The term hydrocolloids includes all the polysaccharides and proteins that are widely used in industrial sectors. Hydrocolloids are important parts of our daily diet in food systems such as yogurt, mayonnaise and salad dressing, ice cream, dessert, bakery products, and so on [1,2]. The increasing occurrence of different diseases in the world has given rise to a demand for healthy foods containing natural compounds such as hydrocolloids (e.g., dietary fiber) and phytochemical compounds (e.g., antioxidants, and so on) with a high level of compounds with health benefits . For many years, hydrocolloids have been used in food systems as functional ingredients for the control of microstructure, texture, flavor, and shelf life. In fact, these are a diverse group of high‐molecular‐weight polymers and may be named thickeners, gelling agents, stabilizers, bulking agents, and emulsifiers on the basis of their functionality [ 1,4]. Beside functional attributes, hydrocolloids are presently being reported to have many increasing applications in healthy foods.
The alteration of people's lifestyle has been caused by a growing awareness of the relationship between diet and health and new processing technologies. These changes have led to the production of novelty food with a high level of fiber and low‐fat content. Consequently, this has increased the demand for hydrocolloids in the food industry .
The term dietary fiber was first used in 1953 by Eben Hipsley in his observation publication noting that populations with diets high in fiber‐rich foods tended to also have lower rates of pregnancy toxemia . Previously, the analytical term crude fiber had been used for the portion of plant foods that escaped solvent, acid, and alkali extractions . The WHO (World Health Organization) and FAO (Food and Agriculture Organization) agree with the AACC (American Association of Cereal Chemists) definition but with a slight variation. They state that dietary fiber is a polysaccharide with 10 or more monomeric units which is not hydrolyzed by endogenous hormones in the small intestine .
Epidemiological evidence suggests that a high intake of dietary fiber is associated with numerous health benefits. The fiber hypothesis proposed by Burkitt and Trowel suggested some three decades ago that there was a link between the consumption of a diet rich in fiber and the level of protection against many of the “First World diseases” [ 7,9]. In previous research papers, the dietary fiber properties of various food hydrocolloids have been discussed. Intakes of food containing dietary fiber reduced the risk for developing different diseases such as coronary heart disease, diabetes, obesity, and so on [ 4 10–13]. In addition, it has been suggested that public awareness of these important ingredients will be required. Although several review papers have been published reporting on the health benefits of commercial food hydrocolloids [ 2, 4,14,15], none of them has addressed novel hydrocolloids in particular. So, the important points of this chapter are the investigation of the health aspects of novel hydrocolloids on the basis of recent publications.
With the spread of different disease in the world and the increasing demand for functional and healthy food products, scientists have conducted research to solve these problems. Hydrocolloids as food ingredients related to unique functional properties have been used for many years. These ingredients can be used as fibers with specific health benefits. The literature has examples of novel food hydrocolloids that exhibit important roles in foods as new dietary fiber sources in addition to their traditional applications as thickening, coating, gelling, and emulsifying agents.
Dietary fiber and whole grains are an abundant source of nutrients including vitamins, minerals, and slowly digestible carbohydrates. Also, they contain phytochemicals that are not classified as essential nutrients but may play important roles in human health .
First, researchers found that a diet with guar gum prolongs mouth to cecum transit time, delays gastric emptying, slows down the increase in postprandial glycemia, and aids colonic function [17–19]. In the following sections, the proposed health benefits of well‐known and novel food hydrocolloids as dietary fiber will be introduced. The health aspects of commercial hydrocolloids have been deeply studied, and some of them are summarized in Table 24.1. Numerous papers are annually published on the characterization of new hydrocolloids with health claims, and a wide range of novel hydrocolloids are reported to have health benefits in line with good functional properties in food systems. In Table 24.2, some recent studies on the possible health effects of novel hydrocolloids are presented.
