Integrated approach applying ultrasound-assisted extraction to recover bioactive material from Chondrus crispus

Rhodophyta represents the largest seaweed phylum including a wide variety of species, such as Chondrus crispus Stackhouse, with benefits for consumers health due to their nutritional value and bioactive compounds. This work aimed to optimize the extraction of compounds from C. crispus using a three-step optimization process. The first step consisted in pigment extraction using ultrasound-assisted extraction; the performance of an ultrasonic probe (20 kHz, 750 W) and a bath (40 kHz, 120 W) for 20 or 40 min was compared. The second step corresponded to protein extraction and the third step was the carrageenan formation. Step 1 extracts contained two carotenoids (fucoxanthin and lutein), 5 chlorophyll-a derivatives and pheophythin-a, phenolic compounds and revealed moderate antiradical activity against DPPH^•, ABTS^•+ and O₂^•-, but no activity against ^•NO and cholinesterases. Proteins and carrageenan's yields were between 3.6 and 41 g/100 g and 29.7–36.1 g/100 g, respectively. Considering all the performed analyses, the use of ultrasonic bath (40 kHz, 120 W) for 40 min is efficient to extract valuable compounds from C. crispus, which is advantageous from an economic point of view and therefore more attractive for industrial purposes. The obtained extracts may find possible future application in human diet or as additives for pharmaceutic and cosmetic industry.