Valorisation of floral industry by-products as sources of bioactive compounds for functionalized biopolymer-based packaging: a mini review

1 Introduction

The global floral and perfumery industry produces millions of tons of biomass annually, much of which is discarded after the extraction of essential oils or after the commercial use of fresh flowers. Petals, calyces, stems and distillation residues are typically composted or disposed of as low-value waste, despite their rich phytochemical composition. These materials contain high concentrations of phenolic acids, flavonoids, anthocyanins, carotenoids, tannins and volatile terpenoids, all of which exhibit strong antioxidant and antimicrobial properties (Živanović et al., 2025). Their valorisation represents a promising strategy to reduce waste, increase resource efficiency and generate natural compounds suitable for food-contact applications. In parallel, the food packaging sector is undergoing a profound transformation driven by environmental concerns, regulatory pressure and consumer demand for sustainable materials. Biopolymers such as chitosan, pectin, alginate, starch, and cellulose derivatives have emerged as alternatives to conventional plastics (Giosafatto et al., 2026). However, their intrinsic limitations including hydrophilicity, limited mechanical strength and insufficient barrier properties; have hindered their widespread adoption. The incorporation of natural bioactive compounds into biopolymer matrices offers a dual advantage: it enhances the functional performance of the material and introduces active properties capable of extending food shelf life (Avitabile et al., 2026). The convergence of these two trends, biopolymer development and floral waste valorisation creates a unique opportunity for circular innovation. Floral by-products can be transformed into high-value extracts through green extraction technologies and subsequently used to functionalize biopolymer-based packaging. This approach aligns with the principles of the circular bioeconomy, reduces environmental impact, and supports the transition toward sustainable food systems. The present review examines the chemical potential of floral waste, the extraction methods suitable for recovering bioactive compounds and the strategies for integrating these compounds into nanostructured biopolymer matrices.

2 Potential of floral industry by-products

Floral by-products represent a chemically rich and diverse biomass whose composition varies according to species, cultivation conditions and processing methods, but several classes of bioactive compounds are consistently present. Phenolic acids such as gallic, caffeic and ferulic acid contribute to strong antioxidant activity and can inhibit lipid oxidation in food systems. Flavonoids including quercetin, kaempferol and rutin exhibit antimicrobial and anti-inflammatory properties and can stabilize biopolymer matrices through hydrogen bonding (Avitabile et al., 2024a). Anthocyanins, responsible for the vivid colours of many flowers, provide antioxidant activity and can act as natural pH indicators, enabling the development of smart packaging capable of monitoring food freshness (Hasanah et al., 2023; Khezerlou et al., 2023). Carotenoids such as lutein and β-carotene are abundant in species like Calendula officinalis and Tagetes erecta. These compounds offer UV-protective properties and can improve the photostability of biopolymer films. Terpenoids, including linalool, geraniol, citronellol and eucalyptol are characteristic of aromatic flowers such as lavender, rose, jasmine and Callistemon citrinus (Laganà et al., 2020) and possess strong antimicrobial activity of inhibiting foodborne pathogens. Distillation residues from the fragrance industry often retain significant amounts of these compounds, making them particularly valuable for extraction. Beyond their chemical richness, floral waste also provide sensory properties: many extracts retain pleasant aromas that can enhance the sensory appeal of packaging materials or mask undesirable odors. This characteristic is especially relevant for coatings applied directly to fresh produce. The combination of antioxidant, antimicrobial and aromatic properties make floral by-products an ideal source of natural additives for active packaging (Figure 1). Despite their chemical richness, the practical valorisation of floral by-products faces several obstacles that limit industrial uptake. Floral residues are highly perishable, with enzymatic browning, microbial growth and moisture accumulation occurring within hours after harvest (Fernandes et al., 2019). Their heterogeneous composition - arising from differences in cultivar, growth conditions, maturity stage and post-harvest handling - makes it difficult to obtain extracts with reproducible phytochemical profiles (Azwanida, 2015). Furthermore, the logistics of storage and transport require controlled temperature and humidity to prevent degradation of phenolics and volatile terpenoids. These challenges highlight the need for improved supply-chain management, pre-treatments (drying, stabilization) and robust analytical protocols to ensure consistent extract quality.

