Distribution of monomeric, dimeric and polymeric products of stigmasterol during thermo-oxidation

Anna-Maija Lampi (Corresponding Author), Suvi Kemmo, Anu Mäkelä, Susanna Heikkinen, Vieno Piironen

Research output: Contribution to journalArticleScientificpeer-review

23 Citations (Scopus)

Abstract

When plant sterols are oxidized at moderate temperatures (≤100 °C), products mainly derive from hydroperoxides, but at temperatures close to 200 °C, thermal reactions such as dehydration and condensation become important. Although sterols are often subjected to frying conditions, very little is known of their thermal reactions. In this study, stigmasterol was thermo‐oxidized at 180 °C, and the formation of dimers and polymers and the amounts of monomers were measured by high‐performance size‐exclusion chromatography. The products were further characterized by polarity using solid‐phase extraction fractionation. During heating, the amounts of monomers decreased at a steady rate, and those of dimers and polymers increased. After 3 h of heating, 21% of the material existed in higher‐molecular‐weight products. The amount of polar monomers increased especially during the first hour, demonstrating the formation of oxides and their further reactions, while that of mid‐polar monomers decreased constantly, indicating losses of stigmasterol. Polar dimers contributed to approximately 60% of the dimers, and polar polymers to approximately 78% of the polymers, which suggests that in most higher‐molecular‐weight products at least one of the sterol moieties was oxidized. This study showed that a significant proportion of thermo‐oxidation products are not polar monomeric oxides which are commonly analyzed as oxidation products.
Original languageEnglish
Pages (from-to)1027-1034
JournalEuropean Journal of Lipid Science and Technology
Volume111
Issue number10
DOIs
Publication statusPublished - 2009
MoE publication typeA1 Journal article-refereed

Fingerprint

Stigmasterol
stigmasterol
Dimers
polymers
Polymers
Monomers
oxidation
heat
Oxidation
Sterols
Heating
Oxides
sterols
oxides
Hot Temperature
Phytosterols
Temperature
Thermooxidation
phytosterols
frying

Keywords

  • Dimers
  • HPSEC
  • Polymers
  • Stigmasterol
  • Thermo-oxidation

Cite this

Lampi, Anna-Maija ; Kemmo, Suvi ; Mäkelä, Anu ; Heikkinen, Susanna ; Piironen, Vieno. / Distribution of monomeric, dimeric and polymeric products of stigmasterol during thermo-oxidation. In: European Journal of Lipid Science and Technology. 2009 ; Vol. 111, No. 10. pp. 1027-1034.
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abstract = "When plant sterols are oxidized at moderate temperatures (≤100 °C), products mainly derive from hydroperoxides, but at temperatures close to 200 °C, thermal reactions such as dehydration and condensation become important. Although sterols are often subjected to frying conditions, very little is known of their thermal reactions. In this study, stigmasterol was thermo‐oxidized at 180 °C, and the formation of dimers and polymers and the amounts of monomers were measured by high‐performance size‐exclusion chromatography. The products were further characterized by polarity using solid‐phase extraction fractionation. During heating, the amounts of monomers decreased at a steady rate, and those of dimers and polymers increased. After 3 h of heating, 21{\%} of the material existed in higher‐molecular‐weight products. The amount of polar monomers increased especially during the first hour, demonstrating the formation of oxides and their further reactions, while that of mid‐polar monomers decreased constantly, indicating losses of stigmasterol. Polar dimers contributed to approximately 60{\%} of the dimers, and polar polymers to approximately 78{\%} of the polymers, which suggests that in most higher‐molecular‐weight products at least one of the sterol moieties was oxidized. This study showed that a significant proportion of thermo‐oxidation products are not polar monomeric oxides which are commonly analyzed as oxidation products.",
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Distribution of monomeric, dimeric and polymeric products of stigmasterol during thermo-oxidation. / Lampi, Anna-Maija (Corresponding Author); Kemmo, Suvi; Mäkelä, Anu; Heikkinen, Susanna; Piironen, Vieno.

In: European Journal of Lipid Science and Technology, Vol. 111, No. 10, 2009, p. 1027-1034.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Distribution of monomeric, dimeric and polymeric products of stigmasterol during thermo-oxidation

AU - Lampi, Anna-Maija

AU - Kemmo, Suvi

AU - Mäkelä, Anu

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AU - Piironen, Vieno

PY - 2009

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N2 - When plant sterols are oxidized at moderate temperatures (≤100 °C), products mainly derive from hydroperoxides, but at temperatures close to 200 °C, thermal reactions such as dehydration and condensation become important. Although sterols are often subjected to frying conditions, very little is known of their thermal reactions. In this study, stigmasterol was thermo‐oxidized at 180 °C, and the formation of dimers and polymers and the amounts of monomers were measured by high‐performance size‐exclusion chromatography. The products were further characterized by polarity using solid‐phase extraction fractionation. During heating, the amounts of monomers decreased at a steady rate, and those of dimers and polymers increased. After 3 h of heating, 21% of the material existed in higher‐molecular‐weight products. The amount of polar monomers increased especially during the first hour, demonstrating the formation of oxides and their further reactions, while that of mid‐polar monomers decreased constantly, indicating losses of stigmasterol. Polar dimers contributed to approximately 60% of the dimers, and polar polymers to approximately 78% of the polymers, which suggests that in most higher‐molecular‐weight products at least one of the sterol moieties was oxidized. This study showed that a significant proportion of thermo‐oxidation products are not polar monomeric oxides which are commonly analyzed as oxidation products.

AB - When plant sterols are oxidized at moderate temperatures (≤100 °C), products mainly derive from hydroperoxides, but at temperatures close to 200 °C, thermal reactions such as dehydration and condensation become important. Although sterols are often subjected to frying conditions, very little is known of their thermal reactions. In this study, stigmasterol was thermo‐oxidized at 180 °C, and the formation of dimers and polymers and the amounts of monomers were measured by high‐performance size‐exclusion chromatography. The products were further characterized by polarity using solid‐phase extraction fractionation. During heating, the amounts of monomers decreased at a steady rate, and those of dimers and polymers increased. After 3 h of heating, 21% of the material existed in higher‐molecular‐weight products. The amount of polar monomers increased especially during the first hour, demonstrating the formation of oxides and their further reactions, while that of mid‐polar monomers decreased constantly, indicating losses of stigmasterol. Polar dimers contributed to approximately 60% of the dimers, and polar polymers to approximately 78% of the polymers, which suggests that in most higher‐molecular‐weight products at least one of the sterol moieties was oxidized. This study showed that a significant proportion of thermo‐oxidation products are not polar monomeric oxides which are commonly analyzed as oxidation products.

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