**5. Alginates as valuable resource**

Alginates are used in the food, cosmetic, paper, agricultural, pharmaceutical, and biomedical industries and in other various industries; some are now starting to apply the alginates. The alginates overall are the main seaweed polymer, in terms of quantities, used by industry. There are different purity classes of alginates ready to apply for different uses; with that, the price of alginates varies according to the purity state and applications on the industry. For instance, the alimentary grade sodium alginate is priced at USD 6.5 and 11.0/kg, while pharmaceutical grade is valued at USD 13 and 15.5/kg. In Asia, more specifically in the Korean peninsula and in Japan, *Saccharina japonica* (formerly *Laminaria japonica*) has a big demand which resulted in a higher price, which resulted in the introduction of buying alginates from other countries [16]. Alginate market is expected to grow annually between 2 and 3%. The uses of alginate in the industry, such as textile printing, account for nearly half of the global market. On the biomedical, medical, and pharmaceutical industries, it has an implication of nearly 20% of the global market, and it is expected to grow between 2 and 4% in the global market, lying on the applications of alginic acid derivatives in wound healing and regular basis innovations and developments in controlled-release technologies. Paper industry only reports to nearly 5% of the global market [17].

Alginates are mainly used as thickeners and stabilizers in the food, pharmaceutical, and cosmetic industries, because they are easy to use, has a low cost, are well tolerated in the human, and can be easily modified for determined objective and in the different fields.

Today, the global seaweed industry is worth more than USD 6 billion per annum (approximately 12 million tons per annum in volume) of which 85% is in the food area for human consumption. Seaweed-derived polysaccharides (carrageenan, agar, and alginates) make up almost 40% of the world's hydrocolloid market [18].

The global alginate market size was valued at USD 624.0 million in 2016. The demand for alginates in the food industry will be increasing by consumption of frozen desserts, ice creams, beer, and yogurt; with that, it is anticipated to push a salient market growth of alginate value and use.

The application of the alginates in the food industry is permitted and regulated by the major regulatory agencies including the FDA and European Commission, which stimulates the high interest in alginate. The increasing of food industry in Asia, due to the growth in habitants, is expected to run a higher demand of alginate in that area. Therefore, this alginates-based products acceptance by the manufacturing industries is expected to growth, such as biomedical industry and its high demand for alginate with high quality. The product is mainly used in the

**7**

*Introductory Chapter: Alginates - A General Overview DOI: http://dx.doi.org/10.5772/intechopen.88381*

superior product performance [19].

North Atlantic Area and China).

**5.1 Agricultural applications**

high viscosity or high gel strength [20].

water retention, which is a basic soil property.

tion against pathogens or insect damage [26].

can upsurge the water-retention capacity in such soils.

pharmaceutical industry for the production of controlled-release drugs due to

Corporations in the market devote to the investigation and development of new advanced product grades to captivate costumers. Extraordinary financing by national governments and alginate industries on route to the growth of seaweed processing is predicted to help the alginate-based industry's expansion and success. Nevertheless, such high search for alginate can have as outcome a limited raw material availability, and the alginate industry is now evaluating the production of alginate with seaweeds of aquaculture (mainly offshore, at this moment in the

There is a large market for any brown seaweed that has an alginate of medium to

Alginate present in the brown algae (in the form of alginic acid) constituted a functional element of the traditional fertilizers, allowing the water retention in the soils. So, the principal function of alginate on agricultural area was as a soil conditioner. Being a superabsorbent (SAP) or water-retaining material is an advantage of alginate. They are natural materials that can absorb large amounts of water, as much as hundreds of times their own mass. These alginates are generally known in agriculture as nonionic or ionic moisture-holding hydrogels for increasing soil

The reservation of moisture or water in the soil is the major process consequence in which all plantations depend. The large pore spaces in arenaceous soils restrain the soil from holding water, and the soil dries out regularly, and precious nutrients wash away past the plant roots. The inclusion of alginate can solve the lack of retention of water and raise nutrient disponibility. High-capacity absorbents definitely

Superabsorbents (SAP) in agricultural areas have been designed and developed to provoke an enrichment of the abiotic properties of soil by rising their water-retention ability, developing a better water usage efficiency, enhancing soil permeability and infiltration rates, contributing to lower the irrigation frequency, lowering the compaction shift, preventing erosion and water drainage, enhancing plant performance, increasing soil aeration, lowering the dissolution of fertilizers, developing a better adsorption capacity or enhancing the uptake of some nutrient elements by the plants, and provoking a raise of the microbial activity [21].

