Lipid, fatty acid, protein, amino acid and ash contents in four Brazilian red algae species

Seaweed in the Diet as a Source of Bioactive Metabolites and a Potential Natural Immunity Booster: A Comprehensive Review

Seaweed plays an essential role in the survival of marine life, provides habitats and helps in nutrient recycling. It is rich in valuable nutritious compounds such as pigments, proteins, polysaccharides, minerals, vitamins, omega-rich oils, secondary metabolites, fibers and sterols. Pigments like fucoxanthin and astaxanthin and polysaccharides like laminarin, fucoidan, galactan and ulvan possess immune-modulatory and immune-enhancing properties. Moreover, they show antioxidative, antidiabetic, anticancer, anti-inflammatory, antiproliferative, anti-obesity, antimicrobial, anticoagulation and anti-aging properties and can prevent diseases such as Alzheimer's and Parkinson's and cardiovascular diseases. Though seaweed is frequently consumed by Eastern Asian countries like China, Japan, and Korea and has gained the attention of Western countries in recent years due to its nutritional properties, its consumption on a global scale is very limited because of a lack of awareness. Thus, to incorporate seaweed into the global diet and to make it familiar as a functional food, issues such as large-scale cultivation, processing, consumer acceptance and the development of seaweed-based food products need to be addressed. This review is intended to give a brief overview of the present status of seaweed, its nutritional value and its bioactive metabolites as functional foods for human health and diseases owing to its immunity-boosting potential. Further, seaweed as a source of sustainable food and its prospects along with its issues are discussed in this review.

Comparative evaluation of the flavor characteristics and nutritional value of different varieties of Gracilariopsis lemaneiformis by sensory flavor chemistry

Gracilariopsis lemaneiformis is an important edible marine alga, currently recognized as the second most productive seaweed in China. In this study, the flavor and nutritional components of three varieties of G. lemaneiformis-981, LuLong No. 1, and NB-18 were investigated using sensory flavor chemistry, emphasizing their potential flavor properties and health benefits. The e-tongue and e-nose profiles of G. lemaneiformis were analyzed for the first time, revealing significant differences between NB-18 and the other two varieties. Free amino acids, 5'-nucleotides, and volatile compounds (VOCs) were also evaluated. NB-18 exhibited significantly lower levels of VOCs and higher content of Glu, contributing to its superior sensory characteristics. Furthermore, it demonstrated a higher proportion of polyunsaturated fatty acids (PUFAs) and the lowest trans-fatty acid content. In conclusion, NB-18 stands out as a nutrient-rich, high-protein seaweed with excellent flavor and considerable market value, providing a strong basis for future large-scale promotion and cultivation.

Analysis of Nutritional Composition and Flavor Patterns by Variety (Porphyra dentata and Porphyra yezoensis) in Dried Laver from Jeonnam, Korea

This study analyzed 192 samples of Porphyra dentata (P-dent) and 201 samples of Porphyra yezoensis (P-yezo) from Jeonnam in Korea. Principal component analysis (PCA) and correlation analysis were conducted to establish a nutritional component dataset for laver. The analysis revealed that P-dent had higher moisture and weight but lower protein content than P-yezo. Ca, Mg, and Fe levels were higher in P-dent, while P, Na, and Zn levels were higher in P-yezo. Fatty acids composition analysis indicated that P-dent contained higher levels of linoleic acid, while P-yezo exhibited higher levels of oleic acid and eicosapentaenoic acid (EPA). P-yezo had significantly higher levels of chlorophyll and carotenoids compared to P-dent. Conversely, P-dent exhibited higher L* and b* color values, resulting in a brighter, more yellowish appearance. Sensory analysis indicated that P-yezo was more intense in saltiness and umami, whereas P-dent had higher sourness and sweetness. The principal component analysis (PCA) results showed a clear distinction between P-dent and P-yezo, and 184 correlations among factors (nutrients, characteristics, etc.) were identified. These results contribute to a new database for evaluating the quality of Jeonnam laver.

Production, Transport, Fate and Effects of Lipids in the Marine Environment

Lipids form energy storage depots, cellular barriers and signaling molecules. They are generated and metabolized by enzymes under the influence of biotic and abiotic factors, and some-the long-chain polyunsaturated ω3 and ω6 fatty acids and cholesterol-are essential for optimal health in marine organisms. In addition, lipids have direct and indirect roles in the control of buoyancy in marine fauna ranging from copepods to whales. Phytoplankton account for about half of the planet's carbon fixation, and about half of that carbon goes into lipids. Lipids are an important component of the ocean's ability to sequester carbon away from the atmosphere through sinking and especially after transfer to zooplankton. Phytoplankton are the main suppliers of ω3 polyunsaturated fatty acids (PUFAs) in the marine environment. They also supply cholesterol and many phytosterols to ocean ecosystems; however, genomics is indicating that members of the Cnidaria, Rotifera, Annelida, and Mollusca phyla also have the endogenous capacity for the de novo synthesis of ω3 PUFAs as well as phytosterols. It has been predicted that ω3 long-chain PUFAs will decrease in marine organisms with climate change, with implications for human consumption and for carbon sequestration; however, the responses of ω3 PUFA supply to future conditions are likely to be quite diverse.

Iodine identification in major edible seaweed Kappaphycus alvarezii and establishment of an iodine reduction method for its protein extract for utilization as a protein source

Kappaphycus alvarezii is the most widely cultivated seaweed globally. The use of the protein contained in K. alvarezii as an alternative protein source seems to be an effective countermeasure against the protein crisis. Here, we identified the iodine chemical species in K. alvarezii and developed an iodine reduction method. We used various fractionation methods and showed that almost all the iodine in the K. alvarezii alkali extract is present as an iodinated protein, and reducing the amount of iodine per protein was difficult. Subsequently, an iodine reduction method was established to cleave the covalent bonds between the protein and iodine, and we could successfully reduce the amount of iodine per protein by approximately half.

