Challenges in Functional Food Products with the Incorporation of Some Microalgae

Diet and health are two of the most important aspects of people’s lives, and they merge in the study of functional foods. It is widely acknowledged that the relationship between diet and disease is the cornerstone of preventative nutrition. “Functional foods” are frequently recognized as a newly developing area. However, this concept was originally detailed in ancient Indian Vedic literature and in traditional Chinese medicine. One of the most important ideas in eastern philosophy is that “medicine and food come from the same source”. This idea is reflected in the desire to make functional foods [8].

In the 1980s, in response to growing healthcare expenses, the determination to make functional foods initially arose in Japan. In order to ensure the safety of certain foods, the Ministry of Health and Welfare devised a regulatory system [9,10]. Its main aim is to improve the well-being of the country’s aging citizens. The Japanese Ministry of Education, Science, and Culture began a national examination into the link between food and medical science in 1984 [11]. The term “functional food” was coined by Swinbanks and O’Brien [12] in Nature under the headline ”Japan examines the boundary between food and medicine”. Food for Specified Health Use and “Food with Nutrient Function Claims” are two types of labeling that make health claims [10].

The functional food market is a mostly global market that is not recognized by legislation everywhere. The term “functional food” can be defined in a variety of ways. Foods are “identical in appearance for conventional foods, ingested as part of a normal diet, with demonstrated physiological advantages and/or to minimize the risk of chronic illness beyond fundamental nutritional functions” [13]. The International Food Information Council defines functional foods as “foods or dietary components that may deliver health advantages beyond basic nutrition” [14]. A food is deemed functional “if it is demonstrated to affect beneficially one or more target functions in the body, beyond adequate nutritional effects, in a manner that is relevant to improve the state of health and well-being and/or a reduction in disease risk”, according to the European Commission’s Concerted Action on Functional Food Science in Europe [15].

There are multiple ways in which foods can be considered functional: (i) as a natural food, (ii) as a food to which a component has been added or removed, (iii) as a food with one or more components that have been modified, (iv) as a food whose bioavailability has been altered, or (v) as some combination of these. Table 1 illustrates categories of functional foods obtained from the study of Arvanitoyannis and Van Houwelingen-Koukaliaroglou [16].

The desire for nutritious and useful foods has prompted the exploration of new food categories to supplement the typical diet and the discovery of more holistic approaches to disease prevention and treatment [10,17]. Microalgae have received remarkable attention for the use of their biomass to develop multifunctional food products that are beneficial to human health.

Microalgae are unicellular photosynthetic microorganisms capable of converting solar energy into biochemical energy [18] and biomass containing a variety of useful substances for health, food and feed additives, cosmetics, and energy generation [19,20]. Nutrients and other health benefits can be gained from consuming microalgal biomass as a dietary supplement. Microalgae contain nutrient-rich bioactive compounds such as protein, essential amino acids, sulfated polysaccharides, enzymes, fibers, lipids, carotenoids, and vitamins [19,20,21,22]. The primary components of microalgal biomass are summarized in Table 2. Highly bioavailable protein is one of the major substances found in microalgae. Most microalgae biomass can contain more than 50% protein as dry weight.

Microalgae include an abundance of vitamins (e.g., A, C, niacin, B1, B2, B6, etc.) and minerals (e.g., magnesium, potassium, iodine, iron, and calcium). Due to their high amounts of essential nutrients (Table 2, Table 3 and Table 4), microalgal biomasses are an important food source, especially in Asian countries such as China, Japan, and Republic of Korea [35]. Asian nations have utilized green microalgae as a dietary supplement or food source for hundreds of years. They are currently consumed worldwide for their rich nutritional content [19,20,36].

A few green microalgae (e.g., Dunaliella salina, Chlorella vulgaris, and Haematococcus pluvialis) and some cyanobacteria (e.g., Arthrospira platensis, synonym of Spirulina platensis) are biotechnologically important. They can be used as nutritional supplements for human food and additives for animal feed [22]. This is why they are commercialized. Arthrospira platensis and Chlorella vulgaris have been highlighted as natural sources of protein, whereas Dunaliella salina and Haematococcus pluvialis are considered natural sources of pigment (especially because of their content of β-carotene and astaxanthin, respectively) [19,20,22].

