The increasing global concern over plastic waste and its environmental impact has led to a growing interest in the development of sustainable packaging alternatives. This study focuses on the innovative use of expired dairy products as a potential resource for producing edible packaging materials. Expired milk and yogurt were selected as the primary raw materials due to their protein and carbohydrate content. The extracted casein was combined with various concentrations of chitosan, glycerol, and squid ink, leading to the studied samples. Chitosan was chosen due to its appealing characteristics, including biodegradability, and film-forming properties, and casein was utilized for its superior barrier and film-forming properties, as well as its biodegradability and non-toxic nature. Glycerol was used to further improve the flexibility of the materials. The prepared hydrogels were characterized using various instrumental methods, and the findings reveal that the expired dairy-based edible packaging materials exhibited promising mechanical properties comparable to conventional plastic packaging and improved barrier properties with zero-oxygen permeability of the hydrogel membranes, indicating that these materials have the potential to effectively protect food products from external factors that could compromise quality and shelf life.

Biomass valorization and bio-based material development are of major research interest following the spirit of the circular economy. Aloe vera cultivation is a widespread agricultural activity oriented toward supplement production because of its well-known antioxidant and antimicrobial properties. Aloe vera juice production also produces a large amount of biomass byproducts that are usually landfilled. On the other hand, cellulose nanocrystals are widely used in several applications, such as biomaterials, bio-compatible polymers, nanocomposites, food packaging, medicines, cosmetics, and sensors, due to their unique physical, mechanical, optical, electrical, and healing properties as well as their compatibility with biological tissues. This study introduces a novel approach combining the microwave-assisted extraction (MAE) of cellulose from this residue with the subsequent isolation of cellulose nanocrystals (CNCs). The MAE process, which exhibits a rapid heating and penetrating ability, was optimized to maximize the cellulose yield under various conditions (microwave power, solvent ratio, and time). Analysis using FTIR, XRD, SEM, and DMA indicated that isolated pure cellulose nanocrystals and a stable PVA–CNC porous hydrogel network were produced. The PVA–CNC hydrogel was synthesized to enable the formation of a semi-crystalline network that imparts the material with enhanced mechanical properties. Both final products of this study could potentially be used for various applications.

Cellulose nanocrystals are of major research interest because of their use in biodegradable bioplastcs and food packaging, biomaterials, medical and pharmaceutical applications, cosmetics, electronics, and construction materials. This study introduces an approach combining microwave-assisted extraction (MAE) of cellulose from Aloe Vera plant residue and subsequent isolation of cellulose nanocrystals (CNCs) utilizing sulfuric acid hydrolysis. The MAE process, characterized by its rapid heating and penetrating ability, was optimized to maximize cellulose yield from raw biomass sources under various conditions (microwave power, solvent ratio, and time). Following extraction, the purified cellulose was subjected to sulfuric acid hydrolysis under controlled conditions to yield CNCs, with the aim of preserving the intrinsic crystalline structure while enhancing the material's physicochemical properties. The search for biocompatible and biodegradable materials suitable for biomedical applications has led to significant interest in hydrogels composed of natural polymers. Among these, hydrogels synthesized from cellulose and polyvinyl alcohol (PVA) have emerged as promising candidates due to their unique physical properties and compatibility with biological tissues. This study presents the formulation, characterization, and potential biomedical applications of a cellulose/PVA hydrogel. The hydrogel was synthesized to enable the formation of a semi-crystalline network that imparts the material with enhanced mechanical properties.