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Applications of Alginates in Food
Abstract
Alginates are a group of viscous polysaccharides derived from brown seaweeds and produced as an extracellular matrix by some
bacterial species. Traditionally, alginates have been used as thickeners, emulsifiers and stabilising agents in a number of
food applications. A number of new food applications are emerging for alginates, based on their unique biochemical and biophysical
properties. These applications are discussed within this review, as are the nutritional properties of dietary alginates, and
their physiological actions in humans.
... Alginate, a natural anionic polymer obtained mainly from brown algae, has found application in various fields thanks to its biocompatibility, biodegradability, availability, chemical stability, and the ability to form stable hydrogels. Furthermore, it has a GRAS status and can therefore be used in a variety of foods, including foods for infants and young children with special medical purposes [2], meat, seafood, fruit, vegetables, pasta, noodles [3]; encapsulation of various bioactives and probiotics, which can then be added desorption processes are then described by suitable mathematical models, and kinetic parameters are estimated and compared to determine the influence of the type of molecule and molecular weight on the aforementioned processes. ...
... The solutions were then placed in a heated magnetic oil bath (IKA HBR 4 digital, IKA-Werk, Staufen, Germany) at 30 • C and 200 rpm, and 1000 plain beads were placed in each adsorbate solution [51]. Immediately after the addition of the alginate hydrogel beads, a stop clock was started and the supernatant samples were taken in the following time intervals: for the glucose solution, t = 0, 1, 2, 3, 4, 5, 10, 20, 30, 40, 50, 60, and 90 min; for the gallic acid solution, t = 0, 2,4,6,8,10,20,30,40,50,60,90, 120, and 180 min; and for the BSA solution, t = 0, 1,2,3,4,5,6,8,10,20,30,60, and 120 min. Samples were placed in Eppendorf tubes and stored in a freezer until further analysis. ...
The aim of this work was to analyze and compare the adsorption and desorption processes of carbohydrates (glucose as a model molecule), polyphenols (gallic acid as a model molecule), and proteins (bovine serum albumin, BSA as a model molecule) on alginate microcapsules. The adsorption and desorption processes were described by mathematical models (pseudo-first-order, pseudo-second-order, and Weber–Morris intraparticle diffusion model for adsorption, and first-order, Korsmeyer–Peppas, and the Higuchi model for desorption) in order to determine the dominant mechanisms responsible for both processes. By comparing the values of adsorption rate (k2) and initial adsorption rate (h0) based on the pseudo-first-order model, the lowest values were recorded for BSA (k1 = 0.124 ± 0.030 min−1), followed by glucose (k1 = 0.203 ± 0.041 min−1), while the model-obtained values for gallic acid were not considered significant at p < 0.05. For glucose and gallic acid, the limiting step of the adsorption process is the chemical sorption of substances, and the rate of adsorption does not depend on the adsorbate concentration, but depends on the capacity of the hydrogel adsorbent. Based on the desorption rates determined by the Korsmeyer–Peppas model (k), the highest values were recorded for gallic acid (k = 3.66236 ± 0.20776 g beads/mg gallic acid per min), followed by glucose (k = 2.55760 ± 0.16960 g beads/mg glucose per min) and BSA (k = 0.78881 ± 0.11872 g beads/mg BSA per min). The desorption process from alginate hydrogel microcapsules is characterized by the pseudo Fickian diffusion mechanism.
... Ion exchange is an important mechanism for biosorption of heavy metals which replaces light metals (predominantly Ca 2+ and Mg 2+ , since monovalent Na + and K + cannot form robust cross-linkages). The affinity of alginate and fucoidan to metal ions depends on stereochemical effects, where larger ions (Pb 2+ >Cu 2+ >Cd 2+ >Zn 2+ >Ni 2+ >Ca 2+ >Mg 2+ ) tend to bind better to algal functional groups (Pan et al. 2000;Brownlee et al. 2009). However, in the current study, cadmium bound better to alginate than lead, indicating that electronegativity can play a role. ...