Table 24.1 Health benefits of most well‐known hydrocolloids.
|Pectin and Guar gum||Cholesterol‐lowering effect|||
|Psyllium||Blood glucose and insulin lowering effect|||
|Alginate||Enhancing satiety and controlled energy intake|||
|Hydroxypropylmethylcellulose (HPMC)||Anti‐diabetic effect|||
|Oat β‐glucan||Hypoglycemic effect, satiety effect||[24,25]|
|Gum arabic||Reduction of blood pressure, anti‐obesity effect||[26,27]|
|Cellulose||Anti‐obesity effect, blood‐glucose‐lowering effect, Cholesterol‐lowering effect||[28–30]|
|Resistant starch||Blood glucose and insulin control|||
|Barley β‐glucan||Satiety effect|||
|Alginate||Active compounds carrier|||
Table 24.2 Possible health benefits of novel hydrocolloids (extracted from the published works during the years 2010–2017).
|Cyanobacteria Nostoc commune polysaccharides||Antioxidant activity||
|Almond gum polysaccharides (Prunus amygdalus)||
|Sulfated polysaccharide from Ulva pertusa (Chlorophyta)||Antihyperlipidemic activity||
|Levan and its derivative from Bacillus subtilis NRC1aza||Antitumor activity
|Levan polysaccharide||Anti‐diabetic activity||
|Artemis sphaerocephala Krasch. Gum||Antioxidant activity
|Extracted polysaccharides from Bryopsis plumosa||Antioxidant activity||
|Polysaccharides from Sargassum thunbergii||Antitumor activity||
|Acidic polysaccharide from Tuber sinoaestivum||Immunomodulator effect||
|Polysaccharides from Diaphragma juglandis fructus||Antioxidant activity
|Peach‐gum‐derived polysaccharides||Anti‐diabetic effect||
|Lycium barbarum L. Polysaccharides||Anticancer effect
|Zizyphus jujuba Mill Polysaccharide||Antioxidant activity
|Plantago spp. Polysaccharide||Immunomodulatory effect
|Morus spp. Polysaccharide||Antioxidant activity
|Rehmannia glutinosa polysaccharide||Anticancer activity||
|Malva aegyptiaca polysaccharides||Antioxidant activity
|Cress (Lepidium sativum) seed gum||Hypoglycemic activity
Diabetes mellitus is a chronic metabolic disorder characterized by a high blood glucose level (hyperglycemia) due to insulin deficiency and/or insulin resistance . Diabetes is spreading worldwide, affects approximately 4% of the population, and is expected to increase by 5.4% in 2025. Diabetes is a multifactorial disease which is characterized by hyperglycemia, defects in reactive oxygen species scavenging enzymes, and high‐oxidative‐stress‐induced damage to pancreatic beta cells . Generally, diabetes mellitus is a group of metabolic diseases characterized by hyperglycemia resulting from defects in insulin secretion, insulin action, or both. Diabetes mellitus is classified into two groups: type‐1 diabetes is characterized by the destruction of pancreatic β‐cells. Type‐2 diabetes is the major form of diabetes mellitus and is caused by insulin resistance and impaired insulin production, secretion, and function . For diabetes mellitus therapy, a series of agents, including sulfonylureas, thiazolidinedione, α‐glucosidase inhibitors, and Biguanide, which are commercial products, have been used for decades. But these drugs have adverse effects depending on the amount consumed (weight gain, liver damage, bone loss, diarrhea, vomiting, and so on). As the treatment of this disease usually involves very long periods, in some cases, serious problems may occur. Although new drugs such as DPP‐4 inhibitors and GLP‐1 analogs have been introduced to the market, but their high price as well as the absence of clear safety characteristics have led to a large demand for natural drugs to treat diabetes mellitus. The new trend is for patients to use functional foods and complementary or alternative medicine. Researchers report that a variety of active compounds from natural products such as polysaccharides and dietary fibers have a high potential for application in diabetes mellitus treatment .