Proximate composition, fatty acid characteristics, amino acid profile and mineral content of fish Acanthurus sohal

The study's objective was to explore the chemical composition of Acanthurus sohal fish flesh and their nutritional quality. Fish samples were caught in the Red Sea, prepared, and analysed for proximate composition, fatty acid, amino acid and mineral content. The results revealed that fish flesh contained 71.1 % moisture, 20.7 % crude protein, 5 % crude lipids and 1.7 % ash. The fatty acids were dominant by 61.93 % saturated fatty acids. Palmitic was the most common (40.35 %) saturated fatty acids, while monounsaturated fatty acids and polyunsaturated fatty acids accounted for 22.59 % and 15.48 %, respectively. The fish fat consisted of appreciable amounts of odd-numbered fatty acids heptadecanoic and heptadecenoic acids standing for 1.62 % and 1.45 %, respectively. The fatty acids were predominated by C16, C18 and C20 fatty acids. The percentage of n-6/n-3 reached 2.26. Seventeen amino acids were identified in A. sohal flesh protein, eight of which were essential amino acids (EAAs); they amounted to 375.47 mg/g crude protein. Lysine was the most common EAA (64.49 mg/g crude protein). Aromatic amino acid and sulphur amino acid constituted 112.43 and 47.56 mg/g protein, respectively. The following macroelement concentration ranking was identified: Ca > P > K > Na > Mg, while the concentration of vital elements was Fe > Zn > Cu > Cr > I > Se > Co.

Extraction and antioxidant capacity of mycosporine-like amino acids from red algae in Japan

Mycosporine-like amino acids (MAAs) are the natural UV-absorbing compounds with antioxidant activity found in microalgae and macroalgae. We collected red algae Asparagopsis taxiformis, Meristotheca japonica, and Polysiphonia senticulosa from Nagasaki, where UV radiation is more intense than in Hokkaido, and investigated the effect of UV radiation on MAA content. It was suggested that A. taxiformis and M. japonica contained shinorine and palythine, while UV-absorbing compound in P. senticulosa could not be identified. The amounts of these MAAs were lower compared to those from Hokkaido. Despite an increase in UV radiation in both regions from February to April, MAA contents of red algae from Nagasaki slightly decreased while those from Hokkaido significantly decreased. This difference was suggested the amount of inorganic nitrogen in the ocean. Antioxidant activity of MAAs increased under alkaline conditions. The extract containing MAAs from P. senticulosa showed the highest antioxidant activity among 4 red algae.

Determination of the Nutrient and Toxic Element Content of Wild-Collected and Cultivated Seaweeds from Hawai'i

For centuries, Hawaiians have gathered seaweed for food, medicine, and ceremonial purposes. Seaweed contains nutrients, but some varieties can accumulate toxic elements. We measured target macrominerals (Na, Mg, P, K, Ca), microminerals (B, V, Mn, Co, Cu, Zn, Mo), and nonessential/toxic elements (As, Sr, Cd, Sn, Hg, Pb, and U) in a sample of wild-collected and cultivated seaweeds from Hawai'i. The samples consisted of brown (Sargassum aquifolium, Sargassum echinocarpum), red (Gracilaria parvispora, Halymenia formosa, Halymenia hawaiiana), and green (Ulva ohnoi) seaweed. Elemental composition was determined by inductively coupled plasma (ICP)-atomic emission spectroscopy and ICP-mass spectrometry (MS). Speciation of As was conducted by using liquid chromatography-ICP-MS. S. echinocarpum per 80 g serving was high in Ca (~37% daily value [DV]), U. ohnoi was high in Mg (~40%DV), H. formosa was high in Fe (~40%DV), and G. parvispora was high in Mn (~128%DV). In this study, the highest amounts of toxic elements were observed in S. aquifolium and S. echinocarpum (27.6 mg inorganic As/kg fdw), G. parvispora (43.3 mg Pb/kg fdw) and H. formosa (46.6 mg Pb/kg fdw). These results indicate that although seaweeds from Hawai'i contain a variety of nutrients, some species can accumulate high amounts of toxic elements.

Rehashing Our Insight of Seaweeds as a Potential Source of Foods, Nutraceuticals, and Pharmaceuticals

In a few Southeast Asian nations, seaweeds have been a staple of the cuisine since prehistoric times. Seaweeds are currently becoming more and more popular around the world due to their superior nutritional value and medicinal properties. This is because of rising seaweed production on a global scale and substantial research on their composition and bioactivities over the past 20 years. By reviewing several articles in the literature, this review aimed to provide comprehensive information about the primary and secondary metabolites and various classes of bioactive compounds, such as polysaccharides, polyphenols, proteins, and essential fatty acids, along with their bioactivities, in a single article. This review also highlights the potential of seaweeds in the development of nutraceuticals, with a particular focus on their ability to enhance human health and overall well-being. In addition, we discuss the challenges and potential opportunities associated with the advancement of pharmaceuticals and nutraceuticals derived from seaweeds, as well as their incorporation into different industrial sectors. Furthermore, we find that many bioactive constituents found in seaweeds have demonstrated potential in terms of different therapeutic attributes, including antioxidative, anti-inflammatory, anticancer, and other properties. In conclusion, seaweed-based bioactive compounds have a huge potential to play an important role in the food, nutraceutical, and pharmaceutical sectors. However, future research should pay more attention to developing efficient techniques for the extraction and purification of compounds as well as their toxicity analysis, clinical efficacy, mode of action, and interactions with regular diets.