... In fact, the M/G-ratio determines the strength of alginate gels, where folded G-rich gels are more rigid, and linear M-rich gels are softer. M-blocks appear more selective for Cd 2+ while G-blocks have a higher affinity for Ca 2+ (Brownlee et al. 2009). Accordingly, cadmium levels correlated with M/G-ratio in the current study. ...
The increasing interest in seaweed as a food resource in Western societies raises concerns about associated potentially toxic elements (PTEs), including arsenic, cadmium, mercury, lead, and iodine. Hence, this study examined variation in PTEs by including samples of four different species (Ulva lactuca, Palmaria palmata, Alaria esculenta, and Saccharina latissima) from Ireland, as well as of a single species (S. latissima) from three different harvest sites and with different thallus parts analyzed from a single harvest site. Comparing different species from the Irish site, U. lactuca showed the overall lowest PTE levels, while S. latissima and A. esculenta had notably higher levels of arsenic (105±3 and 57.9±5.5 mg kg⁻¹ DW, respectively) and cadmium (0.839±0.046 and 1.03±0.05 mg kg⁻¹ DW, respectively), and S. latissima had highest iodine levels (2480±210 mg kg⁻¹ DW). Lead was higher in P. palmata and U. lactuca but below maximum limits. Further analysis of S. latissima from three sites (Ireland, Norway, Sweden) showed site-specific variations in inorganic arsenic (0.192–9.69 mg kg⁻¹ DW), lead (0.0751–0.269 mg kg⁻¹ DW), and cadmium (0.554–1.16 mg kg⁻¹ DW). Saccharina latissima from the Swedish site exhibited uneven PTE distribution in tissue of different age. In terms of tolerable intake levels, iodine and cadmium posed most concern for seaweed consumption. After processing, total ash content decreased, leading to reductions in total arsenic (61.1%), inorganic arsenic (92.4%), lead (49.4%), and iodine (72.8%). Cadmium and mercury were difficult to remove. This study offers insights into the chemical food safety of seaweed, both pre- and post-processing, for introduction into expanding European markets.
Graphical abstract
... Another alginate application is stabilizing fruit drinks and beer. Alginate is useful in mayonnaise and salad dressing which we know of as water-in-oil emulsions [48]. Calcium alginate structures are considered by the meat industry as an alternative to natural casings from animals. ...
Seaweeds are one of the rich sources of minerals, protein, vitamins, edible fibers, and also have different functional polysaccharides necessary for human nutrition. Alginates are natural polymers that are part of the polysaccharides group. Alginate is a naturally occurring biopolymer that is found in the cell walls of algae or brown seaweed. Sodium alginate is one of the best-known members of the hydrogel group. The hydrogel is a water-swollen and cross-linked polymeric network produced by the simple reaction of one or more monomers. It has a linear (unbranched) structure based on d-mannuronic and l-guluronic acids. The placement of these monomers depending on the source of its production is alternating, sequential, and random. Sodium alginate is the most commonly used form of alginate used in wide range of applications in various industries including the food industry, medicine, tissue engineering, wastewater treatment, the pharmaceutical industry, and fuel. This review discusses its chemical structure along with its production process and application in various industries.
This chapter provides an overview of the use of alginate in food and beverage formulations. The first section discusses the regulatory considerations of the use of alginate in food, including its safety and labeling requirements. The second section provides a brief historical review of the rise of alginate in the food industry. The third section focuses on alginate as a functional ingredient in food, including its ability to act as a gelling agent, thickener, and stabilizer. The fourth section highlights the use of alginate in some selected products, such as alternatives to dairy products, bakery products, meat and fish, and egg replacement. Finally, the fifth section discusses the role of alginate in the human diet and its potential health benefits, such as its ability to lower cholesterol levels and improve digestion. Overall, this chapter aims to provide a comprehensive overview of the use of alginate in food and beverage formulations and its potential applications in human nutrition.
