In vitro bioaccessibility of macular xanthophylls from commercial microalgal powders of Arthrospira platensis and Chlorella pyrenoidosa

Abstract

The bioaccessibility of the major carotenoids present in two commercial microalgal supplements in powder form was investigated through a standardized in vitro digestion method. The dried biomass of Arthrospira platensis contained β-carotene (36.8 mg/100 g) and zeaxanthin (20.8 mg/100 g) as the main carotenoids as well as a high content of saturated fatty acids (61% of total fatty acids), whereas that of Chlorella pyrenoidosa was rich in lutein (37.8 mg/100 g) and had a high level of unsaturated fatty acids (65% of total fatty acids). In the case of the latter, lutein bioaccessibility was not statistically enhanced after the replacement of porcine bile extract with bovine bile extract in the in vitro digestion protocol and after the addition of coconut oil (17.8% as against to 19.2% and 19.2% vs. 18.5%, respectively). In contrast, the use of bovine bile extract along with co-digestion with coconut oil significantly enhanced the bioaccessibility of zeaxanthin from A. platensis, reaching the highest bioaccessibility of 42.8%.

Keywords: Spirulina; bioaccessibility; carotenoids; dietary supplements; microalgae; simulated digestion.

FIGURE 1

HPLC‐DAD chromatogram of carotenoids in Arthrospira platensis extract. Peaks: 1, zeaxanthin; 2, chlorophyll a; 3, chlorophyll a isomer; 4, β‐cryptoxanthin; 5, echinenone; 6, 13‐cis‐β‐carotene; 7, all‐trans‐β‐carotene; 8, 9‐cis‐β‐carotene; 9, α‐carotene. Peaks 2–7 and 8–9 were tentatively identified based on the spectral characteristics and elution order previously reported in the literature

FIGURE 2

HPLC‐DAD chromatogram of carotenoids in Chlorella pyrenoidosa extract. Peaks: 1, unidentified chlorophyll; 2, lutein; 3, unidentified chlorophyll

FIGURE 3

In vitro bioaccessibility (%) of lutein from Chlorella pyrenoidosa and of zeaxanthin and β‐carotene from Arthrospira platensis after the in vitro digestion using porcine bile extract as against bovine bile extract. Values are gives as mean ± SD (*** extremely significant p < .001)

FIGURE 4

In vitro bioaccessibility (%) of lutein from Chlorella pyrenoidosa and of zeaxanthin and β‐carotene from Arthrospira platensis after the in vitro digestion using bovine bile extract and with bovine bile extract along with 5% coconut oil. Values are gives as mean ± SD (* significant p < .05)

FIGURE 5

Zeaxanthin signal (a) and micellar concentration (mg/100 g) (b) after the in vitro digestion of Arthrospira platensis using porcine bile extract (PB), bovine bile extract (BB), and bovine bile extract along with 5% coconut oil (BB + 5% CO). Values are gives as mean ± SD (* significant p < .05, *** extremely significant p < .001)