Are you interested in redox chemistry, enzymes, alternative proteins and analytical chemistry? You will learn about redox enzymes implication in alternative proteins from alfalfa

The continuous growth of global population results in a sharp increase in protein demand. Protein sources with lower climate impact is required to fulfil such demands. One of the potential protein sources of such proteins is RuBisCO, which is the major soluble protein in leafy plant materials. The protein has been shown to contain excellent essential amino acid profile, and therefore is promising for food applications. Potential source of RuBisCO is the perennial legumes alfalfa, white clover and red clover which suits the Danish climate and yields a high biomass as it can be harvested multiple times a year. However, the redox enzymes are a problem (Amer et al., 2020, Tanambell et al., 2022), which we need to overcome (Møller et al., 2021). 

The numbers of different redox enzymes present in green biomass have not been identified. The underlying mechanisms of action and specificity of the PPOs and interaction with other radical oxidative species generating enzymes, peroxidase and LOX present in green protein needs to be investigated. Although some redox enzymes may be present in low amounts, they can still be a challenge to protein quality due to their high activity. After identifying major redox enzymes and underlying mechanisms and interactions, different antioxidants and chelators will be tested for their ability to inhibit the enzymes, thereby avoiding cross-linking and browning of protein.

The student will be aligned with a 10-15 people group working with alternative proteins and natural
colorants biorefinery, stability and application. Ad hoc supervision in the lab will be provided. At weekly meetings the student will present her/his work and discuss design of experiments, results and perspective of the work. The student will present her/his data at a midterm seminar.


References

• Dalsgaard, T. K.; Triquigneaux, M.; Deterding, L.; Summers, F. A.; Mortensen, G.; Mason, R. P., Oxidation of α-lactalbumin after a lactoperoxidase-catalysed reaction: An oxidomics approach applying immuno-spin trapping and mass spectrometry. Int. Dairy J. 2014, 38, 154-159.
• Lardinois, O. M.; Medzihradszky, K. F.; Ortiz de Montellano, P. R., Spin trapping and protein cross-linking of the lactoperoxidase protein radical. J. Biol. Chem. 1999, 274, 35441-8.
• Dalsgaard, T. K.; Triquigneaux, M.; Deterding, L.; Summers, F.; Ranguelova, K.; Mortensen, G.; Mason, R. P., Site-specific detection of radicals on alpha-lactalbumin after a riboflavin-sensitized reaction, detected by immuno-spin trapping, ESR, and MS. J. Agric. Food Chem. 2013, 61, 418-26.
• Møller, AH, Hammershøj, M., Passos, N, Tanambell, H, Stødkilde, Lene, Ambye-Jensen, M, Danielsen, M, Jensen, SK, Dalsgaard, TK (2021). Biorefinery of green biomass – how to extract and evaluate high quality leaf protein for food? J. Agric. Food Chem. 69 (48), 14341 – 14357 doi.org/10.1021/acs.jafc.1c04289
• Tanambell, H., Møller, A. H., Corredig, M., & Dalsgaard, T. K.. RuBisCO from alfalfa–native subunitspreservation through sodium sulfite addition and reduced solubility after acid precipitation followed by freeze-drying. LWT, 2022, 154, 112682. doi.org/10.1016/j.lwt.2021.112682