The growing interest in laver as a food product and as a source of substances beneficial to health has led to global consumer demand for laver produced in a limited area of northeastern Asia. Here we review research into the benefits of laver consumption and discuss future perspectives on the improvement of laver product quality. Variation in nutritional/functional values among product types (raw and processed (dried, roasted, or seasoned) laver) makes product-specific nutritional analysis a prerequisite for accurate prediction of health benefits. The effects of drying, roasting, and seasoning on the contents of both beneficial and harmful substances highlight the importance of managing laver processing conditions. Most research into health benefits has focused on substances present at high concentrations in laver (porphyran, Vitamin B12, taurine), with assessment of the expected effects of laver consumption. Mitigation of chemical/microbiological risks and the adoption of novel technologies to exploit under-reported biochemical characteristics of lavers are suggested as key strategies for the further improvement of laver product quality. Comprehensive analysis of the literature regarding laver as a food product and as a source of biomedical compounds highlights the possibilities and challenges for application of laver products.

https://www.mdpi.com/1660-3397/18/1/14/pdf

Health Functionality and Quality Control of Laver (Porphyra, Pyropia): Current Issues and Future Perspectives as an Edible Seaweed.

Seaweeds are indiscriminately said to contain significant amounts of vitamin C, but seaweeds are a diverse group, which may limit the ability to generalize. Several studies have been performed on vitamin C in seaweed, and this review covers these findings, and concludes on how much vitamin C is found in seaweeds. A systematic review of vitamin C in 92 seaweed species was conducted followed by analyzing the 132 data entries. The average vitamin C content was 0.773 mg g−1 seaweed in dry weight with a 90th percentile of 2.06 mg g−1 dry weight. The vitamin C content was evaluated based on taxonomical categories of green, brown and red seaweeds (Chlorophyta (phylum), Phaeophyceae (class), and Rhodophyta (phylum)), and no significant differences were found between them. The vitamin C content was compared to other food sources, and this showed that seaweeds can contribute to the daily vitamin C intake, but are not a rich source. Moreover, seasonal variations, analytical methods, and processing impacts were also evaluated.

https://www.mdpi.com/2304-8158/10/1/198/pdf

Vitamin C from Seaweed: A Review Assessing Seaweed as Contributor to Daily Intake.

This review describes the nutritional composition and polyphenol content of red algae. The nutrient composition of red algae is highly varied between different genera. Red algae are low-calorie foods, given their high concentration of protein and dietary fiber. They also have higher protein content than brown and green algae, with average values as high as 18.8 g/100 g. The digestibility of red algae proteins is moderate, however, due to their high level of dietary fiber and polyphenols. They have low fat content, but the quality of their fatty acids is very high. They contain essential fatty acids, also oleic acid, arachidonic acid, EPA, and DHA, which are considered beneficial to health. The omega-6/omega-3 ratio is very low (median = 0.8) which is very beneficial for human health. Red algae also have very high amounts of dietary fiber-higher than in terrestrial vegetables-and are especially rich in soluble fiber. It also contains minerals, in high concentrations; among those sodium and iodine stand out. Their sodium/potassium ratio is low, so consumption of red algae would not imply risk for people with hypertension or cardiovascular diseases. The polyphenol content in red algae is very high, but is lower than brown algae.

