Microalgae Characterization for Consolidated and New Application in Human Food, Animal Feed and Nutraceuticals

Abstract

The exploration of new food sources and natural products is the result of the increase in world population as well as the need for a healthier diet; in this context, microalgae are undoubtedly an interesting solution. With the intent to enhance their value in new commercial applications, this paper aims to characterize microalgae that have already been recognized as safe or authorized as additives for humans and animals (Chlorella vulgaris, Arthrospira platensis, Haematococcus pluvialis, Dunaliella salina) as well as those that have not yet been marketed (Scenedesmus almeriensis and Nannocholoropsis sp.). In this scope, the content of proteins, carbohydrates, lipids, total dietary fiber, humidity, ash, and carotenoids has been measured via standard methods. In addition, individual carotenoids (beta-carotene, astaxanthin, and lutein) as well as individual saturated, monounsaturated, and polyunsaturated fatty acids have been identified and quantified chromatographically. The results confirm the prerogative of some species to produce certain products such as carotenoids, polyunsaturated fatty acids, and proteins, but also show how their cellular content is rich and diverse. H. pluvialis green and red phases, and Nannochloropsis sp., in addition to producing astaxanthin and omega-3, contain about 25⁻33% w/w proteins on a dry basis. D. salina is rich in beta-carotene (3.45% w/w on a dry basis), S. Almeriensis is a source of lutein (0.30% w/w on a dry basis), and the C. vulgaris species is a protein-based microalgae (45% w/w on a dry basis). All, however, can also produce important fatty acids such as palmitic acid, γ-linolenic acid, and oleic acid. Considering their varied composition, these microalgae can find applications in multiple sectors. This is true for microalgae already on the market as well as for promising new sources of bioproducts such as S. almeriensis and Nannochloropsis sp.

Keywords: Arthospira platensis; Chlorella vulgaris; Dunaliella salina; Haematococcus pluvialis; Nannochloropsis sp.; Scenedesmus almeriensis; bio-products; carotenoids; lipids; market; protein.

Figure 1

Protein, carbohydrates, lipids, total dietary fiber and carotenoids compositions (w/w on a dry basis ± SD (n = 3)) of Arthrospira platensis platensis, Scenedesmus almeriensis, Haematococcus pluvialis (green phase), Haematococcus pluvialis (red phase), Chlorella vulgaris, Dunaliella salina, Nannochloropsis sp.

Figure 2

Beta-carotene, lutein and astaxanthin quantified in the three species Dunaliella salina, Haematococcus pluvialis (red phase), and Scenedesmus Almeriensis (the values are expressed in mg/g on dry weight ± SD (n = 3)).

Figure 3

Fatty acids compositionexpressed as saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs) (the pie charts are presented from left to right, from the top row to the bottom row on the basis of the increasing order of the total amount of fatty acids): (a) Arthrospira platensis; (b) Scenedesmus almeriensis; (c) Chlorella vulgaris; (d) Haematococcus pluvialis (gree phase); (e) Haematococcus pluvialis (red phase); (f) Dunaliella salina; (g) Nannocholoropsis sp. The values are reported in percentages. A standard deviation of less than 5% was found (n = 3).