The alginate of seaweed directly suppresses the pathogens [22]. Indeed, alginate pellets developed as carrier material for biocontrol agents have been reported to reduce multiplication of *Rhizoctonia* (fungi) disease in potato [23], while incorporation of *Ascophyllum nodosum* extract into the planting medium caused delay and reduced incidence of *Verticillium* (fungi) wilt of pepper plants [24]. Therefore, it's proven that alginates are involved in host defense mechanisms [25]. Of particular interest in agriculture are those that elicit defensive responses resulting in protec-

In other cases, the alginate will have other particular function, as the main characteristic of alginate as product principal emulsifier and to delivery control of actives ingredients in agricultural field. The active ingredient is mixed with alginates for their safer, easier, and more accurate handling as well as for their effective application in the field and, at the same time, preventing the immediate release of the active ingredient, so the main drawback associated with these formulations can be avoided. These alginate-based systems are able to deliver the active ingredient gradually for a long period of time in a specified target with

*Alginates - Recent Uses of This Natural Polymer*

constituents of alginate [13].

**5. Alginates as valuable resource**

nearly 5% of the global market [17].

salient market growth of alginate value and use.

the different fields.

loid market [18].

The extraction of alginate is done by mild acid treatments that remove undesirable compounds (normally, hydrochloric acid) and modify the cell wall alginate into alginic acid to obtain the best extract efficacy because the intercellular mucilage has been regarded as the principal site of alginic acid [15]. The alginic acid is recovered as a soluble sodium form by neutralizing with sodium carbonate or sodium hydroxide. The insoluble residue is removed by filtration, flotation, or centrifugation, and the soluble alginate is precipitated by conversion into alginic acid or calcium/sodium alginate. The alginic acid is then converted into the required counter ion by neutralization with appropriate hydroxides or chlorites. The difference in the alginate recovery process depends on the source and structure of

Alginates are used in the food, cosmetic, paper, agricultural, pharmaceutical, and biomedical industries and in other various industries; some are now starting to apply the alginates. The alginates overall are the main seaweed polymer, in terms of quantities, used by industry. There are different purity classes of alginates ready to apply for different uses; with that, the price of alginates varies according to the purity state and applications on the industry. For instance, the alimentary grade sodium alginate is priced at USD 6.5 and 11.0/kg, while pharmaceutical grade is valued at USD 13 and 15.5/kg. In Asia, more specifically in the Korean peninsula and in Japan, *Saccharina japonica* (formerly *Laminaria japonica*) has a big demand which resulted in a higher price, which resulted in the introduction of buying alginates from other countries [16]. Alginate market is expected to grow annually between 2 and 3%. The uses of alginate in the industry, such as textile printing, account for nearly half of the global market. On the biomedical, medical, and pharmaceutical industries, it has an implication of nearly 20% of the global market, and it is expected to grow between 2 and 4% in the global market, lying on the applications of alginic acid derivatives in wound healing and regular basis innovations and developments in controlled-release technologies. Paper industry only reports to

Alginates are mainly used as thickeners and stabilizers in the food, pharmaceutical, and cosmetic industries, because they are easy to use, has a low cost, are well tolerated in the human, and can be easily modified for determined objective and in

Today, the global seaweed industry is worth more than USD 6 billion per annum (approximately 12 million tons per annum in volume) of which 85% is in the food area for human consumption. Seaweed-derived polysaccharides (carrageenan, agar, and alginates) make up almost 40% of the world's hydrocol-

The global alginate market size was valued at USD 624.0 million in 2016. The demand for alginates in the food industry will be increasing by consumption of frozen desserts, ice creams, beer, and yogurt; with that, it is anticipated to push a

The application of the alginates in the food industry is permitted and regulated by the major regulatory agencies including the FDA and European Commission, which stimulates the high interest in alginate. The increasing of food industry in Asia, due to the growth in habitants, is expected to run a higher demand of alginate in that area. Therefore, this alginates-based products acceptance by the manufacturing industries is expected to growth, such as biomedical industry and its high demand for alginate with high quality. The product is mainly used in the

**6**

pharmaceutical industry for the production of controlled-release drugs due to superior product performance [19].

Corporations in the market devote to the investigation and development of new advanced product grades to captivate costumers. Extraordinary financing by national governments and alginate industries on route to the growth of seaweed processing is predicted to help the alginate-based industry's expansion and success. Nevertheless, such high search for alginate can have as outcome a limited raw material availability, and the alginate industry is now evaluating the production of alginate with seaweeds of aquaculture (mainly offshore, at this moment in the North Atlantic Area and China).

