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A. R. C. Braga and V. V. de Rosso
ellipsoidea, making the carotenoids more exposed and, consequently, more easily
micellarized during the digestion process. Similar results have already been reported
by Gille et al. (2016), who tested the sonication of the microalgae Chlorella vulgaris
and Chlamydomonas reinhardtii for 15 min using 5 cycles/min at a frequency of
20 kHz and observed an increase in bioaccessibility of ≥10% for lutein and ≥ 15%
for β-carotene. However, the sonication process contributed to losses in carotenoid
contents, probably due to temperature- and oxygen-mediated degradation reactions,
with lutein and β-carotene contents being 21% and 35% lower when the sonication
of C. reinhardtii was performed, respectively. Thus, the use of biomass pretreatment processes may contribute to increase bioaccessibility but may result in loss of
carotenoid stability.
The use of cellulase as pretreatment to assist in the breakdown of microalgae
cells was tested by Gille et al. (2019) in Phaeodactylum tricornutum, to increase
carotenoid yield. One-hundred U of cellulase at pH 3.5—4.0 were added in 200 mg
of biomass in HBSS medium under stirring for 4 h at 37 °C. After simulated digestion,
the micellar fraction was applied in a Caco-2 cell model. Fucoxanthin, zeaxanthin,
and β-carotene were the main carotenoids present in P. Tricornutum. Surprisingly,
fucoxanthin showed 52% of bioaccessibility, a value considered high compared to
other dietary sources. However, other studies carried out with macroalgae fucoxanthin showed a bioaccessibility of 70% for this carotenoid (Asai et al. 2008),
probably due to the presence of high contents of unsaturated fatty acids, which are
present both in microalgae and in higher algae. Regarding cell absorption in Caco-2
model, the authors observed that zeaxanthin and fucoxanthin were the most abundant carotenoids in the cell monolayer. In addition, fucoxanthin was metabolized to
fucoxanthinol due to the enzymatic activity of the cells, while β-carotene was not
detected in the basolateral fraction (Gille et al. 2019).
The incorporation of unsaturated fatty acids is a recurring alternative to ensure
carotenoid micellarization during in vitro digestion processes. Granado-Lorencio
et al. (2009) added olive oil to the biomass of Scenedesmus almeriensis and observed
a significant increase of lutein and zeaxanthin in the micellar fraction.
Information on the digestion, absorption, and metabolism of chlorophylls and
their derivatives is limited. Some studies focused on the isolation of chlorophyll
derivatives in feces of humans and animals, assuming minor absorption. Since natural
chlorophylls are adapted by heat and acid, they can be inclined to degradation when
exposed to the severe digestive environment. Select chlorophyll derivatives have been
shown to exhibit different properties in in vitro assays (Chernomorsky et al. 1999,
Ferruzzi et al. 2001).
Sodium copper chlorophyllin (SCC), a mixture of water-soluble chlorophyll
derivatives, is used as both a food colorant and as a common dietary supplement
and, as observed for chlorophyll, limited information is available on its digestion
and absorption by humans. Stability of SCC was studied during simulated gastric
and small intestinal digestion by Ferruzzi et al. (2002). The authors prepared three
test preparations from an aqueous stock solution of SCC. The first preparation simply
contained aqueous SCC (W). The second preparation consisted of a homogenized
mixture of SCC and 10% corn oil (wt/wt) in water (WCO). The third preparation
A. R. C. Braga and V. V. de Rosso
ellipsoidea, making the carotenoids more exposed and, consequently, more easily
micellarized during the digestion process. Similar results have already been reported
by Gille et al. (2016), who tested the sonication of the microalgae Chlorella vulgaris
and Chlamydomonas reinhardtii for 15 min using 5 cycles/min at a frequency of
20 kHz and observed an increase in bioaccessibility of ≥10% for lutein and ≥ 15%
for β-carotene. However, the sonication process contributed to losses in carotenoid
contents, probably due to temperature- and oxygen-mediated degradation reactions,
with lutein and β-carotene contents being 21% and 35% lower when the sonication
of C. reinhardtii was performed, respectively. Thus, the use of biomass pretreatment processes may contribute to increase bioaccessibility but may result in loss of
carotenoid stability.
The use of cellulase as pretreatment to assist in the breakdown of microalgae
cells was tested by Gille et al. (2019) in Phaeodactylum tricornutum, to increase
carotenoid yield. One-hundred U of cellulase at pH 3.5—4.0 were added in 200 mg
of biomass in HBSS medium under stirring for 4 h at 37 °C. After simulated digestion,
the micellar fraction was applied in a Caco-2 cell model. Fucoxanthin, zeaxanthin,
and β-carotene were the main carotenoids present in P. Tricornutum. Surprisingly,
fucoxanthin showed 52% of bioaccessibility, a value considered high compared to
other dietary sources. However, other studies carried out with macroalgae fucoxanthin showed a bioaccessibility of 70% for this carotenoid (Asai et al. 2008),
probably due to the presence of high contents of unsaturated fatty acids, which are
present both in microalgae and in higher algae. Regarding cell absorption in Caco-2
model, the authors observed that zeaxanthin and fucoxanthin were the most abundant carotenoids in the cell monolayer. In addition, fucoxanthin was metabolized to
fucoxanthinol due to the enzymatic activity of the cells, while β-carotene was not
detected in the basolateral fraction (Gille et al. 2019).
The incorporation of unsaturated fatty acids is a recurring alternative to ensure
carotenoid micellarization during in vitro digestion processes. Granado-Lorencio
et al. (2009) added olive oil to the biomass of Scenedesmus almeriensis and observed
a significant increase of lutein and zeaxanthin in the micellar fraction.
Information on the digestion, absorption, and metabolism of chlorophylls and
their derivatives is limited. Some studies focused on the isolation of chlorophyll
derivatives in feces of humans and animals, assuming minor absorption. Since natural
chlorophylls are adapted by heat and acid, they can be inclined to degradation when
exposed to the severe digestive environment. Select chlorophyll derivatives have been
shown to exhibit different properties in in vitro assays (Chernomorsky et al. 1999,
Ferruzzi et al. 2001).
Sodium copper chlorophyllin (SCC), a mixture of water-soluble chlorophyll
derivatives, is used as both a food colorant and as a common dietary supplement
and, as observed for chlorophyll, limited information is available on its digestion
and absorption by humans. Stability of SCC was studied during simulated gastric
and small intestinal digestion by Ferruzzi et al. (2002). The authors prepared three
test preparations from an aqueous stock solution of SCC. The first preparation simply
contained aqueous SCC (W). The second preparation consisted of a homogenized
mixture of SCC and 10% corn oil (wt/wt) in water (WCO). The third preparation