Innovative Ultrasound-Assisted Approaches towards Reduction of Heavy Metals and Iodine in Macroalgal Biomass

Abstract

The aim of this work was to evaluate the potential of ultrasound (US), alone or in combination with mild heating and/or EDTA towards reduction of As, Cd, I, and Hg content of Laminaria hyperborea. Concentrations of As, Cd, I, and Hg of 56.29, 0.596, 7340, and <0.01 mg kg−1 of dry weight, respectively, were found in L. hyperborea blades. Treatment with US at 50 °C increased approx. 2-fold the amount of As released, although did not affect significantly the content of Cd or I, as compared to control (no US) samples. Reducing the temperature to 8 °C significantly decreased the effect of US, but heating at 80 °C did not cause a significant effect as compared to treatments at 50 °C. On the other hand, treatment with 0.1 N EDTA at 50 °C enhanced the percentage of Cd released by approximately 7-fold, regardless of sonication. In the present work, the combination of US and EDTA at 50 °C for 5 min led to a significant reduction of the As (32%), Cd (52%) and I (31%) content in L. hyperborea, thus improving the product’s safety for consumers.

Phytochemical and Potential Properties of Seaweeds and Their Recent Applications: A Review

“…Water-soluble vitamins, such as vitamin C, are abundant in Ulva lactuca, Eucheuma cottonii, Caulerpa lentillifera, Sargassum polycstum, and Gracilaria spp. and aid in the inhibition of low-density lipoprotein (LDL) oxidation and the creation of thrombosis/atherosclerosis [220]. Red algae have significantly higher levels of dried carotene (e.g., 197.9 mg/g in Codium fragile and 113.7 mg/g in Gracilaria chilensis) than other vegetables (e.g., 17.4 mg/g in Macrocystis pyrifera) [98], while brown seaweeds (e.g., Undaria pinnatifida) have greater concentrations of a-tocopherol/vitamin E (99% vitamins) than green and red seaweeds [107].…”

Microbiological Food Safety of Seaweeds

“…The same methodology may be used for seaweeds as well, and the increased cook loss would then have to be considered. This cook loss, may on one hand contain heavy metals, which are desired to be removed from the seaweed, but on the other hand, there is a significant loss of nutrients by use of US [140].…”

Assessment of Food Quality and Safety of Cultivated Macroalgae

“…Cultivation depth did not have any significant effect on the content of arsenic, cadmium, lead, or mercury [ 11 ]. Technologies intended to reduce the content of heavy metals and iodine include ultrasound-assisted approaches as investigated by Noriega-Fernandez et al [ 12 ]. The potential of ultrasound (US), alone or in combination with mild heat treatment and/or EDTA towards reduction of As, Cd, I, and Hg in Laminaria hyperborea was evaluated.…”

“…The potential of ultrasound (US), alone or in combination with mild heat treatment and/or EDTA towards reduction of As, Cd, I, and Hg in Laminaria hyperborea was evaluated. The combined application of US, mild heating, and EDTA led to 32%, 52%, and 31% release of As, Cd, and I, respectively, from L. hyperborean , thus significantly improving the products’ food safety for consumers [ 12 ]. However, most of the reduction could be achieved by heat treatment alone, while US treatment was less important.…”