Nutritional Composition and Bioactive Compounds of Red Seaweed: A Mini-Review

Discovery of high-yielding microalgae rich in valuable lipids, proteins, pigments, or carbohydrates is essential to the growth of nutraceutical and biofuel industries. Therefore, bioprospecting of microalgae from diverse environmental conditions has become highly significant to meet the demand of such bioresources globally. In this context, bioprospecting of three species of microalgae isolated from bloomed freshwaters of Kerala, India, was carried out; morphological and molecular characterizations revealed two of the algae as new species to science and named accordingly. The industrial potentials of these algae (Fasciculochloris boldii (MH992105.1), Sphaerocystis antoni-kadavilaii Ray & Prasanth sp. nov. (MK005299.1), and Chlorella zachariaii Ray & Prasanth sp. nov. (MH930447.1)) were assessed in terms of biomass yield and biochemical profile. The alga Sphaerocystis antoni-kadavilaii with a biomass yield of 176.8 ± 2.0% increase L−1 day−1, lipid productivity of 4.4 ± 0.3 mg L−1 day−1, the protein content of 46.1%, is found promising, in comparison with the known species such as Spirulina sp. and Chlorella sp. It is high in chlorophyll a, and total carotenoid content as well. The alga Fasciculochloris boldii showed high lipid content of 26.8 ± 1.1% and the alga Chlorella zachariaii showed 30.1% of omega-3 fractions in its total fatty acids. The Fourier transform infrared spectroscopy confirmed biodiesel feasibility of lipids from all these algae. However, the alga Fasciculochloris boldii with high proportions of saturated fatty acids in its lipid (71.2%) can be considered as a potential species for biodiesel as the biodiesel from the same also shows the required cetane number (63.3) and low iodine value (38.9).

Bioprospecting of Three Rapid-Growing Freshwater Green Algae, Promising Biomass for Biodiesel Production

Eutrophic, bloomed waters are known for fast-growing microalgae of high biomass yield. The biochemical composition of algae may vary from species to species. Identification of fast-growing local algal species, their experimental culture for assessing biomass yield and biochemical screening of the same for desirable metabolites is crucial to the prospects of algal technology. The freshwater algal diversity of Kerala - one of the biodiversity hotspots of the world, remains poorly explored. In this context, we assessed the yield and biochemical profile of hitherto uninvestigated 14 fast-growing microalgae of eutrophic bloomed freshwaters of Kerala. The biomass yield, carbohydrate, protein, pigment and lipid content of these species were significantly different. The alga Pseudococcomyxa simplex showed the highest biomass yield of 196.5 ± 3.04% increase L−1 day−1. The alga Kirchnerialla lunaris with 58.95% protein was found superior to the other algae in this regard. The species Scenedesmus obliquus was significantly higher in total lipids (32.05% of dry biomass) than the other algae. The alga Monoraphidium griffithii with 42.92% of omega groups of fatty acids in its lipid appeared a highly valuable species. The algae, Radiococcus nimbatus (12.77 ± 2.31 mg g−1 of chlorophyll a), Myrmecia bisecta (5.87 ± 0.01 mg g−1 of chlorophyll b) and Monoraphidium griffithi (7.50 ± 0.02 mg g−1 carotenoid) appeared superior to the others in pigment content. Fourier-Transform-Infrared Spectroscopy of the biodiesel prepared from the lipids of all the algae confirmed the biodiesel feasibility of the same. The bioresource potentials of the 14 algal species revealed are new to science.

Biomass yield and biochemical profile of fourteen species of fast-growing green algae from eutrophic bloomed freshwaters of Kerala, South India

Genus Pyropia is one of the nutritionally rich marine algae. Among Indian Pyropia species, Pyropia acanthophora has been documented as a new addition with its new variety robusta. Biodiversity assessment revealed that P. acanthophora var. robusta reported only on the central west coast of India during monsoon (June to September). The nutritional composition of the collected samples was evaluated for proximate analysis along with vitamin C, dietary fiber, pigments, minerals, and fatty acid composition. The protein content was in the range of 14.11 ± 0.62 to 18.36 ± 0.90 g (100 g)−1 dry wt. Lipid content ranged from 1.65 ± 0.25 to 2.56 ± 0.40 g (100 g)−1 dry wt., and the concentrations of PUFA among these lipids were found in considerable quantity. Dietary fiber was also obtained in high concentration and ranged from 45.13 ± 1.30 to 63.0 ± 4.40 g (100 g)−1 dry wt. In this study, the level of K, Na, Mg, Fe, I, and P were appreciably high. Thus, the nutritional analysis of P. acanthophora var. robusta confirmed that it has potential to be used as an ingredient for nutritional supplements.

Monica Gajanan Kavale

Papers

Nutritional profiling of Pyropia acanthophora var. robusta (Bangiales, Rhodophyta) from Indian waters