DESENVOLVIMENTO E CARACTERIZAÇÃO FÍSICO ... - UFSM

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was higher than in mango and pineapple wine 9,7 . The value for residual sugar shows that the
fermentation was successful and classifies the wine as dry. Volatile acidity and pH attach to
jelly pam wine durability based on Jackson 27 .
Validation Parameters for major volatile compounds
In general, the volatile compounds have shown a good linearity in the range of
concentrations studied, as regression coefficients (R 2 ) varying between 0.991 (hexanoic acid)
and 0.998 (propanol) (Table 2), with a linear range between 0.1 to 50 mg/l. The precision was
studied as repeatability (n = 6 intra-day) and intermediate precision (n = 4 inter-days) and
expressed as relative standard deviation (%RSD) in the model wine. Percent RSD values range
from 6.5% (propanol) to 10.9% (hexanoic acid) were found for repeatability and between 7.2
and 10.3% for intermediate precision. The LOD and LOQ were visually calculated from the
ratio of the peak areas to the average noise and are given in Table 2.
The results for limit of quantitation and detection were dependent on the
physicochemical characteristics of the volatile compounds, in this sense, ethyl hexanoate and
possessed the lowest detection limit (0.01 mg/l) among the studied compounds. The slope of
the calibration line is also sowed in Table 2; according to Ferreira 28 the slope is a measure of
method sensitivity and depends on both extraction efficiency and detector response for each
compound. In this sense, ethyl hexanoate followed by isoamyl alcohol presented the higher
sensitivity for the method; both compounds show a good response detector and also reached
the highest percent of recovery. The recovery percentages obtained assigned to the method an
acceptable accuracy at the three tested levels. The percentage recovery ranged between 86 and
96% for hexanoic acid and isoamyl alcohol, respectively.
Optimization of solid-phase microextraction conditions for minor volatile compounds
Typically SPME headspace sampling was selected for this study. HS-SPME is an
equilibrium technique that requires a previous optimization step of the sampling conditions, in
order to obtain high recoveries of volatiles compounds and a good precision of the method 29,30 .
The main parameters for optimizing an extraction system were evaluated for jelly palm wine,
fiber adsorbent phase, salt addition and extraction temperature and time. The results of the
optimization performed in this study (Table 3) shows that, among the three fibers evaluated,
under the same conditions (35 °C for 45 min with 30% of salt, NaCl), the highest values for