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A. R. C. Braga and V. V. de Rosso
10.1 Introduction
Microalgae have been recognized as the foundation of the food chain in aquatic
ecosystems. In addition, they constitute a large and diversified group which includes
primitive prokaryotic or eukaryotic photosynthetic microorganisms. Due to their
simple constitution, they are able to grow quickly and live in difficult environments
such as the ones that present extreme temperatures, absence of oxygen, high salinity,
and exposure to ultraviolet radiation. One of the most prominent characteristics of
algae is their color, which is determined by their pigments, hence, microalgal biomass
is attracting worldwide attention. These pigments are colorful chemical substances
that are part of the photosynthetic system of microalgae and are distinguished into
three classes: carotenoids, chlorophylls, and phycobiliproteins. In addition to color,
pigments have health-promoting properties and a broad range of potential industrial
applications. Consumers are becoming increasingly aware of the correlation between
diet, health, and disease prevention; in this context, dietary intake of microalgae has
been shown to have the ability to protect organisms against various chronic disorders,
such as cancer, diabetes, atherosclerosis, coronary disease, ischemic brain development, metabolic syndromes, gastrointestinal, and liver diseases, as well as neurodegenerative diseases such as Alzheimer’s disease and Parkinson’s disease. Despite
the beneficial properties of pigments provided by microalgae, their effectiveness
at preventing or treating a range of diseases depends on their bioaccessibility and
bioavailability. The digestion process comprises several steps, which promote an
intense variation of the conditions to which pigments are exposed, and therefore,
could in numerous ways compromise the health benefits of consuming microalgae
pigments. Several methods to determine the bioaccessibility and bioavailability of
pigments have been developed and studied in the last years, each one with its particularities in order to maximize and improve the results regarding this subject. Therefore,
the present chapter aims to present the main methods used to assess the bioaccessibility and bioavailability of pigments from microalgae to better understand the
processes involved, consequently providing information about the most accepted
analytical protocols in measurement of pigments bioavailability.
10.2 Challenges to assess bioavailability of microalgae
pigments
Microalgae pigments of major commercial interest are carotenoids, especially: 1Dunaliella salina (β-carotene); 2- Haematococcus pluvialis (astaxanthin, canthaxanthin and lutein); 3- Chlorella vulgaris (canthaxanthin and astaxanthin); 4- Coelastrella striolata var. multistriata (canthaxanthin, astaxanthin and β-carotene); and 5Scenedesmus almeriensis (lutein and β-carotene) (Guedes et al. 2011). Chlorophylls
and phycobiliproteins are still of limited interest due to the insipient market.
A. R. C. Braga and V. V. de Rosso
10.1 Introduction
Microalgae have been recognized as the foundation of the food chain in aquatic
ecosystems. In addition, they constitute a large and diversified group which includes
primitive prokaryotic or eukaryotic photosynthetic microorganisms. Due to their
simple constitution, they are able to grow quickly and live in difficult environments
such as the ones that present extreme temperatures, absence of oxygen, high salinity,
and exposure to ultraviolet radiation. One of the most prominent characteristics of
algae is their color, which is determined by their pigments, hence, microalgal biomass
is attracting worldwide attention. These pigments are colorful chemical substances
that are part of the photosynthetic system of microalgae and are distinguished into
three classes: carotenoids, chlorophylls, and phycobiliproteins. In addition to color,
pigments have health-promoting properties and a broad range of potential industrial
applications. Consumers are becoming increasingly aware of the correlation between
diet, health, and disease prevention; in this context, dietary intake of microalgae has
been shown to have the ability to protect organisms against various chronic disorders,
such as cancer, diabetes, atherosclerosis, coronary disease, ischemic brain development, metabolic syndromes, gastrointestinal, and liver diseases, as well as neurodegenerative diseases such as Alzheimer’s disease and Parkinson’s disease. Despite
the beneficial properties of pigments provided by microalgae, their effectiveness
at preventing or treating a range of diseases depends on their bioaccessibility and
bioavailability. The digestion process comprises several steps, which promote an
intense variation of the conditions to which pigments are exposed, and therefore,
could in numerous ways compromise the health benefits of consuming microalgae
pigments. Several methods to determine the bioaccessibility and bioavailability of
pigments have been developed and studied in the last years, each one with its particularities in order to maximize and improve the results regarding this subject. Therefore,
the present chapter aims to present the main methods used to assess the bioaccessibility and bioavailability of pigments from microalgae to better understand the
processes involved, consequently providing information about the most accepted
analytical protocols in measurement of pigments bioavailability.
10.2 Challenges to assess bioavailability of microalgae
pigments
Microalgae pigments of major commercial interest are carotenoids, especially: 1Dunaliella salina (β-carotene); 2- Haematococcus pluvialis (astaxanthin, canthaxanthin and lutein); 3- Chlorella vulgaris (canthaxanthin and astaxanthin); 4- Coelastrella striolata var. multistriata (canthaxanthin, astaxanthin and β-carotene); and 5Scenedesmus almeriensis (lutein and β-carotene) (Guedes et al. 2011). Chlorophylls
and phycobiliproteins are still of limited interest due to the insipient market.