Acid-Induced Gelation of European Eel Protein Isolate Fortified with Fish Oil: Enhancement of Physicochemical, Microstructural and Thermal Properties
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European Eel, Emulsion Protein Isolate-based Gel, FTIR, Thermogravimetric, SEM
Abstract
Aims: This study aimed to investigate the gelation capacity of European Eel Protein Isolate (EPI) through the development of novel emulsion protein isolate-based gels (EPIGs). Furthermore, the research evaluated the extent to which fortification with bioactive European eel oil (EO) modulates the structural and functional attributes of these acid-induced gel matrices.
Methods: EPIGs were synthesized via thermal treatment (90°C for 60 min) of EPI solubilized in 20% (v/v) acetic acid, followed by emulsification with EO at two distinct weight ratios: 1:2 and 1:4 (EO:EPI, w/w). The resulting gel structures were characterized using Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), texture profile analysis (TPA), and scanning electron microscopy (SEM).
Results: A 4% (w/v) EPI solution in acetic acid achieved gelation at 54°C, demonstrating superior thermal stability and significant gelling potential. FTIR analysis confirmed the successful incorporation of EO into the gel matrix, while TGA results indicated a slight increase in thermal degradation onset temperatures associated with higher EO concentrations, increasing from 375°C (EPIG1:4) to 382°C (EPIG1:2). Texture analysis revealed that incorporation of EO modestly augmented gel elasticity (from 12.93 mm to 13.19 mm), a phenomenon attributed to the stabilizing interactions between the lipid droplets and the protein network. Microstructural appraisal via SEM indicated that a higher EO load (EPIG1:2) induced the formation of larger pores, whereas the EPIG1:4 formulation exhibited a more cohesive and compact architecture with reduced porosity.
Keywords: European Eel; Emulsion Protein Isolate-based Gel; FTIR; Thermogravimetric; SEM.
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References
Chaijan, M., Panpipat, W., & Benjakul, S. (2010). Physicochemical and gelling properties of short-bodied mackerel (Rastrelliger brachysoma) protein isolate prepared using alkaline-aided process. Food and Bioproducts Processing, 88(2–3), 174–180. https://doi.org/10.1016/j.fbp.2009.11.003
Chen, L., Remondetto, G. E., & Subirade, M. (2006). Food protein-based materials as nutraceutical delivery systems. Trends in Food Science & Technology, 17(5), 272–283. https://doi.org/10.1016/j.tifs.2005.12.011
Cho, D., Lee, S., & Frey, M. W. (2012). Characterizing zeta potential of functional nanofibers in a microfluidic device. Journal of Colloid and Interface Science, 372(1), 252–260. https://doi.org/10.1016/j.jcis.2012.01.007
Datta, L. P., Manchineella, S., & Govindaraju, T. (2020). Biomolecules-derived biomaterials. Biomaterials, 230(119633), 119633. https://doi.org/10.1016/j.biomaterials.2019.119633
Dickinson E. (2015). Colloids in food: ingredients, structure, and stability. Annual Review of Food Science and Technology, 6, 211–233 https://doi.org/10.1146/annurev-food-022814-015651
Farjami, T., & Madadlou, A. (2019). An overview on preparation of emulsion-filled gels and emulsion particulate gels. Trends in Food Science & Technology, 86, 85–94. https://doi.org/10.1016/j.tifs.2019.02.043
Folch, J., Lees, M., & Stanley, G. H. (1957). A simple method for the isolation and purification of total lipids from animal tissues. Journal of Biological Chemistry, 226(1), 497–509.