There is a large market for any brown seaweed that has an alginate of medium to high viscosity or high gel strength [20].

## **5.1 Agricultural applications**

Alginate present in the brown algae (in the form of alginic acid) constituted a functional element of the traditional fertilizers, allowing the water retention in the soils. So, the principal function of alginate on agricultural area was as a soil conditioner. Being a superabsorbent (SAP) or water-retaining material is an advantage of alginate. They are natural materials that can absorb large amounts of water, as much as hundreds of times their own mass. These alginates are generally known in agriculture as nonionic or ionic moisture-holding hydrogels for increasing soil water retention, which is a basic soil property.

The reservation of moisture or water in the soil is the major process consequence in which all plantations depend. The large pore spaces in arenaceous soils restrain the soil from holding water, and the soil dries out regularly, and precious nutrients wash away past the plant roots. The inclusion of alginate can solve the lack of retention of water and raise nutrient disponibility. High-capacity absorbents definitely can upsurge the water-retention capacity in such soils.

Superabsorbents (SAP) in agricultural areas have been designed and developed to provoke an enrichment of the abiotic properties of soil by rising their water-retention ability, developing a better water usage efficiency, enhancing soil permeability and infiltration rates, contributing to lower the irrigation frequency, lowering the compaction shift, preventing erosion and water drainage, enhancing plant performance, increasing soil aeration, lowering the dissolution of fertilizers, developing a better adsorption capacity or enhancing the uptake of some nutrient elements by the plants, and provoking a raise of the microbial activity [21].

The alginate of seaweed directly suppresses the pathogens [22]. Indeed, alginate pellets developed as carrier material for biocontrol agents have been reported to reduce multiplication of *Rhizoctonia* (fungi) disease in potato [23], while incorporation of *Ascophyllum nodosum* extract into the planting medium caused delay and reduced incidence of *Verticillium* (fungi) wilt of pepper plants [24]. Therefore, it's proven that alginates are involved in host defense mechanisms [25]. Of particular interest in agriculture are those that elicit defensive responses resulting in protection against pathogens or insect damage [26].

In other cases, the alginate will have other particular function, as the main characteristic of alginate as product principal emulsifier and to delivery control of actives ingredients in agricultural field. The active ingredient is mixed with alginates for their safer, easier, and more accurate handling as well as for their effective application in the field and, at the same time, preventing the immediate release of the active ingredient, so the main drawback associated with these formulations can be avoided. These alginate-based systems are able to deliver the active ingredient gradually for a long period of time in a specified target with

a desired rate [27–29]. The controlled-release systems do not release the active ingredient at once; this technique therefore lowers the pesticide residues in soil and thus reduces the direct effect of pesticide. After their degradation, these are helpful as compost in the field [30].

Alginate is also used as an inoculant carrier for plant growth-promoting bacteria [31, 32] and for bacteria with biodegradation ability [33].

#### **5.2 Biomedical applications**

The conventional role of alginate in the biomedical area includes being used as thickening, gel-forming, and stabilizing agents, as alginate can play a significant role in controlled-release drug products. But the main use of alginate in the biomedical area is actually in hydrogel form, used in the wound healing [34], drug delivery, and tissue engineering applications. Alginate hydrogels are biocompatible and structurally identical to the macromolecular-based components in the human body and can regularly be convoyed into the body by minor invasive techniques of administration to the select human body [35].

In this area, there is a need that the alginate used and tested is pure as maximum as possible, because the impurities will compromise the biocompatibility of the biomaterial with alginate [36].

The utmost captivating characteristics of alginate for the biomedical applications involve the natural biocompatibility, mild gelation conditions, and easy adaptation to assemble alginate derivatives with new properties and characteristics. Alginate has a safe clinical sheet for biomedical applications as a wound dressing material and pharmaceutical component and has been harmlessly inserted in a wide range of utilizations.

The conception of new biomaterials is centralized on the resemblance in the functions of the extracellular matrices of body tissues, as these can manage the host feedback/responses in an accurate behavior, and materials derived from natural sources have gained a lot of interest, mainly because of their inherent biocompatibility. At this moment, alginate and its derivatives are one of the best chemically known biopolymers in the world, and it has been extensively investigated and used for many biomedical applications, due to its biocompatibility, low toxicity, relatively low cost, and mild gelation by addition of divalent cations such as Ca2+ [37].