Clay-based aerogels have attracted considerable attention in recent decades due to their natural, low-toxicity features and controllable, porous structures. By incorporating various additives and processing under specific conditions, clay-based aerogel composites have tremendous potential in a wide range of applications. In this chapter, first a series of reinforced clay aerogels enhanced by various polymer matrixes, fibers, or other chemicals are briefly introduced and display the enhancing mechanical and other resultant properties. The state of the art of the clay-based aerogel processing and impact factors are discussed to elucidate the strategy to tailor aerogels with specific morphology. The impressive properties and applications, attributed to the incorporation of additives and the design of the structure, are highlighted, and mechanisms behind these features are also concluded. In the end, the current gap and future direction about the development are identified. This chapter is expected to provide sufficient background and experience to assist the development of the advanced, clay-based aerogels in academia and industry.
BACKGROUND: Probiotics may offer a safe intervention in acute infectious diarrhoea to reduce the duration and severity of the illness. OBJECTIVES: To assess the effects of probiotics in proven or presumed acute infectious diarrhoea. SEARCH STRATEGY: We searched the Cochrane Infectious Diseases Group's trials register (July 2010), the Cochrane Controlled Trials Register (The Cochrane Library Issue 2, 2010), MEDLINE (1966 to July 2010), EMBASE (1988 to July 2010), and reference lists from studies and reviews. We also contacted organizations and individuals working in the field, and pharmaceutical companies manufacturing probiotic agents. SELECTION CRITERIA: Randomized and quasi-randomized controlled trials comparing a specified probiotic agent with a placebo or no probiotic in people with acute diarrhoea that is proven or presumed to be caused by an infectious agent. DATA COLLECTION AND ANALYSIS: Two reviewers independently assessed the methodological quality of the trial and extracted data. Primary outcomes were the mean duration of diarrhoea, stool frequency on day 2 after intervention and ongoing diarrhoea on day 4. A random-effects model was used. MAIN RESULTS: Sixty-three studies met the inclusion criteria with a total of 8014 participants. Of these, 56 trials recruited infants and young children. The trials varied in the definition used for acute diarrhoea and the end of the diarrhoeal illness, as well as in the risk of bias. The trials were undertaken in a wide range of different settings and also varied greatly in organisms tested, dosage, and participants' characteristics. No adverse events were attributed to the probiotic intervention. Probiotics reduced the duration of diarrhoea, although the size of the effect varied considerably between studies. The average of the effect was significant for mean duration of diarrhoea (mean difference 24.76 hours; 95% confidence interval 15.9 to 33.6 hours; n = 4555, trials = 35) diarrhoea lasting > 4 days (risk ratio 0.41; 0.32 to 0.53; n = 2853, trials = 29) and stool frequency on day 2 (mean difference 0.80; 0.45 to 1.14; n = 2751, trials = 20). The differences in effect size between studies was not explained by study quality, probiotic strain, the number of different strains, the viability of the organisms, dosage of organisms, the causes of diarrhoea, or the severity of the diarrhoea, or whether the studies were done in developed or developing countries. AUTHORS' CONCLUSIONS: Used alongside rehydration therapy, probiotics appear to be safe and have clear beneficial effects in shortening the duration and reducing stool frequency in acute infectious diarrhoea. However, more research is needed to guide the use of particular probiotic regimens in specific patient groups. This is the abstract of a Cochrane Review published in the Cochrane Database of Systematic Reviews (CDSR) 2010, Issue 11, DOI: 10.1002/14651858.CD003048.pub3. (www.thecochranelibrary.com). For full citation and authors details see reference 1
The latest volume in the successful Special Publication Series captures the most recent research findings in the field of food hydrocolloids. The impressive list of contributions from international experts includes topics such as: * Hydrocolloids as dietary fibre * The role of hydrocolloids in controlling the microstructure of foods * The characterisation of hydrocolloids * Rheological properties * The influence of hydrocolloids on emulsion stability * Low moisture systems * Applications of hydrocolloids in food products Gums and Stabilisers for the Food Industry 12, with its wide breadth of coverage, will be of great value to all who research, produce, process or use hydrocolloids, both in industry and academia.