Elucidation and quantification health-promoting phenolic compounds, antioxidant properties and sugar levels of ultrasound assisted extraction, aroma compositions and amino acids profiles of macroalgae, Laurencia papillosa

Currently, sustainability is one of the most critical issues confronting society today. The growing of macroalgae in ocean farms appears more sustainable than agriculture on land due to it does not require any fresh water, chemical fertiliser, or soil. Macroalgae have been shown to be a sustainable marine source of amino acids, novel bioactive phenolic and aroma compounds that can be exploitation in food, cosmetic, nutraceuticals, pharmacological applications. Despite starting the huge cultivation of macroalgae in world, bioactive compounds in the edible macroalgae have not been well characterized. Ultrasound assisted extraction (UAE) and conventional extraction (CE) techniques were compared and red macroalgae, L. papillosa extracts were characterized. The highest amount of amino acid was glutamic acid (GLU) and composed of 35% was essential amino acids. UAE at 10% amplitude for 15 min showed significantly highest (p < 0.05) phenolic (212.03±3.03 mg gallic acid equivalent/100 g) as well as antioxidant activity determined by DPPH (105.69±3.02 µmol Trolox/100 g), ABTS (238.69±2.23 µmol Trolox/100 g) radical assay and FRAP value (72.47±3.13 µmol Trolox/100 g) when in comparison with CE. Furthermore, bioactive compounds in extracts were indicated as phlorotannins, flavonoids, phenolic acids and other polyphenols using liquid chromatography coupled to diode array detection and electrospray ionisation tandem mass spectrometry (LC-DAD-ESI-MS/MS). This result confirmed higher antioxidant capacity detected with the UAE. A total of 46 volatile organic compounds were identified and quantified by GC-FID/MS with HS-SPME system. This study emerges as first report to novel extraction method used and deeply characterization of L papillosa. The results seem that significant potential application in the functional food, active packaging and nutraceuticals industry.

Brown algae and their multiple applications as functional ingredient in food production

Brown algae are considered one of the resources that can contribute to transforming our global food system by promoting healthier diets and reducing environmental impact. In this sense, this review article aims to provide up-to-date information on the nutritional and functional improvement of brown algae when they are applied to different food matrices. Brown algae present sulfated polysaccharides (alginates, fucoidans, and laminarins), proteins, minerals, vitamins, dietary fibers, fatty acids, pigments, and bioactive compounds that can positively contribute to the development of highly nutritious food products, as well as used reformulate products already existing, to remove, reduce, increase, add and/or replace different components and obtain products that confer health-promoting properties. This review demonstrates that there is a tendency to use seaweed for the production of functional foods and that the number of commercially produced products from seaweed is increasing, that is, seaweed is a sector whose global market is expanding.

Biochemical and Nutritional Characterization of Edible Seaweeds from the Peruvian Coast

In Peru, the number of species of edible seaweeds within the genera Chondracanthus, Porphyra (hereafter P.), Pyropia (hereafter Py.), and Ulva has not been fully established, nor is there a significant level of information available related to their chemical and nutritional composition. This study involved the biochemical analysis of species belonging to ten genera of macroalgae, known edible and some of which have the potential to be used as food, including six red (Callophyllis, Chondracanthus, Mazzaella, Porphyra, Pyropia, and Rhodymenia), two green (Ulva and Codium), and two brown (Eisenia and Lessonia) species collected along the Peruvian coast (6°-17° S). In the evaluation of 37 specimens, differences were found in the proximal composition, amino acid composition, and fatty acid profiles, which were specific to subgroups and supported their taxonomic classification, mainly at the order level. The red algae Porphyra/Pyropia (Bangiales) had the highest average percentage of protein (24.10%) and carbohydrates (59.85%) and the lowest percentage of ash (7.95%). Conversely, the brown alga Eisenia (Laminariales) had the lowest average percentage of protein, with different values related to the structure: 14.11% at the level of the frond and 9.46% at the level of the stipe. On the other hand, Bryopsidales green algae showed the highest average percentages of lipids (5.38%). The moisture percentages ranged from 4 to 16%, and no relevant significant differences were shown between the orders. The characteristic amino acids in all of the studied groups were glutamic acid, aspartic acid, alanine, and leucine. The highest average of the essential amino acids ratio was obtained for the Gigartinales red algae (48.65%), and the highest values of the essential amino acid index (EAAI) were obtained for the Ulvales, Laminariales, Gigartinales, and Rhodymeniales algae (EAAI > 0.92). The highest average relative percentage of fatty acids was obtained for polyunsaturated fatty acids, followed by saturated fatty acids. The major component of the ω6 fatty acids from red and brown algae was arachidonic acid (C20:4n - 6). The highest level of ω3 fatty acids was observed for the eicosapentaenoic acids (EPA) in red algae. The highest median ω6/ω3 ratio was displayed by the red alga Callophyllis variegata (Gigartinales). A detailed knowledge of edible seaweeds, and those considered potentially edible, would help to diversify the diet based on macroalgae in Peru.

Effects of Glyphosate-Based Herbicide on Primary Production and Physiological Fitness of the Macroalgae Ulva lactuca

The use of glyphosate-based herbicides (GBHs) worldwide has increased exponentially over the last two decades increasing the environmental risk to marine and coastal habitats. The present study investigated the effects of GBHs at environmentally relevant concentrations (0, 10, 50, 100, 250, and 500 μg·L⁻¹) on the physiology and biochemistry (photosynthesis, pigment, and lipid composition, antioxidative systems and energy balance) of Ulva lactuca, a cosmopolitan marine macroalgae species. Although GBHs cause deleterious effects such as the inhibition of photosynthetic activity, particularly at 250 μg·L⁻¹, due to the impairment of the electron transport in the chloroplasts, these changes are almost completely reverted at the highest concentration (500 μg·L⁻¹). This could be related to the induction of tolerance mechanisms at a certain threshold or tipping point. While no changes occurred in the energy balance, an increase in the pigment antheraxanthin is observed jointly with an increase in ascorbate peroxidase activity. These mechanisms might have contributed to protecting thylakoids against excess radiation and the increase in reactive oxygen species, associated with stress conditions, as no increase in lipid peroxidation products was observed. Furthermore, changes in the fatty acids profile, usually attributed to the induction of plant stress response mechanisms, demonstrated the high resilience of this macroalgae. Notably, the application of bio-optical tools in ecotoxicology, such as pulse amplitude modulated (PAM) fluorometry and laser-induced fluorescence (LIF), allowed separation of the control samples and those treated by GBHs in different concentrations with a high degree of accuracy, with PAM more accurate in identifying the different treatments.