The great challenge in this area is complementing the physical feature of alginate gels with specific use in a precise utilization. Taking in consideration the great range of different possible cross-linking approaches, employing molecules with diversified chemical structures, molecular weights, and cross-linking capabilities will usually turnout gels applicable for specifics different types of application [36].

Alginate-based wound dressings keep the physiologically humid microenvironment, lowering the risks of a bacterial infection at the wound location and promoting an easy wound healing. Drug compounds, from small chemical drugs to macromolecular proteins, can be liberated from alginate gels in a skillful way, revolving around in the cross-links types and cross-linking methodology applied.

The therapy of acute and chronic wounds is a major need in various areas of medicine, and alginate-based wound dressings have various beneficial properties. Traditional wound dressings, such as gauze, provide principally a good barrier property—maintaining the wound dry by granting the evaporation of wound exudates and preventing the passage of pathogens into the wound [38]. In the opposite way, the modern dressings, likewise the alginate dressings, contribute to a moist wound environment and aid an easy wound healing [39].

New wound dressing types with alginate that are more functional and bioactive have been studied and developed up to this date.

**9**

chitin [48].

*Introductory Chapter: Alginates - A General Overview DOI: http://dx.doi.org/10.5772/intechopen.88381*

tissue [41].

hypothesis in these strategies.

of alginate into the body [36].

from the body with 100% efficiency [47].

degradation rate of the gels [50].

Alginate gels are additionally an excellent compound for cell transplantation in the tissue engineering area. The main objective of tissue engineering was to develop and produce man-made tissue and organ replacements for patients who suffer the loss or failure of an organ or tissue [40]. In this field, hydrogels are used to deliver cells to the specific location, providing an area for new tissue formation and, moreover, controlling the structure and function of the engineered

Even with recent developments in the area, the treatment of bone injuries is restricting because of the poor healing and complex bone healing system. In this case, alginate gels have been tested with success in bone regeneration by delivery of

Alginate gels have been described to be effective for transplanting chondrogenic

Alginate gels are also being actively investigated for their ability to mediate the regeneration and engineering of a variety of other tissues and organs, including skeletal muscle, nerve, the pancreas, and the liver. Actual plans for skeletal muscle regeneration involve the cell transplantation, growth factor delivery, or a combination of both approaches [44, 45], and alginate gels have been described as potential

Alginate derivatives containing cell-adhesive peptides have been gaining significant attraction in the last years. These derivatives are normally prepared by chemically including peptides as side chains, applying carbodiimide chemistry to connect via the carboxylic groups of the sugar residues. Considering that alginate intrinsically do not have mammalian cell adhesiveness, pertinent ligands are essential to develop and manage cellular interactions, principally for cell culture [36].With that, the alginate gels are now being utilized much more as a model system for mammalian cell culture in this field. And one of the advantages is that the gels can be

The absence of mammalian cell receptors joined with the low protein adsorption to the gels enables the utilization of these materials in many ways as an ideal blank slate, with highly specific and quantitative modes for cell adhesion that can be incorporated. Also development demonstrated with in vitro studies can be readily translated in vivo, because of the inherent biocompatibility and easy introduction

Alginate hydrogels have been widely investigated to date in many drug delivery applications, due to their adjustable swelling properties in response to temperature changes, leading to on-demand modulation of drug release from the gels [46].

Alginate is a nondegradable material in mammals, as the mammals do not have enzymes (i.e., alginase) that can break the alginate chains, but ionically cross-linked alginate-base gels can be disassociated by release of the divalent ions cross-linking the gel into the surrounding media. Despite the gel dissolution, the average molecular weights of many commercially available alginates are higher than the renal clearance threshold of the kidneys, and presumably dissolved alginate isn't removed

Alginate has also been greatly explored in plenty drug delivery systems merged with chitosan, and this blend forms ionic complexes. Chitosan is a derivative of

Alginate is an attractive and exceptional contender for the protein drug delivery systems, considering that alginate-based materials/gels can incorporate proteins [49, 50]. The delivery in this scenario can be easily exploited by modifying the

Also, alginate can serve as an agent against heavy metal poisoning, and it is proven that it can be an effective coadjuvant in the case of food poisoning [51].

osteoinductive factors, bone-forming cells, or a mixture of both [42].

adapted to 2D or more physiologically relevant 3D culture systems.

cells to recover damaged cartilage in animal models [43].

*Alginates - Recent Uses of This Natural Polymer*

helpful as compost in the field [30].

