# An Overview of the Alternative Use of Seaweeds to Produce Safe and Sustainable Bio-Packaging
## 4 Promising Seaweeds to Produce Bioplastics
### Active Biofilms  
The incorporation of seaweeds into other polymers changes the mechanical, thermal, optical, and chemical properties of the materials. [PERSON] et al. [129], in a recent published work, focused on the potential development of active packaging, which is identified as packaging that interacts with the product in a positive way, to improve the safety and shelf-life of the product and to maintain the original sensory properties. The inclusion of seaweed extracts into biofilm formulation can provide a defense for the product against bacteria, oxidation, and UV rays.  
However, it is important to verify the biological effect of mixed and pure polysaccharides in biofilms. In some studies, crude extracts incorporated into biofilms exhibit antimicrobial activity. For example, mixed polysaccharides extracted from the brown seaweed _Nizamudinia zanardini_ inhibited the growth of _E. coli_ and _P. aeruginosa_, while crude fucoidans extract from the _Saragassum polycystum_ exhibited inhibitory effects against _V. harveyi_, _S. aureus_, and _Escherichia coli_[130, 131]. In addition, crude polysaccharides extracted from red alga _G. ornota_ showed antimicrobial activity against _Escherichia coli_[132]. The antimicrobial activity of pure carrageenan did not exhibit an effect against _S. aureus_, _Escherichia coli_, or _L. monocytogenes_[133, 134]. Meanwhile, in the study of [PERSON] et al. [135], pure \(\kappa\)-carrageenan from _Kappaphycus alvarezii_ was used to evaluate the antimicrobial activity of the Gram-positive bacteria _S. aureus_ and _B. cereus_, and the Gram-negative bacteria _E. coli_ and _P. fluorescens_. In vitro results show antimicrobial activity only against Gram-positive bacteria, and no growth inhibition of Gram-negative bacteria. The inclusion of \(\kappa\)-carrageenan in polyvinyl acetate (PVA) film showed an effective zone of inhibition against _S. aureus_ and _B. cereus_, proving that the antimicrobial activity of the pure extract could be retained and affect the film, protecting the wrapped products. Aqueous seaweed extract from _Kappaphycus alvarezii_ also showed an increased antioxidant activity after incorporation into PVA film, compared to pure PVA film [135]. Lipid oxidation has a strong impact on food quality; it can lead to a decrease in shelf-life and nutritional value of food [136]. Thus, the formulation of packaging with antioxidant compounds leads to a decrease in the amount of lipid oxidation and protein degradation within the packaging, avoiding degradation of the product coated on the film. [PERSON] et al. [137] investigated the antioxidant activity of the green seaweed _Ulva lactuca_, the red seaweeds _Gracilaria lemaneiformis_ and _Sarcodia cyclotenensis_, and the brown alga _Durvillaea antarctica_. Their results showed that crude polysaccharide from the green seaweed showed the highest activity, followed by _Durvillaea antarctica_ and _Sarcodia cyclotenensis_.  
Moreover, the inclusion of seaweed components in biofilm can lead to a photoprotective effect on packaging; some species possess photoprotective compounds capable of absorbing UV rays. Methanol extracts of _Sargassum_ sp. and _Eucheuma cottoni_ showed photoprotective activity against UV radiation, probably due to the presence of flavonoids, phenols, and triterpenoids [138]; they can potentially be used as a raw material for sunscreen products or be included in biofilm formulation, enhancing the properties of active packaging.  
Although the biological activities of pure seaweed compounds/extracts incorporated into biofilms should be further investigated, several studies have shown that most seaweed polysaccharides exhibit antioxidant, antimicrobial, and photoprotection activities, suggesting that their inclusion in biofilms can lead to the manufacture of safe and active packaging.