Arthrospira platensis is a species of planktonic photosynthetic cyanobacteria that thrives in large areas of biomass inside tropical and subtropical aquatic environments characterized by elevated levels of carbonate and bicarbonate salts, as well as an alkaline pH of 9 [46]. As an eco-friendly process, Arthrospira platensis can be cultivated on animal effluent (a low-cost medium) [47]. Arthrospira production in effluents from animal dung has many benefits, such as large cost savings and the resolution of waste disposal issues. Conditions such as temperature, nutrient levels, and salinity cause the composition of algal biomass to change [5,48,49]. Nutrient starvation closely changes the composition of biomass; nitrogen starvation leads to an increase in lipid accumulation [48], and phosphorus deficiency results in increased fat and carbohydrate levels [48].

Arthrospira platensis (synonym of Spirulina platensis) is one of the most nutrient-dense foods on the planet, and its use as a dietary supplement is increasing. It is gaining popularity as a nutritional supplement around the globe. It is rich in proteins, essential amino acids, polyunsaturated fatty acids, pigments, vitamins, and phenolics [36,50,51]. Arthrospira platensis has protein content ranging from 55 to 70% of its dry weight (dw), which is greater than that of egg (approximately 10% of its weight [52] and 17.0% in the yolk [53]) and meat (17–20% [54]) [36,55]. Proteins in milk and egg have a high digestibility rate of about 97% [56]. Secondly, meat, fish, and poultry have a high digestibility rate. Cyanobacteria such as Arthrospira also have a high digestibility rate of approximately 86% [57,58]. Knowing the definitions of some terms, such as digestibility, bioavailability, and bioaccessibility, helps us to understand the metabolism of nutrients. Digestibility refers to the amount of nutrients absorbed by an individual, and it is usually calculated by subtracting the amount of nutrients in the feces from the amount of food ingested [59].

Arthrospira, which also contains antioxidants, phytonutrients, probiotics, and nutraceuticals, is the most nutrient-dense, concentrated bacterium known in the diets of humans [20,36,60]. This cyanobacterium is not only recognized as one of the most valuable sources of protein, but also contains highly valuable fatty acids [linoleic (19–26%), gamma-linolenic (16–25%), oleic (3–8%), and palmitic (34–42%)]; vitamins (provitamin A, vitamin C, vitamin E, etc.); phenolic compounds; minerals such as iron, calcium, chromium, copper, magnesium, manganese, phosphorus, potassium, sodium, and zinc; and pigments (chlorophyll-a, phycocyanin, etc.) [27,36,60,61]. Arthrospira is also rich in the PUFAs—polyunsaturated fatty acids—as PUFAs account for 42–45% of total fatty acids [22]. These are crucial parts of a well-rounded diet that aid in nervous system development and help prevent or alleviate various diseases [20]. In Western diets, carotenoids play a vital role, accounting for roughly 30% of daily vitamin A consumption [36]. Zeaxanthin and β-carotene are all examples of carotenoids found in Arthrospira [62]. In a recent study, the dry weight content of A. platensis was reported to be 20.78 mg/100 g and 36.75 mg/100 g for carotenoids/zeaxanthin and β-carotene, respectively [62]. Due to its impressive nutrient makeup, which can be employed for therapeutic purposes, Arthrospira is quickly emerging as a comprehensive solution to diverse demands. The United Nations deemed Arthrospira to be the best food for the future at a food conference, and it is gaining popularity today [63]. Today, Arthrospira biomass is used to make nutritional supplements like dry powder, flakes, and capsules that are marketed as “superfoods” [20,36]. In a previous review, the effects of Spirulina supplementation (considering its antioxidant, immunomodulatory and anti-inflammatory effects) on pathological conditions in the population were examined by Calella et al. [64]. In this review, 18 studies consisting of 1621 records were evaluated. Spirulina platensis has been observed to be beneficial in both infectious and non-infectious patients. Improvement was observed in all cases (except male infertility). However, clinical studies about Spirulina are still very few. Therefore, many high-quality clinical studies are needed.

