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.

Modern bioeconomy and sustainability demands lead food technology in the development of novel biobased edible food preservatives. Herein, the development and characterization of novel polysaccharide (xanthan gum and kappa-carrageenan)-based nanoemulgels (NGs) enhanced with essential oil derivatives; pure citral (CT); pure carvacrol (CV); and various CT:CV ratios (25:75, 50:50, and 75:25) are presented. The obtained NGs are applied as active edible coatings for extending the shelf life of Protected Designation of Origin (PDO) green table olives of Chalkidiki. The zeta potential demonstrated the high stability of the treatments, while light scattering measurement and scanning electron microscopy images confirmed the <100 nm droplet size. EC₅₀ indicated high antioxidant activity for all the tested samples. The fractional inhibitory concentration (FIC) confirmed the synergistic effect of NG with a CT:CV ratio at 50:50 against Staphylococcus aureus and at CT:CV ratios 25:75 and 75:25 against E. coli O157:H7. NG coatings with CT:CV ratios at 50:50 and at 25:75 effectively controlled the weight loss at 0.5%, maintained stable pH levels, and preserved the visual quality of green olives on day 21. The synergistic effect between CT and CV was confirmed as they reduced the spoilage microorganisms of yeasts and molds by 2-log [CFU/g] compared to the control and almost 1 log [CFU/g] difference from pure CT and CV-based NGs without affecting the growth of beneficial lactic acid bacteria crucial for fermentation. NGs with CT:CV ratios at 50:50 and at 25:75 demonstrated superior effectiveness in preventing discoloration and maintaining the main sensory attributes. Overall, shelf life extension was achieved in 21 compared to only 7 of the uncoated ones. Finally, this study demonstrates the potential of polysaccharide-based NGs in mixtures of CT and CV for the shelf life extension of fermented food products.

The growing demand for sustainable food preservation drives interest in edible nanoemulsions encapsulating bioactive compounds. This study developed casein–lecithin-based nanoemulsions combining carvacrol (CV)—a compound with potent antimicrobial and moderate antioxidant activity—with vitamin E (VitE)—a powerful antioxidant—as multifunctional food coatings. Three formulations were prepared via homogenization: NE-CV (2% CV), NE-VitE (2% VitE), and NE-CV/VitE (1% each). Physicochemical characterization revealed monomodal size distributions (22.7–57.7 nm), with successful encapsulation confirmed by FTIR. NE-CV/VitE exhibited intermediate particle size (34.4 nm) and zeta potential (−19.8 mV). Antioxidant activity followed NE-VitE > NE-CV/VitE > NE-CV, with the co-encapsulated system preserving VitE’s radical scavenging (EC₅₀ 10.76 µL/mL, DPPH). Remarkably, NE-CV/VitE demonstrated enhanced antibacterial activity against E. coli, requiring half the CV concentration (0.07 mg/mL) versus NE-CV alone (0.15 mg/mL), while maintaining CV dose-dependent activity against S. aureus (0.30 mg/mL). Nanoencapsulation significantly reduced CV cytotoxicity in human lymphocytes at concentrations up to 50 μg/mL (48.8% cytostasis vs. 58.9% for free CV), with no genotoxic effects observed within this range, while preserving full bioactivity. In fresh minced pork over 6-day refrigerated storage, NE-CV/VitE coating maintained pH stability (5.65–5.75), preserved red color (a* values 6.24 vs. 4.99 uncoated), reduced lipid oxidation (TBARS 0.74 vs. 0.82 mg MDA/kg), and achieved a 99% reduction (2-log) in total viable counts versus uncoated controls. The CV/VitE co-encapsulated nanoemulsion represents an integrated, safe, and effective multifunctional preservation technology with synergistic antimicrobial enhancement and uncompromised antioxidant protection, offering a natural alternative for comprehensive food quality preservation.

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.

Nowadays bioeconomy and sustainability trend drive food technology in the development of novel biobased edible food preservatives to enhance food shelf-life and safety. This study explored the development, characterization, and application of novel polysaccharide-based nanogels enhanced with essential oil derivatives carvacrol and citral, investigating their potential synergistic effects as active edible coatings for extending the shelf life of Chalkidiki PDO green table olives. Nanogels were formulated using xanthan gum and kappa-carrageenan and tested in various ratios (25:75, 50:50, 75:25). Physicochemical characterization of nanogels was done via zeta potential dynamic light scattering measurements and scanning electron microscopy images, while preliminary tests demonstrated high antioxidant activity. Antimicrobial assessments revealed significant bactericidal effects, with FIC results confirming a synergistic effect of NGCTCV 50:50 against Staphylococcus aureus and NGCTCV 25:75 and 75:25 against. The nanogel coatings were applied to Chalkidiki green table olives and evaluated over a 21-day storage period. The NGCTCV 50:50 and 25:75 coatings effectively reduced weight loss, maintained stable pH levels, and preserved visual quality, while inhibiting spoilage microorganisms without affecting beneficial lactic acid bacteria crucial for fermentation. Lab colorimetry confirmed the ability of these nanogels to prevent discoloration, maintaining the olives' characteristic green color. Sensory analysis indicated that NGCTCV 50:50 and 25:75 outperformed both individual nanogels and uncoated samples, effectively extending shelf life by over 14 days. Finally, this study demonstrates the potential of polysaccharide-based nanogels, particularly in the 50:50 and 25:75 ratios, for improving the shelf life of perishable food products, with promising applications in fermented food preservation.