**5.2 Biomedical applications**

biomaterial with alginate [36].

range of utilizations.

[31, 32] and for bacteria with biodegradation ability [33].

administration to the select human body [35].

wound environment and aid an easy wound healing [39].

have been studied and developed up to this date.

New wound dressing types with alginate that are more functional and bioactive

a desired rate [27–29]. The controlled-release systems do not release the active ingredient at once; this technique therefore lowers the pesticide residues in soil and thus reduces the direct effect of pesticide. After their degradation, these are

Alginate is also used as an inoculant carrier for plant growth-promoting bacteria

The conventional role of alginate in the biomedical area includes being used as thickening, gel-forming, and stabilizing agents, as alginate can play a significant role in controlled-release drug products. But the main use of alginate in the biomedical area is actually in hydrogel form, used in the wound healing [34], drug delivery, and tissue engineering applications. Alginate hydrogels are biocompatible and structurally identical to the macromolecular-based components in the human body and can regularly be convoyed into the body by minor invasive techniques of

In this area, there is a need that the alginate used and tested is pure as maximum

as possible, because the impurities will compromise the biocompatibility of the

The utmost captivating characteristics of alginate for the biomedical applications involve the natural biocompatibility, mild gelation conditions, and easy adaptation to assemble alginate derivatives with new properties and characteristics. Alginate has a safe clinical sheet for biomedical applications as a wound dressing material and pharmaceutical component and has been harmlessly inserted in a wide

The conception of new biomaterials is centralized on the resemblance in the functions of the extracellular matrices of body tissues, as these can manage the host feedback/responses in an accurate behavior, and materials derived from natural sources have gained a lot of interest, mainly because of their inherent biocompatibility. At this moment, alginate and its derivatives are one of the best chemically known biopolymers in the world, and it has been extensively investigated and used for many biomedical applications, due to its biocompatibility, low toxicity, relatively low cost, and mild gelation by addition of divalent cations such as Ca2+ [37]. The great challenge in this area is complementing the physical feature of alginate gels with specific use in a precise utilization. Taking in consideration the great range of different possible cross-linking approaches, employing molecules with diversified chemical structures, molecular weights, and cross-linking capabilities will usually turnout gels applicable for specifics different types of application [36]. Alginate-based wound dressings keep the physiologically humid microenvironment, lowering the risks of a bacterial infection at the wound location and promoting an easy wound healing. Drug compounds, from small chemical drugs to macromolecular proteins, can be liberated from alginate gels in a skillful way, revolving around in the cross-links types and cross-linking methodology applied. The therapy of acute and chronic wounds is a major need in various areas of medicine, and alginate-based wound dressings have various beneficial properties. Traditional wound dressings, such as gauze, provide principally a good barrier property—maintaining the wound dry by granting the evaporation of wound exudates and preventing the passage of pathogens into the wound [38]. In the opposite way, the modern dressings, likewise the alginate dressings, contribute to a moist

**8**

Alginate gels are additionally an excellent compound for cell transplantation in the tissue engineering area. The main objective of tissue engineering was to develop and produce man-made tissue and organ replacements for patients who suffer the loss or failure of an organ or tissue [40]. In this field, hydrogels are used to deliver cells to the specific location, providing an area for new tissue formation and, moreover, controlling the structure and function of the engineered tissue [41].

Even with recent developments in the area, the treatment of bone injuries is restricting because of the poor healing and complex bone healing system. In this case, alginate gels have been tested with success in bone regeneration by delivery of osteoinductive factors, bone-forming cells, or a mixture of both [42].

Alginate gels have been described to be effective for transplanting chondrogenic cells to recover damaged cartilage in animal models [43].

Alginate gels are also being actively investigated for their ability to mediate the regeneration and engineering of a variety of other tissues and organs, including skeletal muscle, nerve, the pancreas, and the liver. Actual plans for skeletal muscle regeneration involve the cell transplantation, growth factor delivery, or a combination of both approaches [44, 45], and alginate gels have been described as potential hypothesis in these strategies.

Alginate derivatives containing cell-adhesive peptides have been gaining significant attraction in the last years. These derivatives are normally prepared by chemically including peptides as side chains, applying carbodiimide chemistry to connect via the carboxylic groups of the sugar residues. Considering that alginate intrinsically do not have mammalian cell adhesiveness, pertinent ligands are essential to develop and manage cellular interactions, principally for cell culture [36].With that, the alginate gels are now being utilized much more as a model system for mammalian cell culture in this field. And one of the advantages is that the gels can be adapted to 2D or more physiologically relevant 3D culture systems.

