Seaweed is becoming a popular food source due to its high nutritional content, but may also contain potentially toxic elements (PTEs). This study investigates trends in PTEs in several species of seaweed collected in Iceland, and variations between thallus section, location, and season. As (3.8-265 mg kg-1), Cd (0.06-18 mg kg-1) and U (0.03-1.9 mg kg-1) were highest in Phaeophyta collected in February, whilst certain Chlorophyta contained the highest levels of Pb ( 0.02-1.8 mg kg-1) and Fe (25-13607 mg kg-1). Samples contained high levels of essential trace elements but elevated levels of Cd – 19 samples exceeded the maximum level (3 mg kg-1) in food supplements. As levels were also high where over half of samples exceeded the 40 mg kg-1 ML for As in seaweed-derived animal feed. Certain species grown in Iceland may be prone to high levels of Cd and not be suitable for consumption in large quantities.
Tag: macroalgae
The short harvesting period of cultivated brown seaweed in Europe can make it difficult for cultivators to produce high quality seaweed biomass all year round. Hence there is a need for novel processing and preservation methods. Acid preservation is a well-known method to preserve food, where the aim is to reduce the pH below 4.5 to inhibit microbial growth. To evaluate the effectiveness of acid preservation, a shelf-life experiment was conducted with Saccharina latissima and Alaria esculenta. The biomass was either treated with lactic or citric acid and stored for approximately seven months. Physicochemical (including proximate composition, trace minerals, total phenolic content (TPC), texture and pH), microbial-, sensory attributes, and antioxidant (ORAC, DPPH) analyzes were performed on the preserved biomass during storage. The proximate composition, color, pH, and texture of the acid-preserved seaweed were relatively stable throughout the storage. However, a decrease was observed in TPC and antioxidant properties (assessed by DPPH) with the acid treatments. Acid preservation is, thus, a good method to stabilize the studied biomass for food and feed applications, but less applicable if intended for antioxidant purposes. However, the acid treated biomass might be suitable as an ingredient for a wide range of value-added products.
Ascophyllum nodosum contains many valuable compounds, including polyphenols, peptides, and carotenoids that have been shown to exhibit biological activities. These compounds are not a priority ingredient in seaweed meal products for the current users. Hence, the aim of the study was to investigate the chemical and bioactive characteristics of A. nodosum as affected by seasonal variation and evaluate the potential benefits of alternative processing and the utilization of side streams for product development. The analysis of raw materials, press liquid, and press cake from alternative processing and the commercial seaweed meal at different harvesting periods indicated that the chemical composition is linked to the reproductive state of the algae. Phenolic content and ORAC activity increased following the seaweed's fertile period, making alternative processing more promising in July and October compared to June. Several valuable ingredients were obtained in the press liquid, including polyphenols, which can be used in the development of new high-value bioactive products. The suggested alternative processing does not have a negative effect on the composition and quality of the current seaweed meal products. Hence, the extraction of valuable ingredients from the fresh biomass during the processing of seaweed meal could be a feasible option to increase the value and sustainability of seaweed processing.