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    Topic review

    Antioxidant Molecules from Plant Waste

    Subjects: Others
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    (This entry belongs to Entry Collection "Aging and Public Health ")


    The fruit, vegetable, legume, and cereal industries generate many wastes, representing an environmental pollution problem. However, these wastes are a rich source of antioxidant molecules such as terpenes, phenolic compounds, phytosterols, and bioactive peptides with potential applications mainly in the food and pharmaceutical industries, and they exhibit multiple biological properties including antidiabetic, anti-obesity, antihypertensive, anticancer, and antibacterial properties. The aforementioned has increased studies on the recovery of antioxidant compounds using green technologies to value plant waste, since they represent more efficient and sustainable processes. In this review, the main antioxidant molecules from plants are briefly described and the advantages and disadvantages of the use of conventional and green extraction technologies used for the recovery and optimization of the yield of antioxidant naturals are detailed; finally, recent studies on biological properties of antioxidant molecules extracted from plant waste are presented here.

    1. Introduction 

    According to the Food and Agriculture Organization of the United Nations [1], globally, agriculture produces 8.65 billion tons of food per year. Along the agricultural food supply chain, a large amount of waste of fruits, vegetables, cereals, and pulses is produced, mainly during post-harvest, processing, and household consumption [2][3]. The levels of agricultural waste vary from region to region. For example, the United States of America generates about 15 million tons of fruit and vegetable waste, while China generates 32 million tons [4]. Cereals waste represents 10–12% of North America and Europe’s total production, while Asia is up to 18% [5]. In Mexico, the processing of fruits, vegetables, and cereals generates about 76 million tons of waste per year [6].

    The main agricultural wastes of peels, pomace, seeds, leaves, resin, and others are produced each year and are commonly disposed of in the environment, causing serious pollution and environmental problems. However, these wastes represent one of the main sources of low-cost antioxidants molecules, including terpenes, phytosterols, phenolic compounds, and peptides [7][8][9][10]. The antioxidant molecules could be used as food additives, pharmaceuticals, or therapeutic agents, because they have been shown to play an important role in the prevention and adjunctive treatment of diseases such as diabetes, cancer, hypertension, and metabolic syndrome [11][12][13][14][15].

    Therefore, the revaluing of plant-derived waste is a topic of interest to the scientific community. The attention has been focused on studying the recovery technologies for antioxidant molecules, especially those that are friendly to the environment, also known as green extraction technologies or non-conventional technologies such as enzyme-aided extraction, ultrasonic and microwave-assisted extraction, pressurized liquid extraction, and supercritical fluid extraction. These green technologies have replaced conventional technologies such as maceration and hydrodistillation, due to their high yield, reduced extraction process time, and mild conditions that prevent or reduce the degradation of the antioxidant molecules maintaining their quality, but above all, because the compounds of interest are recovered from sustainable processes [16][17][18].

    2. Plant Waste as Source of Bioactive Compounds

    Waste from inedible parts of plants such as peel, leaves, stem, seed, and root can be generated during the harvesting, post-harvesting, or processing [19]. They constitute a low-cost source of antioxidant molecules, including terpenes, polyphenols, phytosterols, and peptides, which exhibit antidiabetic, anti-obesity, antihypertensive, anticancer, and antibacterial properties [12][20][21][22][23]. However, these residues might have a negative impact on the environment. In this regard, as an effort to reduce the environmental consequences of plant waste and their potential exploitation, studies have focused on giving added value to plants waste through green extraction of antioxidant molecules, for intensifying their use as functional additives, or as a therapeutic alternative in the treatment or prevention of chronic diseases such as cardiovascular diseases, diabetes, and cancer [24].

    Peels and pomace of fruits such as mango, apple, grape, pomegranate, pineapple, banana, and orange are the main waste of the agri-food industry, which might present a greater content of phenolic compounds than the edible portion [19][25]. On the other hand, the oil industry of almond, rapeseed meal, and coconut; the processing of cereals (mainly wheat, rice, and oat); and the pitting process of fruits such as olive, plump, tomato, and peach generate large amounts of protein-rich residues, which have recently been used for the production of bioactive peptides [9][26][27][28][29][30][31][32][33]. Terpenes have been extracted mainly from essential oils from leaves, resins, and cones of trees such as Pinus taedaPistacia lentiscus, etc. [34]. Oils from fruits (e.g., melon, mango, orange, berries, papaya, apple, passion fruit, and guava seeds) and cereals (e.g., wheat, oat, and rice) are generally known to be the best natural sources of dietary plant sterols known as phytosterols [35][36][37].

