Green extraction of proteins, umami and other free amino acids from brown macroalgae Ascophyllum nodosum and Fucus vesiculosus

Effects of different curing concentrations and drying times on the microbial community structure and metabolites of dried Spanish mackerel

Cured Spanish mackerel has a promising market owing to its nutritious nature as well as ease of transportation and preservation. However, the nutritional and flavor formation mechanism of Spanish mackerel after curing and drying is unclear. To overcome this problem, the effects of different processing conditions on the free amino acid, microbial community, and flavor of Spanish mackerel were explored. Staphylococcus and Cobetia are the main microorganisms in cured mackerel and are closely associated with the formation of their quality. Compared with fresh mackerel, cured mackerel contains increased levels of protein, fat, and chloride, contributing to its distinctive flavor. The contents of free amino acids in the BA64 group were substantially higher than those in other groups, particularly the contents of threonine, glycine, and tyrosine. These findings will contribute to the development of high-quality cured Spanish mackerel products and cured aquatic products.

Various extracts of the brown seaweed Cystoseira barbata with different compositions exert biostimulant effects on seedling growth of wheat

Worldwide, where the demand for novel and greener solutions for sustainable agricultural production is increasing, the use of eco-friendly products such as seaweed-derived biostimulants as pre-sowing treatment represent a promising and important approach for the future. Cystoseira barbata, a brown seaweed species abundant in the Mediterranean Region, was collected from the Marmara Sea and subjected to water, alkali, and acidic extractions, and the biostimulant activity of these extracts was tested on wheat (Triticum durum cv. Saricanak-98) using different rates through application to the seeds or germination medium (substrate) applications. The different extracts were characterized by mineral, total phenolic, free amino acid, mannitol, polysaccharide, antioxidant concentrations and hormone-like activity. The effects of the extracts on growth parameters, root morphology, esterase activity, and mineral nutrient concentrations of wheat seedlings were investigated. Our results suggest that the substrate application was more effective in enhancing the seedling performance compared to the seed treatment. High rates of seaweed extracts applied to substrates increased the shoot length and fresh weight of wheat seedlings by up to 20 and 25%, respectively. The substrate applications enhanced the root fresh weights of wheat seedlings by up to 25% when compared to control plants. Among the biostimulant extract applications, the water extract at the highest rate yielded the most promising results in terms of the measured parameters. Cystoseira barbata extracts with different compositions can be used as effective biostimulants to boost seedling growth. The local seaweed biomass affected by mucilage problems, has great potential as a bioeconomy resource and can contribute to sustainable practices for agriculture.

Ultrasound, microwave and enzyme-assisted multiproduct biorefinery of Ascophyllum nodosum

This study investigated the multiproduct (fucoidans, β-glucans, proteins, carotenoids, fatty acids, amino acids and polyphenols) valorization of the invasive macroalgae Ascophyllum nodosum within a green biorefinery concept using ultrasound (US), microwave (MW) treatment followed by supercritical CO2 (SC-CO2) with co-solvent and enzymatic extraction. Water and 50% aqueous ethanol were used as green extraction solvents. The extraction methods using 50% ethanol as extraction solvent improved the yields of phenolic compounds and glucan and enhanced in vitro antioxidant activity. The characterization of SC-CO2 extracts revealed that pretreatment with US and MW improved the 2-fold yield of carotenoids, total phenolics and fatty acids. However, US/MW pretreatment and enzymatic extraction did not improve the yields of proteins and free amino acids. Overall, using concurrent green US/MW-assisted extraction methods enhanced the yields of the bioactive compounds in a short duration and provided extracts with a better antioxidant capacity in the field of food applications.

Ascophyllum nodosum (Linnaeus) Le Jolis from Arctic: Its Biochemical Composition, Antiradical Potential, and Human Health Risk

Ascophyllum nodosum is a brown seaweed common in Arctic tidal waters. We have collected A. nodosum samples from the Barents Sea (BS), Irminger Sea (IS), and Norwegian Sea (NS) in different reproductive stages and have evaluated their biochemical composition, radical scavenging potential, and health risks. The total content of dominating carbohydrates (fucoidan, mannitol, alginate, and laminaran) ranged from 347 mg/g DW in NS to 528 mg/g DW in BS. The proportion of two main structural monosaccharides of fucoidan (fucose and xylose) differed significantly between the seas and reproductive phase, reaching a maximum at the fertile phase in the BS sample. Polyphenols and flavonoids totals were highest in NS A. nodosum samples and increased on average in the following order: BS < IS < NS. A positive correlation of free radical scavenging activity for seaweed extracts with polyphenols content was observed. The concentration of elements in A. nodosum from the Arctic seas region was in the following order: Ca > Mg > Sr > Fe > Al > Zn > As total > Rb > Mn > Ba > Cu > Co. Seaweeds from BS had the lowest metal pollution index (MPI) of 38.4. A. nodosum from IS had the highest MPI of 83. According to the calculated target hazard quotient (THQ) and hazard index (HI) values, Arctic A. nodosum samples pose no carcinogenic risk to adult and child health and are safe for regular consumption. Our results suggest that the Arctic A. nodosum has a remarkable potential for food and pharmaceutical industries as an underestimated source of polysaccharides, polyphenols, and flavonoids.

