Most esters found in wine are produced by yeast, after cell division has essentially ceased.
Straight-chain forms are synthetized from alcoholysis of the corresponding acids, which have been