3 Green extraction technologies for floral by-products

The recovery of bioactive compounds from floral waste requires extraction methods that preserve chemical integrity while minimizing environmental impact. Traditional solvent extraction is effective but often relies on organic solvents and long processing times. Green extraction technologies offer more sustainable alternatives and are increasingly adopted for food-grade applications. Ultrasound-assisted extraction (UAE) is widely used for floral matrices due to its ability to disrupt plant cell walls and enhance mass transfer (Briliantama et al., 2022). The cavitation effect generated by ultrasound waves accelerates the release of phenolic compounds and flavonoids, reducing extraction time and solvent consumption. UAE is particularly suitable for delicate materials such as rose petals and lavender residues, where thermal degradation must be avoided. Microwave-assisted extraction (MAE) provides rapid heating and efficient solvent penetration, making it ideal for compounds with moderate thermal stability, such as carotenoids and certain flavonoids (Mobasheri et al., 2025). MAE can significantly increase extraction yields while reducing energy consumption. Its main limitation is the potential degradation of highly volatile terpenoids, which require careful optimization of temperature and time. Supercritical CO₂ extraction is the method of choice for volatile and lipophilic compounds, including terpenoids and aromatic molecules. CO₂ is non-toxic, non-flammable, and leaves no solvent residues, making it suitable for food-contact applications (Allay et al., 2025). The tunability of pressure and temperature allows selective extraction of specific compounds. Distillation residues from jasmine, rose, and Callistemon citrinus are particularly well suited to this technique. Natural deep eutectic solvents (NADES) represent an emerging class of green solvents with high solubilizing power for polyphenols and flavonoids. NADES are biodegradable, low-toxicity, and compatible with food applications. Their ability to form hydrogen bonds with phenolic compounds enhances extraction efficiency. NADES-based extraction is gaining attention for the valorisation of floral waste due to its sustainability and versatility (Bezerra and Koblitz, 2025). Aqueous enzymatic extraction offers another environmentally friendly approach. Enzymes such as pectinases, cellulases, and hemicelluloses break down plant cell walls, releasing bound phenolic compounds. This method is particularly effective for biomass rich in pectins and cellulose, such as marigold and calendula petals. Enzymatic extraction operates under mild conditions, preserving the integrity of heat-sensitive compounds. Hydrodistillation, although one of the oldest extraction methods used in the fragrance industry, remains highly relevant for the valorisation of floral by-products and deserves explicit consideration within green extraction frameworks (Yeddes et al., 2025). Hydrodistillation involves the co-distillation of plant material with water or steam, enabling the recovery of essential oils and hydrosols rich in volatile terpenoids, aromatic alcohols, and oxygenated compounds. While traditionally considered energy-intensive, modern hydrodistillation systems have been optimized to reduce water consumption, improve heat recovery, and minimize environmental impact (Soares et al., 2025). Importantly, hydrodistillation generates two valuable fractions: an essential oil phase containing highly concentrated volatile compounds, and an aqueous distillate (hydrolate) enriched in water-soluble aromatic molecules. Both fractions can be incorporated into biopolymer matrices, with essential oils providing strong antimicrobial activity and hydrosols contributing antioxidant and aromatic properties. Moreover, the solid residues remaining after hydrodistillation still contain significant amounts of polyphenols and flavonoids, making them suitable for subsequent extraction through UAE, MAE, or NADES. This multi-step valorisation approach positions hydrodistillation as a central component of integrated biorefinery strategies for floral waste (Rassem et al., 2022). Overall, the choice of extraction method depends on the chemical profile of the floral biomass, the target compounds, and the intended application in active packaging. Hydrodistillation remains indispensable for volatile compounds, while UAE, MAE, and NADES excel in recovering phenolic and antioxidant molecules. Supercritical CO₂ extraction provides high-purity lipophilic fractions, and enzymatic extraction offers a mild, selective approach for bound phenolics. Together, these technologies form a versatile toolkit for transforming floral by-products into high-value bioactive ingredients suitable for the functionalization of sustainable packaging materials.