The absence of mammalian cell receptors joined with the low protein adsorption to the gels enables the utilization of these materials in many ways as an ideal blank slate, with highly specific and quantitative modes for cell adhesion that can be incorporated. Also development demonstrated with in vitro studies can be readily translated in vivo, because of the inherent biocompatibility and easy introduction of alginate into the body [36].

Alginate hydrogels have been widely investigated to date in many drug delivery applications, due to their adjustable swelling properties in response to temperature changes, leading to on-demand modulation of drug release from the gels [46].

Alginate is a nondegradable material in mammals, as the mammals do not have enzymes (i.e., alginase) that can break the alginate chains, but ionically cross-linked alginate-base gels can be disassociated by release of the divalent ions cross-linking the gel into the surrounding media. Despite the gel dissolution, the average molecular weights of many commercially available alginates are higher than the renal clearance threshold of the kidneys, and presumably dissolved alginate isn't removed from the body with 100% efficiency [47].

Alginate has also been greatly explored in plenty drug delivery systems merged with chitosan, and this blend forms ionic complexes. Chitosan is a derivative of chitin [48].

Alginate is an attractive and exceptional contender for the protein drug delivery systems, considering that alginate-based materials/gels can incorporate proteins [49, 50]. The delivery in this scenario can be easily exploited by modifying the degradation rate of the gels [50].

Also, alginate can serve as an agent against heavy metal poisoning, and it is proven that it can be an effective coadjuvant in the case of food poisoning [51].

On the medical side, there has been an increment of interest to use alginate as a pharmaceutical ingredient to treat some diseases or health problems:

Diabetes—This bioactivity is related to the hypoglycemic activity from alginate [52].

Cholesterol—The alginate on the assay in article [52] with rats provides interesting results, with cholesterol excretion from the rats and hypocholesterolemic effect from alginate.

Obesity—The capacity of alginate to swell and so occupy space on the stomach of the patient provides a satiety effect which can help people lose weight and provide a management tool for the medical personnel [53];

Digestive tract problems—The alginate is used as dietary fiber and can regulate the intestinal tract.

#### **5.3 Bioremediation applications**

Environmental bioremediation is a profitable and promising technology, which can lead to complete mineralization of organic pollution. Bioaugmentation (introduction of selected microorganisms to supplement indigenous populations) is one of the bioremediation approaches [54]. Entrapment in alginate gel is a widely used approach for immobilization of microorganisms to improve their viability (**Figure 1f**) [55].

Alginate is a natural chelating agent and a bio-adsorbent of heavy metals in aqueous solution; it has high affinity and binding capacity for metal ions and, thus, is widely used as a heavy metal adsorbent for environmental protection [56]. Alginate-clay composites are suitable for environmental remediation as sorbents of heavy metals [57] and persistent organic pollutants [58].

#### **5.4 Cosmetic applications**

Alginates are an omnipresent ingredient of cosmetics. They usually are utilized as emulsifiers, consistency enhancers, and thickening agents in cosmetic formulas, forming a moisture-retaining surface film. They can have some kind of active effect, such as skin protection, because they retain water and maintain the skin rehydrated [59].

Alginates are water-insoluble; however, they can swell, as mentioned before. Thus, they are like hyaluronic acid, so they can absorb more water as much as several hundreds of times its weight.

They are used in hand jellies and lotions, ointment bases, pomades and other similar preparations, greaseless creams, dentifrices, and other products that became more green and environmentally friendly [60, 61].

Alginate has also been described as an anti-oxidative agent and can be applied to prevent skin aging and cutaneous disorders. Additionally, antioxidants can help to maintain the organoleptic properties of cosmetic products by inhibiting lipid oxidation, thus avoiding changes in appearance, odor, and flavor [62].

#### **5.5 Food applications**

Alginates are commonly used in the food industry as natural additives; they have codes from the European Union as food additives, and these codes vary with the ion type associated with alginic acid [15, 63].

European codes for alginates are as follows: alginic acid, E400; sodium alginate, E401; potassium alginate, E402; ammonium alginate, E403; calcium alginate, E404; and propylene glycol alginate, E405.

**11**

*Introductory Chapter: Alginates - A General Overview DOI: http://dx.doi.org/10.5772/intechopen.88381*

intake by human, and preventing obesity [53].

