# Sustainability in Bio-Based Edible Films, Coatings, and Packaging for Small Fruits
## 3 Biological Sources of the Compounds Used in Films, Coatings, and Packaging
### Agricultural Processing Byproducts
#### 3.2.2 Materials from Cereals  
Cereals have emerged as a significant source of materials for developing sustainable bio-based edible films, coatings, and packaging [49; 58]. These materials offer numerous advantages, including biodegradability, renewability, and abundance [59]. The most commonly used cereal-derived compounds for these applications are starches and proteins [60]. Starch, a polysaccharide in high concentrations in cereals such as corn, wheat, and rice, has gained considerable attention in edible packaging. Its film-forming properties, low cost, and wide availability make it an attractive option for sustainable packaging solutions [43]. Starch-based films and coatings have demonstrated excellent oxygen barrier properties and moderate moisture resistance, making them suitable for various food packaging applications [42]. [PERSON] et al. [58] indicate that starch-based films, particularly those with a high amylose content, hold substantial promise as eco-friendly packaging solutions for preserving food products. While starch offers promising characteristics for edible packaging, another agricultural by-product, zein, presents complementary properties that expand the potential applications of bio-based packaging materials. Indeed, zein, a corn protein, can be used at higher concentrations in film formulations, providing unique properties to the coating [42; 61]. This prolamine protein extracted from corn has excellent film-forming abilities and creates transparent, glossy, and hydrophobic films with good barrier properties against oxygen and moisture [2; 50]. Zein films are particularly effective for coating nuts, candies, and pharmaceutical tablets due to their resistance to microbial attack [62]. Wheat gluten, another cereal protein, has been extensively studied for its film-forming abilities. Gluten-based films possess good mechanical strength and barrier properties against gases and aromas [54]. However, their hydrophilic nature often necessitates incorporating plasticizers or other additives to improve moisture resistance. Rice bran protein, a by-product of rice milling, has also been explored for its potential in edible packaging. Films made from rice bran protein have good mechanical properties and moderate water vapor permeability [63]. Additionally, these films can be enhanced with various bioactive compounds to impart antimicrobial or antioxidant properties. Recent innovations in cereal-based materials for edible packaging include the development of composite films that combine different cereal components. Composite films are two types of biomolecules, like hydrocolloids and lipids, combined to prepare films [63].  
For instance, starch-protein blends have been created to leverage the strengths of both materials, resulting in films with improved mechanical and barrier properties [43; 54]. Incorporating nanoparticles, such as cellulose nanocrystals or nanoclays, into cereal-based films has also been investigated. Compared to their non-reinforced counterparts, these nanocomposites often exhibit enhanced mechanical strength, barrier properties, and thermal stability [2; 42]. Furthermore, researchers have explored the potential of cereal by-products, such as bran and husks, in developing sustainable packaging materials. These efforts reduce waste and add value to agricultural residues [63]. In conclusion, cereal-derived materials offer many possibilities for developing sustainable bio-based edible films, coatings, and packaging. Their abundance, biodegradability, and versatile properties make them promising candidates for replacing conventional plastic packaging in various food applications. Ongoing research continues to focus on improving the performance of these materials and expanding their potential uses in the food packaging industry.