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Light Increases Astaxanthin Absorbance in Acetone Solution through Isomerization Reactions.

Oleksandr Virchenko1, Tryggvi Stefánsson1

  • 1Algalif Iceland ehf., Bogatrod 10, 262 Reykjanesbaer, Iceland.

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|January 21, 2023
PubMed
Summary

Light exposure significantly impacts astaxanthin analysis, causing variability in UV/Vis spectrometry and HPLC measurements. This highlights the need for standardized analytical methods to ensure accurate astaxanthin quantitation.

Keywords:
Haematococcus pluvialis oleoresinastaxanthin isomersastaxanthin light sensitivityastaxanthin quantitative analysis

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Area of Science:

  • Analytical Chemistry
  • Phytochemistry
  • Spectroscopy

Background:

  • Astaxanthin quantitative analysis exhibits high inter-laboratory variability.
  • Standard analytical methods may lack robustness for accurate astaxanthin measurement.

Purpose of the Study:

  • To assess the impact of light exposure on astaxanthin measurements using UV/Vis spectrometry and HPLC.
  • To evaluate the influence of different carotenoid matrices on light-induced analytical variations.

Main Methods:

  • Analysis of four Haematococcus pluvialis-derived astaxanthin oleoresin samples.
  • UV/Vis spectrometry and HPLC measurements following the USP monograph.
  • Comparison of measurements in light-proof versus light-exposed conditions using different flasks.

Main Results:

  • Light exposure increased astaxanthin absorbance by 8-11% (UV/Vis) and 7-17% (HPLC) within 3 hours.
  • Changes in absorbance and isomeric distribution (13Z, 9Z, All-E) were observed.
  • Light-dependent degradation of the internal standard (apocarotenal) affected HPLC results.

Conclusions:

  • Conventional astaxanthin quantitation methods show poor robustness due to light sensitivity.
  • Method harmonization and revision are necessary to improve the reproducibility of astaxanthin analysis.