Viscous forms of dietary fiber have been shown to improve blood glucose control by trapping ingested carbohydrates inside the viscous gel formed after digestion. As a result, sugars are absorbed into the bloodstream more slowly, limiting the rise in blood glucose seen after a meal. High‐viscosity fibers usually reduce the palatability of products, and this property is a major problem for practical application, although they are necessary for maximizing the beneficial effect on blood glucose . In addition, some suggest that insoluble fiber increases the passage rate of foodstuff through the gastrointestinal tract, decreasing the absorption of nutrients (such as simple carbohydrates). Insoluble fiber can cause reduced appetite and food intake, and short‐chain fatty acids (via fermentation) have been shown to reduce the postprandial glucose response . Recently, an improvement in glycemic control was observed with psyllium in patients with type‐2 diabetes mellitus .
Jia et al.  investigated the hypoglycemic and hypolipidemic activities of Laminaria japonica polysaccharides (LJPs) by alloxan injection and found that LJP administration prevented body weight loss, decreased fasting blood glucose levels, and increased serum insulin levels in diabetic mice. Furthermore, it decreased total cholesterol, total triglyceride, and LDL‐C levels, and increased HDL‐C levels in these mice . The same results were also seen in the studies of Li et al. .
Huang et al.  isolated a fucose‐containing exopolysaccharide from a culture broth of Enterobacter cloacae Z0206 with molecular weight 1.1 × 106 Da and composed of fucose, glucose, galactose, glucuronic acid, and pyruvic acid in the approximate molar ratio 2:1:3:1:1, and found that exopolysaccharide exhibited hypoglycemic and hypolipidemic effects, possibly through regulating AMP‐activated protein kinase and SirT1‐mediated effects on carbohydrate and lipid metabolism. Selenium‐ECZ‐EPS (exopolysaccharide) is a water‐soluble selenium‐enriched exopolysaccharide which is isolated from the submerged culture broth of E. cloacae Z0206. Se‐ECZ‐EPS significantly reduces fasting blood glucose, glycated serum proteins (GSPs), total cholesterol, and total triglyceride contents in the liver .
Cunha et al.  found that galactomannan from Caesalpinia ferrea seeds lowered hyperglycemia in diabetic rats and significantly decreased serum TAG (mediated effects on carbohydrate and lipid metabolism). The anti‐diabetic benefits of these hydrocolloids are associated with smooth glucose uptake and slow starch digestion . As seaweed contains a large number of soluble polysaccharides, they therefore have potential functions as dietary fiber. Thus, they might be considered to have beneficial effects on cardiovascular diseases risk factors .
There has been increasing interest in researching natural antioxidants since they can protect the human body from free radicals and retard the progress of many chronic diseases and cancer . Accordingly, there is a growing interest in applying new natural antioxidant compounds to prevent metabolic disorders of oxidative stress origin . A number of natural polysaccharides and their derivatives have been demonstrated to possess potent antioxidant activities and potential applications as antioxidants .
In the last decade, it has been reported that some seaweed sulfated polysaccharides (such as carrageenan and fucoidan) showed antioxidant activities [77–79]. The antioxidant capacity of commercial carrageenan from Gigartina skottsbergii and Schizymenia binderi, and fucoidan from Lessonia vadosa was also evaluated by the oxygen radical absorbance capacity method . In addition, peach‐gum‐derived oligosaccharides showed high hydroxyl radical scavenging activity (86.12%) and 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging activity (91.70%) at a concentration of 100 µg ml−1 as well as high reducing capacity at a concentration of 50 µg ml−1 .
Bouaziz et al.  reported that almond gum oligosaccharide (by enzymatic hydrolysis) had significant antioxidant and antimicrobial activity. This oligosaccharide has been tested in beef meat preservation, and microbial growth and lipid oxidation were monitored for nine days at 4 °C. They found significant inhibitions (p < 0.05) of lipid oxidation and microbial growth in ground beef meat containing almond gum oligosaccharide .
