A Global Study by 1H NMR Spectroscopy and SPME-GC/MS of the in Vitro Digestion of Virgin Flaxseed Oil Enriched or not with Mono-, Di- or Tri-Phenolic Derivatives. Antioxidant Efficiency of These Compounds

The effect of enriching virgin flaxseed oil with dodecyl gallate, hydroxytyrosol acetate or gamma-tocopherol on its in vitro digestion is studied by means of proton nuclear magnetic resonance and solid phase microextraction followed by gas chromatography/mass spectrometry. The extent and pattern of the lipolysis reached in each sample is analyzed, as is the bioaccessibility of the main oil components. None of the phenolic compounds provokes inhibition of the lipase activity and all of them reduce the lipid oxidation degree caused by the in vitro digestion and the bioaccessibility of oxidation compounds. The antioxidant efficiency of the three tested phenols is in line with the number of phenolic groups in its molecule, and is dose-dependent. The concentration of some minor oil components such as terpenes, sesquiterpenes, cycloartenol and 24-methylenecycloartenol is not modified by in vitro digestion. Contrarily, gamma-tocopherol shows very low in vitro bioaccessibility, probably due to its antioxidant behavior, although this increases with enrichment of the phenolic compounds. Oxidation is produced during in vitro digestion even in the presence of a high concentration of gamma-tocopherol, which remains bioaccessible after digestion in the enriched samples of this compound.This work has been funded by the Spanish Ministry of Economy and Competitiveness (MINECO, AGL2015-65450-R, AEI/FEDER-EU) and by the Basque Government and its Departments of Universities and Research (EJ-GV, IT-916-16)

Polylactic acid as a promising sustainable plastic packaging for edible oils

The influence of renewable packaging materials on the oxidative stability of sunflower oil was investigated to evaluate whether they could be used as alternatives to conventional plastics. Two renewable bottle materials, polylactic acid (PLA) and bio-polyethylene (Green-PE) were compared to conventional plastics consisting of virgin and recycled polyethylene terephthalate (PET, r-PET) and regular polyethylene (PE), in a storage study over a period of 56 days. The results showed that the progress of lipid oxidation in PLA was similar to PET and r-PET until day 28, while it was significantly increased in PE and Green-PE. Benzene was detected as the only migration compound in the oil stored in PET and r-PET, with concentrations of 0.153 ± 0.027 µg/g and 0.187 ± 0.024 µg/g after 56 days of storage. The study concluded that PLA could be used as an alternative packaging material for edible oils to replace PET.This work was kindly funded by the Austrian Science Fund (FWF): P 34512. J. Alberdi-Cedeño thanks the EJ-GV for a postdoctoral grant (POS_2020_1_0040). The authors want to thank Sandra Auernigg-Haselmaier for the technical assistance with the LC-MS and the NMR core facility of the Division of Pharmaceutical Chemistry at the University of Vienna for providing access to the NMR instruments

Characterization of edible oils main and minor components and study of their evolution during oxidation, nixtamalization and in vitro digestion processes by non-conventional tecniques DI-SPME-GC/MS and1H NMR spectroscopy

665 p.En la presente tesis doctoral, por un lado, se abordó el estudio de la caracterización de aceites vegetales de diferente origen botánico, prestando atención a su composición en componentes minoritarios mediante el empleo de una técnica analítica desarrolla en nuestro laboratorio, Inmersión Directa-Microextracción en Fase Sólida seguida de Cromatografía de Gases / Espectrometría de Masas (ID MEFS-CG/EM).Asimismo, se estudiaron los cambios que sufren los componentes lipídicos del aceite de maíz cuando éste es sometido a condiciones oxidativas y/o tratamiento tecnológico, nixtamalización y la elaboración de tortillas, mediante Resonancia Magnética Nuclear de Protón (RMN de 1H) y Inmersión Directa-Microextracción en Fase Sólida seguida de Cromatografía de Gases / Espectrometría de Masas (ID MEFS-CG/EM). Los aspectos composicionales abordados fueron la evolución de la concentración delos componentes mayoritarios y minoritarios, así como la evolución de la concentración de los nuevoscompuestos formados derivados de la degradación de los anteriores. Cabe señalar que algunos de loscompuestos detectados derivados de la degradación de los compuestos tanto mayoritarios comominoritarios del aceite, no habían sido descritos previamente durante el proceso de oxidación de aceites yestán relacionados con diversas enfermedades.Por último, se abordó el estudio de la digestión in vitro en diferentes aceites vegetales, oliva,maíz y lino virgen, prestando especial atención a las reacciones de lipólisis y de oxidación, e intentandorelacionar la bioaccesibilidad de los componentes mayoritarios de los aceites con su composición, si lahubiera. Además, estos mismos aceites fueron enriquecidos con diferentes compuestos fenólicos, alphaygamma-tocoferol, hidroxitirosol acetato y galato de dodecilo, a diferentes concentraciones y sometidosa las mismas condiciones de digestión in vitro, con el objeto de estudiar el efecto que el enriquecimientocon ciertos compuestos fenólicos ejerce sobre el grado de lipólisis y la estabilidad oxidativa de losmismos