Chlorella vulgaris is a green microalga that might be exploited as a food source [19,20]. Aside from being offered in health food stores and as fish feed, Chlorella has become a popular supplement. Chlorella was considered a commercial microalga for use as a protein source (50–60% dw) [19,65]. The amino acid profile of a protein determines its nutritional quality. The essential amino acids produced by C. vulgaris biomass (Table 3) compare favorably and even exceed the conventional human nutrition profile recommended by the World Health Organization (WHO) and Food and Agricultural Organization (FAO) [21,24]. C. vulgaris, under optimal growth conditions, can reach a lipid content of 5–40% dw consisting of glycolipid waxes, phospholipids, and trace amounts of free fatty acids [21]. Diverse growth circumstances lead to changes in the composition of fatty acids (e.g., palmitic acid, stearic acid, palmitoleic acid, and oleic acid) that are suitable for different uses [24]. The β 1–3 glucan found in C. vulgaris is an essential polysaccharide with numerous beneficial effects on human health [24]. Additionally, it contains 9–18% dietary fiber, 1–2% chlorophyll, vitamins (like B1, B2, B3, B5, B6, B7, B9, B12, E, C, A, and vitamin K), and minerals (like Mg, K, Fe, and Ca). Chlorella’s most important commercial product is a series of by-products that are employed in the preservation of fruits and vegetables [66].

Dunaliella salina is a green halophilic microalga that is cultivated as a source of beta-carotene (up to 14% of its dry weight), glycerol, and photosynthetic pigment [30,67]. The orange pigment, β–carotene, is also used as a vitamin A supplement. Large-scale D. salina production may be found in both Australia and Israel; the commercial cultivation of this alga as a source of β-carotene dates back to the 1980s [30]. With a combined pond area of almost 900 hectares, the two Australian facilities are the world’s largest commercial microalgae production facility. For the pharmaceutical and nutraceutical industries, these plants generate “natural” β-carotene in the form of oil suspensions, beadlets, and water-soluble powder. Additionally, D. salina is harvested and dried and can be used as animal feed. Its algal biomass can be processed into a variety of useful substances such as glycerol, protein, enzymes, fatty acids, and vitamins.

To increase β-carotene production from D. salina, the nutritional and environmental conditions in which the algae thrive can be changed [68]. Conditions such as salinity, irradiance, and nutrients alter the composition of D. salina biomass [68,69]. High salinity and irradiance stimulate β-carotene production in the halophilic microalga, which appears orange-red in masking due to increased β-carotene. Due to its provitamin and antioxidant activities, the US Food and Drug Administration (FDA) has classified Dunaliella as a food source that is Generally Regarded as Safe (GRAS), and it is primarily utilized for human and animal nutrition, food coloring, and cosmetics [20].

The microalga Haematococcus pluvialis is known for its capacity to collect high levels of astaxanthin. The annual biomass yield of H. pluvialis can reach over 300 tons [70], making it a popular choice in the biotechnology sector for the production of astaxanthin. The economic value of astaxanthin exceeds USD 240 million per year [71], with a market price of around USD 2000 per kilogram. Astaxanthin is a highly sought-after carotenoid [72]. In addition to neutralizing singlet oxygen, astaxanthin is an excellent scavenger of harmful free radicals [72,73]. The life cycle of H. pluvialis contains two distinct stages: the green motile stage and the red non-motile stage [74,75]. Unfavorable culture conditions like poor nutrients cause the vegetative motile green cells (macrozooids) to turn into red, non-motile hematocyst cells (aplanospores) [75]. In order to concentrate the biomass from the exhausted culture media, harvesting procedures are implemented once the non-motile hematocyst red cell has reached the mature state. Environmental variables such as culture medium, temperature, pH, and the amount of light are important factors for optimal growth conditions to achieve high cell density and astaxanthin accumulation in H. pluvialis [73,74,75]. Carotenogenesis is induced when cells are subjected to stressful circumstances caused by nutritional (nitrogen and phosphorus) deficiency, excessive salinity, and a combination of multiple stress factors that stimulate the accumulation of astaxanthin [73]. Depending on the conditions of cultivation, the production of astaxanthin in H. pluvialis might range from 3.8 to 5.0% dw [34,73,75,76].

Microalgae have been studied as a potential food source, especially a protein source for humans, since as early as the 1950s. The commercial cultivation of Chlorella and Arthrospira for protein supply began in the 1960s and 1970s, respectively [19,77]. The cultivation of Dunaliella and Haematococcus (especially β-carotene and astaxanthin) for food coloring was developed in the 1980s [19]. During the first decade of the twenty-first century, scientists started mass-producing polyunsaturated fatty acids, particularly omega-3. Due to their simple cultivation with high protein content and nutritional value, Chlorella and Arthrospira platensis are at the forefront of the microalgal market [63,78].