Background: Foods containing strong-gelling fibers may provide a safe and efficacious strategy for reducing food intake by stimulating endogenous satiety signaling.
Objective: A novel, 2-part beverage, consisting of alginate-pectin and calcium components, that forms a stable, fibrous gel in the stomach was tested to determine its effects on subjective satiety and food intake in overweight and obese women.
Design: The investigation was a within-subjects, double-blind, placebo-controlled study. Subjects (n = 29) ingested a 2-part beverage twice per day (once before breakfast and once midafternoon) for 7 d. Three alginate-pectin formulations were tested: 1.0 g, 2.8 g, and control (no fiber). Subjective satiety and ad libitum food intake were measured on days 1 and 7 of each 1-wk treatment period with a 1-wk washout between testings.
Results: A significant reduction in food intake was observed at dinner for both formulations compared with the control formulation. The effects of the gel beverage differed as a function of rigid dietary restraint status. Women in the lower 50th percentile of rigid restraint consumed 12% less energy during the day and 22% less for the evening snack in the 2.8-g condition compared with the control condition. No effect was found for women in the upper 50th percentile of rigid restraint.
Conclusions: Consumption of a postingestion, calcium-gelled fiber beverage twice daily reduced energy intake in overweight and obese women with low rigid restraint scores. Use of foods designed to enhance satiety may be an effective adjunctive therapy for weight loss; however, more research is needed to determine how dietary restraint alters this response.
The effects of three different hydrocolloids guar gum, sodium alginate and gum acacia on the flow behaviour properties, serum loss and flow value of tamarind sauce were studied. The hydrocolloids were added to the sauce at different concentrations (0 to 1.5%) and rheology was studied at different temperatures (20 to 70°C). The power law and Arrhenius equations were used to determine the consistency index, flow behaviour index, Activation energy and arrhenius constant. Multiple regression equations were fitted to obtain the consistency index and apparent viscosity. The activation energy of flow for the hydrocolloid containing tamarind sauce samples varied from 2.687 to 23.101 kJ/gmol. Guar gum was found to give maximum consistency index, lower flow values and least serum loss followed by sodium alginate and gum acacia.
Study was conducted to determine the level of fat replacer sodium alginate (SAL) while developing low-fat cooked chevon loaves (CCL). In general, incorporation of SAL significantly (p<0.05) increased emulsion stability (ES) and water holding capacity (WHC) of meat emulsion with highest values at 1 and 0.25% SAL levels, respectively. The CCL containing 0.25% SAL showed higher pH, a significant increase in cooking yield (CY), W-B shear force value, flavour and texture scores and a marginal increase in colour and appearance and juiciness scores with highest overall palatability score as compared to other SAL levels. SAL level of 0.25% was found preferable to develop low-fat CCL with better sensory quality.
Dietary fiber is the edible parts of plants or analogous carbohydrates that are resistant to digestion and absorption in the human small intestine with complete or partial fermentation in the large intestine. Dietary fiber includes polysaccharides, oligosaccharides, lignin, and associated plant substances. Dietary fibers promote beneficial physiological effects including taxation, and/or blood cholesterol attenuation, and/or blood glucose attenuation.
