Conventional plastics based on petroleum dominate packaging for food application because of their low cost, barrier properties, and durability, however, their environemntal shows significant ecological risks, with more than million ton accumulating in oceans and landfills every year (Plastics Europe, 2022). In response, research and industry efforts have increasingly focused on bio-based, biodegradable, and edible films obtained from eco-friendly resources, including polysaccharides, lipids, and proteins. Those type of materials not only provide reduced environmental footprints but can also be tailored with functional additives to enhance food preservation and safety.

Coffee (Coffea spp.) counts as among the most widely consumed on a global scale, with the market demonstrating expanded steadily due to rising consumption and a growing global population (McNutt and He, 2019). Cultivated in more than 80 countries, the coffee plant ranks among the top internationally traded commodities, following petroleum and mining industries (Campos-Vega et al., 2015). According to data from the Food and Agriculture Organization (FAO, 2021), Brazil led global green coffee production in 2021, with Vietnam and Indonesia ranking next. Despite the fruit’s widespread cultivation, only the beans are utilized, accounting for under 50% of the whole coffee fruit, are primarily used for consumption (Sengupta et al., 2020). After thermal processing, including drying and grinding, a considerable volume of waste is produced. Once the nutritional components are extracted from the beans, the total waste can reach up to 90–95% of the original fruit (Hernández-Varela and Medina, 2023).

To address this waste issue, one promising approach is the conversion of coffee by-products into value-added products, bio-based or edible films as innovative sustainable packaging materials. This innovation aligns with the United Nations’ 2030 Sustainable Development Agenda, which emphasizes the need for immediate measures to address climate change (UN (United Nations), 2015). Utilization of coffee-derived residues for food purposes have gained notable interest, as demonstrated by 424 publications on the topic, with 36 and 29 studies specifically addressing packaging and edible film materials, respectively, as seen in Figure 1A. This paper aim to highlight recent advancements in the development of sustainable films enriched with coffee by-products, with a focus on their potential to improve material properties for food packaging applications.

To collect relevant information, scientific publications from books and peer-reviewed journals were identified. Literature searches were conducted in databases including Scopus, and Google Scholar, using specific keywords such as “coffee by-product food,” “coffee by-product packaging,” and “coffee by-product bio edible film.” The titles, abstracts, and methods of the retrieved articles were screened to determine their relevance and alignment with the focus of this article.

Coffee processing generates substantial quantities of by-products with diverse chemical compositions, as seen in Figure 1B. Wet processing, involving multiple stages such as de-pulping, fermentation, washing, hulling, and polishing, produces various by-products: pulp, mucilage, wash water, coffee parchment (CP), and silver skin (SS) (Febrianto and Zhu, 2023). Conversely, using the dry process results solely in dried husk, a combination of mucilage, pulp, CP, and SS (dos Santos et al., 2021).

Wet processing offers more selective separation of by-products, enabling targeted utilization based on distinct chemical composition. As an agro-industrial by-product, coffee pulp is enriched with carbohydrates, pectin fractions, nitrogenous compounds, and bioactive phytochemicals. CP contains significant amounts of lignin, hemicellulose, and cellulose (Reis et al., 2020), while SS has a notable protein content (~20% dry weight) (Bessada et al., 2018). Additionally, Spent coffee grounds (SCG), a residue generated during instant coffee manufacturing, and green coffee sediments (GCS), derived from green coffee extract manufacturing, are both abundant in lignocellulosic materials and bioactives such as chlorogenic acid and caffeine (Ribeiro et al., 2018; Saratale et al., 2020; Dias et al., 2023).

These by-products has the potential to be upgraded into materials with added value, particularly for bio/edible film production. Dried materials such as husk, CP, and SS can be processed into fine powders or hydrolyzed into micro/nanocrystalline cellulose for use as functional additives (Sung et al., 2017; Suaduang et al., 2019; Sangta et al., 2024). Moist by-products like pulp and mucilage are suitable for bacterial cellulose production, while phenolic-rich SCG and GCS can be solvent-extracted to enhance film functionality. Lyophilized mucilage has also shown potential as a film-forming matrix (Lee and Oh, 2022; Machado and de Oliveira, 2023a), though its application faces technological barriers due to collection and drying challenges.