Characterization of edible oils main and minor components and study of their evolution during oxidation, nixtamalization and in vitro digestion processes by non-conventional tecniques DI-SPME-GC/MS and1H NMR spectroscopy

665 p.En la presente tesis doctoral, por un lado, se abordó el estudio de la caracterización de aceites vegetales de diferente origen botánico, prestando atención a su composición en componentes minoritarios mediante el empleo de una técnica analítica desarrolla en nuestro laboratorio, Inmersión Directa-Microextracción en Fase Sólida seguida de Cromatografía de Gases / Espectrometría de Masas (ID MEFS-CG/EM).Asimismo, se estudiaron los cambios que sufren los componentes lipídicos del aceite de maíz cuando éste es sometido a condiciones oxidativas y/o tratamiento tecnológico, nixtamalización y la elaboración de tortillas, mediante Resonancia Magnética Nuclear de Protón (RMN de 1H) y Inmersión Directa-Microextracción en Fase Sólida seguida de Cromatografía de Gases / Espectrometría de Masas (ID MEFS-CG/EM). Los aspectos composicionales abordados fueron la evolución de la concentración delos componentes mayoritarios y minoritarios, así como la evolución de la concentración de los nuevoscompuestos formados derivados de la degradación de los anteriores. Cabe señalar que algunos de loscompuestos detectados derivados de la degradación de los compuestos tanto mayoritarios comominoritarios del aceite, no habían sido descritos previamente durante el proceso de oxidación de aceites yestán relacionados con diversas enfermedades.Por último, se abordó el estudio de la digestión in vitro en diferentes aceites vegetales, oliva,maíz y lino virgen, prestando especial atención a las reacciones de lipólisis y de oxidación, e intentandorelacionar la bioaccesibilidad de los componentes mayoritarios de los aceites con su composición, si lahubiera. Además, estos mismos aceites fueron enriquecidos con diferentes compuestos fenólicos, alphaygamma-tocoferol, hidroxitirosol acetato y galato de dodecilo, a diferentes concentraciones y sometidosa las mismas condiciones de digestión in vitro, con el objeto de estudiar el efecto que el enriquecimientocon ciertos compuestos fenólicos ejerce sobre el grado de lipólisis y la estabilidad oxidativa de losmismos

Effect of Encapsulation Material on Lipid Bioaccessibility and Oxidation during In Vitro Digestion of Black Seed Oil

Different encapsulation materials might not only affect lipid hydrolysis but also lipid oxidation during in vitro digestion. Thus, this study aimed to investigate the effect of two commonly used shell materials, starch and gelatin, on the extent of lipolysis and bioaccessibility of the main and some minor lipid compounds, as well as on the oxidative status in encapsulated black seed oil (Nigella sativa) during in vitro digestion. The study was carried out using 1H nuclear magnetic resonance spectroscopy, liquid chromatography-mass spectrometry and high-performance liquid chromatography-UV. It was shown that starch increased the level of lipid hydrolysis in black seed oil during gastric in vitro digestion, while no differences were observed in the intestinal digestates between starch-encapsulated oil and gelatin-encapsulated oil. Similarly, the bioaccessibility of minor compounds (tocopherols, sterols and thymoquinone) was not influenced by the shell materials. However, regarding lipid oxidation, a 20- and 10-fold rise of free oxylipins was obtained in oils encapsulated by starch and gelatin, respectively, after intestinal in vitro digestion. This study evidenced that gelatin rather than starch should be used for the encapsulation of oils to minimize the digestion-induced formation of bioactive oxylipins

Effect of Encapsulation Material on Lipid Bioaccessibility and Oxidation during In Vitro Digestion of Black Seed Oil

Different encapsulation materials might not only affect lipid hydrolysis but also lipid oxidation during in vitro digestion. Thus, this study aimed to investigate the effect of two commonly used shell materials, starch and gelatin, on the extent of lipolysis and bioaccessibility of the main and some minor lipid compounds, as well as on the oxidative status in encapsulated black seed oil (Nigella sativa) during in vitro digestion. The study was carried out using 1H nuclear magnetic resonance spectroscopy, liquid chromatography-mass spectrometry and high-performance liquid chromatography-UV. It was shown that starch increased the level of lipid hydrolysis in black seed oil during gastric in vitro digestion, while no differences were observed in the intestinal digestates between starch-encapsulated oil and gelatin-encapsulated oil. Similarly, the bioaccessibility of minor compounds (tocopherols, sterols and thymoquinone) was not influenced by the shell materials. However, regarding lipid oxidation, a 20- and 10-fold rise of free oxylipins was obtained in oils encapsulated by starch and gelatin, respectively, after intestinal in vitro digestion. This study evidenced that gelatin rather than starch should be used for the encapsulation of oils to minimize the digestion-induced formation of bioactive oxylipins