Cancer treatment strategies are actually focused on improving three main strategies: (1) prevention, based on promoting lifestyles associated with low tumorigenesis risks; (2) surgery, consisting often in the ablation of the tumor, ideally before the epithelial‐mesenchymal transition, which leads to metastasis; and (3) by inducing tumoral cell death via targeted radio‐ or chemotherapy . Epidemiological studies have suggested a reverse association between intake of dietary fiber, the ingested parts of plant materials, and risk of colon cancer. Dietary fibers influence colon carcinogenesis by increased fecal bulk, reduced colonic transit time, and diluted fecal toxin contents, which consequently reduce the exposure of colonic mucosa to the luminal carcinogens. In addition, the interaction between dietary fiber and colonic microbiota and bile acids, and the production of short‐chain fatty acids resulting from fermentation are believed to protect against colon cancer development .
Dahech et al.  investigated the antitumor and anti‐cytotoxic effect of Levan polysaccharide produced by Bacillus licheniformis. In the in vitro antitumor activity test of Levan against some tumor cell lines, relatively significantly high activity was observed against hepatocellular carcinoma, human (HepG2). The strongest inhibiting activity appeared at the highest dosage of Levan (12.5 mg ml−1) .
Immunomodulation is considered an important biological function of natural polysaccharides, which act as immunomodulators or biological response modifiers. Various reports have suggested that polysaccharides and proteoglycans with high arabinose and galactose content exhibit immunomodulatory activities, including complement fixing activities and/or modulation of macrophage function. The results from in vitro tests of cashew nut tree gum exudate using murine peritoneal macrophages showed that this gum can be used as an anti‐inflammatory . Also, a recent study suggested that water‐soluble polysaccharide from Erythronium sibiricum bulb is a potential immunostimulator. An in vitro assay showed that this polysaccharide significantly promoted the proliferation and neutral red phagocytosis of RAW 264.7 macrophage cells. Moreover, it stimulated the production of secretory molecules (nitric oxide, TNF‐α, and IL‐1β) of RAW 264.7 macrophage cell in a dose‐dependent manner . Ji et al.  found that Ziziphus jujuba polysaccharide fractions (RQP1d and RQP2d) induced significant increases in nitric oxide formation in RAW 264.7 cells, and both extracts stimulate the innate immune response. However, RQP1d and RQP2d are dissimilar in their chemical compositions and molecular weights. Low concentrations of RQP2d had a synergistic effect with lipopolysaccharide on splenocyte proliferation. The immunomodulatory actions of polysaccharides are associated with their molecular weights, chemical compositions, glycosidic linkages, and so on .
Various researchers have attempted to find new antimicrobials to inhibit food spoilage and food poisoning, which are important problems in the food industry . Nowadays, it is possible to control pathogenic microorganisms in foods by synthetic antimicrobials. But the increase of bacterial resistance to conventional antimicrobial agents and consumer awareness of the side effects of these compounds has motivated the search for novel substrates of natural origin. According to Kubo et al. and Campos et al., cashew tree gum has antimicrobial activity against several microorganisms, which is attributed to the presence of anacardic acid [86,87].
Peach‐gum‐derived oligosaccharides demonstrated antimicrobial activity against Bacillus subtilis, Staphylococcus aureus, and Escherichia coli at a concentration of 100 µg ml−1 . On the basis of recent researches, almond gum polysaccharides (Prunus amygdalus) have potent antimicrobial activities against the pathogenic strains S. aureus, Pseudomonas aeruginosa, Salmonella typhimurium, Enterococcus faecalis, and E. coli [ 38, 39].
Alginate, fucoidans, and laminaran extracts were tested for their antimicrobial activity against bacteria (E. coli, Staphylococcus, Salmonella, and Listeria). Sodium alginate has been established as a strong antibacterial agent . In addition, alginates can be used as bioactive coatings against Listeria monocytogenes for fish products during refrigerated storage such as cold‐smoked salmon slices and fillets .