The integration of micro/nanocrystalline cellulose and bioactive extracts is increasingly attractive due to their versatility and compatibility with various film matrices. These components support improved transparency, reduced dependence on inorganic fillers, and enhanced antioxidant or antimicrobial properties (Janissen and Huynh, 2017; Boopasiri et al., 2023; Perera et al., 2023), as summarized in Table 1. However, excessive use of untreated husk can negatively affect film appearance (Borghesi et al., 2016). To optimize the potential of these by-products, alternative processes involving the bioactive extraction of materials followed by alkaline/acid hydrolysis can be employed to obtain both bioactive extract and crystalline cellulose (Ng et al., 2021). These materials have demonstrated compatibility with polylactic acid (PLA), polyvinyl alcohol (PVA), gelatin, carrageenan, pectin, and other biodegradable matrices, contributing both structural and biofunctional enhancements.

Mechanical and thermal properties serve as key elements in assessing the performance of bio/edible films. While some biopolymer matrices may have inherent limitations, the incorporation of fillers has been shown to enhance both properties significantly (Pires et al., 2024). Among various bio-based fillers, coffee by-products, particularly SCG and SS, have demonstrated promising effects in improving the physical properties of the films (Table 1), with CP emerging as a recent alternative.

Studies indicate that SCG and SS enhanced the thermal stability of biofilms, especially those based on PLA. Gamiz-Conde et al. (2024) reported that adding these by-products increased the PLA degradation temperature from 361.5 °C to 382 °C. This improvement was possibly due to the nucleation effect of bioactive compounds such as cellulose, hemicellulose, and lignin, which promote crystallinity and facilitate better thermal distribution (Shi et al., 2022). Furthermore, SCG’s antioxidant constituents, including caffeine and chlorogenic acid, contribute to improved thermal-oxidative stability in PVA-based nanocomposites (Giang et al., 2023). Mechanically, SCG and SS enhance the biofilm’s tensile strength and elasticity. Saccani et al. (2022) found that incorporating SS raised PLA’s elastic modulus by approximately 20%. Giang et al. (2023) observed a doubling of tensile strength from 24 MPa to 58 MPa without the addition of other fillers. These improvements were possibly due to the reinforcing effect of the high fiber content in SCG and SS (Hejna, 2020), as well as mechanisms involving particle dispersion strengthening and reinforcement by secondary phases (Petaloti and Achilias, 2024a). The presence of hydroxyl and other polar functional groups in SS and SCG could interact with polar biopolymers through hydrogen bonds or interfacial adhesion, enabling stress transfer from the biomatrix to the by-poduct filler, hence improving mechanical performance (Hejna, 2020). Additionally, SS and SCG contained bioactive compounds such as polyphenols (Hejna, 2020), presuming to stabilize polymers against oxidative degradation during processing or storage. However, excessive filler addition might negatively affect the film’s properties. High concentrations could lead to particle aggregation via Van der Waals forces, resulting in reduced elasticity and increased rigidity (Gamiz-Conde et al., 2024). Overloading could hinder polymer chain mobility, decreasing crystallization and thermal stability (Shi et al., 2022). Fillers above 5% have been associated with diminished mechanical and thermal performance (Gamiz-Conde et al., 2024). Nevertheless, the lack of standardized experimental protocols across studies complicates direct comparison of results. Differences in sample preparation, filler processing, and testing conditions may affect reproducibility and hinder consistent interpretation of findings. Additionally, the water activity of the by-products should be considered. Mirón-Mérida et al. (2019) reported that CP, due to its lower water activity, reduced tensile strength and elongation by limiting the plasticizing effect of glycerol.

