## 1 Introduction
The FX content in microalgae is much higher than that in brown seaweeds; therefore, microalgae have been regarded as potential commercial producers, as indicated by [9]. FX, whose molecular structure was fully described in 1990 [10], has an allelic bond, a conjugated carbonyl, a 5,6-mono peroxide, and an acetyl group that contribute to the unique structure of the molecule (Figure 1). It is also considered one of the most abundant carotenoids in nature, accounting for more than 10% of the total carotenoids produced in nature [12]. There are also other plant sources of fucoxanthin, such as _Undaria pinnatifida_ (wakame) and other macroalgae. Consumption of these species has been very common for many years, particularly in Japan and other East Asian countries [13]. Other sources of fucoxanthin, such as _P. tricornutum_, do not have a history of use as human food, but rather as food for fish and molluss intended for human consumption [14]. _P. tricornutum_ is also a source of polyunsaturated fatty acids such as omega-6 [15]. Fucoxanthin has been evaluated in vitro for its biological activity [16]. Figure 1: Chemical structure of the fucoxanthin molecule [11]. In a biorefinery environment, _P. tricornutum_ can be stimulated to elicit lipid biosynthesis through nutrient depletion and increased CO2 supply, whereas eicosapentaenoic acid (EPA) synthesis can be induced by supplying CO2 and urea as well as strong light [17]. Similarly, in a study in which _P. tricornutum_ was supplemented in the diet of rats, _P. tricornutum_ was estimated to be equivalent to a daily EPA intake of 33 mg/rat [18]. This study found the EPA content of _P. tricornutum_ to be high (2.04% of dry weight). Fucoxanthin has been found in different dietary supplements marketed in the United States. A search for fucoxanthin in the Dietary Supplement Label Database (DSLD) returned 121 dietary supplements. The daily serving sizes of fucoxanthin in these products vary, containing 15-30 mg fucoxanthin per day. Fucoxanthin and its metabolites have shown anti-obesity effects, primarily by promoting energy expenditure in the adipose tissue and modulating blood glucose and insulin levels [19]. Fucoxanthin is an ingredient that is relevant to the supplement market in the United States, and it targets a population of people 4 years of age and above (Table 1). In this study, we evaluated the combination of spirulina and fucoxanthin. spirulina and plant sources of fucoxanthin are valued for their health benefits, as well as their nutritional value. These health benefits have been reported as one of the reasons for the long life expectancy of the Japanese population, which is the highest in the world [20]. This has been attributed to their chemical composition, which produces antitumor, antiallergic, and antithrombotic activities [21; 22; 23]. There are different types of encapsulation in which different compounds are used, such as maltodextrin and guar gum. One of the reasons for using encapsulation was to provide protection to the active ingredients (especially fucoxanthin) against environmental conditions (oxygen, light, temperature, and water), thus avoiding their oxidation and increasing their useful life. The encapsulation of extracts containing different microalgae products and marine active principles has been mentioned by [24], who used an emulsion phase separation technique involving an ionotropic gelation method to prepare chitosan