Obesity has become a worldwide epidemic affecting people on every continent. More than just obesity itself, the major drawback of being obese is the high incidence of the associated health risks, like metabolic syndrome, type‐2 diabetes, and cardiovascular problems. It is generally accepted that a disruption in the balance between energy intake and energy expenditure is an extremely important factor in the incidence of obesity . Its rate is increasing dramatically, and it has been estimated that 58% of the world population will become obese by 2030 . So, one of the interesting approaches of the food industry for the prevention of weight gain is to provide products with high satiating capacities and low‐energy densities. Dietary fibers seem to be ideal candidates for the achievement of this function . Increasing dietary fiber consumption may decrease energy absorption by diluting a diet's energy availability while maintaining other important nutrients . Calame et al. found that blends of gum arabic (EmulGold® and PreVitae®) are able to satiety enhancement and decrease the caloric intake significantly after consumption .
Several studies have been performed that suggest a link between seafood consumption and obesity‐related disorders [92,93]. Several actions have been proposed for the mechanism linking seaweed's polysaccharides and obesity disorders. One of them is the action of fiber in the seaweed's biomass, and another is attributed to antioxidants, minerals, and omega 3 fatty acids that interfere in obesity prevention .
Generally, the capability of dietary fiber to decrease body weight could be related to the following:
In Figure 24.1, the effect of hydrocolloids on the passage rate and enzyme digestion processes of foods during small intestine transfer is shown. Hydrocolloids can play a key role in modulating small intestinal behavior . As seen in Figure 24.1, enzymes and bile are secreted into the first section (duodenum), digestion/absorption and water/salt uptake occur in parallel throughout the rest of the small intestine, and bile is re‐absorbed at the end of the jejunum and in the ileum. The concentration of non‐digested hydrocolloids increases along the small intestine due to the uptake of both water and nutrients .
The presence of hydrocolloids in either viscous soluble form or as an encapsulating matrix is likely to have a major effect on the rate of small intestinal enzymatic digestion of starch, proteins, and lipids. This could be due to one or more of (1) slow transport or restricted access of enzyme to its substrate, (2) direct inhibition of enzyme activity through site‐specific binding, and (3) slow or restricted transport of products from the enzyme to the site of absorption. Recent modeling and experimental data suggest that factor (3) may be important in viscous solutions .
Despite significant development in its prevention, cardiovascular disease remains the leading cause of death in the United States and most Western countries. Saturated fat, cholesterol intake, and increasing cis‐saturated fat intake are the major parameters in the risk of cardiovascular diseases . High consumption of whole grains is associated with a significant reduction in cardiovascular diseases. Psyllium gum and oat β‐glucan are the most widely used sources of soluble fiber and have been approved for health benefits related to protection from cardiovascular diseases by the FDA. The mechanisms for an association between fiber linkage and cardiovascular disease are unclear, but it is suggested that fiber can reduce blood cholesterol levels by altering cholesterol and bile acid absorption and by its effects on hepatic lipoprotein production and cholesterol synthesis [ 74, 10]. The relationship between water‐soluble fibers and decreasing serum LDL cholesterol concentrations are summarized in Figure 24.2. The viscous water‐soluble fibers form a thick unstirred water layer in the intestinal lumen, thereby decreasing the (re)absorption of cholesterol and bile acids. This leads to an increased fecal output of these two components. As a result, hepatic conversion of cholesterol into bile acids increases, hepatic pools of free cholesterol decrease, and – to reach a new steady state – endogenous cholesterol synthesis will increase. This leads to increased activities of 7‐α‐hydroxylase and HMG‐CoA reductase to compensate for the losses of bile acids and cholesterol from the liver stores. In addition, hepatic LDL cholesterol receptors are upregulated to re‐establish hepatic free cholesterol stores. These processes will ultimately lead to decreased serum LDL cholesterol concentrations .