The exploration of bio-based edible films derived from coffee by-products has gained significant interest in response to the growing demand for sustainable packaging. Coffee SS and SCG, key by-products of coffee processing, are rich in bioactive compounds and contribute to enhanced film properties, particularly in terms of barrier performance against gases, water vapor, and UV light which influence product shelf life and quality, as summarized in Table 1. Lignin extracted from coffee SS demonstrated effective moisture barrier enhancement by lowering the water vapor transmission rate (WVTR), thereby extending food shelf life (Tunç and Tuğrul, 2024). Additionally, coffee-derived fillers reduced gas permeability, limiting oxygen and CO₂ diffusion, which were critical for preserving food freshness (Tunç and Tuğrul, 2024). This effect was attributed to the incorporation of lignin, which increased matrix hydrophobicity and compactness while reducing the polymer free volume for gas diffusion, thereby limiting water vapor transmission (Tunç and Tuğrul, 2024). Coffee extracts have also been reported to enhance UV barrier performance. Alginate-lecithin films enriched with medium-roasted coffee extracts significantly reduced UV transmission (200–400 nm), an advantage for protecting light-sensitive products (Socha et al., 2024). Cellulose-based films reinforced with natural pigments from coffee SS exhibited improved tensile strength and UV resistance, combining protective and aesthetic functions (Liu et al., 2023). This phenomenon was because polyphenols and melanoidins provided UV-absorbing chromophores and antioxidant activity that could prevent photodegradation and oxidative damage (Socha et al., 2024). However, while lipid plasticizers were used, they could enhance flexibility, they might also compromise barrier properties (Fadilla et al., 2023; Petaloti and Achilias, 2024a). Gas barrier properties could be highly influenced by the presence of chemical modifications or naturally derived additives in the films (Sisti et al., 2021). Natural additives like dyes enhanced both barrier efficiency and visual appeal without affecting the film’s sustainability (Sisti et al., 2021; Kruszelnicka et al., 2023). Despite these advances, the absence of standardized experimental protocols across studies leads to variability in reported results.

Optimizing formulations, such as varying the ratios of coffee by-products in polymer matrices, could tailor films for specific uses (Liu et al., 2023). Practical challenges remained, including film brittleness and excessive thickness, which hindered usability in commercial packaging (Fadilla et al., 2023). Lastly, the integration of safety regulations and consumer acceptance is essential to support the adoption of coffee by product-based edible films with desired barrier properties in the evolving market for biodegradable packaging (Oliveira et al., 2021).

Coffee by-products, including pulp, husk, SS, and SCG, are rich in bioactive compounds such as chlorogenic acid, caffeic acid, and flavonoids. These compounds exhibit potent antioxidant, antifungal, and antibacterial properties, making coffee waste a promising sustainable ingredient in the development of bioactive edible coatings and films, as documented in Table 1.

Vidal et al. (2022) evaluated the antioxidant activity of cold-pressed green coffee oil (GCO), combined with press cake (CE) and sediment (SE) extracts, in carboxymethyl cellulose (CMC) films using the 2,2-diphenyl-1-picryl hydrazyl (DPPH) assay. Films containing CE and GCO (C-CE) or SE and GCO (C-SE) demonstrated significantly enhanced antioxidant properties, with C-CE and C-SE films recording 3.61 ± 0.01 and 2.03 ± 0.01 mmol Trolox equivalents/g dry weight, respectively. In contrast, plain CMC films showed no detectable antioxidant activity. The enhanced performance was attributed to the higher levels of chlorogenic acids and caffeine in CE and SE. Turan et al. (2024) incorporated cascara extract films made from gelatin and glycerol. All formulations exhibited DPPH radical scavenging activity exceeding 45% even after a tenfold dilution. Reducing the gelatin and glycerol content increased total phenolics, indicating that cascara extract was the main contributor to antioxidant activity. Dordevic et al. (2024) investigated the antioxidant potential of κ-carrageenan films containing SCG using ferric reducing antioxidant power (FRAP), 2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and cupric ion reducing antioxidant capacity (CUPRAC) assays. Films with more than 0.45% SCG showed enhanced activity in the FRAP assay, while the CUPRAC method indicated improved antioxidant potential across all SCG concentrations. ABTS results showed no significant improvement with SCG addition, emphasizing the influence of assay type on antioxidant assessment, as CUPRAC detected both hydrophilic and lipophilic compounds.

