Optimization of ultrasound-assisted extraction of total phenolics and anthocyanin from purple onion peel

Year 2025, Volume: 6 Issue: 2, 42 - 52, 30.12.2025

Ayşegul Zorlu , Ayşe Neslihan Dündar , Oya Irmak Şahin

https://doi.org/10.55147/efse.1831291

Abstract

Purple onion (Allium cepa L.) peels, an abundant agro-industrial by-product, are particularly rich in flavonoids and anthocyanins with strong antioxidant potential. The effective recovery of these biologically active compounds enables the conversion of plant residues into high value-added products, supporting both clean-label ingredient development approaches and circular bioeconomy strategies. This study aimed to optimize ultrasound-assisted extraction (UAE) conditions to maximize the yield of total phenolic content (TPC) and total monomeric anthocyanins (TMAC) from purple onion peel s. A central composite design based on response surface methodology (RSM) was employed to systematically investigate the effects of four independent variables: ethanol concentration (0-100%), solvent-to-solid ratio (10-60 mL/g), extraction temperature (20-60 °C), and extraction time (30-120 min). The results indicated that solvent composition, temperature, and duration significantly influenced bioactive compound recovery. TPC ranged from 237.06 to 1230.96 mg GAE/100 g, while TMAC varied between 1645.84 and 12357.50 mg/kg. Multi-response optimization identified 95% ethanol, 55 mL/g solvent-to-solid ratio, 40 °C, and 105 min as optimal conditions, which were subsequently validated through confirmatory experiments. Extracts obtained under these optimized conditions exhibited desirable color parameters, low water activity values (0.20-0.52), indicating high stability and functional applicability in various formulations. Overall, the integration of UAE with RSM offers an efficient, scalable, and environmentally friendly approach for the extraction of natural pigments and antioxidants from purple onion peels, emphasizing their value as a sustainable ingredient source for food, nutraceutical, and related applications.

Keywords

Purple onion peel , ultrasound-assisted extraction , response surface methodology , phenolic compounds , anthocyanins

