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Chromatographic analysis and comparison of chemical composition of the samples between olive oils in Europe and some chinese oils
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Resumo(s)
Olive oil is a well known vegetable oil due to its beneficial effects on human’s health
and its strong economic importance in the Mediterranean area, being this region alone
responsible for more than 90% of the olive oil’s world production. In other regions such
as the Chinese one, olive oil is not that commonly used, and other vegetable oils such as
tea seed oil, rapeseed oil, sesame oil, corn oil, sunflower oil and peanut oil are rather
used to prepare the daily meals.
The unique characteristics of each type of vegetable oil is directly related to their fatty
acid distribution, being this way the study of the fatty acid composition a good way to
characterize them. So, GC-MS fingerprinting technique was applied for the
characterization of the different oils, being able to identify a total of 22 fatty acids
among the seven tested oils in the CSU’s laboratory. Then, chemometrics were applied
for data analysis, which included Principal Component Analysis (PCA) and Partial
Least Squares – Linear Discriminant Analysis (PLS-LDA), in order to see if (1) it was
possible to group the olive oils according to their region of production in the Iberian
Peninsula, and (2) this fingerprinting method could be validated for the analyses of
vegetable oils through its both inter- and intra-laboratorial comparison.
With PLS-LDA we were able to group the olive oil samples according to their region of
production, and also a clear distinction could be made between olive oil and tea seed oil
by means of a PCA model. In terms of repeatability and intermediate precision, good
results were also obtained from the analyses performed both in CSU and HAPPI. The
same analyses were then performed resorting to a group of 12 fatty acids, and similar
results could be observed as when using all the fatty acids, meaning that these 12 fatty
acids posses sufficient information to characterize the different types of oil.
The use of Palmitic acid as a reference peak instead an internal standard was also tested,
proving to be a good way to perform these analyses.
Descrição
Dissertação de mest., Qualidade em Análises, Faculdade de Ciências e Tecnologia, Univ. do Algarve, 2013
Palavras-chave
Dieta mediterrânica