    3. Conclusions and Future Perspectives

    The use of non-conventional extraction technologies or green technologies to obtain antioxidant molecules such as terpenes, phenolic compounds, phytosterols, and bioactive peptides from plant waste has increased in recent years in order to exploit and give added value to this type of waste, reduce environmental impact, obtain high quality extracts, safe products, reduce energy and solvent consumption, and increase the yield of the final product. Likewise, the number of studies focused on optimizing the conditions of the recovery process of this type of molecule has augmented, due to the nature of the plant material and the structural chemical differences (hydrophilicity and lipophilicity) presented by the antioxidant molecules discussed here, which have been widely studied due to their potential to prevent or treat cardiovascular diseases and others related to metabolic syndrome. However, although there is a wide variety of studies on the potential benefit of antioxidant molecules on human health, clinical studies are needed to confirm the findings reported both in vitro in animal models.

    Extraction of antioxidant molecules by SFE represents a viable option for its potential use at an industrial scale. Antioxidants obtained by SFE maintain their chemical structure and functional properties. Furthermore, the solvent CO2 used in SFE is safe and available. Additionally, SFE is already being used in industrial processes, such as coffee decaffeination, which reveals its scalable potential.

    The entry is from 10.3390/pr8121566


    1. FAO. Strategic Work of FAO for Sustainable Food and Agriculture. Available online: (accessed on 12 November 2020).
    2. FAO. The State of Food and Agriculture Moving Forward on Food Loss and Waste Reduction. Available online: (accessed on 12 November 2020).
    3. Esparza, I.; Jiménez-Moreno, N.; Bimbela, F.; Ancín-Azpilicueta, C.; Gandía, L.M. Fruit and vegetable waste management: Conventional and emerging approaches. Australas. J. Environ. Manag. 2020, 265, 110510.
    4. FAO. Utilization of Fruit and Vegetable Wastes as Livestock Feed and as Substrates for Generation of Other Value Added Products. Available online: (accessed on 12 November 2020).
    5. Belc, N.; Mustatea, G.; Apostol, L.; Iorga, S.; Vlăduţ, V.-N.; Mosoiu, C. Cereal supply chain waste in the context of circular economy. In Proceedings of the 8th International Conference on Thermal Equipment, Renewable Energy and Rural Development (TE-RE-RD 2019), Târgovişte, Romania, 20 August 2019; p. 8.
    6. Leyva-López, N.; Lizárraga-Velázquez, C.E.; Hernández, C.; Sánchez-Gutiérrez, E.Y. Exploitation of agro-industrial waste as potential source of bioactive compounds for aquaculture. Foods 2020, 9, 843.
    7. Balasundram, N.; Sundram, K.; Samman, S. Phenolic compounds in plants and agri-industrial by-products: Antioxidant activity, occurrence, and potential uses. Food Chem. 2006, 99, 191–203.
    8. González-López, Á.M.; Quiñones-Aguilar, E.E.; Rincón-Enríquez, G. Actividad biológica de los terpenos en el área agroalimentaria. In Los Compuestos Bioactivos y Tecnologías de Extracción; Espinosa Andrews, H., García Marquez, E., Gastelum Martínez, E., Eds.; Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco, A. C. (CIATEJ): Guadalajara, Mexico, 2016.