Insights into agar and secondary metabolite pathways from the genome of the red alga Gracilaria domingensis (Rhodophyta, Gracilariales)

Gracilariales is a clade of florideophycean red macroalgae known for being the main source of agar. We present a de novo genome assembly and annotation of Gracilaria domingensis, an agarophyte alga with flattened thallus widely distributed along Central and South American Atlantic intertidal zones. In addition to structural analysis, an organizational comparison was done with other Rhodophyta genomes. The nuclear genome has 78 Mbp, with 11,437 predicted coding genes, 4,075 of which did not have hits in sequence databases. We also predicted 1,567 noncoding RNAs, distributed in 14 classes. The plastid and mitochondrion genome structures were also obtained. Genes related to agar synthesis were identified. Genes for type II galactose sulfurylases could not be found. Genes related to ascorbate synthesis were found. These results suggest an intricate connection of cell wall polysaccharide synthesis and the redox systems through the use of L-galactose in Rhodophyta. The genome of G. domingensis should be valuable to phycological and aquacultural research, as it is the first tropical and Western Atlantic red macroalgal genome to be sequenced.

Effect of long-term storage and harvest site on the fatty acid profiles, mineral and antioxidant properties of selected edible Scottish seaweeds

The limited understanding of the effect of pre-and post-harvest techniques still hinders the full exploitation of seaweed. Here, the effect of harvest site, long term storage and species on the elemental composition, fatty acid profile, lipid content, and antioxidant properties were determined in eight intertidal seaweed species common to Scotland, harvested for potential food application and stored for up to 128 weeks. Result showed that the most significant variation was due to species, with no statistical link found for the combined interaction effect of both storage duration and harvest site in most cases, except for the antioxidant parameters and some selected elements, which was limited to some seaweed species. Overall, our result showed that the chemical profiles of the seaweed species studied were remarkably consistent and unaffected by long term storage. Thus, suggesting that seaweeds sampled from Scotland could be a valuable resource for the development of functional foods.

Nutritional Composition of Beach-Cast Marine Algae from the Brazilian Coast: Added Value for Algal Biomass Considered as Waste

In some coastal areas, large quantities of beach-cast macroalgae can accumulate and are usually considered waste and disposed of. However, due to their biofunctional and nutritional properties, they have great potential as a new source of raw materials. Increasing population growth has made the search for alternative raw materials with valuable nutritional properties urgent; here, beach-cast macroalgae could provide great potential. Our research goal was to characterize the nutritional profile of 12 beach-cast seaweed species from the Brazilian coast to assess their potential valorization. A considerable number of nutritional compounds was observed, such as ash (6.5–59.3%), total dietary fibers (22.1–65.8%), proteins (5.1–21.5%), and carbohydrates (31.4–81.0%), with an expressive abundance of minerals, free amino acids, and fatty acids. Spatoglossum schroederi and Alsidium seaforthii showed protein contents of 21.5 ± 0.2%, 19.7 ± 0.1%, and high amounts of total dietary fiber of 59.2 ± 0.4%, 61.7 ± 4.9%, respectively. The overall profile suggests that beach-cast seaweeds are suitable for nutritional and other bioeconomical purposes, to which different species with different characteristics contribute. Contamination of these seaweeds with unwanted toxic compounds like micropollutants was not studied. However, this must be considered before they are used for human consumption.

Bioprospecting macroalgae, marine and terrestrial invertebrates & their associated microbiota

Abstract The present review aims the discussion of the impact of the bioprospection initiative developed by the projects associated to BIOprospecTA, a subprogram of the program BIOTA, supported by FAPESP. This review brings a summary of the main results produced by the projects investigating natural products (NPs) from non-plants organisms, as examples of the success of this initiative, focusing on the progresses achieved by the projects related to NPs from macroalgae, marine invertebrates, arthropods and associated microorganisms. Macroalgae are one of the most studied groups in Brazil with the isolation of many bioactive compounds including lipids, carotenoids, phycocolloids, lectins, mycosporine-like amino acids and halogenated compounds. Marine invertebrates and associated microorganisms have been more systematically studied in the last thirty years, revealing unique compounds, with potent biological activities. The venoms of Hymenopteran insects were also extensively studied, resulting in the identification of hundreds of peptides, which were used to create a chemical library that contributed for the identification of leader models for the development of antifungal, antiparasitic, and anticancer compounds. The built knowledge of Hymenopteran venoms permitted the development of an equine hyperimmune serum anti honeybee venom. Amongst the microorganisms associated with insects the bioprospecting strategy was to understand the molecular basis of intra- and interspecies interactions (Chemical Ecology), translating this knowledge to possible biotechnological applications. The results discussed here reinforce the importance of BIOprospecTA program on the development of research with highly innovative potential in Brazil.