Panlasigui et al. found that carrageenan‐enriched diets are beneficial for lipid balance in regard to lowering the risk of the cardiovascular disease . In addition, Paxman et al. proposed that alginate has indirect cardiovascular beneficial effects by modulating glucose and cholesterol uptake from the small intestine . Researchers reported that Acacia (sen) SUPERGUM™ is suitable for diabetes mellitus patients and could assist in the control of the systolic blood pressure to reduce the risk of renal impairment .
Oat β‐glucan influences the blood cholesterol levels, and LDL cholesterol‐lowering effects depend on viscosity, which is controlled by the molecular weight and amount of oat β‐glucan solubilized in the intestine .
Previous animal and human studies have reported increased rates of calcium absorption and associated improvements in bone mineral density with ingestion of prebiotics . In addition to encapsulation within hydrocolloid gels, plant tissues, or other food structures, it is possible that nutrients bind directly to food structures. This phenomenon is now recognized as being important for a range of phytonutrients, particularly phenolic compounds, which appear to be bound sufficiently strongly to plant cell walls that they escape solubilization and uptake in the stomach and small intestine .
The dietary fiber fermentation in the large intestine can influence the intestinal absorption of elements. Short‐chain fatty acids are fermentation products that are responsible for lowering the pH of cecal content, which in turn increases mineral solubility, leading to improved mineral absorption. Animal studies have revealed enhanced absorption of calcium, magnesium, and iron with gluco‐oligofructose, fructo‐oligofructose, and inulin in the colon, and five out of eight studies in humans also show a benefit, most importantly in adolescents . In addition, inulin influences the intestinal absorption of calcium and magnesium in rats .
A prebiotic is a food ingredient that is not hydrolyzed by human digestive enzymes in the upper gastrointestinal tract and beneficially affects the host by selectively stimulating the growth and/or activity of one or a limited number of bacteria (Bifidobacteria or Lactobacilli) in the colon that can improve host health . Dietary ingredients such as indigestible carbohydrates modify the gut microflora in favor of probiotics and hence potentially reduce the risk of colorectal diseases . Typical of prebiotics are inulin and oligofructose, both naturally present in a number of fruits and vegetables, and another resistant oligosaccharide such as inline‐type fructans . Although all prebiotic is fiber, not all fiber is prebiotic. Classification of a food ingredient as a prebiotic requires a scientific demonstration that the ingredient :
The ability to favorably alter the intestinal microflora has been demonstrated by a number of other fiber and plant food sources. A specific role for resistant starch in stimulation of bacteria able to produce butyric acid has been reported .
Acacia gum was shown to produce a greater increase in bifidobacteria and lactobacilli than an equal dose of inulin and resulted in fewer gastrointestinal side effects, such as gas and bloating . Polydextrose consumption resulted in a dose‐dependent decrease in Bacteroides, as well as an increase in lactobacilli and bifidobacteria . Wheat dextrin has also been shown to increase lactobacilli and reduce Clostridium perfringens and increase bifidobacteria . Psyllium was found to have a prebiotic effect in healthy women . Some reports exist about the role of prebiotics in cancer prevention , benefits in atopic disease , and reduction of blood cholesterol and triglycerides .
Other applications of hydrocolloids are tissue engineering (including biological signaling, cell adhesion, cell proliferation, cell differentiation, cell responsive degradation, and remodeling), wound dressing/healing, and drug delivery systems; the above three major topics are grouped under biomedical applications. Hydrocolloids have some advantages over synthetic polymers in that they are nontoxic, biodegradable, biocompatible, and less expensive .
Alginate, chitin, chitosan, hyaluronic acid, cellulose, chondroitin sulfate, starch, and their derivatives have been studied as biomaterials for tissue engineering applications . Moreover, chitin and chitosan as scaffolds for tissue engineering , composites of chitosan with hydroxyapatite, and grafted chitosan with carbon nanotubes have been developed for artificial bone and bone regeneration . Application of other polysaccharides for bone, cartilage, and/or skin tissue engineering applications have also been explored .
