Nowadays, several applications of alignates have been seen, mainly as food additives to stabilize and improve food consistency (e.g., baked food, fruit industry, jellies, jams, ice cream, mayonnaise). In the food and pharmaceutical industry they mainly act as a gelling agent, stabilizer and thickener. Īlginates are also characterised by unique biological and pharmacological properties. Assessment of the M/G ratio is also fundamental – for alginates with a high M/G ratios alginates provide elastic gels, whereas for alginate with a low M/G ratios generate brittle gels.

The proportion of the three types of blocks – MM, GG and MG determines the physical properties of alginates – alginates with high G have higher gelling properties, whereas those with high M have higher viscosity. Īlginates are used widely due to their rheological properties, as well as biocompatibility, biodegradability and lack of toxicity. Īlginate chain sequence and the macromolecular conformation. In the presence of polyvalent cations, such as calcium, sodium alginate has the ability to form gel. Among them, sodium alginates are water soluble polymers, which give highly viscous solutions. Alginates are salts of long-chain alginic acids, that in brown seaweeds are present mainly as the calcium salt of alginic acid, although magnesium, potassium and sodium salts are also present. They can be also arranged as homogeneous blocks MM or GG and heterogeneous or alternating as MG, as shown in Figure 1. These units are randomly distributed in a linear chain. They are composed of two hexuronic acids: β-D-mannuronic acid (M) and α-L-guluronic acid (G) linked by 1–4 bonds. In this review paper we describe alginates that are natural polysaccharides extracted mainly from brown seaweeds. This biomass constitutes a production system of bioactive compounds such as polysaccharides, proteins, minerals, lipids including polyunsaturated fatty acids, pigments, vitamins, antioxidants, etc., which are known to have antibacterial, antifungal, antiviral, antioxidative, anti-inflammatory and antitumor properties. Moreover, they are also biocompatible, non-toxic and biodegradable, therefore adequate in other biomedical applications.īrown seaweeds (known also as macroalgae) are abundant in many coastlines and in some of them they represent an almost unexploited but very valuable marine resource.

Their gelling characteristic and absorbable properties enable using alginates as a wound management material. These natural polysaccharides are widely used in the commercial production, as a food ingredient, in the pharmaceutical industry due to their antibacterial, anticancer and probiotic properties. This article presents several techniques used for the analysis of alginate properties. It is important to characterise the obtained alginates in order to their proper applications. By controlling a chemical process makes it possible get various forms of alginates, such as fibres, films, hydrogels or foams. The extraction parameters (e.g., temperature and time of extraction) have critical impact on the alginate physiochemical and mechanical properties and thus, their potential applications. However, novel extraction techniques such as microwave and ultrasound assisted extractions have gained a lot of interest.

Alginates are mainly extracted by using conventional alkaline extraction. The quality and quantity of the alginate obtained with a variable yield prepared from brown seaweeds as a result of many factors, such as type of algae, extraction methods, chemical modification and others.

In this paper, the current state-of-art of extraction of alginates and the determination of their physico-chemical properties as well as their overall applications focussing on biomedical purposes has been presented.

Washing a precipitate chemistry