## 3 Plastics Used for Food Packaging
### Selected Plant-derived Polymers
#### 3.3.3 Polysaccharides
This improves film tensile properties and water vapor permeability, concluding that a HPMC-chitson nanocomposite could be a possible material for food-packaging applications to extend the shelf life of food [158; 220]. Another approach is the preparation of HPMC/chitosan films [221]. [PERSON] et al. examined the incorporation of different lignins in HPMC and HPMC/chitosan films [158; 160]. Results show that lignins are in general more active against Gram-positive bacteria than against Gram-negative bacteria and that films with organosolv lignin possess a higher activity against _S. aureus_ than films with kraft lignin. It was shown that biomass as well extraction process influence the properties of the films and that the antioxidant activity of lignins correlates with different parameters such as genotype and phenotype of biomass, pulping and purification of lignin and the resulting heterogeneity [159]. Cellulose acetate (CA), cellulose acetate propionate (CAP), and cellulose acetate butyrate (CAB) are thermoplastic cellulasic-derived materials developed through esterification of cellulose. CA gets great attention because of its biodegradable nature, excellent optical clarity, and greater toughness [83]. Alginate and corresponding derivatives are one of the most promising carbohydrates for packaging applications, especially for foods that are sensitive to gas permeation [222]. Alginates are naturally occurring indigestible polysaccharides. They are commonly produced from various genera of brown algae [223]. A lot of research on alginate has focused on edible coatings or to improve color and flavors [224; 225]. [PERSON] et al. evaluated the barrier, mechanical, and oil resistance of paper sheets coated with a novel cost-saving coating prepared at different temperatures to be used in packaging purposes. The coating is based on sodium alginate (SA) with new core-shell inorganic particles composed of waste silica fume core covered with cobalt(II) oxide/zinc oxide (CoO.ZnO) oxides. SA is broadly used due to high oil resistance and enhanced greaseproof properties. Very recently, a binary oxide CoO.ZnO on the surface of silica was shown to decrease the penetration of oil and grease through the paper pores leading to lower oil absorption and enhanced mechanical properties. Tensile strength was decreased whereas stiffness showed slight increase in case of paper sheets coated with SA-CoO.ZnO/SiO\({}_{2}\). Incorporation of SA-SiO\({}_{2}\) and SA-CoO.ZnO/SiO\({}_{2}\) in the fiber matrices improved the tear and burst indices properties. The network created by SA film blended with (CoO.ZnO/SiO\({}_{2}\)) pigments on paper sheet substrate drastically changed their mechanical and barrier properties. They are highly dense and organized, causing the creation of smooth distribution of nanoparticles and a strong surface that fills the pores in the paper matrices and increases the air, water vapor, and oil resistance of the samples coated with SA-CoO.ZnO/SiO\({}_{2}\) pigments compared with uncoated paper [223]. Chitosanan is the second most widely found amino-polysaccharide in nature [226]. It is a biopolymer with antibacterial properties that can be found in fungi, insects, crabs, and shrimps and makes up a significant part of the crustacean waste that is discarded every year [227]. Chitosan is intensively investigated for biomedical applications [228] and bioactive packaging solutions [229]. Properties like being microbe resistant, biocompatible, and biodegradable make chitosan attractive for research and use in various applications [230]. In food packaging, potential applications of chitosan blend-based films are for fresh products (vegetable, meat, and fish) and foods with short to medium shelf life [231]. Moreover, chitosan is widely used as a material for nanofibers production due to its ability to form films with antibacterial properties [232; 233]. Moreover, chitosan-based materials exhibit good mechanical properties and a selective permeability to carbon dioxide and oxygen [101; 234].