Seaweed Products: Comparison
Please note this is a comparison between Version 1 by Laura Healy and Version 3 by Jessie Wu.

Seaweed, or, macroalgae, are a plant group of multicellular algae that have been exploited on a large-scale for the extraction of valuable functional food ingredients (primarily alginates, agar, and carrageenan). Seaweed is in the spotlight as a promising source of nutrition for humans as the search for sustainable food production systems continues. Seaweed has a well-documented rich nutritional profile containing compounds such as polyphenols, carotenoids and polysaccharides as well as proteins, fatty acids and minerals. Seaweed processing for the extraction of functional ingredients such as alginate, agar, and carrageenan is well-established. Novel pretreatments such as ultrasound assisted extraction or high-pressure processing can be incorporated to more efficiently extract these targeted ingredients. The scope of products that can be created using seaweed are wide ranging: from bread and noodles to yoghurt and milk and even as an ingredient to enhance the nutritional profile and stability of meat products. There are opportunities for food producers in this area to develop novel food products using seaweed.  

  • seaweed
  • protein
  • antioxidant

1. Introduction

The nutritional and functional properties of seaweed allow it to be examined for a range of food products for human consumption. Furthermore, foods enriched with seaweeds have added health benefits for the consumer, making them value-added products, and a very interesting area to study in new food product development. The unique properties of seaweeds can open up many possibilities for food product development with this focus in mind. For instance, seaweed can be used as a salt replacement in meat products. New product development is a key part of the business growth model of a company. Without it, the company is stagnant. As the market evolves, so too must the products and innovations to keep up with consumer demand.  Table 1 highlights the impact of adding seaweed to various food products such as noodles, bread, jelly, and meat products.

2. Seaweed Powder for Dough Products

Flour is a staple in many human diets worldwide, although its application and the source of raw materials (i.e., grain) vary greatly. Flour is produced by grinding a carbohydrate source (such as grains, roots, beans, nuts, or seeds) to make a fine powder. It may also be fractionated to obtain optimum particle size for incorporation into the dough.
Some nations already have a long-standing tradition of incorporating seaweed in breads. In Germany and Austria, a bread called algenbrot is made with a blend of cereals and up to 3% seaweed, while in Brittany, dulse and kombu variations are used to make Bara mor (“bread of the sea”) [1][147]. Bread consumption is widespread throughout all nations in some form or another, with over nine billion kg of bread produced in the world annually [2][148]. The inclusion of other ingredients into the dough is becoming more popular, as the demand for healthier bread increases. The addition of seaweed into bakery products such as bread dough not only improves the nutritional quality of the food product, it can also enhance the techno-functional properties of the bread. Mamat et al. (2013) reported that the addition of powder from the red seaweed species Kappaphycus alvarezii (at a rate of 2–8%) increased water absorption of the dough, decreased stickiness and showed improved firmness [3][64]. Such findings have implications for food producers as they are urged to look for more natural, sustainable methods of preserving and improving dough quality. Rico et al. (2018) developed novel flour ingredients to create value-added bread products using seven seaweed species for comparison with carob (a fruit used to produce locust bean gum for the food industry) byproducts for suitability of incorporation to dough [4][149]. They found that, while seaweed is a rich source of phenolic acids displaying antioxidant functionality, carob flour had a higher antioxidant activity than seaweed flours “probably associated with non-extractable phenolic compounds linked with fibre” of the seaweed [4][149]. For this reason, extraction processes as mentioned in Section 3 will be critical in ensuring seaweed is able to meet the requirements for incorporation into products like functional doughs.
Amoriello et al. (2021), found that the inclusion of a number of different algae sources had positive impacts on bread characteristics, however, they were dependent on the type of species and inclusion rate [5][150]. Seaweed inclusion had a darkening effect with a shift towards the green and blue spectrum [5][150]. Crumb porosity was improved by the addition of kombu (Laminariales spp.) and sea lettuce (Ulva spp.), as well as an improvement in the total soluble phenolic compounds, pigments, and antioxidant activity profile of the bread [5][150]. Inclusion of A. nodosum and C. crispus had a positive impact on the mineral profile and dietary fibre content of the end product when added to whole-wheat bread [6][73]. However, inclusion rates of 4% and 2% for the two species, respectively, were optimum due to adverse sensory impacts above these thresholds [6][73]. Other wheat-based products such as pasta showed an improved amino acid and fatty acid profile of the finished pasta product when Undaria pinnatifida was added to the recipe and was successful in passing the sensory screening when included at a rate of 10% [7][151].

