Agar - India

Brief Overview

Agar, commonly known as agar-agar, is a gelatinous substance derived from algae, predominantly found in the cell walls of red algae and obtained through boiling extraction. This complex sulfated polymer is composed of sugar galactose subunits extracted from red algae species like Gelidium cartilagineum and Gracilaria confervoides. Agar consists of two primary polysaccharides, agarose and agaropectin, with agarose making up around 70% of the total composition. Agarose, a linear polymer, comprises agarobiose monomers, a disaccharide consisting of D-galactose and 3,6-anhydro-L-galactopyranose. Agaropectin, a diverse mixture of smaller molecules, contains alternating units of D-galactose and L-galactose, modified by the addition of acidic side groups such as sulfate and pyruvate. In its natural state, agar is often bundled with thin, membranous, agglutinated strips or exists in cut, flaked, or granulated forms. The color of agar may vary from light yellowish-orange to colorless, displaying a resilient texture when wet and a brittle consistency when dry. Powdered agar may appear white to yellowish-white or pale yellow, showing transparency under a microscope in water. In a chloral hydrate solution, the transparency of powdered agar is even more pronounced than in water.

Manufacturing Process

The extraction of agar from seaweed involves a procedure that includes boiling in hot water, followed by freezing and thawing for purification. Conventional commercial extraction techniques involve various steps such as washing, chemical extraction, filtration, gelation, freezing, bleaching, additional washing, drying, and milling.

Food Industry

Agar plays a crucial role as a primary thickening and stabilizing agent in the food sector. It is commonly featured in numerous Asian desserts, where agar solution serves as a prevalent ingredient. This solution is particularly effective as a thickening agent in soups, fruit preservatives, and ice creams. Notably, it can serve as a substitute for pectin in jams and gelatin in marmalades. In culinary practices, agar solution is employed to clarify sauces and is integrated into a variety of dishes, including desserts, sweet jellies, puddings, cakes, and fruit salads. With its substantial fiber content, approximately 80%, agar solution also functions as a regulator for intestinal health.

Research Industry

In laboratory environments, agar finds widespread use as a critical component in growth media, where it is combined with other nutrients for the cultivation of bacteria and fungi. Additionally, agar serves as a key gelating agent for plant cell culture in research applications.