## 4 Dealcohized Grape Pomace Applications in Bio-Based Materials
### Dealcoholized Grape Pomace as an Enhancer or Filler in Bio-Based Materials  
Despite its high availability and industrial potential, only a limited number of studies over the past decade have investigated the use of DGP or grape pomace-derived materials as fillers or enhancers in bio-based materials. However, all available studies report significant improvements in properties such as thermal stability, heat resistance, and overall performance of the resulting biocomposites. [PERSON] et al. [53] examined the incorporation of a grape pomace extract (GPE), along with other phenol-based additives such as tannic acid (TA) and lignocellulosic biomass (LC), into poly(3-hydroxybutyrate) (PHB), a biodegradable polymer known for its limited mechanical performance and narrow processing window. Their results demonstrated that these natural additives significantly improved the thermal resistance of PHB, reduced its degradation during melt processing, and preserved its molecular weight. Rheological analysis revealed a slower viscosity decay in doped samples, indicating that LC functioned as a heterogeneous nucleating agent, which promoted crystallization during cooling and potentially mitigated physical aging. This study highlights the potential of grape pomace-derived additives as sustainable and functional stabilizers for bioplastics, such as PHB, offering an eco-friendly alternative to synthetic polymer stabilizers. Expanding on these findings, similar improvements in thermal and mechanical performance have been observed with other agro-industrial residues, such as sugarcane bagasse and spent grain from beer production, incorporated into polymer matrices like PLA, polypropylene (PP), and high-density polyethylene (HDPE) [54; 55; 56; 57; 58]. These natural fillers typically enhance thermal stability, promote crystallinity, and improve resistance to thermal degradation and aging. Such improvements are often attributed to enhanced interfacial adhesion between the fibers and the polymer matrix, particularly when compatibilizers or chemical modifications are employed to improve compatibility. DGP exhibits similar reinforcing behavior, and its wide availability contributes to a reduction in the required polymer content, thereby increasing the sustainability and cost-effectiveness of the resulting biocomposites. In terms of direct applications, [PERSON] et al. [59] explored the development of biocomposites using bio-based poly(butylene succinate) (BioPBS) reinforced with DGP via melt extrusion and injection molding. Composites containing up to 50 wt% DGP were produced, with specific formulations compatibilized using in situ synthesized maleic anhydride-grafted BioPBS (MA-g-BioPBS). The incorporation of DGP significantly improved both flexural and impact strength, with the 57:40:3 BioPBS/GP/MA-g-BioPBS blend showing the best overall performance, achieving increases of 28.4% and 59% in flexural and impact strength, respectively, compared to neat BioPBS. Additionally, the heat distortion temperature increased by 14.3%, and DGP acted as a reinforcing phase that enhanced the material's mechanical integrity. Scanning electron microscopy revealed improved interfacial adhesion in compatibilized samples, while thermogravimetric analysis confirmed the thermal stability of DGP under processing conditions. More recently, interest has emerged in the development of bioactive laminated composite films incorporating graphene-based polyethylene (GPE). [PERSON] et al. [60] developed bioactive laminated films based on bacterial cellulose (BC) and chitosan, enriched with GPE as an antioxidant and glycerol as a plasticizer, targeting applications in sustainable food packaging. Formulations were systematically varied to evaluate their mechanical and thermal properties. The results indicated strong interactions between components, leading to improved strength and flexibility. Tensile strength values ranged from 16.92 to 32.71 MPa, and films with GPE showed up to a fourfold increase in elongation (from 2.33% to 8.63%) compared to control samples.