Algal polysaccharides are indigestible and exhibit unusual biochemical and fermentative characteristics from which stem interesting biological effects such as antitumoral, immunostimulating and/or prebiotic effects. In this study, we aimed to determine whether oligosaccharides obtained from alginates and laminarans also have such biological activities and can thus be considered as functional foods. The chemical structures of the oligosaccharides were determined using NMR. Both the fermentation and the effects on microbial populations of oligo-alginates and oligo-laminarans were investigated using batch incubations with, and continuous culture of, human faecal bacteria. The kinetic and intensity of fermentation were measured by continuous monitoring of gas production and determination of final pH value, respectively. Effects on intestinal flora activity and composition were determined via metabolite quantification and main bacterial genera enumeration. Cytotoxic, proliferative and differentiating effects were estimated after exposure of epithelial (Caco-2), monocytic (THP1) and lymphocytic T (Jurkat) cell lines. Despite very different biochemical structures, the two oligo-alginates exhibited similar fermentation patterns. As with native alginates, they required adaptation prior to their metabolism. However, this adaptation did not result in any change in the global bacterial composition. No noticeable biological effect was detected for oligo-alginates, In contrast to native laminarans, oligo-laminarans did not require adaptation prior to their fermentation. Propionate production was stimulated but no significant modification of the balance between the main bacterial genera was observed during continuous culture of human fecal flora. Oligo-laminarans exhibited slightly inhibitory effects on Caco-2 cells, inhibited mononuclear cell proliferation and stimulated the expression of ICAM-1 by monocytic cells. This last property appears promising, and may allow algal oligosides to be used as functional foods and/or components.
The most important hydrocolloid food gelling agents are gelatine, starch, pectin, carrageenan and alginate, but also agar, celluloses, gellan gum, konjac, milk proteins and soy proteins can be used as gelling agents. Xanthan gum is widely used in weakly gelled type foods such as salad dressings. Dairy dessert gels, jams and table jellies are typical examples of gelled foods, but also meat products or noodles can be gels. Hydrocolloids can form molecular gels through association of parts of the molecules forming ‘junction zones’. The type of binding in the junction zone and the amount of molecules forming the junction zones are the most important hydrocolloid interactions are charge effects, steric hindrance, excluded volume effects and incompatibility. If particles are present, adsorption and depletion flocculation can take place. Gel properties are important for flavour release from gelled foods, whereas the clarity and surface smoothness of gels mainly depend on the presence and structure of insoluble components.
A total of 26 species of seaweeds (1 green, 21 brown, and 4 red algae) and 6 polysaccharides were screened for their antihypertensive and antihyperlipidemic activities using rats in order to evaluate their potential application for the prevention of cardiovascular diseases. Although diets containing some pulverized seaweeds moderately elevated total cholesterol (TC), free cholesterol (FC), and low density lipoprotein (LDL), marked antihypertensive and antihypercholesterolemic activities were found in almost all seaweeds, some of which are commonly used as food. In addition, serum levels of high density lipoprotein (HDL) were enhanced 46.0% by seaweed powder diets. Six polysaccharides derived from active 'seaweed species were investigated, and appreciable suppression of hypertension and hypercholesterolemia was observed for all samples. They also markedly enhanced the serum level of HDL. © 1994, The Japanese Society of Fisheries Science. All rights reserved.
Digestibility of the edible brown alga kombu was studied by feeding rats for 28 days. Food intake of both rats fed with basal and kombu diets was statistically similar. Body weights of kombu groups were significantly lighter, but their fecal weights were heavier, when compared with their counterparts with diets excluding kombu. There were no major differences in the weights of liver, pancreas, and kidney, but cecum, small intestine, and large intestine of rats fed with kombu were significantly heavier than those without kombu. With the kombu diet, in the early feeding period protein digestibility was signi-ficantly lower than in the control, but the digestibility of kombu groups recovered to the level of the control in the late feeding period. Fat digestibility in the kombu diet was significantly higher than that in the basal diet. Digestibility of insoluble and total dietary fibers in the kombu diet tended to increase in the feeding period. Alginate digestibility significantly increased, and the molecular weight of alginate was down by 60%. Since the molar ratio of mannuronic and guluronic acids in alginate decreased significantly in the feeding period, mannuronic acid may be more decomposable in comparison with guluronic acid in rats.