Introduction
Globally, an estimated 1.3 to 1.6 billion tons of food are wasted each year, with fruits and vegetables accounting for a significant proportion due to their perishable nature and losses during processing and consumption (Gupta et al., 2024). However, fruit and vegetable by-products – including peels, seeds, pomace, stems, and leaves – are rich in valuable bioactive compounds with potential applications in the food, pharmaceutical, cosmetic, and sustainable packaging industries. The utilization of these by-products not only reduces environmental pollution but also adds significant economic value, aligning with circular economy models and the United Nations' Sustainable Development Goals (SDGs).
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Fig. 1. Fruit and vegetables residues (Ali et al., 2023)
Nutritional and Bioactive Components in Fruit and Vegetable By-products
Fruit and vegetable by-products are rich in diverse biochemical constituents, including antioxidants (flavonoids, polyphenols), vitamins (C, E), minerals, essential fatty acids, and natural pigments such as anthocyanins, carotenoids, betalains, and chlorophyll (Benucci et al., 2022; Kuyu, 2015). Several studies have shown that in many cases, these compounds are present in higher concentrations in the peel or seed than in the edible portion of the produce (Ali et al., 2023). For example, apple peels are abundant in chlorogenic acid and procyanidin B2; mango seeds contain flavonoids and phenolic acids; citrus peels are rich in limonoids, vitamin C, and essential oils. These compounds exhibit strong antioxidant capacity, capable of neutralizing free radicals – the primary culprits in cell aging and chronic diseases such as cardiovascular disease, diabetes, and cancer (Pereira et al., 2022).
Beyond their nutritional value, these compounds exert potent biological activities, supporting the prevention of chronic conditions including neurodegenerative disorders (Ali et al., 2023; Kuyu, 2015).
Applications of Fruit and Vegetable By-products
Amid growing concerns over the negative health effects of synthetic additives, there is an increasing trend toward using natural food additives. Fruit and vegetable by-products serve as promising sources of natural pigments, flavors, antioxidants, and bio-preservatives (Benucci et al., 2022). The use of biocatalytic enzymes such as cellulase, pectinase, and hemicellulase facilitates the release of bioactive compounds by breaking down plant cell walls in an eco-friendly manner, as opposed to chemical extraction. This “green” approach is widely applied in the functional food and cosmetic industries. Examples include:
- Anthocyanins from eggplant peels, purple cabbage, and grape pomace – natural red/purple colorants with antioxidant activity.
- Lycopene from tomato peels – known for its potential to prevent prostate cancer and cardiovascular diseases.
- Citrus essential oils – extracted from orange peels, used as flavoring agents in beverages and foods.
Additionally, mango pomace, orange peel, and other fruit residues can be used as functional additives in baked goods, snacks, or fermented beverages (Kuyu, 2015; Ali et al., 2023).
- Fermentation and Microbial Biotechnology
Fermentation, a traditional biotechnology process, has undergone significant innovation. Beneficial microorganisms such as Lactobacillus, Saccharomyces cerevisiae, and Bacillus subtilis can transform fruit and vegetable by-products into high-value products, including: Probiotic fermented beverages from fruit peels, organic acids (e.g., lactic acid, acetic acid) used as natural preservatives, and immunomodulatory metabolites, such as exopolysaccharides or antimicrobial peptides (Kesa et al., 2021).
- Development of Biodegradable Food Packaging
Beyond food additives, fruit and vegetable by-products are valuable materials for producing biofilms, edible coatings, and biodegradable packaging. Common materials include: Pectin from citrus peels, starch from potato peels, fibers from banana peels or carrot pomace.
When combined with biopolymers such as chitosan or polylactic acid (PLA), these materials form biodegradable packaging with excellent barrier properties. In some cases, these materials also exhibit antioxidant and antimicrobial properties, extending shelf life (Gupta et al., 2024; Ali et al., 2023).
Furthermore, the integration of nanotechnology – such as the incorporation of silver nanoparticles or nanocellulose – enhances preservation performance. However, further research is required to evaluate the safety and migration behavior of nanoparticles in food-contact applications.
- Green and Sustainable Extraction Technologies
To efficiently recover bioactive compounds from fruit and vegetable by-products, various sustainable extraction techniques have been developed, including:
- Supercritical CO₂ extraction (SFE) – used for non-polar compounds such as essential oils and carotenoids.
- Microwave-assisted extraction (MAE) and ultrasound-assisted extraction (UAE) – energy-efficient methods that improve yield and reduce processing time.
- High hydrostatic pressure (HHP) and cold plasma treatments – enhance bioavailability and preserve bioactivity (Gupta et al., 2024).
These technologies align with the goals of sustainable production in the food industry while ensuring higher recovery rates and compound integrity.
- Challenges and Future Perspectives
Despite promising potential, the practical application of fruit and vegetable by-products in the food industry still faces challenges. These include:
- High costs of advanced extraction technologies
- Limited stability of natural pigments and bioactives
- Lack of clear legal frameworks for classifying “food waste” as raw materials (Benucci et al., 2022)
- Consumer hesitation toward products made from food waste
Nonetheless, with support from circular economy policies and global commitments such as SDG 12.3 (halving food waste by 2030), fruit and vegetable by-product valorization presents a feasible and valuable solution for both environmental and economic benefits.
Conclusion
Biotechnology plays a vital role in unlocking the potential of fruit and vegetable by-products, transforming what is often discarded into valuable raw materials. Through modern approaches involving enzymatic processes, microbial fermentation, and genetic engineering, a wide range of bioactive compounds can be harnessed to produce functional food ingredients, natural additives, and sustainable packaging solutions.
The reuse of agricultural waste not only reduces environmental burden but also creates new economic opportunities aligned with the principles of a circular, sustainable food system. In the near future, fruit and vegetable by-products may become essential resources in the advancement of the food and biotech industries.
References
- Ali, Z., Gupta, N., Singh, J., Bhat, A., Sood, M., Bandral, J. D., & Reshi, M. (2023). Utilization of By-Products of Fruits and Vegetables in Food Industries. Chemical Science Review and Letters, 12(45), 49–54. https://doi.org/10.37273/chesci.cs205312558
- Benucci, I., Lombardelli, C., Mazzocchi, C., & Esti, M. (2022). Natural colorants from vegetable food waste: Recovery, regulatory aspects, and stability—A review. Comprehensive Reviews in Food Science and Food Safety, 21, 2715–2737. https://doi.org/10.1111/1541-4337.12951
- Gupta, R. K., Ali, E. A., El Gawad, F. A., Daood, V. M., Sabry, H., Karunanithi, S., & Srivastav, P. P. (2024). Valorization of fruits and vegetables waste byproducts for development of sustainable food packaging applications. Waste Management Bulletin, 2, 21–40. https://doi.org/10.1016/j.wmb.2024.08.005
- Kuyu, C. G. (2015). Review on Potential Use of Fruit and Vegetables By-Products as a Valuable Source of Natural Food Additives. Food Science and Quality Management, 45, 47–51. https://www.researchgate.net/publication/285592477
- Pereira, J. A., Berenguer, C. V., Andrade, C. F., & Câmara, J. S. (2022). Unveiling the bioactive potential of fresh fruit and vegetable waste in human health from a consumer perspective. Applied sciences, 12(5), 2747.
M.Sc. Tran Thi Thu Ngan
Faculty of Engineering and Technology, Van Hien University