Influence of extraction methods on Ulvan water holding capacity and rheological properties: a systematic review

Abstract

Ulvan, a sulfated polysaccharide derived from green algae such as Ulva and Enteromorpha sp., possesses water-binding capability, making it a valuable natural hydrocolloid in the food sector. Physicochemical properties, such as water-holding capacity (WHC) and rheology, influence their use as thickeners, stabilizers, and gelling agents. Ulvan extraction methods, including hot water extraction (HWE), microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE), enzymatic extraction (EAE), and chemical solvent extraction (CAE), have a substantial impact on these qualities. The purpose of this review is to investigate the effects of extraction procedures on the WHC and rheological properties of ulvan to maximize its use in food items. A systematic literature review (SLR) was conducted, which involved scanning publications in databases such as Google Scholar, Scopus, and ScienceDirect. According to the evaluation results, HWE and EAE retain a branched structure and high sulfate content, making them acceptable for applications requiring strong gel and high WHC. In contrast, the MAE, UAE, and CAE approaches generate linear ulvan that enhances viscosity at high concentrations. The use of UAE and EAE can improve monomer retention, although careful management is required to maintain the sulfate concentration and molecular weight.