**5.6 Dental medicine applications**

cuts, in a single-step methodology.

ture, as with reversible hydrocolloids [64].

the shelf life of packed food products [56].

**5.7 Other areas of alginate application**

from renewable natural resources.

obtained with high gloss inks.

the structure of food.

conditions [63].

status.

of undercuts.

Seaweed polysaccharide applications in food industries are based mainly on their stabilizing, emulsifying, and gel-forming ability. They are widely used as food additives in jams, jellies, ice creams, dairy products, etc., to improve and stabilize

Water-in-oil emulsions likewise the mayonnaise and the salad fillings are less liable to fractionate toward their original oil and water phases if thickened with alginate. When the emulsion is acidic, the sodium alginate will precipitate into insoluble alginic acid forms; to resolve this problem, propylene glycol alginate (PGA) is used for acidic emulsions, because this compound is stable in mild acid

The advantage of alginate in the food industry is that humans do not have enzymes to break the molecule; therefore, alginate behaves as a dietary fiber, enhancing the satiety and reducing the food intake of humans, lowering the energy

Hydrocolloids were the first elastic materials to be used in the dental field, and their results are fundamental to form a first "idea" about the patient's oral health

The alginate is used as irreversible footprint compound to emulate a footprint faithfully, giving details in a high-definition footprint although there is an existence

The main alginate advantages are the fact that they are low cost, do not react adversely on the patient, and can be easily manipulated and that the technique can be performed within a short period of time and has simple execution, lack of instrumentation, and high-definition footprint, even with the presence of under-

Alginate picking reaction is a chemical reaction of irreversible precipitation; therefore they cannot return in soluble form using physical means, such as tempera-

Packaging dominates the waste generated from plastics. Since the European Union synthetic plastic ban, alginate is one of the most suitable alternatives to fabricate packaging material due to their nontoxicity, biodegradability, and derivability

With the bibliography analysis, it can be resumed that additives such as nonmaterial and antimicrobial compounds can improve various characteristics of the films and the packaging with antimicrobial activity is highly desirable in films to improve

In textile printing, alginates are used as thickeners for the paste containing the dye. These pastes may be applied to the fabric by the use of either screen or roller printing equipment. These combine chemically with cellulose in the fabric. Alginates don't interact with the dyes; also they can be washed out of the finalized textile and are considered the first-rate thickeners to the reactive dyes [20]. The principal alginate application in the paper industry is in surface sizing. Alginate is mixed with starch sizing giving a smooth uninterrupted film and a surface with less fluffing. The oil resistance derivate from alginate films allows a size with improved greaseproof and oil-resistant properties. This can enhance the gloss

*Alginates - Recent Uses of This Natural Polymer*

alginate [52].

from alginate.

the intestinal tract.

(**Figure 1f**) [55].

**5.4 Cosmetic applications**

**5.5 Food applications**

several hundreds of times its weight.

type associated with alginic acid [15, 63].

and propylene glycol alginate, E405.

more green and environmentally friendly [60, 61].

tion, thus avoiding changes in appearance, odor, and flavor [62].

**5.3 Bioremediation applications**

On the medical side, there has been an increment of interest to use alginate as a

Cholesterol—The alginate on the assay in article [52] with rats provides interesting results, with cholesterol excretion from the rats and hypocholesterolemic effect

Obesity—The capacity of alginate to swell and so occupy space on the stomach

Digestive tract problems—The alginate is used as dietary fiber and can regulate

Diabetes—This bioactivity is related to the hypoglycemic activity from

of the patient provides a satiety effect which can help people lose weight and

Environmental bioremediation is a profitable and promising technology, which can lead to complete mineralization of organic pollution. Bioaugmentation (introduction of selected microorganisms to supplement indigenous populations) is one of the bioremediation approaches [54]. Entrapment in alginate gel is a widely used approach for immobilization of microorganisms to improve their viability

Alginate is a natural chelating agent and a bio-adsorbent of heavy metals in aqueous solution; it has high affinity and binding capacity for metal ions and, thus, is widely used as a heavy metal adsorbent for environmental protection [56]. Alginate-clay composites are suitable for environmental remediation as sorbents of

Alginates are an omnipresent ingredient of cosmetics. They usually are utilized as emulsifiers, consistency enhancers, and thickening agents in cosmetic formulas, forming a moisture-retaining surface film. They can have some kind of active effect, such as skin protection, because they retain water and maintain the skin rehydrated [59]. Alginates are water-insoluble; however, they can swell, as mentioned before. Thus, they are like hyaluronic acid, so they can absorb more water as much as