Due to their valuable chemical composition, microalgae have several commercial applications today, including (i) increasing the nutritional value of food and animal feed, (ii) playing an essential role in aquaculture, and (iii) the manufacturing of cosmetics [19,79,80]. Also, microalgae are farmed extensively as a source of very important biochemicals. As an example, PUFAs are added to infant formulas and dietary supplements, and pigments play a significant role as natural colors [19,20]. Three essential microalgal features can be transformed into technical and economic benefits. Microalgae are a very biodiverse group with a broad range of biochemical characteristics; as a result, they generate a variety of bioactive chemicals and unique lipids, proteins, essential amino acids, and carbohydrates [80,81,82].

Microalgae can be an extremely intriguing natural source of novel chemicals with biological activity that might be enable them to be exploited as functional components [19,36,83,84]. A variety of secondary (biologically active) metabolites are produced by some microalgal species that live in habitats subjected to heavy stress (such as changes in salt concentration and temperature, nutrient availability, or UV-V irradiation). As a result of their rapid adaptation to changing environmental conditions, these microalgal species have developed a wide range of unique secondary (biologically active) metabolites. Due to the taxonomic variety of microalgae, the hunt for novel physiologically active chemicals may be viewed as an almost limitless topic of study [30,73,85].

There are many different types of microalgae, but only a few are safe for human consumption. The FDA in the US awards the GRAS (Generally Recognized as Safe) classification to newly approved foods only after rigorous scientific testing has shown their safety. Several microalgae, such as Arthrospira platensis, Chlorella vulgaris, and Dunaliella bardawil, are examples of GRAS-approved microalgae [19,20,86]. The European Union’s Food and Feed Systems are regulated by the European Commission and the European Food Safety Authority. Spirulina and Chlorella are approved and the most widely consumed microalgae, and their entire biomass can be used in culinary products and marketed directly to consumers in European countries [19,20].

Arthrospira is the most healthy product known to humankind, according to the WHO. Moreover, Arthrospira is the most suitable food for the future, according to UNESCO. It is one of the main foods that can be grown on long-term space missions, according to NASA and the European Space Agency. The long history of Arthrospira’s use means that it can be commercialized in the European Union (EU) without having to comply with new food regulations [87]. The composition of Arthrospira, as well as the health benefits associated with consuming Arthrospira (or compounds derived from it), indicate that it has the potential to become a significant food and to be employed as an ingredient in the development of functional foods in the future [19,20,86]. It is “one of the greatest protein sources”, according to the FDA. Arthrospira from microalgae is allowed to be used by an intergovernmental organization to combat malnutrition [19,20].

Polyunsaturated fatty acids (PUFAs) found in microalgae (Table 4) have been shown to be effective in the prevention and treatment of a wide range of diseases, including cancer and cardiovascular disease [20,41,88]. PUFAs, particularly n-3 PUFAs such as α-linolenic acid (ALA, C18:3n-3), EPA (C20:5n-3), docosapentaenoic acid (DPA, C22:5n-3), and DHA (C22:6n-6), have been reported to be useful in preventing or treating numerous disorders (such as cancer, arthritis, cardiovascular diseases, asthma, type 2 diabetes, inflammatory bowel disorders, depression, and kidney and skin diseases) [19,20,89,90]. Considered nutraceuticals such as EPA and DHA have been extracted from several microalgal species farmed for this purpose [19,20,91]. According to the FDA, dietary sources of PUFAs such as EPA and DHA reduce the risk of coronary heart disease [19,20]. Microalgae are now farmed largely for the production of DHA, which is added to foods [92].

Cell wall polysaccharides differ among microalgal species [20,93]. Polysaccharides produced from marine microalgae are promising in many ways. This is because they are antioxidant, antiviral, and anticoagulant [94]. They are also much less toxic. Red microalgae such as Porphyridium sp. contain sulfated polysaccharides with anti-inflammatory properties [94]. Sulfated polysaccharides are the most thoroughly researched category of algal polysaccharides [20,95]. Sulfated polysaccharides obtained from Arthrospira also have an antiviral property [96,97]

Bioactive chemicals, such as β-carotene (D. salina), astaxanthin (H. pluvialis), EPA, and DHA (Chrypthecodinium cohnii) [98], can be used in goods or taken as supplements [5]. As nutritional supplements, algal biomasses are supplied as pills, capsules, and liquids (Figure 1).