3. Seaweed Snacks: Convenience Is Key to the Modern Consumer

Nutritionally, the addition of seaweed to extruded products (often thought of as unhealthy “snack” products) can enhance the overall profile of the product and promote the consumption of seaweed in everyday life [8][119]. The natural saltiness flavour profile of seaweed makes it a prime candidate as a salt alternative, with added benefits of the nutritional factors outlined in Section 2. When incorporated into a spice mix at a rate of up to 20%, the product had a high consumer acceptability, with an enhanced protein, fibre, and mineral content [9][146]. This saltiness profile makes it a suitable ingredient to incorporate into fermented products. Successful fermentation of kelp with lactic-acid bacteria was carried out and improved the phenolic content and antioxidant activity of the sauerkraut-like end products [10][152].
An opportunity to develop sweet or sweet–savory snacks in the Japanese market was identified by Kumar, 2021 #236, in an assessment on market demand and potential areas for exploitation by the food industry. This researchtudy also identifies creative ways to develop new products such as increasing the plant protein content of existing products to deliver a higher-protein product to the consumer within an established market space [11][153]. In this way, popular texture markets (crispy, dry snacks) are targeted, though with an innovative component (“environmentally sustainable ingredients”, “plant protein”, “natural”) [11][153]. Descriptive analysis (texture and flavour profiles) is key to gathering information on sensory preferences and help guide innovators towards the best markets for new product development.
Extrusion , as discussed in Section 3.3.1, is a method by which ingredients can be processed on a large-scale to make convenient snack foods. Extruded foods can “provide nutritious products and combine quality ingredients and nutrients” to make food products that are made up of exact proportions of each ingredient [12][154]. When included as an ingredient in a rye-based extruded snack, seaweed (Fucus vesiculosus) was found to have positive nutritional benefits to the food through the addition of natural antioxidants and improving the oxidative stability of the snack product [13][155]. The extrusion process did not impact the antioxidant activity of the seaweed within the snack end product [13][155]. The inclusion of seaweed in extruded snack products is a welcome innovation to fortify the product and increase its nutritional quality, thus improving the overall quality of the snack food [8][119]. However, inclusion rates of seaweed need to be carefully selected by manufacturers as increased rates (over 7.5%) are associated with a lowered acceptability score through sensory testing [8][119].

4. Seaweed as a Supplementation in Dairy Products

Seaweed extracts from A. nodosum and F. vesiculosus at low inclusion rates (<1%) were found to be stable in milk and improved the antioxidant activity (DPPH and FICA) of the product in varying degrees [14][145]. Historically, seaweed such as Chondus cripus, or carrageen moss, has been consumed by boiling in milk to create a jelly-like dessert [1][147]. dulse, duileasc (Gaelic), or P. palmata, was commonly consumed in Northern European countries alongside dishes of “dried fish and butter or with milk and bread” [1][147]. In Northern Ireland, dulse champ is a dish of mashed potatoes with milk, butter, and cooked dulse as seasoning [1][147]. As a thickening agent seaweed has been used in sauces and soups, with its inclusion in Indonesian cooking to enhance the thickening properties of coconut milk [15][156]. Today, carrageenan is a widespread ingredient in the food industry to make dairy gels [16][157] and to stabilize products such as ice cream [17][158]. As a plant source, carrageenan is a valuable alternative to gelatin for the vegan market. O’Sullivan et al. (2016) found that seaweed added to yoghurt had no impact on pH, microbiology, and whey separation of the yoghurt product and that some treatments experienced lower levels of lipid oxidation [18][159]. Seaweed can be used as an ingredient to create novel fermented milks, with results showing probiotic bacteria growth stimulation in milks with added seaweed (species dependent) [19][160]. Seaweed can be added to cheese as a means of enhancing end product nutritional parameters. In a study where 10 g of dried seaweed was added for every 1 kg of curd, there was a significantly higher rate of antioxidant activity (correlated with the phenolic profile of the seaweed) when compared with the control cheese [20][161]. Dry matter and pH value were affected by the inclusion of seaweed, however, microbiota was not significantly affected [20][161].

