Ultrasound and enzymatic processing of Palmaria palmata – effects on biochemical components

Palmaria palmata is gaining commercial interest in the northern hemisphere as a source of nutrients and bioactive compounds. However, the complex cell wall limits digestibility and extraction efficiency. This study investigated the use of ultrasound (US) and enzyme-assisted extraction (EAE), individually and in combination, to enhance the extraction of valuable components from P. palmata and to reduce iodine content. The US treatment was tested at two energy inputs (2.0 W/g and 9.1 W/g) alongside EAE using the multifunctional carbohydrase mixture Depol 793 EAE effectively degraded the cell wall components of P. palmata, resulting in a solid fraction rich in proteins. In contrast, the liquid fraction was enriched with sugars (xylose, glucose and galactose) and ash. In contrast, US alone did not affect extraction, and no additive or synergistic effects were observed when combining US with EAE. No significant reduction in iodine was obtained for any of the treatments, ranging from 10 % to 18 %. This study confirms that EAE is a promising approach for nutrient extraction from P. palmata, and future studies should explore additional enzymes and optimize US conditions to further improve extraction efficiency, in addition to including analysis of toxic elements to identify potential challenges for safe consumption.