Freshwater Edible Algae Polysaccharides: A Recent Overview of Novel Extraction Technologies, Characterization, and Future Food Applications

Freshwater edible algae have been consumed as a source of food and nutrition for humans as well as animals for centuries. Among the several bioactive components in freshwater algae, polysaccharides are considered the most important due to their numerous health benefits. Freshwater edible algae polysaccharides (FEAPs) are complex carbohydrate molecules that are considered a promising source of natural functional ingredients in the food industry owing to their potential functional properties and health benefits such as antioxidant, antimicrobial, antidiabetic, antitumor, and prebiotic activities. They are also known for their high molecular weight, high water-holding capacity, and excellent gelling and thickening properties, making them a natural alternative to synthetic thickeners and stabilizers. Therefore, this review aims to present an overview of the importance of FEAP, their extraction and purification techniques, monosaccharide composition, structural properties, and applications. The complexity of their extraction and purification procedures and limited research on their properties can sometimes limit their practical applications. Despite these challenges, there are opportunities for expanding FEAP production by developing sustainable production systems, processing technologies and increasing consumer awareness and thereby creating more opportunities in the food, pharmaceutical, cosmetic, and biotechnology industries as a natural source of bioactive compounds, which contributes to sustainable food security and environmental sustainability. The present review focused on the prominence of polysaccharides isolated from fresh water algae, novel technologies used for their extraction, purification, structural characterization, and their potential application in food industries.