Publicação
Characterisation of the polar lipid profile of the olive pulp by using lipidomics
| Resumo: | The consumption of olives, the fruits of the olive tree (Olea europaea L.), in the form of table olives and olive oil has increased significantly in the last two decades worldwide. However, the nutritional value of this complex matrix rich in lipids, whose pulp represents ca. 75% of its dry weight, is not yet fully known. Its lipid fraction comprises essentially triacylglycerols but also free fatty acids, sterols and polar lipids. However, the profile of these polar lipids, such as phospholipids and glycolipids, compounds with various health benefits and bioactive properties, is practically unknown, with the need for their characterisation. As such, this study characterised the polar lipidome of the olive pulp of three varieties and two geographic regions through emerging techniques of high resolution and sensitivity, based on chromatography and mass spectrometry. The work began by extracting total lipids from the pulp, followed by fractionation of the total extract and characterisation of the polar lipid-rich fractions. The fractionation process by solid-phase extraction was tested, and the efficiency of this protocol in the recovery of polar lipids in qualitative and quantitative terms was confirmed. The analysis of the total lipid extract and polar lipid-rich fractions by thin-layer chromatography allowed verification of the pulp’s lipidome complexity. The analysis of the polar lipid-rich fractions by HILIC HPLC-ESI-MS/MS allowed the identification and structural characterization of one hundred and eighty-eight lipid species: one hundred and thirty-two phospholipids, thirty-five glycolipids, fifteen sphingolipids and six betaines. In addition to identifying several new molecular species, several lipid classes have also been reported in the olive pulp for the first time. This work has also revealed the fatty acid composition of the polar lipidome of the olive pulp, comprising monounsaturated, polyunsaturated, saturated, monohydroxy and dihydroxy fatty acyl chains. Finally, the polar lipid-based multivariate statistical analysis allowed the successful identification of lipid markers that can discriminate the botanical and or geographic origin of olives, thus demonstrating the uniqueness of the polar lipidome profile of each group of olives under study. With the identification of potentials bioactive lipids, this work has also allowed valuing the olive fruit as a beneficial food for health and several potential industrial applications such as the food, cosmetics, pharmaceuticals, nutraceutical and feed industries. |
|---|---|
| Autores principais: | Costa, Tiago Jardim |
| Assunto: | Olive Oil Polar lipids Fatty acids Lipidomics Solid-phase extraction Chromatography Mass spectrometry Botanical origin Geographical origin |
| Ano: | 2021 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade de Aveiro |
| Idioma: | inglês |
| Origem: | RIA - Repositório Institucional da Universidade de Aveiro |
| Resumo: | The consumption of olives, the fruits of the olive tree (Olea europaea L.), in the form of table olives and olive oil has increased significantly in the last two decades worldwide. However, the nutritional value of this complex matrix rich in lipids, whose pulp represents ca. 75% of its dry weight, is not yet fully known. Its lipid fraction comprises essentially triacylglycerols but also free fatty acids, sterols and polar lipids. However, the profile of these polar lipids, such as phospholipids and glycolipids, compounds with various health benefits and bioactive properties, is practically unknown, with the need for their characterisation. As such, this study characterised the polar lipidome of the olive pulp of three varieties and two geographic regions through emerging techniques of high resolution and sensitivity, based on chromatography and mass spectrometry. The work began by extracting total lipids from the pulp, followed by fractionation of the total extract and characterisation of the polar lipid-rich fractions. The fractionation process by solid-phase extraction was tested, and the efficiency of this protocol in the recovery of polar lipids in qualitative and quantitative terms was confirmed. The analysis of the total lipid extract and polar lipid-rich fractions by thin-layer chromatography allowed verification of the pulp’s lipidome complexity. The analysis of the polar lipid-rich fractions by HILIC HPLC-ESI-MS/MS allowed the identification and structural characterization of one hundred and eighty-eight lipid species: one hundred and thirty-two phospholipids, thirty-five glycolipids, fifteen sphingolipids and six betaines. In addition to identifying several new molecular species, several lipid classes have also been reported in the olive pulp for the first time. This work has also revealed the fatty acid composition of the polar lipidome of the olive pulp, comprising monounsaturated, polyunsaturated, saturated, monohydroxy and dihydroxy fatty acyl chains. Finally, the polar lipid-based multivariate statistical analysis allowed the successful identification of lipid markers that can discriminate the botanical and or geographic origin of olives, thus demonstrating the uniqueness of the polar lipidome profile of each group of olives under study. With the identification of potentials bioactive lipids, this work has also allowed valuing the olive fruit as a beneficial food for health and several potential industrial applications such as the food, cosmetics, pharmaceuticals, nutraceutical and feed industries. |
|---|