Assessment of Antioxidant Capacity and Phytochemical Composition of Brown and Red Seaweeds Sampled off Red Sea Coast

Seaweeds are becoming a viable source of biologically active composites with a hopeful application as nutraceuticals, functional food components, and medicinal agents. In the present study, the antioxidant capacity and biochemical compositions of four seaweeds; Polycladia indica and Turbinaria ornata (Phaeophyceae) and Laurencia obtusa and Sarconema scinaioides (Rhodophyceae), were estimated. The results indicated that T. ornata showed the maximum value of total phenolic compound (TPC), flavonoid content, β-carotene, carbohydrate and has maximum percentage of DPPH radical scavenging capacity, total antioxidant capacity (TAC), and total reducing capacity (TRC) (72.48%, 15.02%, and 53.24% inhibition, respectively), while the highest contents of ascorbic acid, lipid, calcium, and zinc were observed in L. obtusa. P. indica showed the highest protein contents, dietary fibers, sodium, potassium, magnesium, and total amino acids. Glutamic, aspartic, proline, and methionine were the most frequent amino acids in the four selected seaweeds. Brown seaweeds (T. ornata and P. indica) attained the highest percent of the total polyunsaturated (ω6 and ω3) essential fatty acids. The biochemical content of these seaweed species, as well as their antioxidant properties, make them interesting candidates for nutritional, pharmacological, and therapeutic applications.

Seasonal Nutritional Profile of Gelidium corneum (Rhodophyta, Gelidiaceae) from the Center of Portugal

Gelidium corneum is a well-known agarophyte, harvested worldwide for its high agar quality. However, the species also exhibits an interesting nutritional profile, but with seasonal variations. Therefore, to evaluate the nutritional value of G. corneum, ash, crude protein, total lipids, and carbohydrates were analyzed at different times of the year. The heavy metals mercury, arsenic, lead, cadmium, and tin, as well as iodine were also measured. Finally, the seasonal antioxidant capacity of G. corneum extracts was evaluated. Our results indicate that the biomass is rich in protein (up to 16.25 ± 0.33%) and carbohydrates (up to 39.5 ± 3.29%), and low in lipids (up to 2.75 ± 0.28%), and especially in the summer, the AI, TI indexes, n-6/n-3 and h/H ratios (0.93, 0.6, 0.88 and 1.08, respectively) are very interesting. None of the contaminants exceeded the legally established limits, and the iodine values were adequate for a healthy diet. Finally, the antioxidant capacity is fair, with the DPPH ≤ 10.89 ± 1.46%, and ABTS ≤ 13.90 ± 1.54% inhibition, FRAP ≤ 0.91 ± 0.22 AAE.g⁻¹, and TPC ≤ 6.82 ± 0.26 GAE.g⁻¹. The results show that G. corneum is an attractive resource, with potential use as food or as a food supplement.

Single Cell Protein: A Potential Substitute in Human and Animal Nutrition

Single cell protein (SCP) is the first product of the fermentation process and has proven to be a good protein alternative. Food competition is becoming more intense as the world’s population continues to grow. Soon, SCP may be able to compensate for a protein deficit. Various global businesses are focusing on SCP production, and the scope of its application is expanding as time and knowledge increases. High quantities of SCP can be produced by microorganisms, such as algae, yeast, fungi and bacteria, due to their fast development rate and the significant level of protein in their chemical structure. Beside proteins, SCP contains carbohydrates, nucleic acids, lipids, minerals, vitamins and several important amino acids. SCP has been an effective substitute for more expensive protein sources such as fish and soybean products. In conclusion, SCP can easily replace traditional protein sources in human and animal feed without detrimental effects. Potential substrate candidates and optimization strategies for SCP production have been extensively studied. This review article focuses on the various aspects of SCP, from its production, using different substrates, player microorganisms and nutritional benefits, to its economic aspects.

Exogenous Application of 5-Aminolevulinic Acid Promotes Coloration and Improves the Quality of Tomato Fruit by Regulating Carotenoid Metabolism

5-Aminolevulinic acid (ALA) plays an important role in plant growth and development. It can also be used to enhance crop resistance to environmental stresses and improve the color and internal quality of fruits. However, there are limited reports regarding the effects of ALA on tomato fruit color and its regulatory mechanisms. Therefore, in this study, the effects of exogenous ALA on the quality and coloration of tomato fruits were examined. Tomato (Solanum lycopersicum "Yuanwei No. 1") fruit surfaces were treated with different concentrations of ALA (0, 100, and 200 mg⋅L-1) on the 24th day after fruit setting (mature green fruit stage), and the content of soluble sugar, titratable acid, soluble protein, vitamin C, and total free amino acids, as well as amino acid components, intermediates of lycopene synthetic and metabolic pathways, and ALA metabolic pathway derivatives were determined during fruit ripening. The relative expression levels of genes involved in lycopene synthesis and metabolism and those involved in ALA metabolism were also analyzed. The results indicated that exogenous ALA (200 mg⋅L-1) increased the contents of soluble sugars, soluble proteins, total free amino acids, and vitamin C as well as 11 kinds of amino acid components in tomato fruits and reduced the content of titratable acids, thus improving the quality of tomato fruits harvested 4 days earlier than those of the control plants. In addition, exogenous ALA markedly improved carotenoid biosynthesis by upregulating the gene expression levels of geranylgeranyl diphosphate synthase, phytoene synthase 1, phytoene desaturase, and lycopene β-cyclase. Furthermore, exogenous ALA inhibited chlorophyll synthesis by downregulating the genes expression levels of Mg-chelatase and protochlorophyllide oxidoreductase. These findings suggest that supplementation with 200 mg⋅L-1 ALA not only enhances the nutritional quality and color of the fruit but also promotes early fruit maturation in tomato.

New Insights on the Sporulation, Germination, and Nutritional Profile of Gracilaria gracilis (Rhodophyta) Grown under Controlled Conditions

The red seaweed Gracilaria gracilis is a widely cultivated species known for its high agar content. It is also an important source of proteins, minerals, and vitamins. The chemical profile of seaweed depends on the cultivation methods used and the growing conditions to which they are exposed. Thus, two independent methods of sporulation and germination were tested upon Gracilaria gracilis grown in controlled conditions. During the tests, different substrates, culture media and incubation times were tested to induce cystocarp maturation. The results showed that cystocarp maturation and spore release were successful, with a visible volume increase and format change in the protruding cystocarps. Furthermore, the process of maturation to germination was accomplished, fulfilling the complete life cycle. In parallel, the nutritional profile of the biomass obtained was evaluated and compared with the nutritional values of biomass collected from the environment. Results showed no significant differences between wild specimens and cultivated ones in organic matter, ash content, lipid content, carbohydrates, or phycocolloid content. The present work, therefore, presents two simple alternative methods with potential applications in start-ups aimed at the cultivation of seaweed. Through these methods, it is possible to obtain biomass with nutritional characteristics similar to those obtained in the wild.