References

• AOAC International. (2005). Official Method 2005.02: Total monomeric anthocyanin pigment content of fruit juices, beverages, natural colorants, and wines by pH differential method. In Official Methods of Analysis (18th ed.). AOAC International.
• Bae, E. K., & Lee, S. J. (2008). Microencapsulation of avocado oil by spray drying using whey protein and maltodextrin. Journal of microencapsulation, 25(8), 549-560. doi:10.1080/02652040802075682
• Benítez, V., Mollá, E., Martín-Cabrejas, M. A., Aguilera, Y., López-Andréu, F. J., Cools, K., Terry, L. A., & Esteban, R. M. (2011). Characterization of industrial onion wastes (Allium cepa L.): Dietary fibre and bioactive compounds. Plant Foods for Human Nutrition, 66(1), 48-57. doi:10.1007/s11130-011-0212-x
• Bitwell, C., Indra, S. S., Luke, C., & Kakoma, M. K. (2023). A review of modern and conventional extraction techniques and their applications for extracting phytochemicals from plants. Scientific African, 19, e01585. doi:10.1016/j.sciaf.2023.e01585
• Cacace, J. E., & Mazza, G. (2003). Optimization of extraction of anthocyanins from black currants with aqueous ethanol. Journal of Food Science, 68(1), 240-248. doi:10.1111/j.1365-2621.2003.tb14146.x
• Castañeda-Ovando, A., Pacheco-Hernández, M. L., Páez-Hernández, M. E., Rodríguez, J. A., & Galán-Vidal, C. A. (2009). Chemical studies of anthocyanins: A review. Food Chemistry, 113, 859-871. doi:10.1016/j.foodchem.2008.09.001
• Chadorshabi, S., Hallaj-Nezhadi, S., & Ghasempour, Z. (2022). Red onion skin active ingredients, extraction and biological properties for functional food applications. Food Chemistry, 386, 132737. doi:10.1016/j.foodchem.2022.132737.
• Chemat, F., Rombaut, N., Sicaire, A.G., Meullemiestre, A., Fabiano‑Tixier, A.S., & Abert‑Vian, M. (2017). Ultrasound assisted extraction of food and natural products: Mechanisms, techniques, combinations, protocols, and applications. Ultrasonics Sonochemistry, 34, 540–560. https://doi.org/10.1016/j.ultsonch.2016.06.035.
• Çalışkan Koç, G., & Dirim, S. N. (2013). The effects of the different drying conditions and the amounts of maltodextrin addition during spray drying of sumac extract. Food and Bioproducts Processing, 91(4), 539-548. doi:10.1016/j.fbp.2013.06.004
• Elleuch, M., Bedigian, D., Roiseux, O., Besbes, S., Blecker, C., & Attia, H. (2011). Dietary fibre and fibre-rich by-products of food processing: Characterisation, technological functionality and commercial applications: A review. Food Chemistry, 124(2), 411-421. doi:10.1016/j.foodchem.2010.06.077
• Elsebaie, E. M., & Essa, R. Y. (2018). Microencapsulation of red onion peel polyphenols fractions by freeze drying technicality and its application in cake. Journal of Food Processing and Preservation, 42(7), e13654. doi:10.1111/jfpp.13654.
• Food and Agriculture Organization of the United Nations. (2021). FAOSTAT: FAO statistical databases. https://www.fao.org/faostat/en/
• Giusti, M. M., & Wrolstad, R. E. (2001). Characterization and measurement of anthocyanins by UV-visible spectroscopy. Current Protocols in Food Analytical Chemistry, Unit F1.2. doi:10.1002/0471142913.faf0102s00
• González-Centeno, M. R., Comas-Serra, F., Femenia, A., Rosselló, C., & Simal, S. (2015). Effect of power ultrasound application on aqueous extraction of phenolic compounds and antioxidant capacity from grape pomace (Vitis vinifera L.): Experimental kinetics and modeling. Ultrasonics Sonochemistry, 22, 506-514. doi:10.1016/j.ultsonch.2014.05.027 González‑de‑Peredo, A. V., Vázquez‑Espinosa, M., Espada‑Bellido, E., Ferreiro‑González, M., Carrera, C., Barbero, G. F., & Palma, M. (2021). Development of optimized ultrasound‑assisted extraction methods for the recovery of total phenolic compounds and anthocyanins from onion bulbs. Antioxidants, 10(11), Article 1755. doi:10.3390/antiox10111755.
• He, B., Zhang, L. L., Yue, X. Y., Liang, J., Jiang, J., Gao, X. L., & Yue, P. X. (2016). Optimization of ultrasound-assisted extraction of phenolic compounds and anthocyanins from blueberry (Vaccinium ashei) wine pomace. Food Chemistry, 204, 70-76. doi:10.1016/j.foodchem.2016.02.094.
