Impact of thermal processing on the nutrients, phytochemicals, and metal contaminants in edible algae

Abstract

Edible algae products have increasingly become a larger component of diets worldwide. Algae can be a source of essential micronutrients and bioactive phytochemicals, although select varieties also often contain elevated concentrations of heavy metal contaminants. Due to the effects thermal processing of foodstuffs can have on levels of nutrients, phytochemicals, and contaminants, it is important to consider the role processing has on the levels of these components in algae food products. Here, we evaluate the literature covering how different types of processing, including commercial thermal application and in-home preparation, affect constituents such as vitamins, minerals, carotenoids, pigment compounds, and metal contaminants. Overall, the literature suggests that there are optimum processing conditions and specific cooking techniques that can be used to increase retention of important nutritional components while also reducing concentrations of metal contaminants. Although further research is needed on how thermal processing affects individual compounds in algae and their ultimate bioavailability, these data should be taken into consideration in order to inform design of product processing to both increase retention of nutritional components and limit metal contaminants.

A survey of arsenic, mercury, cadmium, and lead residues in seafood (fish, crustaceans, and cephalopods) from the south‐eastern Mediterranean Sea

“…With regards to human safety, crustacean shells may play an important role in As accumulation. While shells are not considered an edible part of seafood, shellfish is often prepared for consumption with shells intact, and should be considered as some studies suggest the potential conversion of organic arsenic into iAs following thermal processing or gastrointestinal digestion (Ho & Redan, 2020; Liao et al., 2018) thus leading to a potentially higher exposure.…”

Microbiological Food Safety of Seaweeds

“…Brown seaweeds commonly have an unacceptable high concentration of iodine which may be reduced by up to 94% by boiling for a few minutes. However, boiling causes loss of flavonoids and water-soluble nutrients which limits the prevalence [116].…”

Effect of acidification and thermal treatment on quality characteristics of high‐moisture laver ( Porphyra spp.)

“…The effects of thermal processing on the quality properties of seaweeds in terms of bioactive substances (Amorim et al, 2012), nutritional components (Maehre et al, 2015), metal pollutants (Ho & Redan, 2020), and flavors (Sanchez-Garcia et al, 2020) have been reported. However, the color and texture as two main indicators are used to evaluate the quality of instant laver products, which are influenced by the composition of raw materials and processing parameters.…”

“…There are many pigments in laver, and the change in color may be related to the degradation of pigments during heating(Tello-Ireland et al, 2011). The color of algae was mainly determined by the composition and content of chlorophyll, phycocyanin, and PE(Ho & Redan, 2020). In order to explore the reasons for the change of color under different circumstances, changes in pigment of laver during heating were summarized in Table2.…”