    9. Görgüç, A.; Özer, P.; Yılmaz, F.M. Microwave-assisted enzymatic extraction of plant protein with antioxidant compounds from the food waste sesame bran: Comparative optimization study and identification of metabolomics using LC/Q-TOF/MS. J. Food Process. Preserv. 2020, 44, e14304.
    10. Yoshida, Y.; Niki, E. Antioxidant effects of phytosterol and its components. J. Nutr. Sci. Vitaminol. 2003, 49, 277–280.
    11. Alongi, M.; Melchior, S.; Anese, M. Reducing the glycemic index of short dough biscuits by using apple pomace as a functional ingredient. LWT Food Sci. Technol. 2019, 100, 300–305.
    12. Dang, Y.; Zhou, T.; Hao, L.; Cao, J.; Sun, Y.; Pan, D. In vitro and in vivo studies on the angiotensin-converting enzyme inhibitory activity peptides isolated from broccoli protein hydrolysate. J. Agric. Food Chem. 2019, 67, 6757–6764.
    13. Guesmi, F.; Prasad, S.; Tyagi, A.K.; Landoulsi, A. Antinflammatory and anticancer effects of terpenes from oily fractions of Teucruim alopecurus, blocker of IκBα kinase, through downregulation of NF-κB activation, potentiation of apoptosis and suppression of NF-κB-regulated gene expression. Biomed. Pharmacother. 2017, 95, 1876–1885.
    14. Gautam, M.; Thapa, R.K.; Gupta, B.; Soe, Z.C.; Ou, W.; Poudel, K.; Jin, S.G.; Choi, H.-G.; Yong, C.S.; Kim, J.O. Phytosterol-loaded CD44 receptor-targeted PEGylated nano-hybrid phyto-liposomes for synergistic chemotherapy. Expert Opin. Drug Del. 2020, 17, 423–434.
    15. Santos, I.B.; de Bem, G.F.; Cordeiro, V.S.C.; da Costa, C.A.; de Carvalho, L.; da Rocha, A.P.M.; da Costa, G.F.; Ognibene, D.T.; de Moura, R.S. Supplementation with Vitis vinifera L. skin extract improves insulin resistance and prevents hepatic lipid accumulation and steatosis in high-fat diet-fed mice. Nutr. Res. 2017, 43, 69–81.
    16. Fierascu, R.C.; Fierascu, I.; Avramescu, S.M.; Sieniawska, E. Recovery of natural antioxidants from agro-industrial side streams through advanced extraction techniques. Molecules 2019, 24, 4212.
    17. Kumar, K.; Yadav, A.N.; Kumar, V.; Vyas, P.; Dhaliwal, H.S. Food waste: A potential bioresource for extraction of nutraceuticals and bioactive compounds. Bioresour. Bioprocess. 2017, 4, 18.
    18. Saini, A.; Panesar, P.S.; Bera, M.B. Valorization of fruits and vegetables waste through green extraction of bioactive compounds and their nanoemulsions-based delivery system. Bioresour. Bioprocess. 2019, 6, 26.
    19. Panzella, L.; Moccia, F.; Nasti, R.; Marzorati, S.; Verotta, L.; Napolitano, A. Bioactive phenolic compounds from agri-food wastes: An update on green and sustainable extraction methodologies. Front. Nutr. 2020, 7, 60.
    20. Colantuono, A.; Ferracane, R.; Vitaglione, P. In vitro bioaccessibility and functional properties of polyphenols from pomegranate peels and pomegranate peels-enriched cookies. Food Funct. 2016, 7, 4247–4258.
    21. Hou, J.; Zhang, Y.; Zhu, Y.; Zhou, B.; Ren, C.; Liang, S.; Guo, Y. α-Pinene induces apoptotic cell death via caspase activation in human ovarian cancer cells. Med. Sci. Monit. 2019, 25, 6631–6638.
    22. Gajendran, B.; Durai, P.; Varier, K.M.; Chinnasamy, A. A novel phytosterol isolated from Datura inoxia, RinoxiaB is a potential cure colon cancer agent by targeting BAX/Bcl2 pathway. Bioorg. Med. Chem. 2020, 28, 115242.
    23. Urquiaga, I.; Troncoso, D.; Mackenna, M.J.; Urzua, C.; Perez, D.; Dicenta, S.; de la Cerda, P.M.; Amigo, L.; Carreno, J.C.; Echeverria, G.; et al. The consumption of beef burgers prepared with wine grape pomace flour improves fasting glucose, plasma antioxidant levels, and oxidative damage markers in humans: A controlled trial. Nutrients 2018, 10, 1388.
