Source and Processing

Agar finds its origin in several species of red algae, with Gracilaria and Gelidium being prominent sources. The extraction process involves boiling the seaweed, followed by filtration to obtain a liquid extract. After cooling, agar solidifies into a gel-like substance. Further processing involves drying and forming the final agar product.

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Main function in Confections

Agar is widely employed in the confectionery industry for its exceptional gelling properties. It serves as a gelling agent, imparting structure and stability to a variety of sweets, jellies, and candies. Due to its ability to form a robust gel at relatively low concentrations, agar is a good choice for confectionery manufacturers seeking to achieve desired textures or even using it with other stabilizers to create differentiated textures.

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Molecular Structure

The chemical constituents of agar vary with its origin. Agar is basically the sulfuric ester of a long-chain galactan. It consists of a mixture of two polysaccharides, agarose and agaropectin. Agarose is a neutral polysaccharide with little or no ester sulfate groups, while agaropectin

contains 5–10% sulfate groups. Agarose consists of a linear chain of agarobiose disaccharide units alternating 1–4 linked, 3,6- anhydro-L-galactose units and 1–3 linked D-galactose units.

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Properties

Gelling properties: The gelling mechanism of agar involves hydrating agarose, a linear polymer with galactose and 3,6-anhydrogalactose units. As the agar solution cools, agarose molecules form a three-dimensional network through hydrogen bonding, creating a stable gel structure. The helical coils of agarose align, trapping water within the gel. The resulting gel is characterized by thermal reversibility, melting when reheated. This mechanism is based on molecular associations and hydrogen bonding.

Hygroscopicity: Agar exhibits moderate hygroscopicity, meaning it can absorb and retain moisture from the surrounding environment. This property contributes to the texture and shelf life of confections, preventing them from becoming overly dry or brittle.

Solubility: Agar is insoluble in cold water but dissolves readily in hot water, forming a clear solution. This solubility characteristic is vital during the manufacturing process, allowing for easy incorporation into confectionery formulations.

Shelf stability: Confections containing agar demonstrate excellent shelf stability. The gel structure created by agar helps prevent syneresis, maintaining the integrity of the product over time. This contributes to extended shelf life and ensures a consistent consumer experience.

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Regulatory

In the United States, agar is Generally Recognized As Safe (GRAS) for use in food and is regulated by the Food and Drug Administration (FDA). It is listed under the Code of Federal Regulations (CFR) Title 21, Section 172.620, as a substance that can be used as a thickening agent, stabilizer, or gelling agent in various food applications, including confections. Adherence to specified usage levels ensures the safe incorporation of agar into confectionery products.