Abstract
Haematococcus pluvialis microalgae is a promising source of astaxanthin, an excellent antioxidant carotenoid. H. pluvialis, as well as other species, could find more extensive applications as healthy food for a variegated carotenoids composition in addition to astaxanthin. Official method has not currently been used for this purpose. The objective of this work was to propose a method to characterize carotenoids in H. pluvialis after the comparison between spectrophotometric and liquid chromatography analysis. In addition, in order to improve the use of astaxanthin in the food industry, thermal stability was investigated. In this context, the effect of temperature at 40–80 °C, over a 16 h storage period was tested on astaxanthin produced by H. pluvialis. A further test was carried out at room temperature (20 °C) for seven days. A decrease in the astaxanthin concentration was observed at all tested temperatures with a decrease >50% of all-trans isomer at 80 °C after 16 h and an increase of 9-cis and 13-cis isomers. In conclusion, the obtained results showed the importance of evaluating the degradation effect of temperature on astaxanthin used as a food additive for a future greater enhancement of this bioproduct in the food field.
Highlights
Carotenoids are a class comprised of ~600 liposoluble, thermo-labile, colored compounds that are contained in plants, fruits, and microalgae with the main function of capturing the wavelengths of light for photosynthesis and chlorophyll protection of the cell from photo damage [1,2]
H. pluvialis red phase lyophilized biomass was purchased from the company MICOPERI BLUE GROWTH® (Ravenna, Italy) and β-carotene (22040 Sigma) and lutein
Butylated hydroxytoluene (BHT) antioxidant and solvent as dimethyl sulfoxide (DMSO), dichloromethane, hexane, acetonitrile, methanol, and H2 O uHPLC grade were purchased from Sigma-Aldrich
Summary
Carotenoids are a class comprised of ~600 liposoluble, thermo-labile, colored compounds that are contained in plants, fruits, and microalgae with the main function of capturing the wavelengths of light for photosynthesis and chlorophyll protection of the cell from photo damage [1,2]. Some carotenoids have found applications in food and feed markets as additives for human and animal nutrition, and as supplements in the nutraceutical industry for their natural coloring and antioxidant properties [3,4,5]. These compounds have a relatively high market value in which microalgal carotenoids have even reached a value of 1.2 billion USD with growing prospects [6]. Astaxanthin is a xanthophyll, a carotenoid characterized by the presence of hydroxyl groups or oxygen molecules in the molecular structure, which are found in nature in the form of isomers, all-trans, 9-cis, and 13-cis (Figure 1).
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