Sequential extraction of fucoidan, laminarin, mannitol, alginate and protein from brown macroalgae Ascophyllum nodosum and Fucus vesiculosus

The study involves development of a green biorefinery process for obtaining fucoidan, laminarin, mannitol, alginate and protein from dry and fresh Fucus vesiculosus and Ascophyllum nodosum using hydrochloric acid and a green extraction solvent. After the extraction of fucoidan which was the targeted biomolecule, an extract and by-product (residual biomass) were obtained. The extract was passed through an ultrafiltration membrane, where fucoidan was obtained in the ultrafiltration retentate while ultrafiltration permeate was analysed for laminarin and mannitol. The residual biomass was used for obtaining alginate using ultrasound (20 kHz, 64 % amplitude and 32 min, optimum parameters for alginate extraction based on our previous study). All the samples, showed good results for alginate, laminarin and mannitol, indicating that the by-products can be utilised using this green extraction process. The comparison of both dry and fresh seaweed is relevant from an industry perspective, as fresh seaweed can directly be used for extraction, avoiding drying which adds significantly to the cost of the process. Life cycle impact assessment of the complete seaweed value chain has been carried out to identify the energy demand and key environmental hotspots. This biorefinery process can be used by industry to improve their processes and utilise the by-products generated efficiently.

Seaweeds in Food: Current Trends

Edible seaweeds are an excellent source of macronutrients, micronutrients, and bioactive compounds, and they can be consumed raw or used as ingredients in food products. However, seaweeds may also bioaccumulate potentially hazardous compounds for human health and animals, namely, heavy metals. Hence, the purpose of this review is to analyze the recent trends of edible seaweeds research: (i) nutritional composition and bioactive compounds, (ii) the use and acceptability of seaweeds in foodstuffs, (iii) the bioaccumulation of heavy metals and microbial pathogens, and (iv) current trends in Chile for using seaweeds in food. In summary, while it is evident that seaweeds are consumed widely worldwide, more research is needed to characterize new types of edible seaweeds as well as their use as ingredients in the development of new food products. Additionally, more research is needed to maintain control of the presence of heavy metals to assure a safe product for consumers. Finally, the need to keep promoting the benefits of seaweed consumption is emphasized, adding value in the algae-based production chain, and promoting a social algal culture.

Slaughter performance of the main goose breeds raised commercially in China and nutritional value of the meats of the goose breeds: a systematic review

A number of goose breeds are raised commercially in China. However, the data on the slaughter performance of the goose breeds and the nutritional value of their meats lack a thorough comparative analysis. In this systematic review, the slaughter performance of the goose breeds and nutritional value of their meats were comparatively analyzed to provide an overview of the characteristics of the goose breeds raised commercially in China. Fifteen goose breeds were selected from 27 research articles published up to January 2022 on the slaughter performance of the goose breeds raised commercially in China and their nutrient composition after literature searching, literature screening, variety selection, and data collation. The slaughter indexes of the goose breeds and the basic nutrient composition, amino acid composition, and fatty acid composition of the meats of the goose breeds were standardized using min-max normalization and compared. The results suggest that the slaughter indexes and nutritional indicators of the meats of Yangzhou white goose, Xupu goose, Landaise geese, and Sichuan white goose are more balanced than those of the meats of the other goose breeds. The results of this review can lay the foundation for optimizing the breeding methods of the commercially raised goose breeds and processing methods of the meats of the geese. © 2022 Society of Chemical Industry.

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.

Ultrasonic-Assisted Extraction and Antioxidant Potential of Valuable Protein from Ulva rigida Macroalgae

Ulva green macroalgae or sea lettuce are rich sources of protein with nutritional benefits that promote health as a future plant-based functional ingredient in the food industry. Alkaline pretreatment improved ultrasonic-assisted protein extraction from Ulva rigida biomass. Parameters affecting ultrasonic-assisted extraction of protein were type of solvent, biomass-solvent ratio, biomass preparation and extraction cycle. In vitro digestibility was evaluated from oven- and freeze-dried biomass. Results showed highest concentration and extraction yield of protein from U. rigida using alkaline rather than acid and distilled water. A high biomass-solvent ratio at 1:10 or 0.1 g mL^-1 increased protein extraction. Higher alkaline concentration increased protein extraction. Highest protein extractability was 8.5% dry matter from freeze-dried U. rigida biomass, with highest protein extraction and antioxidant activity from extraction of U. rigida macroalgae at high alkaline concentrations. U. rigida macroalgae oven-dried biomass presented suitable human digestibility. Efficient pretreatment of U. rigida maximized protein hydrolysate and bioactive peptide production for wide-ranging applications.