Seasonal Changes in the Nutritional Composition of Agarophyton vermiculophyllum (Rhodophyta, Gracilariales) from the Center of Portugal

Seaweeds exhibit high nutritional value due to a balanced concentration of proteins, vitamins and minerals, a high concentration of low digestibility polysaccharides, and reduced levels of lipids, many of which are n-3 and n-6 fatty acids. The species Agarophyton vermiculophyllum is no exception and, as such, a comprehensive study of the chemical and nutritional profile of this red seaweed was carried out for 1 year. Seasonal variations in moisture, ash, protein and amino acids content, crude fibers, ascorbic acid, agar, lipids, and the corresponding fatty acid profile, were analyzed. We found low levels of fatty acids and a high protein content, but also noticed interesting seasonal change patterns in these compounds. The present study gives insights on the environmental conditions that can lead to changes in the nutritional composition of this species, aiming, therefore, to bring new conclusions about the manipulation of environmental conditions that allow for maximizing the nutritional value of this seaweed.

Environmental factors shape the epiphytic bacterial communities of Gracilariopsis lemaneiformis

Macroalgae host various symbionts on their surface, which play a critical role in their growth and development processes. However, there is still incomplete understanding of this epiphytic bacteria-host algae interactions. This study comprehensively analysed variation of the epiphytic bacterial communities (EBC) composition of red macroalga Gracilariopsis lemaneiformis at different geographic locations and environmental factors (i.e., nitrogen and phosphorus), which shape the EBC composition of G. lemaneiformis. The composition and structure of EBC were characterized using high throughput sequencing of the V3-V4 hypervariable region of the 16S rRNA gene. The results revealed that epiphytic bacteria varied significantly among three different geographic locations in China, i.e., Nan'ao Island (NA), Lianjiang County (LJ), and Nanri Island (NR). Redundancy analysis (RDA) showed that the relative abundance of Bacteroidetes, Firmicutes, Verrucomicrobia, and Epsilonbacteraeota at NR were strongly positively correlated with total nitrogen (TN), total phosphorus (TP), nitrate nitrogen (NO₃-N), and dissolved inorganic nitrogen (DIN), but negatively correlated with nitrite nitrogen (NO₂-N). The relative abundance of Cyanobacteria at NA and LJ were strongly positively correlated with NO₂-N, but negatively correlated with TN, TP, NO₃-N, and DIN. Besides, the Mantel test results indicated that the EBC composition was significantly correlated with these environmental factors, which was also confirmed by Spearman correlation analysis. Thus, environmental factors such as NO₃-N and DIN play a key role in the community composition of epiphytic bacteria on G. lemaneiformis. This study provides important baseline knowledge on the community composition of epiphytic bacteria on G. lemaneiformis and shows correlation between different epiphytic bacteria and their surrounding environmental factors.

Effects of exogenous vitamin B12 on nutrient removal and protein expression of algal-bacterial consortium

Chlorella vulgaris and Bacillus licheniformis consortium was added to synthetic wastewater with exogenous vitamin B₁₂. In the presence of 100 ng/L vitamin B₁₂, removal efficiencies of TN, NH₃-N, PO₄^3-P, and COD were 80.1%, 76.8%, 87.9%, and 76.7%, respectively. The functional groups on the cell surface of the consortium, including -NH, -CH₃, C=O, C=C, and P-O-C, increased with 100 ng/L vitamin B₁₂. These functional groups improved the biological adsorption of the consortium; however, higher concentrations of vitamin B₁₂ resulted in an occlusion of the functional groups. Furthermore, there were 5 significantly enriched protein pathways, namely carbon fixation in photosynthetic organisms; amino acid metabolic pathways; the pathway of one carbon pool by folate; nitrogen metabolism; and photosynthesis. Most proteins in these pathways were upregulated, which enhanced carbon fixation and photosynthesis in the algal cells. Simultaneously, B₁₂ promoted significant upregulation of proteins associated with the quorum-sensing pathway, which promoted the interaction between algae and bacteria.

Proteins extracted from seaweed Undaria pinnatifida and their potential uses as foods and nutraceuticals

Isolation and utilization of proteins from seaweeds have been a novel trend in the world at present due to the increasing demand for healthy non-animal proteins. The attention of scientific community has been paid on the protein derived from seaweed Undaria pinnatifida due to their high nutritional quality and bioactivity. This article aims to provide an integrated overview on methods of extraction, isolation and purification of U. pinnatifida-derived proteins and composition, nutritional value and potential nutraceutical and food applications with an interest to stimulate further research to optimize the utilization. Potential food applications of U. pinnatifida derived proteins are nutritional components in human diet, food ingredients and additives, alternative meat and meat analogues and animal and fish feed. Excellent antioxidant, antihypertension, anticoagulant, anti-diabetes, antimicrobial and anti-cancer activities possessed by proteins of U. pinnatifida enable the use of these proteins in various nutraceutical applications. A number of studies have been carried out on antioxidant and antihypertensive activities of U. pinnatifida proteins, whereas other bioactivites are yet to be further studied. Hence, more research works are crucial to be done in order to facilitate and promote the emerging novel foods and nutraceuticals, using proteins from seaweed U. pinnatifida.