They are used in hand jellies and lotions, ointment bases, pomades and other similar preparations, greaseless creams, dentifrices, and other products that became

Alginate has also been described as an anti-oxidative agent and can be applied to prevent skin aging and cutaneous disorders. Additionally, antioxidants can help to maintain the organoleptic properties of cosmetic products by inhibiting lipid oxida-

Alginates are commonly used in the food industry as natural additives; they have codes from the European Union as food additives, and these codes vary with the ion

European codes for alginates are as follows: alginic acid, E400; sodium alginate, E401; potassium alginate, E402; ammonium alginate, E403; calcium alginate, E404;

pharmaceutical ingredient to treat some diseases or health problems:

provide a management tool for the medical personnel [53];

heavy metals [57] and persistent organic pollutants [58].

**10**

Seaweed polysaccharide applications in food industries are based mainly on their stabilizing, emulsifying, and gel-forming ability. They are widely used as food additives in jams, jellies, ice creams, dairy products, etc., to improve and stabilize the structure of food.

Water-in-oil emulsions likewise the mayonnaise and the salad fillings are less liable to fractionate toward their original oil and water phases if thickened with alginate. When the emulsion is acidic, the sodium alginate will precipitate into insoluble alginic acid forms; to resolve this problem, propylene glycol alginate (PGA) is used for acidic emulsions, because this compound is stable in mild acid conditions [63].

The advantage of alginate in the food industry is that humans do not have enzymes to break the molecule; therefore, alginate behaves as a dietary fiber, enhancing the satiety and reducing the food intake of humans, lowering the energy intake by human, and preventing obesity [53].

## **5.6 Dental medicine applications**

Hydrocolloids were the first elastic materials to be used in the dental field, and their results are fundamental to form a first "idea" about the patient's oral health status.

The alginate is used as irreversible footprint compound to emulate a footprint faithfully, giving details in a high-definition footprint although there is an existence of undercuts.

The main alginate advantages are the fact that they are low cost, do not react adversely on the patient, and can be easily manipulated and that the technique can be performed within a short period of time and has simple execution, lack of instrumentation, and high-definition footprint, even with the presence of undercuts, in a single-step methodology.

Alginate picking reaction is a chemical reaction of irreversible precipitation; therefore they cannot return in soluble form using physical means, such as temperature, as with reversible hydrocolloids [64].

### **5.7 Other areas of alginate application**

Packaging dominates the waste generated from plastics. Since the European Union synthetic plastic ban, alginate is one of the most suitable alternatives to fabricate packaging material due to their nontoxicity, biodegradability, and derivability from renewable natural resources.

With the bibliography analysis, it can be resumed that additives such as nonmaterial and antimicrobial compounds can improve various characteristics of the films and the packaging with antimicrobial activity is highly desirable in films to improve the shelf life of packed food products [56].

In textile printing, alginates are used as thickeners for the paste containing the dye. These pastes may be applied to the fabric by the use of either screen or roller printing equipment. These combine chemically with cellulose in the fabric. Alginates don't interact with the dyes; also they can be washed out of the finalized textile and are considered the first-rate thickeners to the reactive dyes [20].

The principal alginate application in the paper industry is in surface sizing. Alginate is mixed with starch sizing giving a smooth uninterrupted film and a surface with less fluffing. The oil resistance derivate from alginate films allows a size with improved greaseproof and oil-resistant properties. This can enhance the gloss obtained with high gloss inks.

If papers or boards need to be waxed, alginate in the size maintains the wax at the surface.

Alginates provide a better coating runnability than other similar compounds/ products, specifically in hot, on-machine coating applications.

They are also exceptional film formers and enhance the ink printability and resistance. In the size, the normal mixture of alginate is 5–10% of the total weight of starch. Alginate is used in the starch adhesives to form corrugated boards, because it stabilizes the viscosity of the adhesive and allows control of its rate of penetration [20].

The applications of alginates in new areas has proven the multi-role capacity of alginates, such as supportive agent for silicon nanopowder to yield a stable battery anode that possesses reversible capacity eight times higher than that of the stateof-the-art graphitic anodes. Improved performance characteristics prevent the dramatic volume changes during electrochemical alloying and de-alloying with Li, which typically leads to rapid anode degradation [65].

In the specialized clothing industry, the alginate anti-fire capacity was proven to be effective. The new alginate-based materials are showing enormous potential to be applied in building insulation materials and textile industry [66–68]