5. Seaweed for Meat and Fishery Products

Apart from textural, stabilizing, and gelling functional properties, as mentioned in previous sections, seaweed can offer other functions to food such as prepared seafood products. When included in fish surimi (an East Asian fish paste product), the edible green seaweed Ulva intestinalis has a positive impact by having a lower TBARS (thiobarbituric acid reactive substances, a measure of lipid peroxidation) value when compared with the control, showing a potential use in product quality and shelf-life extension [21][162].
Seaweed extracts were included in minced tilapia preservation as a natural alternative to synthetic preservatives and the resulting product successfully met regulatory quality standards including microbiological limits [22][163]. In canned salmon, seaweed was incorporated as a natural means of preserving the product [23][164]. Due to the natural antioxidants within the seaweed extracts, the addition of seaweed had some positive improvements to the salmon product such as a decrease in secondary peroxidation when compared to the control sample, a higher PUFA content, and lower oxidized odours with no impact on sensory quality parameters [23][164].
The demand for healthier meat products is increasing due to consumer demand for higher quality meat parameters, one of which is lower salt content. Seaweed can enhance the nutritional profile of meat by increasing the omega-3 content, decreasing the omega 6:omega 3 ratio and decreasing the TI (thrombogenic index), a measure used to determine the impact of food on heart health [24][165]. Meat products made with seaweed had improved sodium profiles as well as a better mineral profile (specifically for K, Ca, Mg, and Mn) and amino acid profile (serine, glycine, alanine, valine, tyrosine, phenylalanine, and arginine), depending on the species tested (wakame and sea spaghetti saw no significant impact on the amino acid profile of the meat product) [24][165]. Pork liver pâté was enhanced by the addition of seaweed, with an increase in protein content of 2–3%, and a similar degree of protection against oxidation when compared to a synthetic antioxidant compound (BHT or Butylated hydroxytoluene) [25][166]. Such results demonstrate the unique ability of seaweed to not only enhance the nutritional profile of food and they offer a natural preservation benefit through antioxidant activity. Seaweed can be used as an ingredient in other meat products such as patties and frankfurters as a means of reducing sodium and saturated fatty acid content of the products, while simultaneously adding minerals, omega-3 fatty acids, and polyphenols, therefore offering the consumer a healthier option than the original product [26][167].

6. Seaweed for Gluten-Free Products

Due to their hydrocolloid content and known functional properties, ase discussed in Section 2.3, seaweed can be used as a textural aid ingredient in gluten-free products. When added to a mixture of gluten-free pasta dough and compared with a gluten-free pasta control, the seaweed-containing pasta presented similar textural properties to the control, though with significantly higher fibre and mineral content [27][143]. The addition of K. alvarezii to a gluten-free pasta mixture was found to improve the overall quality of the pasta through an increased viscous elasticity, higher calcium and dietary fibre content, improved cooking properties, and greater consumer preference for gluten-free pasta when compared with a gluten-free control pasta [28][168].
Vestå, 2022 #585 reported that the inclusion of the seaweed hydrocolloid alginate in a gluten-free bread mixture was successful in terms of textural quality, however, consumer acceptability of the product was lower than control samples.

7. Seaweed Gastronomy

Japan is probably the most well-known seaweed-consuming nation in the world. However, many other countries and cultures have long-standing traditions with seaweed consumption. Island nations such as Ireland and Iceland have seaweed recipes that have been handed down through generations. Such records may see a revival in the coming years as Western countries seek a renewal of seaweed in their diet. Modern takes on traditional ingredients is a popular trend in the culinary industry, as was seen in a collaboration between Michelin-starred chef Koji Shimomura and scientist Hiroya Kawasaki who designed a new seaweed dish based on nutritional value and taste [29][169]. Rioux (2017) reviewed seaweeds as an ingredient to be utilized by the food industry as a traditional ingredient for a “new gastronomic sensation”, recognizing its potential to deliver valuable bioactive nutrients to the consumer, as well as using seaweed as “a vector of flavour and texture” [30][170]. Perhaps overlooked is the fact that seaweed is already a very common ingredient in our foods and many of us unknowingly consume it as an ingredient on a daily basis as a textural agent. Considering the large market size of these hydrocolloids, it is clear there is a lack of research in the area of the physicochemical properties of seaweed and its impact on gastronomy, and the potential applications in novel food innovation, as highlighted by Mourisen (2012) [31][171]. Here, the scope of seaweed and its use in gastronomy is reviewed, as well as the “unexplored” areas of potential research, such as an assessment of the biophysical properties of omega-3 fatty acids found in seaweed or the definition of the physics of the taste sensory system stimulated by glutamate present in seaweed [31][171]. As discussed, seaweeds are exploited for a number of physicochemical properties to enhance a wide range of food and other ingredients. Molecular gastronomy is a branch of the food industry which focuses on applying scientific principles to produce innovative products or dishes [32][172]. Examples of seaweed in molecular gastronomy include the use of alginate to produce spherical features with thin membranes enclosing a liquid or agar to make “spaghetti” or “caviar” type gels [33][173].