Hydrocolloids have been widely used to prepare wound healing materials. Collagen sponge dressing was used to treat skin wounds in the rat . Hooper et al. studied the antimicrobial activity of a RESTORE silver alginate dressing with a silver‐free control dressing using a combination of in vitro culture and imaging techniques. The data highlighted the rapid speed of kill and antimicrobial suitability of this RESTORE silver alginate dressing on wound isolates and its overwhelming ability to manage a microbial wound bioburden in the management of infected wounds . Moreover, sodium alginate films containing natural essential oils have been reported that may be applied as disposable wound dressings .
Various hydrocolloid‐based drug delivery systems have been developed for specific targeted delivery or controlled release. The release of entrapped drugs or certain molecules can be triggered by the changes of conditions such as pH, ions, temperature, certain molecules, and so on . Several hydrocolloids such as pectin, chitin, chitosan, guar gum, xanthan gum, gellan gum, dextran, and chondroitin have also been developed for drug delivery or controlled drug release [118,119].
Some hydrocolloids can be applied to prevent the human enamel from erosion (dissolution and softening). For examples, Beyer et al.  reported that pectin, alginate, and gum arabic have potential to reduce citric acid erosion in soft drinks. The suggested interactions of such biopolymers with the enamel surface and between biopolymers are graphically shown in Figure 24.3. In the case of enamel erosion, two interactions are proposed: (1) interaction between negatively charged carboxyl groups of polymers and Ca2+‐ions of the enamel surface and (2) interaction between negatively charged carboxyl groups of different polymer molecules in the presence of positively charged Ca2+‐ions by forming a chelate complex .
In addition, some fiber‐containing foods may need to be avoided in certain allergies. In fact, dietary fiber is fermented in the colon by anaerobic bacteria into short‐chain fatty acids, mainly acetate, butyrate, and propionate. These short‐chain fatty acids bind metabolite‐sensing G‐protein‐coupled receptors. These receptors are expressed on epithelial cells as well as on immune cells .
Moreover, seaweeds contain a variety of polysaccharides and fibers that can be used in the prevention and treatment of various diseases in humans . For examples, fucoidans are fucose‐containing sulfated heteropolysaccharides ; fucoxanthin is a metabolite ; carrageenans  are extracted from red seaweeds, where this substance plays a structural function; and laminarin is an active component from the brown seaweeds . They have been documented in various biological activities including antiviral, anti‐inflammatory, anticoagulant, antiangiogenic, immunomodulatory, and anti‐adhesive activity. Moreover, the anti‐constipation effect of some hydrocolloids such as psyllium, gellan gum, karaya gum, and xanthan have been reported .
There has been an extremely alarming growth in chronic diseases such as cardiovascular disease, diabetes mellitus, and cancer, which has been connected to the overconsumption of high‐fat as well as high‐calorie foods. Also, the immoderate consumption of food carbohydrates has been a source of concern, and a joint FAO/WHO report has required people to decrease the consumption of sugars and to correspondingly increase dietary fiber consumption . Hydrocolloids are the most important groups of food components that, in addition to functionality, have beneficial characteristics in the digestive tract and subsequent nutritional and health outcomes. Food industries are changing the production approach in response to people's awareness and increasing demand for healthy food products. Nowadays, hydrocolloids (particularly dietary fiber) as one of the health components have been considered. As mentioned above and on the basis of published data, it can be suggested that usually, bioactive polysaccharides of natural origin such as algae have several biological effects in both in vitro and in vivo experiments. The information reviewed here may be helpful to design product formulations with novel hydrocolloids in view of their potential for therapeutic use or for use as ingredients in functional foods. In fact, the application of novel hydrocolloids as dietary fibers and functional ingredients is vital for the future studies and development of food industries.