• He, J., & Giusti, M. M. (2010). Anthocyanins: natural colorants with health-promoting properties. Annual review of food science and technology, 1(1), 163-187. doi:10.1146/annurev.food.080708.100754.
• Kaderides, K., Goula, A. M., & Adamopoulos, K. G. (2015). A process for turning pomegranate peels into a valuable food ingredient using ultrasound-assisted extraction and encapsulation. Innovative Food Science & Emerging Technologies, 31, 204-215. doi:10.1016/j.ifset.2015.08.006
• Lee, K. A., Kim, K. T., Kim, H. J., Kim, Y. J., Lee, H. J., & Paik, H. D. (2014). Antioxidant activities of onion (Allium cepa L.) peel extracts produced by ethanol, hot water, and subcritical water extraction. Food Science and Biotechnology, 23(2), 615-621. doi:10.1007/s10068-014-0084-6
• Li, Y., Guo, C., Yang, J., Wei, J., Xu, J., & Cheng, S. (2006). Evaluation of antioxidant properties of pomegranate peel extract in comparison with pomegranate pulp extract. Food Chemistry, 96(2), 254‑260. doi:10.1016/j.foodchem.2005.02.03.
• Liu, Z., Zhang, M., & Luo, Z. (2025). Effect of wall materials on physicochemical properties and bitterness masking of freeze-dried navel orange peel powder. Food Bioscience, 66, 106226. doi:10.1016/j.fbio.2025.106226.
• Montgomery, D.C. (2013) Design and analysis of experiments. Eight Edition, John Wiley & Sons Inc., Hoboken.
• Mutavski, Z., Vidović, S., Lazarević, Z., Ambrus, R., Motzwickler-Németh, A., Aladić, K., & Nastić, N. (2025). Stabilization and preservation of bioactive compounds in black elderberry by-product extracts using maltodextrin and gum arabic via spray drying. Foods, 14(5), 723. doi:10.3390/foods14050723
• Nayak, B., Dahmoune, F., Moussi, K., Remini, H., Dairi, S., Aoun, O., & Khodir, M. (2015). Comparison of microwave, ultrasound and accelerated‑assisted solvent extraction for recovery of polyphenols from Citrus sinensis peels. Food Chemistry, 187, 507‑516. doi:10.1016/j.foodchem.2015.04.081
• Nile, S. H., Keum, Y. S., Nile, A. S., Jalde, S. S., & Patel, R. V. (2018). Antioxidant, anti‐inflammatory, and enzyme inhibitory activity of natural plant flavonoids and their synthesized derivatives. Journal of Biochemical and Molecular Toxicology, 32(1), e22002. doi:10.1002/jbt.22002
• Nuutila, A. M., Puupponen-Pimiä, R., Aarni, M., & Oksman-Caldentey, K.-M. (2003). Comparison of antioxidant activities of onion and garlic extracts by inhibition of lipid peroxidation and radical scavenging activity. Food Chemistry, 81(4), 485-493. doi:10.1016/S0308-8146(02)00476-4
• Pinelo, M., Rubilar, M., Jerez, M., Sineiro, J., & Núñez, M. J. (2005). Effect of solvent, temperature, and solvent‑to‑solid ratio on the total phenolic content and antiradical activity of extracts from different components of grape pomace. Journal of Agricultural and Food Chemistry, 53(6), 2111-2117. doi:10.1021/jf0488110
• Podsędek, A., Sosnowska, D., Redzynia, M., & Koziołkiewicz, M. (2008). Effect of domestic cooking on the red cabbage hydrophilic antioxidants. International Journal of Food Science and Technology, 43(10), 1770-1777. doi:10.1111/j.1365-2621.2007.01697.x
• Prakash, D., Singh, B.N. and Upadhyay, G. (2007) Antioxidant and free radical scavenging activities of phenols from onion (Allium cepa). Food Chemistry, 102, 1389-1393. doi:10.1016/j.foodchem.2006.06.063
• Rodríguez-Juan, E., Rodríguez-Romero, C., Fernández-Bolaños, J., Florido, M. C., Garcia-Borrego, A. (2021). Phenolic compounds from virgin olive oil obtained by natural deep eutectic solvent (NADES): Effect of the extraction and recovery conditions. Journal of Food Science and Technology, 58(2), 552-561. doi:10.1007/s13197-020-04567-3.
• Rodríguez-Roque, M. J., de Ancos, B., Sánchez-Moreno, C., Cano, M. P., Elez-Martínez, P., & Martín-Belloso, O. (2015). Impact of food matrix and processing on the in vitro bioaccessibility of vitamin C, phenolic compounds, and hydrophilic antioxidant activity from fruit juice-based beverages. Journal of Functional Foods, 14, 33-43. doi:10.1016/j.jff.2015.01.020