4 Incorporation of floral extracts into biopolymer matrices

The integration of floral extracts into biopolymer matrices requires careful consideration of compatibility, stability, and release mechanisms. Successful incorporation of floral extracts requires careful control of polymer-extract compatibility, which depends on polarity, hydrogen-bonding capacity and ionic interactions. Phenolic compounds interact strongly with chitosan through electrostatic and hydrogen-bonding mechanisms, whereas anthocyanins require pH values below 4 to maintain their flavylium cation form and avoid colour loss. Extract loading typically ranges from 0.5% to 5% w/w, as higher concentrations may plasticize the matrix, reduce tensile strength or alter film transparency. Conversely, moderate phenolic loading can increase crosslinking density and improve mechanical performance (Avitabile et al., 2024a; Avitabile et al., 2024b). Chitosan is one of the most widely used biopolymers for active packaging due to its intrinsic antimicrobial activity and film-forming properties. The incorporation of floral extracts into chitosan films enhances antioxidant activity, improves UV protection, and can create synergistic antimicrobial effects (Avitabile et al., 2024b). The cationic nature of chitosan facilitates interactions with phenolic compounds, improving film cohesion and mechanical strength. Pectin and alginate films are particularly suitable for hydrophilic extracts rich in polyphenols (Urbonavičiūtė et al., 2023; Vallejo-Castillo et al., 2020). These polysaccharides form gels through ionic crosslinking and can encapsulate bioactive compounds within their network. Floral extracts can improve the oxygen barrier properties of pectin-based films and modulate their mechanical behaviour. The mild processing conditions required for pectin and alginate films help preserve the activity of sensitive compounds such as anthocyanins. Starch-based films benefit from the incorporation of floral extracts through improved mechanical strength, enhanced hydrophobicity, and increased thermal stability (Matheus et al., 2025). Phenolic compounds can interact with starch chains, reducing retrogradation and improving film flexibility. The addition of carotenoid-rich extracts can impart natural coloration and UV-protective properties. Cellulose-based films, including those reinforced with nanocellulose, offer excellent transparency and oxygen barrier properties (Akl et al., 2021). The incorporation of floral extracts enhances antioxidant activity and can improve the photostability of the films. Nanocellulose provides a high surface area for interactions with phenolic compounds, improving their dispersion and stability. The choice of biopolymer matrix depends on the chemical nature of the extract, the desired functional properties, and the intended food application. In all cases, the integration of floral extracts contributes to the development of packaging materials that are both sustainable and functionally enhanced.

5 Nanostructuring approaches for enhanced stability and functionality

Nanostructuring plays a crucial role in improving the stability, bioavailability and controlled release of floral extracts within biopolymer matrices (Koshy et al., 2023). Most floral extracts are highly sensitive to heat, light, oxygen and pH fluctuations, and many terpenoids are volatile. Nanostructuring strategies mitigate these issues by providing physical barriers and controlled-release matrices. Nanoemulsions and pickering emulsions protect hydrophobic terpenoids from evaporation and oxidation, while nanocellulose or lignin nanoparticles stabilize phenolics through adsorption and hydrogen bonding (Sarma et al., 2026; Rashid et al., 2024). Beyond the stabilization of floral extracts, it is also important to consider the practical aspects of using flower waste for industrial applications. Nanoemulsions can be prepared using energy or energy methods and can be stabilized with natural emulsifiers compatible with food applications. Pickering emulsions, stabilized by solid particles rather than surfactants, offer exceptional stability and are well suited for the encapsulation of floral extracts (Koirala et al., 2023). Nanocellulose, chitin nanocrystals, and protein nanoparticles can adsorb irreversibly at the oil-water interface, protecting volatile compounds from oxidation and evaporation. Pickering emulsions provide controlled release properties and can enhance the antimicrobial and antioxidant activity of the final packaging material. Reinforced systems represent another important nanostructuring approach. The incorporation of nanocellulose, lignin nanoparticles, or chitin nanocrystals into biopolymer matrices improves mechanical strength, barrier properties, and thermal stability (Faisal et al., 2023). These nanofillers can also interact with phenolic compounds, enhancing their stability and modulating their release. Lignin nanoparticles provide strong antioxidant activity and otective properties, complementing the functionality of floral extracts (Zhang et al., 2025). Electrospun nanofibers offer a high surface area and tunable porosity, making them ideal for the encapsulation and controlled release of floral extracts. Electrospinning allows the incorporation of both hydrophilic and hydrophobic compounds and can produce multilayer structures with distinct functional properties. Nanofibrous coatings can be applied directly to food surfaces or used as active layers in multilayer packaging systems (Chen et al., 2022; Ebrahimi et al., 2025). Nanostructuring not only enhances the performance of floral extracts but also improves the overall functionality of biopolymer films. The combination of natural bioactive compounds with advanced material engineering creates packaging systems capable of addressing multiple preservation challenges simultaneously.