Amino Acid Profile and Protein Quality Assessment of Macroalgae Produced in an Integrated Multi-Trophic Aquaculture System

Seaweeds are a recognized source of bioactive compounds and techno-functional ingredients. However, its protein fraction is still underexplored. The aim of this study was to determine the total and free amino acid profile and protein content of four seaweeds species (Porphyra dioica, Porphyra umbilicalis,Gracilaria vermiculophylla, and Ulva rigida) produced in an integrated multi-trophic aquaculture system, while assessing their protein quality. Samples were submitted to acid and alkaline hydrolysis (total amino acids) and to an aqueous extraction (free amino acids) followed by an automated online derivatization procedure, and analyzed by reverse phase-high performance liquid chromatography. Protein-, non-protein and total-nitrogen were quantified by the Kjeldahl method. Crude and true protein contents were estimated based on the nitrogen and amino acid composition. Protein quality was assessed based on the amino acids profile. Porphyra species presented the highest protein content compared to the remaining three seaweed species tested. All samples presented a complete profile of essential amino acids and a high quality protein profile, according to World Health Organization and Food and Agriculture Organization standards. Methionine and tryptophan were the first limiting amino acids in all species. Red species (Porphyra and Gracilaria) presented high levels of free alanine, glutamic, and aspartic acids. The results highlight the potential of using seaweeds as an alternative and sustainable source of protein and amino acids for human nutrition and industrial food processing.

Sustainable Food Production and Nutraceutical Applications from Qatar Desert Chlorella sp. (Chlorophyceae)

Microalgae isolated from the Qatari desert was identified as thermotolerant, with a rich metabolite profile that is appropriate for use as food and health supplements. In this research, a species of Chlorella, QUCCCM3, from the Qatar University Culture Collection of Cyanobacteria and Microalgae, was investigated for its growth characteristics and metabolite compositions for use as potential feedstock for food production. The strain was cultivated at 30, 35, and 40 °C, covering the annual average low and high temperatures in Qatar. The highest growth rates were recorded for cultures at 30 °C with 0.64 ± 0.04 day^-1, followed by a growth rate of 0.54 ± 0.06 day^-1 at 40 °C, indicating its thermotolerance ability. The biomass exhibited a high protein content (43 ± 2.3%), with existence of lysine (4.13%) as an essential amino acid, and docosahexaenoic acid, linoleic acid, and alpha-linolenic acid as important omega fatty acids present. On the other hand, Chlorella sp. QUCCCM3 also exhibited a high capacity for scavenging free radicals with an antiproliferative effect against chronic myeloid leukemia K562 cancer cells. The results indicate that Chlorella sp. QUCCCM3 is a promising candidate that can be produced year-round, in the Qatar environment, for commercial applications such as feed and nutraceutical supplements.

Characteristics of lipid biosynthesis of Chlorella pyrenoidosa under stress conditions

Effects of high light, high salt, nitrogen and phosphorus deficiency on growth and lipid production of Chlorella pyrenoidosa were investigated in a flat-plate photoreactor, and the oil quality indexes such as CN, IV, SV, CFPP, DU, and LCSF were also evaluated. The results show that the growth of C. pyrenoidosa was inhibited under the stress conditions, but the intracellular lipid content was significantly increased. Moreover, the combustion performance, oxidation stability, low temperature fluidity, and other oil quality indicators under these nutrient stress conditions were significantly improved. Importantly, it is found that starch was preferentially synthesized by algal cells, while with the prolongation of stress time, starch was gradually degraded, and the degraded carbon skeleton was mainly used for lipid synthesis.

Effects of a moderate iron overload and its interaction with yacon flour, and/or phytate, in the diet on liver antioxidant enzymes and hepatocyte apoptosis in rats

The effect of moderate Fe overload in the diet and its interaction with phytate, and/or yacon flour (YF), recognized as an inhibitor, and facilitator, of Fe absorption, respectively, was evaluated in healthy rats. For this purpose the following parameters were analyzed: (1) apparent iron (Fe), copper (Cu) and zinc (Zn) absorption; (2) blood Fe; (3) blood lipids (cholesterol, tryacylglicerol); (4) blood AST and ALT; (5) liver histology (histopathology, hemosiderin depots, apoptosis index; (6) liver fatty acid incorporation; (7) liver antioxidant enzyme activity. Moderate Fe overload may cause change in some liver markers (hemosiderin depots, apoptosis index and GPx) and blood lipids (total cholesterol and VLDL) and the interaction with yacon flour, and phytate, in the Fe overloaded diets may exert a protective effect on these alterations.

Fatty acid and lipophilic vitamin composition of seaweeds from Antalya and Çanakkale (Turkey)

The lipophilic vitamin and fatty acid profiles were determined in five edible seaweeds: Corallina elongata J. Ellis & Solander, 1786; Cystoseira barbata (Stackhouse) C. Agardh, 1820; Jania rubens (Linnaeus) J.V. Lamouroux, 1816; Laurencia obtusa (Hudson) J.V. Lamouroux, 1813 and Sargassum vulgare C. Agardh, 1820. Saturated fatty acids (SFAs) were the major fatty acid group, and16:0 formed the highest SFA content (34–40%). 16:0 was higher in the brown seaweeds (C. barbata, 40.55%; S. vulgare, 37.11%) than in the red seaweeds (C. elongata, 36.5%; L. obtusa, 34.57%; J. rubens, 34.22%). The other major fatty acids in the seaweeds were 18:1n-9 and 16:1n-7 from MUFA in the analyzed species. In addition, EPA was found in significant levels in the red seaweeds, whereas DHA was not detected in the analyzed species. The findings showed that difference among species were not statistically significant (p = 0.09–0.11), yet differences between two families (Sargassaceae and Corallinaceae) were significant (p = 0.006) in the fatty acid profile (p < 0.01). Also, differences between the Corallinaceae and Rhomomelaceae families were partially significant (p = 0.011–0.013) (p < 0.01). K1 and K2 vitamins as well as δ-tocopherol, α-tocopherol and retinol acetate were determined to be present in the seaweed extracts. Finally, ergosterol, stigmasterol and ß-sitosterol were found in all samples in differing ratios per species.