As biopeptides (protein hydrolysates) are more easily absorbed than proteins and amino acids, they are advantageous protein sources for humans [99]. High digestibility (83–90 percent) and all necessary amino acids (50–70 percent dry weight) are found in the biomass of Arthrospira [100]. It has been shown that biomass from microalgae is better for people in terms of nutrition and safety than traditional protein sources [21].

Microalgae are considered excellent sources of vitamins and antioxidants. Water-soluble vitamins and lipids are found in these organisms and can be used in food or as supplements. Folic acid, biotin, and vitamins are all present in microalgae [101]. Vitamin B12 and β-carotene (provitamin A) are found in Arthrospira [21]. Arthrospira consumption has been linked to an increase in gut Lactobacillus and improved dietary absorption of B1 and other vitamins [102]. Arthrospira, Chlorella, and Dunaliella species have been utilized to effectively create large quantities of important chemicals, including lipids, proteins, and pigments, as shown in Table 5 [103,104].

One of the major problems that has adversely affected the microalgae sector is the undesirable sensory properties of microalgae [5]. Products such as powders, tablets, and beverages from dried Arthrospira had a smell or fishy taste [21]. When fresh Arthrospira is added to food or drink, it barely alters the smell and flavor. The integration of microalgae that has not undergone component extraction imparts an unpleasant flavor above a certain concentration, rendering the food undesirable to the majority of customers, especially those who have never consumed algal-based goods. Upon the addition of A. platensis and C. vulgaris into yogurt, the results of a sensory evaluation indicated a more unpleasant flavor of A. platensis compared with C. vulgaris [138]. This inappropriate flavor is caused by the oxidation of polyunsaturated fatty acids and other compounds from microalgae. Adding different amounts of Arthrospira to yogurt (0.25, 0.5, 0.75, and 1%) changes the fermentation process, texture, and nutritional or sensory qualities of the products [139]. The textural qualities and sensory acceptability of the final milk product were preserved when 0.25% Arthrospira was incorporated into the yogurt. According to research by Gyenis et al. [140], fermented milk with 3 g/dm3 of microalgal biomass was the best option in terms of sensory qualities and price [141].

When the addition of microalgae to food products is lowered to decrease the disagreeable taste and odor, this leads to a decrease in protein content and other bioactive substances in food products. In terms of food type, it is easier to include microalgae in baked items such as bread, cookies, and pasta than other dietary items, such as yogurt [19,20]. Batista et al. [142] reported that cookies made with 2% (w/w) Arthrospira achieved positive results regarding their flavor.

Various sources of proteins (e.g., Spirulina, Chlorella, pea, lentil, and broad bean) were added into turkey Burgers to evaluate the physicochemical characteristics, textural attributes, and nutritional value of meat products [143]. The maximum values of amino acids correspond to turkey burgers formed with Spirulina and broad bean proteins. Glutamic acid was the predominant one, obtaining a value of 2.13 g/100 g in the case of broad Spirulina protein [144].

One of the primary obstacles preventing the widespread use of microalgal dry biomass in the food industry is the intense color created by microalgae. As a result of the presence of microalgae, the color of food can be altered, which may not be acceptable to most people, and the quality of commonly consumed foods like bread and dairy products is affected. Nonetheless, it serves a useful purpose for a few other items, such as pasta, since people eat it in a wide variety of colors. An innovative strategy to cover up the taste of microalgae is spray-drying microencapsulation. The unique taste of microalgae was shown to be effectively hidden when octenyl succinic anhydride starch was used as a coating material. It was found that adding microencapsulated Arthrospira to wheat cookies at a 20% (w/w) concentration did not significantly alter either purchase intent or overall acceptance compared to the control group. When 20% (w/w) Arthrospira was added to the biscuits, the protein content increased by 40%, and the ash content increased by 70%, which were significantly higher than in previous works of a similar nature [145].

There are also new ways to handle the bright color of microalgae. The European Food Safety Authority recently approved two pale-colored Chlorella powder products with low chlorophyll content as food raw materials and food supplements [146]. These newest items are more aesthetically neutral and consumer-acceptable than conventional dark green products. Additionally, the C/N ratio of the cultivation medium leads to a change in the color of microalgal biomass [147,148]. Microalgae are viewed as a sustainable, environmentally friendly, and nutritious health product by Spanish consumers, according to a recent evaluation of consumer knowledge and attitudes conducted by Lafarga et al. [36]. However, a lack of information on the product and a lack of consumption habits were barriers to the active consumption of this product. The most appealing aspect of microalgae to consumers is its health advantages. Numerous clinical investigations have established the obvious health benefits of microalgae as nutritional supplements. Therefore, the current scant research shows that educating consumers about microalgae can raise demand for and sales of products that include these microorganisms.