6 Applications as active food packaging

The incorporation of floral extracts into biopolymer-based packaging has been explored for a wide range of food products. Fresh produce benefits from coatings and films enriched with phenolic-rich extracts, which reduce microbial growth, delay ripening, and minimize weight loss (Avitabile et al., 2026; Sarkhel et al., 2026). The antioxidant and antimicrobial properties of floral extracts help maintain colour, texture and nutritional quality during storage (Babić et al., 2025; Thongphichai et al., 2023). Meat and fish products are particularly susceptible to lipid oxidation and microbial spoilage. Packaging materials functionalized with terpenoid-rich extracts from lavender, rosemary, or C. citrinus can inhibit the growth of pathogens such as Listeria monocytogenes and Staphylococcus aureus while reducing oxidative rancidity (Avitabile et al., 2026). These effects contribute to improved sensory quality and extended shelf life. Dairy products, especially high-moisture cheeses, benefit from the antimicrobial and antioxidant properties of floral extracts. Chitosan-based coatings enriched with phenolic compounds can reduce surface microbial growth and delay spoilage. The pleasant aroma of certain floral extracts can also enhance the sensory profile of the product. Bakery products are prone to mold growth, which can be inhibited by packaging materials containing flavonoid-rich extracts. The antioxidant properties of these compounds also help preserve the freshness and colour of baked goods. The incorporation of anthocyanin-rich extracts can provide natural coloration and enable the development of pH-responsive smart packaging capable of indicating spoilage (Hasanah et al., 2023; Khezerlou et al., 2023). The versatility of floral extracts allows their application across diverse food categories. Their multifunctional properties make them ideal candidates for the development of active packaging systems that address both microbial and oxidative challenges.

7 Discussion

Floral industry by-products are an abundant but underutilized biomass rich in phenolic acids, flavonoids, anthocyanins, carotenoids and terpenoids. Their valorisation through green extraction technologies offers a sustainable route to obtain natural bioactive compounds suitable for incorporation into biopolymer-based packaging. When integrated into matrices such as chitosan, pectin, alginate, starch or cellulose derivatives; these extracts significantly enhance antioxidant, antimicrobial and UV-protective properties, improving food preservation and reducing dependence on synthetic additives (Vieria et al., 2022; Xie et al., 2023; Chheng et al., 2025). Despite their potential, several challenges remain. Floral waste composition is highly variable, requiring standardized extraction and characterization methods (Ortega et al., 2022). Many bioactive compounds are sensitive to oxidation and heat, making stabilization and controlled release essential. Several approaches can be considered, such as powdering the residues or separating stalks from petals, yet each additional processing step increases energy consumption and time requirements (Matheus et al., 2025). Additional concerns must be considered when translating floral extract-based packaging to real applications. Chitosan-based materials may pose allergenicity risks for individuals sensitive to crustacean-derived chitin, requiring clear labelling and safety assessment. Hydrophilic biopolymers such as pectin, alginate and starch are susceptible to microbial contamination under high humidity, necessitating proper drying, storage and possibly the inclusion of natural antimicrobial agents. Regulatory approval requires toxicological evaluation and migration studies. Addressing these limitations is essential to ensure safe, scalable and consumer-acceptable packaging solutions. Nanostructuring strategies - such as nanoemulsions, pickering emulsions, nanofillers, and electrospun fibers - help protect these compounds and improve their functional performance (Abbas et al., 2022; Osvaldt Rosales et al., 2023; Chowdhury et al., 2024). Their implementation could be further strengthened by designing multi-layer architectures where nanostructured active layers are physically separated from the food-contact surface, reducing migration concerns while maintaining functional efficacy. Regulatory approval, safety assessments and industrial scalability also represent key steps toward real-world application. In conclusion, the valorisation of floral by-products aligns with circular bioeconomy principles and offers a promising pathway toward multifunctional sustainable packaging (Kumar et al., 2025). Therefore, before scaling up, it is crucial to evaluate the trade-off between process complexity and sustainability (Arenas et al., 2024). Future studies should focus on low-energy valorization routes and integrated biorefinery frameworks to ensure both ecological and economic feasibility (Rashid et al., 2024; Sarma et al., 2026).

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Footnotes

Edited by: Rafael Audino Zambelli, Federal University of Ceará, Brazil

Reviewed by: Zhuoyu Wang, Texas A and M University, United States