Oxylipins Associated to Current Diseases Detected for the First Time in the Oxidation of Corn Oil as a Model System of Oils Rich in Omega-6 Polyunsaturated Groups. A Global, Broad and in-Depth Study by 1H NMR Spectroscopy

For the first time, an important number of oxylipins have been identified and quantified in corn oil submitted to mild oxidative conditions at each time of their oxidation process. This oil can be considered as a model system of edible oils rich in polyunsaturated omega-6 groups. The study was carried out using 1H nuclear magnetic resonance spectroscopy (1H NMR), which does not require chemical modification of the sample. These newly detected oxylipins include dihydroperoxy-non-conjugated-dienes, hydroperoxy-epoxy-, hydroxy-epoxy- and keto-epoxy-monoenes as well as E-epoxy-monoenes, some of which have been associated with several diseases. Furthermore, the formation of other functional groups such as poly-formates, poly-hydroxy and poly-ether groups has also been proven. These are responsible for the polymerization and increased viscosity of the oil. Simultaneously, monitoring of the formation of well-known oxylipins, such as hydroperoxy-, hydroxy-, and keto-dienes, and of different kinds of oxygenated-alpha,beta-unsaturated aldehydes such as 4-hydroperoxy-, 4-hydroxy-, 4-oxo-2E-nonenal and 4,5-epoxy-2E-decenal, which are also related to different degenerative diseases, has been carried out. The provided data regarding the compounds identification and their sequence and kinetics of formation constitute valuable information for future studies in which lipid oxidation is involved, both in food and in other scientific fields. ViewThis work has been funded by the Spanish Ministry of Economy and Competitiveness (MINECO, AGL2015-65450-R, AEI/FEDER-EU) and by the Basque Government and its Departments of Universities and Research (EJ-GV, IT-916-16)

Monitoring of minor compounds in corn oil oxidation by direct immersion-solid phase microextraction-gas chromatography/mass spectrometry. New oil oxidation markers

The aim of this study is to shed light on the evolution of the minor compounds in the corn oil oxidation process, through the information provided by direct immersion-microextraction in solid phase followed by gas chromatography/mass spectrometry (DI-SPME-GC/MS). This methodology enables one, in a single run, to establish the identity and abundance both of original oil minor components, some with antioxidant capacity, and of other compounds coming from both main and minor oil components oxidation. For the first time, some of the compounds formed from oil minor components degradation are proposed as new markers of oil incipient oxidation. Although the study refers to corn oil, the methodology can be applied to any other edible oil and constitutes a new approach to characterizing the oxidation state of edible oils.This work has been funded by the Spanish Ministry of Economy and Competitiveness (MINECO, AGL2015-65450-R) and by the Basque Government and its Departments of Universities and Research (EJ-GV, IT-916-16) and of Economic Development and Infrastructures, Area of Agriculture, Fisheries and Food Policy (EJ-GV, PA19/02). J. Alberdi-Cedeno thanks the EJ-GV for a predoctoral grant

Effect of the Enrichment of Corn Oil With alpha- or gamma-Tocopherol on Its In Vitro Digestion Studied by 1H NMR and SPME-GC/MS; Formation of Hydroperoxy-, Hydroxy-, Keto-Dienes and Keto-E-epoxy-E-Monoenes in the More alpha-Tocopherol Enriched Samples

The aim of this study is the analysis of the in vitro digestion of corn oil, and of the effect of its enrichment with three levels of gamma- and alpha-tocopherol, by using, for the first time, 1H nuclear magnetic resonance (1H NMR) and a solid phase microextraction followed by gas chromatography/mass spectrometry (SPME-GC/MS). The attention is focused on the hydrolysis degree, the degradation of oil’s main components, the occurrence of oxidation reactions and main compounds formed, as well as on the bioaccessibility of oil’s main components, of compounds formed in the oxidation, and, of gamma- and alpha-tocopherol. The lipolysis levels reached are high and show a similar pattern in all cases. The oxidation of corn oil components during in vitro digestion is proven, as is the action of gamma-tocopherol as an antioxidant and alpha-tocopherol as a prooxidant. In the more alpha-tocopherol enriched samples, hydroperoxy-, hydroxy-, and keto-dienes, as well as keto-epoxy-monoenes and aldehydes, are generated. The bioaccessibility of the oil’s main components is high. The compounds formed in the oxidation process during in vitro digestion can also be considered bioaccessible. The bioaccessibility of alpha-tocopherol is smaller than that of gamma-tocopherol. The concentration of this latter compound remains unchanged during the in vitro digestion of the more alpha-tocopherol enriched oil samples.This work has been funded by the Spanish Ministry of Economy and Competitiveness (MINECO, AGL2015-65450-R, AEI/FEDER-EU) and by the Basque Government and its Departments of Universities and Research (EJ-GV, IT-916-16)