85
characteristics are its innate lack of homogeneity, hydrophobicity, and bioincompatibility. The inhomogeneity of lignin hinders its large-scale application in industry.
Therefore, new technologies still need to be developed to obtain high-purity homogeneous lignin. Due to its hydrophobic nature, the solubility of lignin in water
should be considered for its wider applications in the future. Biocompatibility is a
key problem that limits the application of lignin. Measures to improve biocompatibility between lignin and the polymers should be developed without affecting the
mechanism of the copolymers. The antioxidant efficacy of lignin in several phases
may be different. It is thus necessary to evaluate the antioxidant properties in the
corresponding systems. More than anything, in view of its potential use in the biomedical and food fields, the toxicity of lignin-based materials should be evaluated
in detail.
Acknowledgments We sincerely acknowledge the financial support by Post-doctoral Research
Start-up Fund of Henan University of Technology (21450009), the earmarked fund for Modern
Agro-industry Technology Research System (CARS14-1-29), the earmarked fund for National
Natural Science Foundation of China (U1804111) and Technological Innovation Talents of
Colleges and Universities (19HASTIT012).
Conflicts of Interest The authors declare no conflict of interest.
References
Abu-Dalo, M. A., Al-Rawashdeh, N. A. F., & Ababneh, A. (2013). Evaluating the performance of
sulfonated Kraft lignin agent as corrosion inhibitor for iron-based materials in water distribution systems. Desalination, 313, 105–114. https://doi.org/10.1016/j.desal.2012.12.007.
Aguié-Béghin, V., Foulon, L., Soto, P., Crônier, D., Corti, E., Legée, F., Cézard, L., Chabbert,
B., Maillard, M.-N., Huijgen, W. J. J., & Baumberger, S. (2015). Use of food and packaging
model matrices to investigate the antioxidant properties of biorefinery grass lignins. Journal
of Agricultural and Food Chemistry, 63(45), 10022–10031. https://doi.org/10.1021/acs.
jafc.5b03686.
Álvarez, K., Famá, L., & Gutiérrez, T. J. (2017). Chapter 12. Physicochemical, antimicrobial
and mechanical properties of thermoplastic materials based on biopolymers with application in the food industry. In M. Masuelli & D. Renard (Eds.), Advances in physicochemical properties of biopolymers: Part 1 (pp. 358–400). EE.UU.. ISBN: 978-1-68108-454-1.
eISBN: 978-1-68108-453-4, 2017: Bentham Science Publishers. https://doi.org/10.217
4/9781681084534117010015.
Aminzadeh, S., Lauberts, M., Dobele, G., Ponomarenko, J., Mattsson, T., Lindström, M. E., &
Sevastyanova, O. (2018). Membrane filtration of kraft lignin: Structural charactristics and
antioxidant activity of the low-molecular-weight fraction. Industrial Crops and Products, 112,
200–209. https://doi.org/10.1016/j.indcrop.2017.11.042.
An, L., Wang, G., Jia, H., Liu, C., Sui, W., & Si, C. (2017). Fractionation of enzymatic hydrolysis
lignin by sequential extraction for enhancing antioxidant performance. International Journal
of Biological Macromolecules, 99, 674–681. https://doi.org/10.1016/j.ijbiomac.2017.03.015.
An, L., Si, C., Wang, G., Sui, W., & Tao, Z. (2019). Enhancing the solubility and antioxidant
activity of high-molecular-weight lignin by moderate depolymerization via in situ ethanol/
acid catalysis. Industrial Crops and Products, 128, 177–185. https://doi.org/10.1016/j.
indcrop.2018.11.009.
5 Lignin as a Natural Antioxidant: Property-Structure Relationship and Potential…
characteristics are its innate lack of homogeneity, hydrophobicity, and bioincompatibility. The inhomogeneity of lignin hinders its large-scale application in industry.
Therefore, new technologies still need to be developed to obtain high-purity homogeneous lignin. Due to its hydrophobic nature, the solubility of lignin in water
should be considered for its wider applications in the future. Biocompatibility is a
key problem that limits the application of lignin. Measures to improve biocompatibility between lignin and the polymers should be developed without affecting the
mechanism of the copolymers. The antioxidant efficacy of lignin in several phases
may be different. It is thus necessary to evaluate the antioxidant properties in the
corresponding systems. More than anything, in view of its potential use in the biomedical and food fields, the toxicity of lignin-based materials should be evaluated
in detail.
Acknowledgments We sincerely acknowledge the financial support by Post-doctoral Research
Start-up Fund of Henan University of Technology (21450009), the earmarked fund for Modern
Agro-industry Technology Research System (CARS14-1-29), the earmarked fund for National
Natural Science Foundation of China (U1804111) and Technological Innovation Talents of
Colleges and Universities (19HASTIT012).
Conflicts of Interest The authors declare no conflict of interest.
References
Abu-Dalo, M. A., Al-Rawashdeh, N. A. F., & Ababneh, A. (2013). Evaluating the performance of
sulfonated Kraft lignin agent as corrosion inhibitor for iron-based materials in water distribution systems. Desalination, 313, 105–114. https://doi.org/10.1016/j.desal.2012.12.007.
Aguié-Béghin, V., Foulon, L., Soto, P., Crônier, D., Corti, E., Legée, F., Cézard, L., Chabbert,
B., Maillard, M.-N., Huijgen, W. J. J., & Baumberger, S. (2015). Use of food and packaging
model matrices to investigate the antioxidant properties of biorefinery grass lignins. Journal
of Agricultural and Food Chemistry, 63(45), 10022–10031. https://doi.org/10.1021/acs.
jafc.5b03686.
Álvarez, K., Famá, L., & Gutiérrez, T. J. (2017). Chapter 12. Physicochemical, antimicrobial
and mechanical properties of thermoplastic materials based on biopolymers with application in the food industry. In M. Masuelli & D. Renard (Eds.), Advances in physicochemical properties of biopolymers: Part 1 (pp. 358–400). EE.UU.. ISBN: 978-1-68108-454-1.
eISBN: 978-1-68108-453-4, 2017: Bentham Science Publishers. https://doi.org/10.217
4/9781681084534117010015.
Aminzadeh, S., Lauberts, M., Dobele, G., Ponomarenko, J., Mattsson, T., Lindström, M. E., &
Sevastyanova, O. (2018). Membrane filtration of kraft lignin: Structural charactristics and
antioxidant activity of the low-molecular-weight fraction. Industrial Crops and Products, 112,
200–209. https://doi.org/10.1016/j.indcrop.2017.11.042.
An, L., Wang, G., Jia, H., Liu, C., Sui, W., & Si, C. (2017). Fractionation of enzymatic hydrolysis
lignin by sequential extraction for enhancing antioxidant performance. International Journal
of Biological Macromolecules, 99, 674–681. https://doi.org/10.1016/j.ijbiomac.2017.03.015.
An, L., Si, C., Wang, G., Sui, W., & Tao, Z. (2019). Enhancing the solubility and antioxidant
activity of high-molecular-weight lignin by moderate depolymerization via in situ ethanol/
acid catalysis. Industrial Crops and Products, 128, 177–185. https://doi.org/10.1016/j.
indcrop.2018.11.009.
5 Lignin as a Natural Antioxidant: Property-Structure Relationship and Potential…