Mirón-Mérida et al. (2019) examined the antifungal properties of coffee parchment (CP) extract incorporated into gellan gum films. Films containing 8 mg of CP extract showed the highest antifungal activity against Fusarium verticillioides, Fusarium sp., and Colletotrichum gloeosporioides. In contrast, control films without CP showed no inhibition against Fusarium sp. and C. gloeosporioides, suggesting the activity stemmed from bioactives such as gallic acid, chlorogenic acid, p-coumaric acid, and caffeine. Variations in fungal sensitivity were attributed to film thickness, water sensitivity, and fungal cell wall differences. Silva et al. (2024) further demonstrated antibacterial activity of chitosan films incorporating coffee leaf extracts. These films inhibited Gram-positive bacteria (Staphylococcus aureus, Staphylococcus epidermidis) but not Gram-negative bacteria Pseudomonas aeruginosa, likely due to the latter’s outer membrane barrier. Chlorogenic acids contributed to the dual antioxidant and antimicrobial functionality, as also reported by Rebollo-Hernanz et al. (2023), reinforcing the potential of coffee by-products in multifunctional food packaging solutions. Yet, the absence of standardized protocols across assays and film preparations complicates result interpretation and limits cross-study comparability.

Due to the presence of phenolic compounds, aroma compounds, and textural components in coffee by-products, their incorporation may alter the sensory profile of bio/edible films by modifying the composition of volatile and non-volatile compounds, thereby affecting aroma, flavor, mouthfeel, and aftertaste. Shrestha et al. (2021) reported that higher incorporation of phenolic compounds intensified color, astringency, and mouthfeel, consequently altering the overall sensory profile of food products. Wan-Mohtar et al. (2025) explained that the taste and aroma of coffee influence consumer acceptance because of its distinct lipid, protein, and caffeine profiles compared to other beans. However, no studies have reported such phenomena in bio/edible films, opening opportunities to optimize the incorporation of coffee by-products in developing films that align with consumer preferences. Additionally, residual caffeine, tannins, and other phenolic compounds contained in the coffee by-products, at extreme concentrations, may exert cytotoxic effects, requiring careful toxicological assessment before their application in bio/edible film development (Mussatto et al., 2011).

Coffee by-product utilization faces challenges in consistent collection and drying due to seasonality, moisture content, and rapid spoilage. Coffee by-product streams are fragmented (household, commercial, industrial), are often wet and perishable so they need stabilization (e.g., drying), and show variable compositions that complicate consistent processing and quality control (Franca and Oliveira, 2022). Processing into standardized ingredients and integrating them into existing manufacturing lines remains difficult, with higher costs compared to conventional materials (Esquivel and Jiménez, 2011; Selvam et al., 2025). Furthermore, regulatory hurdles, particularly for food-contact applications, pose significant barriers to commercialization (Esquivel and Jiménez, 2011; Selvam et al., 2025).

Coffee by-products offer a promising, cost-effective, and environmentally sustainable alternative for improving the functional and ecological performance of bio/edible films. These agro-industrial residues exhibit a richness in biofunctional compounds such as polyphenols, caffeine, and dietary fibers, which contribute significant antioxidant, antimicrobial, and UV-barrier properties, making them ideal candidates for applications in active food packaging. Several studies indicate that adding coffee by-products into biopolymer matrices can enhance mechanical strength, water vapor barrier properties, as well as thermal stability, while extending the shelf life of highly perishable foods. Despite these encouraging findings, additional research is required to fully exploit the potential of coffee by-products in edible coating development. The future direction could involve the encapsulation and controlled release of coffee-derived bioactives within edible film matrices. Furthermore, the practical application of coffee by-product-based coatings on real food systems should be explored, along with thorough toxicological and sensory evaluations. These assessments are essential to ensure the safety, consumer acceptability, and to address potential concerns such as astringency when coffee-derived coatings are used in direct contact with food. Emerging technologies, such as nanotechnology for precise release mechanisms and 3D printing for customized edible film structures, may open new opportunities for designing next-generation coffee by-product-based packaging. Encapsulation strategies could help stabilize sensitive compounds while mitigating undesirable sensory impacts, thereby improving consumer perception. Integrating these advanced approaches will accelerate the translation of coffee by-product-based edible films from laboratory studies to commercial food applications.