• Sahin, O. I., Dundar, A. N., Uzuner, K., Parlak, M. E., Dagdelen, A. F., & Saricaoglu, F. T. (2023). Lyophilized nano-liposomal system for red onion (Allium cepa L.) peel anthocyanin: Characterization, bioaccessibility and release kinetics. Food Bioscience, 53, 102702. doi:10.1016/j.fbio.2023.102702
• Saikia, S., Mahnot, N. K., & Mahanta, C. L. (2015). Optimization of phenolic extraction from Averrhoa carambola pomace by response surface methodology and its microencapsulation by spray and freeze drying. Food Chemistry, 171, 144-152. doi:10.1016/j.foodchem.2014.08.064
• Sasongko, S. B., Hadiyanto, H., Djaeni, M., Perdanianti, A. M., & Utari, F. D. (2020). Effects of drying temperature and relative humidity on the quality of dried onion slice. Heliyon, 6(7). doi:10.1016/j.heliyon.2020.e04338.
• Schlick-Hasper, E., Bethke, J., Vogler, N., & Goedecke, T. (2022). Flow properties of powdery or granular filling substances of dangerous goods packagings-Comparison of the measurement of the angle of repose and the determination of the Hausner ratio. Packaging Technology and Science, 35(10), 717-782. doi:10.1002/pts.2678
• Shen, L., Pang, S., Zhong, M., Sun, Y., Qayum, A., Liu, Y., Rashid, A., Xu, B., Liang, Q., Ma, H., & Ren, X. (2023). A comprehensive review of ultrasonic assisted extraction (UAE) for bioactive components: Principles, advantages, equipment, and combined technologies. Ultrasonics Sonochemistry, 101, 106646. doi:10.1016/j.ultsonch.2023.106646
• Singleton, V. L., Orthofer, R., & Lamuela-Raventós, R. M. (1999). Analysis of total phenols and other oxidation substrates and antioxidants by means of Folin-Ciocalteu reagent. Methods in Enzymology, 299, 152-178. doi:10.1016/S0076-6879(99)99017-1
• Slimestad, R., Fossen, T., & Vagen, I. M. (2007). Onions: A source of unique dietary flavonoids. Journal of Agricultural and Food Chemistry, 55(25), 10067-10080. doi:10.1021/jf0712503
• Spigno, G., Tramelli, L., & De Faveri, D. M. (2007). Effects of extraction time, temperature and solvent on concentration and antioxidant activity of grape marc phenolics. Journal of Food Engineering, 81(1), 200-208. doi:10.1016/j.jfoodeng.2006.10.021
• Szulc, K., & Lenart, A. (2013). Surface modification of dairy powders: Effects of fluid-bed agglomeration and coating. International Dairy Journal, 33, 55-61. doi:10.1016/j.idairyj.2013.05.021
• Taşova, M., Çiğdem, M. R., Dursun, S. K., & Saraçoğlu, O. (2024). Comparison of physicochemical and biochemical analysis of aronia powders conversed by microwave and hybrid systems. Chemical Papers, 78(13). doi:10.1007/s11696-024-03605-0
• Tian, X.-Y., Bai, J.-W., Fang, Q., Wang, M., Wu, X., & Aheto, J. H. (2021). Phenolic compounds from virgin olive oil obtained by natural deep eutectic solvent (NADES): Effect of the extraction and recovery conditions. Journal of Food Science and Technology, 58(2), 552-561. doi:10.1007/s11947-025-03876-9
• Turchiuli, C., Fuchs, M., Bohin, M., Cuvelier, M. E., Ordonnaud, C., Peyrat-Maillard, M. N., & Dumoulin, E. (2005). Oil encapsulation by spray drying and fluidised bed agglomeration. Innovative Food Science & Emerging Technologies, 6(1), 29-35. doi:10.1016/j.ifset.2004.11.005
• Umeda, W. M., & Jorge, N. (2021). Oxidative stability of soybean oil added of purple onion (Allium cepa L.) peel extract during accelerated storage conditions. Food Control, 127, 108130. doi:10.1016/j.foodcont.2021.108130
• Viuda‑Martos, M., Pérez‑Álvarez, J. A., Sendra, E., Fernández‑López, J. (2012). In vitro antioxidant properties of pomegranate (Punica granatum) peel powder extract obtained as coproduct in the juice extraction process. Journal of Food Processing Preservation, 37(5), 772-776. doi:10.1111/j.1745-4549.2012.00715.x
• Yang, Z., Chen, Z., Yuan, S., & Zhai, W. (2009). Extraction and identification of anthocyanin from purple corn (Zea mays L.). International Journal of Food Science & Technology, 44(12), 2485‑2492. doi:10.1111/j.1365-2621.2009.02045.x
• Zeng, L., Ma, M., Li, C., & Luo, L. (2016). Stability of tea polyphenols solution with different pH at different temperatures. International Journal of Food Properties, 20(1), 1-18. doi:10.1080/10942912.2014.983605