García-Moreno, P. J., Özdemir, N., Stephansen, K., Mateiu, R. V., Echegoyen, Y., Lagaron, J. M., Chronakis, I. S., & Jacobsen, C. (2017). Development of carbohydrate-based nano-microstructures loaded with fish oil by using electrohydrodynamic processing. Food Hydrocolloids, 69, 273–285. https://doi.org/10.1016/j.foodhyd.2017.02.013
Geremias-Andrade, I. M., Souki, N. P. B. G., Moraes, I. C. F., & Pinho, S. C. (2017). Rheological and mechanical characterization of curcumin-loaded emulsion-filled gels produced with whey protein isolate and xanthan gum. *LWT - Food Science and Technology. 86, 166–173. https://doi.org/10.1016/j.lwt.2017.07.063
Harsch, M., Herzog, F., & Karger-Kocsis, J. (2008). Cure-induced normal force development in unfilled and filled epoxy resins. Journal of Composite Materials, 42(21), 2299–2309. https://doi.org/10.1177/0021998308094969
Hattrem, M. N., Molnes, S., Haug, I. J., & Draget, K. I. (2015). Interfacial and rheological properties of gelatin based solid emulsions prepared with acid or alkali pretreated gelatins. Food Hydrocolloids, 43, 700–707. https://doi.org/10.1016/j.foodhyd.2014.07.026
Jamshidi, A., Cao, H., Xiao, J., & Simal-Gandara, J. (2020). Advantages of techniques to fortify food products with the benefits of fish oil. Food Research International (Ottawa, Ont.), 137(109353), 109353. https://doi.org/10.1016/j.foodres.2020.109353
Kharlamova, A., Chassenieux, C., & Nicolai, T. (2018). Acid-induced gelation of whey protein aggregates: Kinetics, gel structure and rheological properties. Food Hydrocolloids, 81, 263–272. https://doi.org/10.1016/j.foodhyd.2018.02.043 Google Scholar
Li, X., Wang, X., Xu, D., Cao, Y., Wang, S., Wang, B., Sun, B., Yuan, F., & Gao, Y. (2018). Enhancing physicochemical properties of emulsions by heteroaggregation of oppositely charged lactoferrin coated lutein droplets and whey protein isolate coated DHA droplets. Food Chemistry, 239, 75–85. https://doi.org/10.1016/j.foodchem.2017.06.078
Li, S., Li, L., Zhu, X., Ning, C., Cai, K., & Zhou, C. (2019). Conformational and charge changes induced by l-Arginine and l-lysine increase the solubility of chicken myosin. Food Hydrocolloids, 89, 330–336. https://doi.org/10.1016/j.foodhyd.2018.10.059
Li, R., Wu, N., Xue, H., Gao, B., Liu, H., Han, T., Hu, X., Tu, Y., & Zhao, Y. (2023). Influence and effect mechanism of disulfide bonds linkages between protein-coated lipid droplets and the protein matrix on the physicochemical properties, microstructure, and protein structure of ovalbumin emulsion gels. Colloids and Surfaces. B, Biointerfaces, 223(113182), 113182. https://doi.org/10.1016/j.colsurfb.2023.113182
Line, V. L. S., Remondetto, G. E., & Subirade, M. (2005). Cold gelation of β-lactoglobulin oil-in-water emulsions. Food Hydrocolloids, 19(2), 269–278. https://doi.org/10.1016/j.foodhyd.2004.06.004
Lu, Y., Mao, L., Zheng, H., Chen, H., & Gao, Y. (2020). Characterization of β-carotene loaded emulsion gels containing denatured and native whey protein. Food Hydrocolloids, 102(105600), 105600. https://doi.org/10.1016/j.foodhyd.2019.105600
Moomand, K., & Lim, L.-T. (2014). Oxidative stability of encapsulated fish oil in electrospun zein fibres. Food Research International (Ottawa, Ont.), 62, 523–532. https://doi.org/10.1016/j.foodres.2014.03.054
Taylor, M. J., Tomlins, P., & Sahota, T. S. (2017). Thermoresponsive Gels. Gels, 3(1), 4. https://doi.org/10.3390/gels3010004
McClements, D. J. (2015). Food emulsions: Principles, Practices, and Techniques (3rd ed.). CRC Press.
