masterThesis
Uso da espectroscopia do infravermelho próximo e técnicas multivariadas para diferenciar escherichia coli e salmonella enteritidis inoculadas em polpa de fruta (abacaxi)
Date
2013-07-31Registration in:
MARQUES, Aline de Sousa. Uso da espectroscopia do infravermelho próximo e técnicas multivariadas para diferenciar escherichia coli e salmonella enteritidis inoculadas em polpa de fruta (abacaxi). 2013. 69 f. Dissertação (Mestrado em Físico-Química; Química) - Universidade Federal do Rio Grande do Norte, Natal, 2013.
Author
Marques, Aline de Sousa
Institutions
Abstract
Aiming to consumer s safety the presence of pathogenic contaminants in
foods must be monitored because they are responsible for foodborne outbreaks
that depending on the level of contamination can ultimately cause the death of
those who consume them. In industry is necessary that this identification be fast
and profitable. This study shows the utility and application of near-infrared (NIR)
transflectance spectroscopy as an alternative method for the identification and
classification of Escherichia coli and Salmonella Enteritidis in commercial fruit pulp
(pineapple). Principal Component Analysis (PCA), Independent Modeling of Class
Analogy (SIMCA) and Discriminant Analysis Partial Least Squares (PLS-DA) were
used in the analysis. It was not possible to obtain total separation between
samples using PCA and SIMCA. The PLS-DA showed good performance in
prediction capacity reaching 87.5% for E. coli and 88.3% for S. Enteritides,
respectively. The best models were obtained for the PLS-DA with second
derivative spectra treated with a sensitivity and specificity of 0.87 and 0.83,
respectively. These results suggest that the NIR spectroscopy and PLS-DA can be
used to discriminate and detect bacteria in the fruit pulp