8. Nonfood Seaweed Products

8.1. Smart Packaging—Technologies to Produce Sustainable, Green Packaging Solutions

As the consumer becomes more environmentally conscious, pressure is put on supermarket retailers to make more sustainable choices when sourcing suppliers to stock in their shops. This not only relates to the sustainability of the food products themselves but perhaps as importantly, to the packaging they come in as well. Proper packaging is a crucial part of the food production system as it allows for extended shelf life and a convenience of handling for both the consumer and supply chain logistics personnel. However, an unfortunate byproduct of this system is the build-up of enormous amounts of packaging waste, most of which is plastic-based. To combat this, recycling is encouraged, however, ultimately, biodegradable or biobased alternatives need to be developed to replace plastic waste. The difference between biodegradable and biobased plastics is the source from which they are manufactured [34][174]. Carina et al. (2021) described biodegradable polymers as being made from “natural and fossil resources” while biobased plastics are made up of 100% extracts “from plants, marine organisms or produced by microorganisms through fermentation” [34][174]. Smart—or active—packaging is defined by Carina et al. (2021) as “a system in which product, packaging and environment interact in a positive way to extend the shelf life, improve the safety as well as the sensory properties and maintain the quality of the product” [34][174].
There are a number of different types of active components in packaging such as oxygen scavengers, carbon dioxide emitters, antimicrobial agents, moisture control, odour absorbance and ethylene scavengers [34][174]. The use of such chemicals in the packaging in direct contact with food for human consumption could be a cause for concern due to the potential toxicity of these agents or the nanocomposites [35][36][37][38][39][40][175,176,177,178,179,180]. As a result, there is interest in developing natural compounds for such a purpose that would be safe to consume by humans.
Polysaccharides extracted from seaweeds are being proposed as valuable sources of such novel packaging [34][174]. Seaweed polysaccharides have a range of well-studied functional properties such as antioxidant activity, antimicrobial activity, photoprotective activity [41][181], and thickening, gelling and stabilizing properties [42][6] that increase its potential as a novel, sustainable packaging source. Furthermore, its antimicrobial properties, such as those in H. elongate have been shown to inhibit the growth of gram-positive and gram-negative bacteria, giving it added value for use as a protective packaging material and thus extending shelf life [34][174]. Doh et al. (2020) developed seaweed nanocomposite films from two brown seaweed species, Lamianria japonica and Sargassum natans [43][182]. When reinforced with CNCs (cellulose nanocrystals) extracted from the seaweeds, the tensile strength of the films, as well as the water, oxygen and light barrier properties were significantly improved when compared with the films without CNCs [43][182].

8.2. Seaweed in Cosmetics

Mycosporine-like amino acids are a group of secondary metabolites found in seaweeds, fungi, and microorganisms like cyanobacteria and microalgae [44][183]. These antioxidant, UV-absorbing molecules are produced in seaweeds when exposed to high levels of UV-A and UV-B [45][184]. Lawrence et al. (2018) evaluated that palythine, an MAA extracted from seaweed, was protective against UV while also offering antioxidant benefits, even when added after sun exposure [46][185]. As a natural active ingredient, seaweed is a valuable ingredient for skincare products such as face masks, where the seaweed also offers the technical ability to form a “thermos-reversible gel that can stabilize the mask preparation” [47][186]. Sulfated polysaccharides extracted from Ecklonia maxima were found to reduce the impact of skin damage, as well as inhibit wrinkle-related enzymes and improve collagen synthesis (when tested on UVB-irradiated human dermal fibroblasts) [48][187]. The researchers determined that the polysaccharides tested have a strong potential to be used in antimelanogenesis and photoprotective activities, and should be targeted as an ideal ingredient for the cosmetic industry [48][187].