The Use of Microalgae for Coupling Wastewater Treatment With CO2 Biofixation

Production and emission of CO2 from different sources have caused significant changes in the climate, which is the major concern related to global warming. Among other CO2 removal approaches, microalgae can efficiently remove CO2 through the rapid production of algal biomass. In addition, microalgae have the potential to be used in wastewater treatment. Although, wastewater treatment and CO2 removal by microalgae have been studied separately for a long time, there is no detailed information available on combining both processes. In this review article, microalgae-based CO2 biofixation, various microalgae cultivation systems,¯ and microalgae-derived wastewater treatment are separately discussed, followed by the concept of integration of CO2 biofixation process and wastewater treatment. In each section, details of energy efficiency and differences across microalgae species are also given.

Application of pressurized liquid extraction (PLE) to obtain bioactive fatty acids and phenols from Laminaria ochroleuca collected in Galicia (NW Spain)

The increase of pathologies like cardiovascular diseases, obesity or diabetes due to the nature of diet is a matter of concern in our society. Because of this, there is a high interest in healthy natural products that could prevent the appearance of such diseases. This paper aims to study the content of fatty acids (FAs) and phenolic compounds of brown alga Laminaria ochroleuca (L. ochroleuca) and to determine the nutritional quality of the lipids extracted using pressurized liquids extraction (PLE) technique. PLE was applied to the algae using four solvents of different polarity (hexane, ethyl acetate, ethanol and ethanol:water 1:1). Results showed that the higher yield (52%), is obtained with ethanol: water solvent, however, both ethyl acetate and ethanol enrich unsaturated fatty acid (USFA) (palmitoleic, linolenic, linoleic, oleic, araquidonic and eicosapenataenoic) in the lipid fraction of L. ochroleuca, providing extracts up to 55% of their total fatty acid content compared to other solvents. The nutritional quality of the lipids in all PLE extracts was assessed by considering the ω-6/ ω-3 fatty acid ratio and two dietary indexes involved in the risks of coronary heart disease, atherogenic (AI) and thrombogenic (TI). The lower (best) index values are for ethanol extract, 4.4 (ω-6/ ω-3), 0.74 (AI) and 1.05 (TI), followed of ethyl acetate, 4.4 (ω-6/ ω-3), 0.87 (AI) and 1.24 (TI). Finally, the antioxidant capacity of PLE alga extracts in terms of total phenol content (TPC) was analyzed by the Folin-Ciocalteu method. The ethanol: water extracts showed the highest TPC with a concentration up to 173.65 mg eq. gallic acid / g PLE extract.

Evaluating the chemical composition and antioxidant activity of three Egyptian seaweeds: Dictyota dichotoma, Turbinaria decurrens, and Laurencia obtusa

Abstract Seaweeds have a growing number of successful applications in the food industry, medicine and in the cosmetic industry, which increases the importance of evaluating their chemical composition. In the present study, three common Egyptian seaweeds (Dictyota dichotoma, Turbinaria decurrens and Laurencia obtusa) were collected from the Red Sea coast, Suez, Egypt. The chemical profile of the three seaweeds was studied beside the antioxidant activity of their extracts. The results indicated that the amount of carbohydrate was greater than the protein and lipid contents in the three seaweeds, with a natural richness in minerals and antioxidants besides considerable amounts of monounsaturated and polyunsaturated fatty acids, including Omega-3 and Omega-6 fatty acids. All essential amino acids for human were found in the three seaweeds, with significant amounts of aspartic and glutamic acids. Furthermore, the results of the antioxidant activity assays were consistent with the antioxidant contents (phenols, flavonoids, alkaloids, vitamin C, carotenoids) of each seaweed. D. dichotoma was the most valuable seaweed of the three species studied, due to its relatively high protein content of 7.28 ± 0.25%, moderate carbohydrate content of 25.35 ± 0.32%, and highest pigment and antioxidant contents. In conclusion, these three seaweeds, especially Dictyota dichotoma, have an interesting chemical composition with a prospective nutritional and pharmaceutical value.

Minerals from Macroalgae Origin: Health Benefits and Risks for Consumers

Seaweeds are well-known for their exceptional capacity to accumulate essential minerals and trace elements needed for human nutrition, although their levels are commonly very variable depending on their morphological features, environmental conditions, and geographic location. Despite this variability, accumulation of Mg, and especially Fe, seems to be prevalent in Chlorophyta, while Rhodophyta and Phaeophyta accumulate higher concentrations of Mn and I, respectively. Both red and brown seaweeds also tend to accumulate higher concentrations of Na, K, and Zn than green seaweeds. Their valuable mineral content grants them great potential for application in the food industry as new ingredients for the development of numerous functional food products. Indeed, many studies have already shown that seaweeds can be used as NaCl replacers in common foods while increasing their content in elements that are oftentimes deficient in European population. In turn, high concentrations of some elements, such as I, need to be carefully addressed when evaluating seaweed consumption, since excessive intake of this element was proven to have negative impacts on health. In this regard, studies point out that although very bioaccessible, I bioavailability seems to be low, contrarily to other elements, such as Na, K, and Fe. Another weakness of seaweed consumption is their capacity to accumulate several toxic metals, which can pose some health risks. Therefore, considering the current great expansion of seaweed consumption by the Western population, specific regulations on this subject should be laid down. This review presents an overview of the mineral content of prevalent edible European macroalgae, highlighting the main factors interfering in their accumulation. Furthermore, the impact of using these marine vegetables as functional ingredients or NaCl replacers in foods will be discussed. Finally, the relationship between macroalgae’s toxic metals content and the lack of European legislation to regulate them will be addressed.