Nasri, R., Taktak, W., Hamdi, M., Ben Amor, N., Kabadou, A., Li, S., & Nasri, M. (2020). Sardinelle protein isolate as a novel material for oil microencapsulation: Novel alternative for fish by-products valorisation. Materials Science & Engineering. C, Materials for Biological Applications, 116(111164), 111164. https://doi.org/10.1016/j.msec.2020.111164
O’Sullivan, J., Murray, B., Flynn, C., & Norton, I. (2016). The effect of ultrasound treatment on the structural, physical and emulsifying properties of animal and vegetable proteins. Food Hydrocolloids, 53, 141–154. https://doi.org/10.1016/j.foodhyd.2015.02.009
Saha, D., & Bhattacharya, S. (2010). Hydrocolloids as thickening and gelling agents in food: a critical review. Journal of Food Science and Technology, 47(6), 587–597. https://doi.org/10.1007/s13197-010-0162-6
Souissi, N., Abdelhedi, O., Mbarek, A., Kammoun, W., Kechaou, H., & Nasri, M. (2017). Gelatin based bio-films prepared from grey triggerfish’ skin influenced by enzymatic pretreatment. International Journal of Biological Macromolecules, 105(Pt 2), 1384–1390. https://doi.org/10.1016/j.ijbiomac.2017.08.181
Surh, J., Decker, E., & McClements, D. (2006). Influence of pH and pectin type on properties and stability of sodium-caseinate stabilized oil-in-water emulsions. Food Hydrocolloids, 20(5), 607–618. https://doi.org/10.1016/j.foodhyd.2005.07.004
Tabarestani, H. S., Maghsoudlou, Y., Motamedzadegan, A., & Mahoonak, A. S. (2010). Optimization of physico-chemical properties of gelatin extracted from fish skin of rainbow trout (Oncorhynchus mykiss). Bioresource Technology, 101(15), 6207–6214. https://doi.org/10.1016/j.biortech.2010.02.071
Taktak, W., Nasri, R., Hamdi, M., Gomez-Mascaraque, L. G., Lopez-Rubio, A., Li, S., Nasri, M., & Karra-Chaâbouni, M. (2018). Physicochemical, textural, rheological and microstructural properties of protein isolate gels produced from European eel (Anguilla anguilla) by heat-induced gelation process. Food Hydrocolloids, 82, 278–287. https://doi.org/10.1016/j.foodhyd.2018.04.008
Taktak, W., Nasri, R., Lopez-Rubio, A., Hamdi, M., Gomez-Mascaraque, L. G., Ben Amor, N., Kabadou, A., Li, S., Nasri, M., & Karra-Chaâbouni, M. (2019). Improved antioxidant activity and oxidative stability of spray dried European eel (Anguilla anguilla) oil microcapsules: Effect of emulsification process and eel protein isolate concentration. Materials Science & Engineering. C, Materials for Biological Applications, 104(109867), 109867. https://doi.org/10.1016/j.msec.2019.109867
Yang, C., Wang, Y., Vasanthan, T., & Chen, L. (2014). Impacts of pH and heating temperature on formation mechanisms and properties of thermally induced canola protein gels. Food Hydrocolloids, 40, 225–236. https://doi.org/10.1016/j.foodhyd.2014.03.011
Yan, B., Jiao, X., Zhu, H., Wang, Q., Huang, J., Zhao, J., Cao, H., Zhou, W., Zhang, W., Ye, W., Zhang, H., & Fan, D. (2020). Chemical interactions involved in microwave heat-induced surimi gel fortified with fish oil and its formation mechanism. Food Hydrocolloids, 105(105779), 105779. https://doi.org/10.1016/j.foodhyd.2020.105779
Ye, A., & Taylor, S. (2009). Characterization of cold-set gels produced from heated emulsions stabilized by whey protein. International Dairy Journal, 19(12), 721–727. https://doi.org/10.1016/j.idairyj.2009.06.003
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Copyright (c) 2026 Wafa Taktak, Sawsan Affes, Marwa Hamdi, Suming Li, Moncef Nasri, Rim Nasri, Maha Karra Chaabouni
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