Macroalgae as biofactories of metal nanoparticles; biosynthesis and food applications

Nanotechnology has opened a new frontier in recent years, capable of providing new ways of controlling and structuring products with greater market value and offering significant opportunities for the development of innovative applications in food processing, preservation, and packaging. Macroalgae (MAG) are the major photoautotrophic group of living beings known as a potential source of secondary metabolites, namely phenolic compounds, pigments, and polysaccharides. Biosynthesis based on the abilities of MAG as nanobiofactories targets the use of algal secondary metabolites as reducing agents to stabilize nanoparticles (NPs). Nowadays, most of the studies are focused on the use of metal (Ag, Au) and metal-oxide (CuO, ZnO) NPs derived from algae. The eco-friendly biosynthesis of metal NPs reduces the cost and production time and increases their biocom-patibility, due to the presence of bioactive compounds in MAG, making them suitable for a wide variety of applications. These compounds have been attributed to the antimicrobial and antioxidant properties responsible for their application through innovative technologies such as nanoencapsulation, nanocomposites, or biosensors in the food industry. Nevertheless, toxicity is a key factor that should be considered, so the applicable regulation needs to guarantee the safe use of metal NPs. Consequently, the aim of this review will be to compile the available information on MAG-mediated metal NPs, their biosynthesis, and potential food applications.

Automated summary

Nanotechnology has opened a new frontier in the food industry by providing new ways of controlling and structuring products with greater market value, especially in areas such as food processing, preservation, and packaging. Macroalgae have been recognized as a potential source of secondary metabolites, such as phenolic compounds, pigments, and polysaccharides, which can be used for biosynthesis of metal nanoparticles (NPs). These biosynthesized metal NPs derived from macroalgae show advantages in terms of cost, production time, and biocompatibility, making them suitable for various applications in the food industry, such as nanoencapsulation, nanocomposites, and biosensors. However, the potential toxicity of metal NPs should be considered, and applicable regulations need to ensure their safe use.