Spirulina is a cyanobacterium that has been used for several centuries due to its nutritional and medicinal properties. This work has evaluated the contents of β-carotene both in Spirulina commercialized as food supplement, purchased from natural product shops, and in S. platensis reared under laboratory conditions. Some carotenoids exhibit pro-vitamin A activity, and β-carotene presents the greatest biological activity. β-Carotene of microalgae was extracted in 90% aqueous methanol. These extracts were saponified and partitioned in n-hexane. Chromatographic analyses were carried out in a Spherisorb column S5 ODS 2 (4.6 x 250 mm), with a mobile phase of methanol:tetrahydrofuran (90:10, v/v) delivered at 2 mL min-1 and chromatograms registered at 450 nm absorbance. Food supplement made with Spirulina presented low content of β-carotene. The highest content of β-carotene was detected in S. platensis cultivated under 24º C with photoperiod of 16 h light and 8 h dark. Considering its pro-vitamin activity, retinol equivalent (RE) was calculated from β-carotene to determine whether alga material could be claimed as an useful or an excellent source of the vitamins A.
Microalga; food supplement; HPLC