    24. Zhang, Y.-J.; Gan, R.-Y.; Li, S.; Zhou, Y.; Li, A.-N.; Xu, D.-P.; Li, H.-B. Antioxidant phytochemicals for the prevention and treatment of chronic diseases. Molecules 2015, 20, 21138–21156.
    25. Fierascu, R.C.; Sieniawska, E.; Ortan, A.; Fierascu, I.; Xiao, J. Fruits by-products-A source of valuable active principles. A short review. Front. Bioeng. Biotechnol. 2020, 8, 319.
    26. González-García, E.; Puchalska, P.; Marina, M.L.; García, M.C. Fractionation and identification of antioxidant and angiotensin-converting enzyme-inhibitory peptides obtained from plum (Prunus domestica L.) stones. J. Funct. Food. 2015, 19, 376–384.
    27. He, R.; Yang, Y.-J.; Wang, Z.; Xing, C.-r.; Yuan, J.; Wang, L.-F.; Udenigwe, C.; Ju, X.-R. Rapeseed protein-derived peptides, LY, RALP, and GHS, modulates key enzymes and intermediate products of renin–angiotensin system pathway in spontaneously hypertensive rat. NPJ Sci. Food 2019, 3, 1–6.
    28. Liu, J.-J.; Gasmalla, M.A.A.; Li, P.; Yang, R. Enzyme-assisted extraction processing from oilseeds: Principle, processing and application. Innov. Food Sci. Emerg. Technol. 2016, 35, 184–193.
    29. Moayedi, A.; Mora, L.; Aristoy, M.C.; Safari, M.; Hashemi, M.; Toldrá, F. Peptidomic analysis of antioxidant and ACE-inhibitory peptides obtained from tomato waste proteins fermented using Bacillus Subtilis. Food Chem. 2018, 250, 180–187.
    30. Vaásquez-Villanueva, R.; Orellana, J.M.A.; Marina, M.L.; García, M.C. Isolation and characterization of angiotensin converting enzyme inhibitory peptides from peach seed hydrolysates: In vivo assessment of antihypertensive activity. J. Agric. Food Chem. 2019, 67, 10313–10320.
    31. Wang, X.; Chen, H.; Fu, X.; Li, S.; Wei, J. A novel antioxidant and ACE inhibitory peptide from rice bran protein: Biochemical characterization and molecular docking study. LWT Food Sci. Technol. 2017, 75, 93–99.
    32. Zheng, Y.; Li, Y.; Li, G. ACE-inhibitory and antioxidant peptides from coconut cake albumin hydrolysates: Purification, identification and synthesis. RSC Adv. 2019, 9, 5925–5936.
    33. Zhou, Q.F.; Zhou, J.X.; Liu, X.J.; Zhang, Y.B.; Cai, S.B. Digestive enzyme inhibition of different phenolic fractions and main phenolic compounds of ultra-high-pressure-treated palm fruits: Interaction and molecular docking analyses. J. Food Qual. 2020, 2020, 8811597.
    34. Teixeira, S.D.; Fiorio, J.L.; Galvan, D.; Sefstrom, C.; Cogo, P.M.; Sales Junior, V.; Rodrigues, M.B.; Hendges, A.P.P.K.; Maia, B.H.L.d.N.S. Investigation on chemical composition and optimization of essential oil obtainment from waste Pinus taeda L. using hydrodistillation. Braz. Arch. Biol. Technol. 2016, 59, e16150043.
    35. da Silva, A.C.; Jorge, N. Bioactive compounds of oils extracted from fruits seeds obtained from agroindustrial waste. Eur. J. Lipid Sci. Technol. 2017, 119, 1600024.
    36. Jiang, Y.; Wang, T. Phytosterols in cereal by-products. J. Am. Oil Chem. Soc. 2005, 82, 439–444.
    37. Uddin, M.; Ferdosh, S.; Haque Akanda, M.J.; Ghafoor, K.; Rukshana, A.; Ali, M.E.; Kamaruzzaman, B.; Fauzi, M.; Shaarani, S.; Islam Sarker, M.Z. Techniques for the extraction of phytosterols and their benefits in human health: A review. Sep. Sci. Technol. 2018, 53, 2206–2223.