Currently, 1178 natural carotenoids have been properly characterized and reported in the literature, which present a huge structural diversity and physicochemical properties. This number comprises a wide distribution of these biomolecules in approximately 700 source organisms including plants, bacteria, fungi, and algae. Besides having a wide applicability as natural dyes, some carotenoids such as β-carotene already have another well-established application such as provitamin A activity. However, due to the structural diversity of these molecules, there are still numerous biochemical and physiological functions to be associated with this class of compounds. Accordingly, these characteristics enable a wide applicability, what drives the global carotenoid market. Thus, with the primary objective of addressing aspects regarding to basic science and applied carotenoid technology, a comprehensive description of the biology, biochemistry, and chemistry of these compounds will be described in this chapter.

This study aimed to investigate the bioaccessibility of carotenoids and chlorophylls from the biomass of microalgae Chaetoceros calcitrans. The samples were submitted to an in vitro digestion protocol, and the compounds were determined by HPLC-PDA-MS/MS. A total of 13 compounds were identified in all tests. After in vitro digestion, the relative bioaccessibility of carotenoids and chlorophylls ranged from 4 to 58%. The qualitative profile of carotenoids reflected the initial sample, with all-E-zeaxanthin (57.2%) being the most bioaccessible compound, followed by all-E-neochrome (31.26%), the latter being reported for the first time in the micellar fraction. On the other hand, among the chlorophylls only pheophytin a (15.01%) was bioaccessible. Furthermore, a chlorophyll derivative (Hydroxypheophytin a’) was formed after in vitro digestion. Considering all compounds, xanthophylls (12.03%) and chlorophylls (12.22%) were significantly (p < 0.05) more bioaccessible than carotenes (11.22%). Finally, the considerable individual bioaccessibilities found, especially for zeaxanthin, demonstrate the bioactive potential of this bioresource. However, the large reduction in the totality of compounds after in vitro digestion suggests that additional technological strategies should be explored in the future to increase the efficiency of micellarization and enhance its bioactive effects.

For over 70 years, microalgae have been considered promising ingredients for developing sustainable, nutritionally rich foods. Their high protein content, presence of essential amino acids, fatty acids, natural pigments, and a myriad of bioactive compounds position them as potential alternatives to conventional ingredient sources. However, despite their significant potential, the large-scale incorporation of microalgae into food products remains limited. This study presents a critical analysis of the main challenges associated with the use of microalgae in the food industry. Key bottlenecks include high production costs, technological difficulties related to biomass processing, and challenges in extracting desirable compounds. Additionally, the strong flavor, odor, and intense coloration of microalgal biomass can negatively affect sensory acceptance in food products. Other limitations involve scalability issues in cultivation systems, risks of contamination during production, and regulatory constraints related to food safety approval. Consumer perception and limited familiarity with microalgae-based foods also contribute to slower market adoption. Therefore, although microalgae represent a promising and sustainable food resource, overcoming technological, economic, and sensory barriers is essential for their broader integration into the food industry and for achieving successful market consolidation.