Despite the fact that cultural influences and future opportunities to mainly investigate customers’ views for adopting new eating habits that involve more novel food items may lead perceptions and attitudes towards food to differ, the results described here might be generalized to other European countries.

Consumers’ ability to tolerate the taste of microalgae-based foods is one such factor [19,20]. Key factors in the development of the microalgae-based foods market will include the type of microalgae used, the method used to prepare the microalgal biomass (i.e., as a dried powder or by processing), the combination of ingredients, and the shape of the final product. Among the many issues with using microalgae in food is their pungent smell and fishy flavor. Participants took a designed test to assess their views toward unfamiliar foods, since food neophobia can alter how well-liked novel foods are [19,20]. Consumers believed that the product was better for their health, and because of this, they were willing to pay a higher price for it. This information may prove helpful in the process of promoting and selling this unique product.

Products containing microalgae would find an interesting consumer base among those who are health-conscious, nutrition-conscious, or concerned with environmental issues and sustainability. Similar arguments can be made in terms of other senses, such as smell and taste. To better meet the needs of our target market and expand our business, we need to have a firm grasp on how microalgae-based food products are perceived by those who consume them.

In addition to problems with customer acceptability and a lack of production capacity, the market for foods made from microalgae has problems with legislation and regulation. Laws and rules governing the consumption of algae differ from country to country.

Some of the obstacles that prevent the widespread adoption of a food or ingredient generated from a “new” organism include customer acceptance, ambiguous regulatory frameworks, and the reluctance of investors to provide financial and commercial backing for these inventions. If academics want their work to be successfully translated into the commercial sector, they must have a firm grasp of these issues. Only a small number of microalgal taxa are currently recognized on a global scale.

Incorporating microalgae into food could also change how bioactive substances in microalgae are absorbed and used by the body. So, there needs to be a full look at the health benefits of foods made from microalgae. This will make it easier to market foods made from microalgae as “functional foods”. Also, the type of product can affect how well consumers accept microalgae and how much is added, so it is important to promote foods made with microalgae.

We must assess the current status of microalgae-based products on the market and those still undergoing research and development, as well as gain a deeper understanding of the constraints and obstacles that can limit the use of microalgae as food ingredients. Considering all these obstacles, it is commonly acknowledged that conventional food production methods are inadequate to meet global food demand; production processes must be modified to be more sustainable and scalable.

There are three factors that affect the safety of algae foods in relation to the algae. These may be physical and chemical pollutions and microbiological contaminations [149]. These factors endanger food safety. Therefore, new technologies are needed to detect these contaminants or pollutants quickly. There are now many new developments in the monitoring of heavy metals, algal toxins, and other contaminants. In the future, not only will there be cheap, fast, and safe detection methods for assessing algal food contamination, but these methods will also be linked to new technologies that work with artificial intelligence, biosensors, and molecular biology.

Foods enriched with either microalgal biomass, microalgal supplements, or biochemical compounds extracted from microalgae are subject to the same regulations that apply to all foods. These products must comply with food regulations, such as the requirement for food to be free from contamination or solvent residues. For example, solvent residues may be present in the production of fatty acids produced from microalgae [150], but this is not permitted by the authorities.

The biochemical content of microalgae is affected by light, humidity, pH, and high temperature, i.e., they are quite unstable [151]. They have a high tendency to deteriorate. It is important to ensure the stability of the biochemical component of microalgae. The important thing is to determine how we can take these ingredients at the highest rate for bioavailability.

To deal with the poor physicochemical stability of microalgae bioactive extracts, especially carotenoid, astaxanthin, and free fatty acids, numerous studies have suggested the coating of these bioactive compounds with biopolymer layer. This can significantly increase the stability of bioactive compounds under different conditions [152]. Encapsulation can ensure bioavailability and stability. Encapsulation generally refers to the process of incorporating a specific ingredient into a matrix, while an “encapsulation system” generally refers to a system designed to encapsulate, protect, and release the target active compounds [153].

The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding author.